mal Trump hires Susie Wiles as first female White House chief of staff By www.christianpost.com Published On :: Fri, 08 Nov 2024 15:45:24 -0500 President-elect Donald Trump announced Thursday that longtime GOP operative Susie Wiles will be his White House chief of staff, making her the first woman to hold the position. Full Article
mal Kamala Harris campaign ends with over $20M in debt: report By www.christianpost.com Published On :: Tue, 12 Nov 2024 09:10:35 -0500 Vice President Kamala Harris’ unsuccessful presidential campaign ended with over $20 million in debt, a report has revealed, as the introspection following the 2024 presidential election continues. Full Article
mal The Teller of Small Fortunes by Leong, Julie By catalog.wiltonlibrary.org Published On :: Wed, 13 Nov 2024 00:04:28 -0500 A wandering fortune teller finds an unexpected family in this warm and wonderful debut fantasy, perfect for readers of Travis Baldree and Sangu Mandanna. Tao is an immigrant fortune teller, traveling between villages with just her trusty mule for company. She only tells "small" fortunes: whether it will hail next week; which boy the barmaid will kiss; when the cow will calve. She knows from bitter experience that big fortunes come with big consequences… Even if it’s a lonely life, it’s better th Full Article New Books
mal World must be more attentive to male virgins By english.pravda.ru Published On :: Fri, 06 May 2016 11:17:00 +0300 Source: REX There are a number of factors that can change the general public’s attitude to late virginity among men. Reason One: it is not so easy for a man to lose virginity Historically, the first sexual experience is a subject of extraordinary pride for men. That is why most boys grow up with the aim of losing virginity as soon as possible. According to France’s National Institute for Demographic Studies (INED), an average West European man has his first sex at age 17. If it takes longer, boys think that there is something amiss with them and unintentionally enhance the possibility of turning from a proud eagle into a timid sparrow. There is another stereotype: men are the first to show an initiative. If they do not, they are automatically associated with a sniveler, a loser and an object of pity. Full Article Health
mal Gamaleya Center virologist: There is no link between cancer and vaccination By english.pravda.ru Published On :: Wed, 14 Jul 2021 20:17:00 +0300 LDPR leader Vladimir Zhirinovsky managed to get revaccinated. For the first time, the politician chose Sputnik V; for the repeated procedure, he opted for CoviVac. As Zhirinovsky explained, "the level of antibodies is gradually decreasing, I wanted to strengthen the defense of my body." Mass vaccination against coronavirus, which is now taking place in all countries, including Russia, still raises a huge number of questions. This is not surprising, given the fact that the coronavirus infection with which we are dealing has not been thoroughly studied yet, and the vaccines for it have not gone through all the required stages of clinical trials. Pravda.R asked most burning questions related to the topic of vaccination to Professor of Virology, Chief Researcher at the Gamaleya Research Center for Epidemiology and Microbiology Anatoly Alshtein. Full Article Health
mal Russian scientists unravel the mystery of Yamal sinkhole By english.pravda.ru Published On :: Tue, 02 Mar 2021 18:59:00 +0300 It is not the melting of permafrost that causes giant gas bubbles to erupt, geophysicists found. This crater in Yamal is the 17th such crater that was found in the region.Vasily Bogoyavlensky, geologist and geophysicist, said that there are many of such "black holes" in the north of Russia. Many of those craters have emerged during the past ten years.The very first crater, which was discovered in 2014, became the famous one. It was a hole about 50 meters deep and 40 meters in diameter. Geologists quickly established that the giant hole in the ground was just a hole, from which methane was bursting out.A cavity is formed in the layers of underground ice as it melts due to the influence of a local anomalous heat flow. This cavity is then filled with gas, and it grows larger, causing the surface on the ground to swell until the frozen rock reaches its ultimate strength and eventually explodes in a pneumatic explosion. Extraterrestrial cryovolcanoes found on Earth Some scientists assumed that the Yamal crater was the first cryovolcano on planet Earth - a volcano that appears in permafrost and spews out jets of gas instead of melted magma. Until recently, such cryovolcanoes were observed only in space - on Neptune's satellite Triton, and on Titan or Enceladus (the moons of Saturn). According to Vasily Bogoyavlensky, the Yamal gas eruptions can be referred to as volcanoes only to a certain degree, although several craters can be defined as such. "I believe that many of these objects can be categorised as ordinary mud volcanoes, but they have their own peculiarities, because the near-surface soil is frozen. It additionally restrains the gas, and the pressure in the cavity can reach high values. As a result, the gas still breaks through the rock," the researcher said. Full Article Science
mal Neo-Malthusians and scientific research By english.pravda.ru Published On :: Wed, 12 Jan 2022 19:25:00 +0300 Green New Deal are three words that have acquired great notoriety in recent times and seem to finally be the answer to the increasingly pressing requests coming from the variegated environmental world. The fear that our planet will undergo an ecological collapse that makes it an uninhabitable hell for humanity and the rest of living creatures, be they animals or plants, has prompted a part of Western society to reconsider its priorities and way of living. A part that is not very large, to be honest, but that has received a lot of attention from media, celebrities, no-profit foundations and now also from some governments. Apparently, the new green revolution will guarantee us a bright future. Drastically reduced industrial pollution, zero-emission cars, super-efficient homes and workplaces, heated and powered by the energy of the sun: these are just some of the promises, written with fire on the rock, the realization of which will give us a new Garden of Eden planetary in size. But will it really be like this? Some of the visionary benefactors who are heralds for these fabulous ideas continue to insist that the Earth is overpopulated and that it would be better to return to the situation of the early twentieth century, when the population on our planet was about a quarter of what it is today. The question then arises spontaneously on how to get back to that level quickly, with what methods and with what results. Full Article Science
mal Global Animal Products earns safety award By www.tdi.texas.gov Published On :: Fri, 18 Nov 2022 00:00:00 CST The Texas Department of Insurance, Division of Workers’ Compensation (DWC) recognized Global Animal Products with a Lone Star Safety Award for their exemplary workplace safety programs and low rates of work-related injuries and illnesses. Full Article
mal Bones of unknown million-year-old animals found in Yakutia By english.pravda.ru Published On :: Fri, 22 Dec 2023 16:22:00 +0300 Bones of unknown animals millions of years of age were found in Yakutia. In the Churapcha region of Yakutia, archeologists found a Paleolithic human site that is believed to be at least 30,000 years old. Bones of unknown animals were found during excavation works. The radiocarbon research of the finds revealed that the found remains were from the Neogene era - a period that began 23 million years ago and ended 2.58 million years ago. Full Article Science
mal Kamala Harris is neither 'comrade' nor 'communist' By english.pravda.ru Published On :: Mon, 19 Aug 2024 15:09:00 +0300 US Vice President and presidential candidate Kamala Harris unveiled her platform. Predictably, Karris advocates for more migrants and more rights for those representing the LGBT* community. Unpredictably, though, Kamala Harris proposed to introduce state regulation of prices. Donald Trump has recently called Kamala Harris a "communist", but she is as far from Marxism as Adolf Hitler was far from pacifism. Modern American pseudo-Marxism and leftism has nothing to do with social justice at all. It is not corporations, not financial monsters, but the middle classes that are supposed to become its victims. Full Article Opinion
mal Why Does Kamala Harris Hate Black Men? By english.pravda.ru Published On :: Fri, 01 Nov 2024 20:49:00 +0300 Craw-Dadding. Actually, Craw-Daddin'. The first time I used it the blonde with me had no conception. Full Article Opinion
mal 43% of data breaches target small businesses in 5 industries By www.retailtechnologyreview.com Published On :: Some industries are more vulnerable to cyber threats hence facing a high risk of experiencing data breaches or other types of cyber attacks in the future. Full Article Surveillance and Security Critical Issues
mal How small businesses go from brick to virtual By english.pravda.ru Published On :: Tue, 02 Nov 2021 15:51:00 +0300 It's difficult to highlight any positives of the recent pandemic. However, if one exists in the business world, it's the virtual infrastructure that was built on the fly to allow companies to make the shift away from traditional brick and mortar operations. If you've been on the fence about a permanent shift in the virtual direction, this is your time to shine. The benefits of going virtual Full Article Business
mal Avery Dennison launches a new direct thermal linerless label solution: AD XeroLinr DT™ By www.retailtechnologyreview.com Published On :: Avery Dennison Label and Packaging Materials EMENA has introduced AD XeroLinr DT, a new FSC-certified and phenol-free direct thermal (DT) linerless solution that drives productivity, reduces waste and advances sustainability. Full Article Print and Label
mal BIXOLON launches SRP-330III 3-inch thermal POS printer series By www.retailtechnologyreview.com Published On :: BIXOLON Europe GmbH, a subsidiary of BIXOLON the global manufacturer of advanced receipt, label and mobile printers, has launched its SRP-330III thermal point-of-sale printer series for all ticketing and receipting operations in the retail, hospitality and transportation sectors, an enhancement of the previous SRP-330II. Full Article Print and Label
mal Retailers and malls embrace facial recognition and video analytics for enhanced security and footfall analysis By www.retailtechnologyreview.com Published On :: Sat, 13 Nov 1520 17:17:45 -0001 In the recent 2-3 years, an increasing number of malls and retail chains have adopted real-time video analytics and facial recognition to enhance security, customer experience and footfall analysis.Some of these technologies are showcased this week at the NRF Protect Conference in Long Beach, California. Full Article Data Capture Exhibitions and Events Surveillance and Security
mal The Dismissal of New Female CEOs: A Role Congruity Perspective By www.newswise.com Published On :: Wed, 13 Nov 2024 06:30:24 EST Full Article
mal This Year's Top 100 Companies See Highest Number of Female Executives By world.kbs.co.kr Published On :: Mon, 11 Nov 2024 18:05:09 +0900 [Domestic] : The number of female executives in the country's top 100 companies has reached a record high. According to global headhunting firm Unico Search on Monday, the number of female executives in South Korea's top 100 companies reached 463 this year, up five-point-five percent, or 24 from last ...[more...] Full Article Domestic
mal What is geothermal energy? - British Geological Survey By news.google.com Published On :: Wed, 23 Sep 2020 15:00:11 GMT What is geothermal energy? British Geological Survey Full Article
mal New report assesses deep geothermal energy in the UK - British Geological Survey By news.google.com Published On :: Mon, 17 Jul 2023 07:00:00 GMT New report assesses deep geothermal energy in the UK British Geological Survey Full Article
mal Small earthquake detected on Shropshire-Staffordshire border - BBC.com By news.google.com Published On :: Fri, 19 Apr 2024 07:00:00 GMT Small earthquake detected on Shropshire-Staffordshire border BBC.com Full Article
mal BGS launches digital version of UK legacy geothermal catalogue - ThinkGeoEnergy - Geothermal Energy News By news.google.com Published On :: Thu, 25 Apr 2024 07:00:00 GMT BGS launches digital version of UK legacy geothermal catalogue ThinkGeoEnergy - Geothermal Energy News Full Article
mal BGS breaks ground on geothermal heating system in Keyworth HQ, UK - ThinkGeoEnergy - Geothermal Energy News By news.google.com Published On :: Tue, 05 Mar 2024 08:00:00 GMT BGS breaks ground on geothermal heating system in Keyworth HQ, UK ThinkGeoEnergy - Geothermal Energy News Full Article
mal Small earthquake recorded under Powys town - Powys County Times By news.google.com Published On :: Sun, 29 Sep 2024 07:00:00 GMT Small earthquake recorded under Powys town Powys County Times Full Article
mal Local MP checks in on development of new geothermal 'living laboratory' in Nottinghamshire - British Geological Survey By news.google.com Published On :: Thu, 19 Sep 2024 07:00:00 GMT Local MP checks in on development of new geothermal 'living laboratory' in Nottinghamshire British Geological Survey Full Article
mal Density functional theory investigation of the phase transition, elastic and thermal characteristics for AuMTe2(M = Ga, In) chalcopyrite compounds By journals.iucr.org Published On :: This study presents the first theoretical predictions of the phase transitions, elastic properties, and thermal behavior of AuMTe2 (M = Ga, In) chalcopyrite compounds. Using density functional theory and the quasi-harmonic Debye model, key mechanical and thermodynamic properties are analyzed, offering insights valuable for future experimental validation. Full Article text
mal Automated selection of nanoparticle models for small-angle X-ray scattering data analysis using machine learning By journals.iucr.org Published On :: 2024-02-29 Small-angle X-ray scattering (SAXS) is widely used to analyze the shape and size of nanoparticles in solution. A multitude of models, describing the SAXS intensity resulting from nanoparticles of various shapes, have been developed by the scientific community and are used for data analysis. Choosing the optimal model is a crucial step in data analysis, which can be difficult and time-consuming, especially for non-expert users. An algorithm is proposed, based on machine learning, representation learning and SAXS-specific preprocessing methods, which instantly selects the nanoparticle model best suited to describe SAXS data. The different algorithms compared are trained and evaluated on a simulated database. This database includes 75 000 scattering spectra from nine nanoparticle models, and realistically simulates two distinct device configurations. It will be made freely available to serve as a basis of comparison for future work. Deploying a universal solution for automatic nanoparticle model selection is a challenge made more difficult by the diversity of SAXS instruments and their flexible settings. The poor transferability of classification rules learned on one device configuration to another is highlighted. It is shown that training on several device configurations enables the algorithm to be generalized, without degrading performance compared with configuration-specific training. Finally, the classification algorithm is evaluated on a real data set obtained by performing SAXS experiments on nanoparticles for each of the instrumental configurations, which have been characterized by transmission electron microscopy. This data set, although very limited, allows estimation of the transferability of the classification rules learned on simulated data to real data. Full Article text
mal The smearing function for a multi-slit very small angle neutron scattering instrument By journals.iucr.org Published On :: This study validates the feasibility of applying a smearing method for the multi-slit very small angle neutron scattering instrument (MS-VSANS) at the China Spallation Neutron Source. Through analysis limited to a vertical range of 8 mm, the study demonstrates consistency between the predicted smearing function and experimental data, marking a significant milestone in utilizing real data from such instruments. Full Article text
mal Grazing-incidence small-angle neutron scattering at high pressure (HP-GISANS): a soft matter feasibility study on grafted brush films By journals.iucr.org Published On :: We present a demonstration of high-pressure grazing-incidence small-angle neutron scattering for soft matter thin films. The results suggest changes in water reorganization at different pressures. Full Article text
mal Improving the reliability of small- and wide-angle X-ray scattering measurements of anisotropic precipitates in metallic alloys using sample rotation By journals.iucr.org Published On :: Rotations of small- and wide-angle X-ray scattering samples during acquisition are shown to give a drastic improvement in the reliability of the characterization of anisotropic precipitates in metallic alloys. Full Article text
mal Small-angle scattering and dark-field imaging for validation of a new neutron far-field interferometer By journals.iucr.org Published On :: A neutron far-field interferometer is under development at NIST with the aim of enabling a multi-scale measurement combining the best of small-angle neutron scattering (SANS) and neutron imaging and tomography. We use the close relationship between SANS, ultra-SANS, spin-echo SANS and dark-field imaging and measurements of monodisperse spheres as a validation metric, highlighting the strengths and weaknesses of each of these neutron techniques. Full Article text
mal Optimal operation guidelines for direct recovery of high-purity precursor from spent lithium-ion batteries: hybrid operation model of population balance equation and data-driven classifier By journals.iucr.org Published On :: This study proposes an operation optimization framework for impurity-free recycling of spent lithium-ion batteries. Using a hybrid population balance equation integrated with a data-driven condition classifier, the study firstly identifies the optimal batch and semi-batch operation conditions that significantly reduce the operation time with 100% purity of product; detailed guidelines are given for industrial applications. Full Article text
mal Grazing-incidence small-angle neutron scattering at high pressure (HP-GISANS): a soft matter feasibility study on grafted brush films By journals.iucr.org Published On :: 2024-11-04 Grazing-incidence small-angle neutron scattering (GISANS) under pressure (HP-GISANS) at the solid (Si)–liquid (D2O) interface is demonstrated for the pressure-induced lateral morphological characterization of the nanostructure in thin (<100 nm) soft matter films. We demonstrate feasibility by investigating a hydrophobic {poly[(2,2,3,3,4,4,5,5-octafluoro)pentyl methacrylate]} (POFPMA)–hydrophilic {poly[2-(dimethylamino)ethyl methacrylate]} (PDMAEMA) brush mixture of strong incompatibility between the homopolymers, anchored on Si, at T = 45°C for two pressures, P = 1 bar and P = 800 bar. Our GISANS results reveal nanostructural rearrangements with increasing P, underlining P-induced effects in tethered polymer brush layers swollen with bulk solvent. Full Article text
mal Small-angle scattering and dark-field imaging for validation of a new neutron far-field interferometer By journals.iucr.org Published On :: 2024-11-08 The continued advancement of complex materials often requires a deeper understanding of the structure–function relationship across many length scales, which quickly becomes an arduous task when multiple measurements are required to characterize hierarchical and inherently heterogeneous materials. Therefore, there are benefits in the simultaneous characterization of multiple length scales. At the National Institute of Standards and Technology, a new neutron far-field interferometer is under development that aims to enable a multi-scale measurement combining the best of small-angle neutron scattering (SANS) and neutron imaging and tomography. Spatially resolved structural information on the same length scales as SANS (0.001–1 µm) and ultra-small-angle neutron scattering (USANS, 0.1–10 µm) will be collected via dark-field imaging simultaneously with regular attenuation radiography (>10 µm). The dark field is analogous to the polarization loss measured in spin-echo SANS (SESANS) and is related to isotropic SANS through a Hankel transform. Therefore, we use this close relationship and analyze results from SANS, USANS, SESANS and dark-field imaging of monodisperse spheres as a validation metric for the interferometry measurements. The results also highlight the strengths and weaknesses of these neutron techniques for both steady-state and pulsed neutron sources. Finally, we present an example of the value added by the spatial resolution enabled by dark-field imaging in the study of more complex heterogeneous materials. This information would otherwise be lost in other small-angle scattering measurements averaged over the sample. Full Article text
mal Improving the reliability of small- and wide-angle X-ray scattering measurements of anisotropic precipitates in metallic alloys using sample rotation By journals.iucr.org Published On :: 2024-11-04 Nanometric precipitates in metallic alloys often have highly anisotropic shapes. Given the large grain size and non-random texture typical of these alloys, performing small- and wide-angle X-ray scattering (SAXS/WAXS) measurements on such samples for determining their characteristics (typically size and volume fraction) results in highly anisotropic and irreproducible data. Rotations of flat samples during SAXS/WAXS acquisitions are presented here as a solution to these anisotropy issues. Two aluminium alloys containing anisotropic precipitates are used as examples to validate the approach with a −45°/45° angular range. Clear improvements can be seen on the SAXS I(q) fitting and the consistency between the different SAXS/WAXS measurements. This methodology results in more reliable measurements of the precipitate's characteristics, and thus allows for time- and space-resolved measurements with higher accuracy. Full Article text
mal The smearing function for a multi-slit very small angle neutron scattering instrument By journals.iucr.org Published On :: 2024-10-29 Besides traditional pinhole geometry, the multi-slit very small angle neutron scattering instrument (MS-VSANS) at the China Spallation Neutron Source also utilizes a multi-slit collimation system to focus neutrons. Using the special focusing structures, the minimum scattering vector magnitude (q) can reach 0.00028 Å−1. The special structures also lead to a significantly different smearing function. By comparing the results of theoretical calculations with experimental data, we have validated the feasibility of a smearing method based on a mature theory for slit smearing. We use the weight-averaged intensity of neutron wavelength as a representative to evaluate the effect from a broad wavelength distribution, concentrating on the effect from the geometry of the multi-slit structures and the detector. The consistency of the theoretical calculation of the smearing function with experimental VSANS scattering profiles for a series of polystyrene standards of different diameters proves the feasibility of the smearing method. This marks the inaugural use of real experimental data from an instrument employing a multi-slit collimation system. Full Article text
mal Influence of device configuration and noise on a machine learning predictor for the selection of nanoparticle small-angle X-ray scattering models By journals.iucr.org Published On :: 2024-09-23 Small-angle X-ray scattering (SAXS) is a widely used method for nanoparticle characterization. A common approach to analysing nanoparticles in solution by SAXS involves fitting the curve using a parametric model that relates real-space parameters, such as nanoparticle size and electron density, to intensity values in reciprocal space. Selecting the optimal model is a crucial step in terms of analysis quality and can be time-consuming and complex. Several studies have proposed effective methods, based on machine learning, to automate the model selection step. Deploying these methods in software intended for both researchers and industry raises several issues. The diversity of SAXS instrumentation requires assessment of the robustness of these methods on data from various machine configurations, involving significant variations in the q-space ranges and highly variable signal-to-noise ratios (SNR) from one data set to another. In the case of laboratory instrumentation, data acquisition can be time-consuming and there is no universal criterion for defining an optimal acquisition time. This paper presents an approach that revisits the nanoparticle model selection method proposed by Monge et al. [Acta Cryst. (2024), A80, 202–212], evaluating and enhancing its robustness on data from device configurations not seen during training, by expanding the data set used for training. The influence of SNR on predictor robustness is then assessed, improved, and used to propose a stopping criterion for optimizing the trade-off between exposure time and data quality. Full Article text
mal A thermal deformation optimization method for cryogenically cooled silicon crystal monochromators under high heat load By journals.iucr.org Published On :: 2024-01-22 A method to optimize the thermal deformation of an indirectly cryo-cooled silicon crystal monochromator exposed to intense X-rays at a low-emittance diffraction-limited synchrotron radiation source is presented. The thermal-induced slope error of the monochromator crystal has been studied as a function of heat transfer efficiency, crystal temperature distribution and beam footprint size. A partial cooling method is proposed, which flattens the crystal surface profile within the beam footprint by modifying the cooling contact area to optimize the crystal peak temperature. The optimal temperature varies with different photon energies, which is investigated, and a proper cooling strategy is obtained to fulfil the thermal distortion requirements over the entire photon energy range. At an absorbed power up to 300 W with a maximum power density of 44.8 W mm−2 normal incidence beam from an in-vacuum undulator, the crystal thermal distortion does not exceed 0.3 µrad at 8.33 keV. This method will provide references for the monochromator design on diffraction-limited synchrotron radiation or free-electron laser light sources. Full Article text
mal Novel correction procedure for compensating thermal contraction errors in the measurement of the magnetic field of superconducting undulator coils in a liquid helium cryostat By journals.iucr.org Published On :: 2024-02-22 Superconducting undulators (SCUs) can offer a much higher on-axis undulator field than state-of-the-art cryogenic permanent-magnet undulators with the same period and vacuum gap. The development of shorter-period and high-field SCUs would allow the free-electron laser and synchrotron radiation source community to reduce both the length of undulators and the dimensions of the accelerator. Magnetic measurements are essential for characterizing the magnetic field quality of undulators for operation in a modern light source. Hall probe scanning is so far the most mature technique for local field characterization of undulators. This article focuses on the systematic error caused by thermal contraction that influences Hall probe measurements carried out in a liquid helium cryostat. A novel procedure, based on the redundant measurement of the magnetic field using multiple Hall probes at known relative distance, is introduced for the correction of such systematic error. Full Article text
mal Determination of optimal experimental conditions for accurate 3D reconstruction of the magnetization vector via XMCD-PEEM By journals.iucr.org Published On :: 2024-02-19 This work presents a detailed analysis of the performance of X-ray magnetic circular dichroism photoemission electron microscopy (XMCD-PEEM) as a tool for vector reconstruction of magnetization. For this, 360° domain wall ring structures which form in a synthetic antiferromagnet are chosen as the model to conduct the quantitative analysis. An assessment is made of how the quality of the results is affected depending on the number of projections that are involved in the reconstruction process, as well as their angular distribution. For this a self-consistent error metric is developed which allows an estimation of the optimum azimuthal rotation angular range and number of projections. This work thus proposes XMCD-PEEM as a powerful tool for vector imaging of complex 3D magnetic structures. Full Article text
mal Modelling the power threshold and optimum thermal deformation of indirectly liquid-nitrogen cryo-cooled Si monochromators By journals.iucr.org Published On :: 2024-04-09 Maximizing the performance of crystal monochromators is a key aspect in the design of beamline optics for diffraction-limited synchrotron sources. Temperature and deformation of cryo-cooled crystals, illuminated by high-power beams of X-rays, can be estimated with a purely analytical model. The analysis is based on the thermal properties of cryo-cooled silicon crystals and the cooling geometry. Deformation amplitudes can be obtained, quickly and reliably. In this article the concept of threshold power conditions is introduced and defined analytically. The contribution of parameters such as liquid-nitrogen cooling efficiency, thermal contact conductance and interface contact area of the crystal with the cooling base is evaluated. The optimal crystal illumination and the base temperature are inferred, which help minimize the optics deformation. The model has been examined using finite-element analysis studies performed for several beamlines of the Diamond-II upgrade. Full Article text
mal Developing an in situ LED irradiation system for small-angle X-ray scattering at B21, Diamond Light Source By journals.iucr.org Published On :: 2024-05-31 Beamline B21 at the Diamond Light Source synchrotron in the UK is a small-angle X-ray scattering (SAXS) beamline that specializes in high-throughput measurements via automated sample delivery systems. A system has been developed whereby a sample can be illuminated by a focused beam of light coincident with the X-ray beam. The system is compatible with the highly automated sample delivery system at the beamline and allows a beamline user to select a light source from a broad range of wavelengths across the UV and visible spectrum and to control the timing and duration of the light pulse with respect to the X-ray exposure of the SAXS measurement. The intensity of the light source has been characterized across the wavelength range enabling experiments where a quantitative measure of dose is important. Finally, the utility of the system is demonstrated via measurement of several light-responsive samples. Full Article text
mal In situ photodeposition of ultra-small palladium particles on TiO2 By journals.iucr.org Published On :: 2024-07-15 In situ and operando investigation of photocatalysts plays a fundamental role in understanding the processes of active phase formation and the mechanisms of catalytic reactions, which is crucial for the rational design of more efficient materials. Using a custom-made operando photocatalytic cell, an in situ procedure to follow the formation steps of Pd/TiO2 photocatalyst by synchrotron-based X-ray absorption spectroscopy (XAS) is proposed. The procedure resulted in the formation of ∼1 nm Pd particles with a much narrower size distribution and homogeneous spreading over TiO2 support compared with the samples generated in a conventional batch reactor. The combination of in situ XAS spectroscopy with high-angle annular dark-field scanning transmission electron microscopy demonstrated the formation of single-atom Pd(0) sites on TiO2 as the initial step of the photodeposition process. Palladium hydride particles were observed for all investigated samples upon exposure to formic acid solutions. Full Article text
mal Area normalization of HERFD-XANES spectra By journals.iucr.org Published On :: 2024-08-06 The normalization of X-ray absorption near-edge structure (XANES) spectra is required for comparing spectral features and extracting quantitative information in analytical techniques such as linear combination analysis, principal component analysis and multivariate curve resolution. Most published data are normalized to the edge-jump, but normalization to the spectral area has also been applied. The latter is particularly attractive if only a small energy range around the absorption can be recorded reliably. Here, the two normalization methods are compared at the L3-edge of Pt, Pd and Rh, and at the Ni K-edge using experimental and calculated spectra. Normalization to the spectral area is found to be a viable approach if the range for the area normalization is sufficiently large. Full Article text
mal 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
mal Investigating the missing-wedge problem in small-angle X-ray scattering tensor tomography across real and reciprocal space By journals.iucr.org Published On :: 2024-08-28 Small-angle-scattering tensor tomography is a technique for studying anisotropic nanostructures of millimetre-sized samples in a volume-resolved manner. It requires the acquisition of data through repeated tomographic rotations about an axis which is subjected to a series of tilts. The tilt that can be achieved with a typical setup is geometrically constrained, which leads to limits in the set of directions from which the different parts of the reciprocal space map can be probed. Here, we characterize the impact of this limitation on reconstructions in terms of the missing wedge problem of tomography, by treating the problem of tensor tomography as the reconstruction of a three-dimensional field of functions on the unit sphere, represented by a grid of Gaussian radial basis functions. We then devise an acquisition scheme to obtain complete data by remounting the sample, which we apply to a sample of human trabecular bone. Performing tensor tomographic reconstructions of limited data sets as well as the complete data set, we further investigate and validate the missing wedge problem by investigating reconstruction errors due to data incompleteness across both real and reciprocal space. Finally, we carry out an analysis of orientations and derived scalar quantities, to quantify the impact of this missing wedge problem on a typical tensor tomographic analysis. We conclude that the effects of data incompleteness are consistent with the predicted impact of the missing wedge problem, and that the impact on tensor tomographic analysis is appreciable but limited, especially if precautions are taken. In particular, there is only limited impact on the means and relative anisotropies of the reconstructed reciprocal space maps. Full Article text
mal A new dual-thickness semi-transparent beamstop for small-angle X-ray scattering By journals.iucr.org Published On :: 2024-08-25 An innovative dual-thickness semi-transparent beamstop designed to enhance the performance of small-angle X-ray scattering (SAXS) experiments is introduced. This design integrates two absorbers of differing thicknesses side by side into a single attenuator, known as a beamstop. Instead of completely stopping the direct beam, it attenuates it, allowing the SAXS detector to measure the transmitted beam through the sample. This approach achieves true synchronization in measuring both scattered and transmitted signals and effectively eliminates higher-order harmonic contributions when determining the transmission light intensity through the sample. This facilitates and optimizes signal detection and background subtraction. This contribution details the theoretical basis and practical implementation of this solution at the SAXS station on the 1W2A beamline at the Beijing Synchrotron Radiation Facility. It also anticipates its application at other SAXS stations, including that at the forthcoming High Energy Photon Source, providing an effective solution for high-precision SAXS experiments. Full Article text
mal The crystal structure of the ammonium salt of 2-aminomalonic acid By journals.iucr.org Published On :: 2024-06-19 The salt ammonium 2-aminomalonate (systematic name: ammonium 2-azaniumylpropanedioate), NH4+·C3H4NO4−, was synthesized in diethyl ether from the starting materials malonic acid, ammonia and bromine. The salt was recrystallized from water as colourless blocks. In the solid state, intramolecular medium–strong N—H⋯O, weak C—H⋯O and weak C—H⋯N hydrogen bonds build a three-dimensional network. Full Article text
mal Multivalent hydrogen-bonded architectures directed by self-complementarity between [Cu(2,2'-biimidazole)] and malonate building blocks By journals.iucr.org Published On :: 2024-08-19 The synthesis and structural characterization of four novel supramolecular hydrogen-bonded arrangements based on self-assembly from molecular `[Cu(2,2'-biimidazole)]' modules and malonate anions are presented, namely, tetrakis(2,2'-biimidazole)di-μ-chlorido-dimalonatotricopper(II) pentahydrate, [Cu3(C3H2O4)2Cl2(C6H6N4)4]·5H2O or [Cu(H2biim)2(μ-Cl)Cu0.5(mal)]2·5H2O, aqua(2,2'-biimidazole)malonatocopper(II) dihydrate, [Cu(C3H2O4)(C6H6N4)(H2O)]·2H2O or [Cu(H2biim)(mal)(H2O)]·2H2O, bis[aquabis(2,2'-biimidazole)copper(II)] dimalonatodiperchloratocopper(II) 2.2-hydrate, [Cu(C6H6N4)2(H2O)]2[Cu(C3H2O4)(ClO4)2]·2.2H2O or [Cu(H2biim)2(H2O)]2[Cu(mal)2(ClO4)2]·2.2H2O, and bis(2,2'-biimidazole)copper(II) bis[bis(2,2'-biimidazole)(2-carboxyacetato)malonatocopper(II)] tridecahydrate, [Cu(C6H6N4)2][Cu(C3H2O4)(C3H3O4)(C6H6N4)2]·13H2O or [Cu(H2biim)2][Cu(H2biim)2(Hmal)(mal)]2·13H2O. These assemblies are characterized by self-complementary donor–acceptor molecular interactions, demonstrating a recurrent and distinctive pattern of hydrogen-bonding preferences among the carboxylate, carboxylic acid and N—H groups of the coordinated 2,2'-biimidazole and malonate ligands. Additionally, coordination of the carboxylate group with the metallic centre helps sustain remarkable supramolecular assemblies, such as layers, helices, double helix columns or 3D channeled architectures, including mixed-metal complexes, into a single structure. Full Article text
mal 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