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Appealing to Voters Through Podcasts, Expert Explains Advantages

Virginia Tech communication professor Megan Duncan discusses why United States presidential candidates Donald Trump and Kamala Harris focused on podcasts in their voter outreach, and what benefits such media bring.




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How New Therapies Are Revolutionizing the Treatment of Juvenile Idiopathic Arthritis

The use of biologic and targeted therapies for children with juvenile idiopathic arthritis (JIA) surpassed more typical therapies in recent years, according to Rutgers Health researchers.




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Media Tip: Cyberthreats Are Growing - So Are Patents for Technology to Combat Them




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Survey: Three-Quarters of S. Koreans Believe Unification is Necessary

[Inter-Korea] :
A new survey finds that three-quarters of South Koreans believe unification of the two Koreas is necessary.  According to the national unification survey for the third quarter released by the Peaceful Unification Advisory Council on Monday, 74-point-six percent of respondents answered in the ...

[more...]




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Most of Nation to See Rain through Saturday

[Science] :
Most parts of the nation are experiencing heavy rain, with up to 120 millimeters expected in some areas through Saturday.  The Korea Meteorological Administration forecast on Friday that the eastern coastal areas of Gangwon Province will see 50 to 100 millimeters of rain through Saturday, adding that ...

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Overcast Skies, Showers Forecast through Tuesday

[Science] :
Overcast skies are forecast nationwide Monday, with showers expected in the south of the country and parts of the central region. According to the Korea Meteorological Administration, overcast conditions and rain are to continue Tuesday. The southernmost island of Jeju is expected to see about 120 ...

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Jeju, Southern Coast to See Heavy Rain through Saturday

[Science] :
Heavy rain is forecast for Jeju Island and the nation’s southern coastal regions through Saturday due to the indirect impact of Typhoon Kong-rey.  According to the Korea Meteorological Administration(KMA) on Friday, Jeju will see between 80 and 150 millimeters of rain through Saturday.  Up to 300 ...

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Goldman Sachs: Trump Tariff Threat Looms Large

[International] :
The U.S. investment bank Goldman Sachs has projected higher tariffs as a result of Donald Trump’s U.S. election victory, not only for China but also for South Korea, Taiwan and other Asian countries. According to the U.S. broadcaster CBNC on Monday, Andrew Tilton, Goldman’s chief Asia-Pacific economist, ...

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Archangel Roles and Significance in Christianity and Catholicism

In Christian tradition, an archangel is among of the most revered and powerful spiritual beings in the celestial hierarchy. Mentioned directly in both the Old and New Testaments, these angels serve as messengers, protectors and agents of God's divine will.




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Han Kang Hopes to Write Three More Books before Turning 60

[Culture] :
Nobel Prize-winning author Han Kang hopes to write three more books over the next six years. Han made the remarks Thursday as she accepted the Pony Chung Innovation Prize at an award ceremony organized by the Pony Chung Foundation. The 53-year-old author, who turns 54 next month, said ages 50 to 60 are ...

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11 Easiest Vegetables to Grow Throughout the Year

Starting your own vegetable garden can be a rewarding and delicious hobby. But choosing the right vegetables can make the difference between a bountiful harvest and a frustrating experience. If you're a beginner, you'll want to start with the easiest vegetables to grow in different seasons.




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NVee's Pre-Idol Life Juggling Three Jobs!


Start your week off right with NVee and DJ Hyerim in another exciting episode of I Feel You! Today, they’re spilling stories about everything from their school days and being the coolest aunts...

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How to Export Bookmarks From Chrome

You love your Chrome browser bookmarks but your computer is on the verge of dying. Is there any way you can save them so they appear on your new computer?




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KOSPI Slips below 2,500 Threshold for First Time since Black Monday in August

[Economy] :
South Korea’s benchmark Korea Composite Stock Price Index(KOSPI) slipped below the two-thousand-500 threshold on Tuesday for the first time since August’s “Black Monday.” The KOSPI dipped 49-point-09 points, or one-point-94 percent, on Tuesday to close at two-thousand-482-point-57. In the ...

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2-Amino-5-oxo-4-(thio­phen-2-yl)-5,6,7,8-tetra­hydro-4H-chromene-3-carbo­nitrile

In the crystal structure of the title compound, inter­molecular N—H⋯N and N—H⋯O hydrogen bonds form a two-dimensional supra­molecular network along the ac plane, contributing to the cohesion of the crystal.




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Exploiting fourth-generation synchrotron radiation for enzyme and photoreceptor characterization

(Time-resolved) macromolecular crystallography at the new ESRF-ID29 beamline is described.




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Morphological control for hollow rod crystals of a photochromic di­aryl­ethene on spherulites by surface properties of substrates

1,2-Bis(3,5-di­methyl-2-thienyl)perfluoro­cyclo­pentene formed its own spherulites by sublimation onto the hydro­philic surfaces of the (0001) planes of α-quartz and sapphire substrates. The formation of different morphologies of these spherulites was attributed to the surface properties of each substrate. Depending on the morphology of the spherulites, hollow rod crystals with cross sections of different sizes and shapes and branching structures were generated on the surfaces of the spherulites.




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Morphological control for hollow rod crystals of a photochromic diarylethene on spherulites by surface properties of substrates

Sublimation methods utilizing the surface properties of substrates can address the challenge of controlling hollow morphologies in rod crystals. Spherulites were formed on the hydrophilic surface of the (0001) planes of α-quartz and sapphire substrates by sublimation of 1,2-bis(3,5-dimethyl-2-thienyl)perfluorocyclopentene (1a). Various types of hollow morphologies, distinguished by the size and shape of their cross sections and by the presence or absence of branching structures, were formed separately on α-quartz and sapphire substrates. Such precise control of the hollow morphologies was attributed to the wettability of each substrate, leading to the formation of spherulites of 1a. In addition, it was indicated that the formation process of the surface morphologies of spherulites was associated with the hollow morphologies of rod crystals of 1a.




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Crystal structures of three uranyl–acetate–bipyridine complexes crystallized from hydraulic fracking fluid

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




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Expression, purification and crystallization of the photosensory module of phytochrome B (phyB) from Sorghum bicolor

Sorghum, a short-day tropical plant, has been adapted for temperate grain production, in particular through the selection of variants at the MATURITY loci (Ma1–Ma6) that reduce photoperiod sensitivity. Ma3 encodes phytochrome B (phyB), a red/far-red photochromic biliprotein photoreceptor. The multi-domain gene product, comprising 1178 amino acids, autocatalytically binds the phytochromobilin chromophore to form the photoactive holophytochrome (Sb.phyB). This study describes the development of an efficient heterologous overproduction system which allows the production of large quantities of various holoprotein constructs, along with purification and crystallization procedures. Crystals of the Pr (red-light-absorbing) forms of NPGP, PGP and PG (residues 1–655, 114–655 and 114–458, respectively), each C-terminally tagged with His6, were successfully produced. While NPGP crystals did not diffract, those of PGP and PG diffracted to 6 and 2.1 Å resolution, respectively. Moving the tag to the N-terminus and replacing phytochromobilin with phycocyanobilin as the ligand produced PG crystals that diffracted to 1.8 Å resolution. These results demonstrate that the diffraction quality of challenging protein crystals can be improved by removing flexible regions, shifting fusion tags and altering small-molecule ligands.




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Room-temperature serial synchrotron crystallography structure of Spinacia oleracea RuBisCO

Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) is the enzyme responsible for the first step of carbon dioxide (CO2) fixation in plants, which proceeds via the carboxylation of ribulose 1,5-biphosphate. Because of the enormous importance of this reaction in agriculture and the environment, there is considerable interest in the mechanism of fixation of CO2 by RuBisCO. Here, a serial synchrotron crystallography structure of spinach RuBisCO is reported at 2.3 Å resolution. This structure is consistent with earlier single-crystal X-ray structures of this enzyme and the results are a good starting point for a further push towards time-resolved serial synchrotron crystallography in order to better understand the mechanism of the reaction.




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Structures of Brucella ovis leucine-, isoleucine-, valine-, threonine- and alanine-binding protein reveal a conformationally flexible peptide-binding cavity

Brucella ovis is an etiologic agent of ovine epididymitis and brucellosis that causes global devastation in sheep, rams, goats, small ruminants and deer. There are no cost-effective methods for the worldwide eradication of ovine brucellosis. B. ovis and other protein targets from various Brucella species are currently in the pipeline for high-throughput structural analysis at the Seattle Structural Genomics Center for Infectious Disease (SSGCID), with the aim of identifying new therapeutic targets. Furthermore, the wealth of structures generated are effective tools for teaching scientific communication, structural science and biochemistry. One of these structures, B. ovis leucine-, isoleucine-, valine-, threonine- and alanine-binding protein (BoLBP), is a putative periplasmic amino acid-binding protein. BoLBP shares less than 29% sequence identity with any other structure in the Protein Data Bank. The production, crystallization and high-resolution structures of BoLBP are reported. BoLBP is a prototypical bacterial periplasmic amino acid-binding protein with the characteristic Venus flytrap topology of two globular domains encapsulating a large central cavity containing the peptide-binding region. The central cavity contains small molecules usurped from the crystallization milieu. The reported structures reveal the conformational flexibility of the central cavity in the absence of bound peptides. The structural similarity to other LBPs can be exploited to accelerate drug repurposing.




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Sheet-on-sheet fixed target data collection devices for serial crystallography at synchrotron and XFEL sources

Fixed targets (`chips') offer efficient, high-throughput microcrystal delivery for serial crystallography at synchrotrons and X-ray free-electron lasers (XFELs). Within this family, sheet-on-sheet (SOS) chips offer noteworthy advantages in cost, adaptability, universality and ease of crystal loading. We describe our latest generation of SOS devices, which are now in active use at both synchrotrons and XFELs.




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A micro-beamstop with transmission detection by fluorescence for scanning-beam synchrotron scattering beamlines

The correct determination of X-ray transmission at X-ray nanoprobes equipped with small beamstops for small- and wide-angle X-ray scattering collection is an unsolved problem with huge implications for data correction pipelines. We present a cost-effective solution to detect the transmission via the X-ray fluorescence of the beamstop with an avalanche photodiode.




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Position-independent product increase rate in a shaker mill revealed by position-resolved in situ synchrotron powder X-ray diffraction

The position- and time-resolved monitoring of a mechanochemical reaction using synchrotron powder X-ray diffraction revealed a position-independent increase rate of product in the jar of a shaker mill.




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Crystal structures and circular dichroism of {2,2'-[(1S,2S)-1,2-di­phenyl­ethane-1,2-diylbis(nitrilophenyl­methanylyl­idene)]diphenolato}nickel(II) and its ethanol solvate

A chiral nickel(II) Schiff base complex derived from 2-hy­droxy­benzo­phenone and (1S,2S)-1,2-di­phenyl­ethyl­enedi­amine shows a λ conformation of the central di­amine chelate ring. The substituents on the C&z-dbnd;N carbon atoms significantly affect the circular dichroism spectra.




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Crystal structure of 1,10-phenanthrolinium violurate violuric acid penta­hydrate

The crystal structure of the co-crystal salt solvate 1,10-phenanthrolinium violurate violuric acid penta­hydrate features a tri-periodic hydrogen-bonded network with the violurate and violuric acid residues each assembled into tapes and the phenanthrolinium cations residing in channels.




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A micro-beamstop with transmission detection by fluorescence for scanning-beam synchrotron scattering beamlines

Quantitative X-ray diffraction approaches require careful correction for sample transmission. Though this is a routine task at state-of-the-art small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS) or diffraction beamlines at synchrotron facilities, the transmission signal cannot be recorded concurrently with SAXS/WAXS when using the small, sub-millimetre beamstops at many X-ray nanoprobes during SAXS/WAXS experiments due to the divergence-limited size of the beamstop and the generally tight geometry. This is detrimental to the data quality and often the only solution is to re-scan the sample with a PIN photodiode as a detector to obtain transmission values. In this manuscript, we present a simple yet effective solution to this problem in the form of a small beamstop with an inlaid metal target for optimal fluorescence yield. This fluorescence can be detected with a high-sensitivity avalanche photodiode and provides a linear counter to determine the sample transmission.




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Position-independent product increase rate in a shaker mill revealed by position-resolved in situ synchrotron powder X-ray diffraction

We investigated the position and time dependence of a mechanochemical reaction induced by ball milling using in situ synchrotron powder X-ray diffraction with changing X-ray irradiation position. The mechanochemical reduction of AgCl with Cu was monitored in situ with the X-rays incident at two different vertical positions on the jar. Our previously developed multi-distance Rietveld method was applied to analyze the in situ diffraction data with a 1 min resolution. Both the vertical and the horizontal sample positions were determined using the sample-to-detector distances from the in situ data. Position dependence was found in the powder spreading and induction time. We reveal that the increase rate of the product is independent of the sample position when measured with a 1 min time resolution, confirming the validity of in situ monitoring of part of the space in a milling jar for a gradual mechanochemical reaction.




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Sheet-on-sheet fixed target data collection devices for serial crystallography at synchrotron and XFEL sources

Serial crystallography (SX) efficiently distributes over many crystals the radiation dose absorbed during diffraction data acquisition, enabling structure determination of samples at ambient temperature. SX relies on the rapid and reliable replacement of X-ray-exposed crystals with fresh crystals at a rate commensurate with the data acquisition rate. `Solid supports', also known as `fixed targets' or `chips', offer one approach. These are microscopically thin solid panes into or onto which crystals are deposited to be individually interrogated by an X-ray beam. Solid supports are generally patterned using photolithography methods to produce a regular array of features that trap single crystals. A simpler and less expensive alternative is to merely sandwich the microcrystals between two unpatterned X-ray-transparent polymer sheets. Known as sheet-on-sheet (SOS) chips, these offer significantly more versatility. SOS chips place no constraint on the size or size distribution of the microcrystals or their growth conditions. Crystals ranging from true nanocrystals up to microcrystals can be investigated, as can crystals grown in media ranging from low viscosity (aqueous solution) up to high viscosity (such as lipidic cubic phase). Here, we describe our two SOS devices. The first is a compact and lightweight version designed specifically for synchrotron use. It incorporates a standard SPINE-type magnetic base for mounting on a conventional macromolecular crystallography goniometer. The second and larger chip is intended for both X-ray free-electron laser and synchrotron use and is fully compatible with the fast-scanning XY-raster stages developed for data collection with patterned chips.




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Crystal structures and circular dichroism of {2,2'-[(1S,2S)-1,2-diphenylethane-1,2-diylbis(nitrilophenylmethanylylidene)]diphenolato}nickel(II) and its ethanol solvate

The title compound, [Ni(C40H30N2O2)] (1), with an optically active Schiff base ligand derived from 2-hydroxybenzophenone and (1S,2S)-1,2-diphenylethylenediamine, was crystallized as the solvent-free and ethanol solvate forms (1 and 1·2C2H5OH). In both structures, the two phenyl groups on the stereogenic centers of the O,N,N,O-tetradentate ligand are axially oriented, and the conformation of the central diamine chelate ring is λ. The circular dichroism (CD) spectra of 1 and the analogous nickel(II) complex [Ni(C30H26N2O2)] (2) in solution show partially similar patterns in the 350–450 nm range, but are mirror images in the longer wavelength region (450–650 nm). In the latter region, the sign of CD for these complexes is sensitive to the substituents on the C=N carbon atoms (phenyl for 1 and methyl for 2) rather than the diamine chelate ring conformation.




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In situ/operando plug-flow fixed-bed cell for synchrotron PXRD and XAFS investigations at high temperature, pressure, controlled gas atmosphere and ultra-fast heating

A plug-flow fixed-bed cell for synchrotron powder X-ray diffraction (PXRD) and X-ray absorption fine structure (XAFS) idoneous for the study of heterogeneous catalysts at high temperature, pressure and under gas flow is designed, constructed and demonstrated. The operating conditions up to 1000°C and 50 bar are ensured by a set of mass flow controllers, pressure regulators and two infra-red lamps that constitute a robust and ultra-fast heating and cooling method. The performance of the system and cell for carbon dioxide hydrogenation reactions under specified temperatures, gas flows and pressures is demonstrated both for PXRD and XAFS at the P02.1 (PXRD) and the P64 (XAFS) beamlines of the Deutsches Elektronen-Synchrotron (DESY).




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Protocol using similarity score and improved shrink-wrap algorithm for better convergence of phase-retrieval calculation in X-ray diffraction imaging

In X-ray diffraction imaging (XDI), electron density maps of a targeted particle are reconstructed computationally from the diffraction pattern alone using phase-retrieval (PR) algorithms. However, the PR calculations sometimes fail to yield realistic electron density maps that approximate the structure of the particle. This occurs due to the absence of structure amplitudes at and near the zero-scattering angle and the presence of Poisson noise in weak diffraction patterns. Consequently, the PR calculation becomes a bottleneck for XDI structure analyses. Here, a protocol to efficiently yield realistic maps is proposed. The protocol is based on the empirical observation that realistic maps tend to yield low similarity scores, as suggested in our prior study [Sekiguchi et al. (2017), J. Synchrotron Rad. 24, 1024–1038]. Among independently and concurrently executed PR calculations, the protocol modifies all maps using the electron-density maps exhibiting low similarity scores. This approach, along with a new protocol for estimating particle shape, improved the probability of obtaining realistic maps for diffraction patterns from various aggregates of colloidal gold particles, as compared with PR calculations performed without the protocol. Consequently, the protocol has the potential to reduce computational costs in PR calculations and enable efficient XDI structure analysis of non-crystalline particles using synchrotron X-rays and X-ray free-electron laser pulses.




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Heitt Mjölnir: a heated miniature triaxial apparatus for 4D synchrotron microtomography

Third- and fourth-generation synchrotron light sources with high fluxes and beam energies enable the use of innovative X-ray translucent experimental apparatus. These experimental devices access geologically relevant conditions whilst enabling in situ characterization using the spatial and temporal resolutions accessible at imaging beamlines. Here, Heitt Mjölnir is introduced, a heated miniature triaxial rig based on the design of Mjölnir, but covering a wider temperature range and larger sample volume at similar pressure capacities. This device is designed to investigate coupled thermal, chemical, hydraulic and mechanical processes from grain to centimetre scales using cylindrical samples of 10 mm × 20 mm (diameter × length). Heitt Mjölnir can simultaneously reach confining (hydraulic) pressures of 30 MPa and 500 MPa of axial stress with independently controlled sample pore fluid pressure < 30 MPa. This internally heated apparatus operates to temperatures up to 573 K with a minimal vertical thermal gradient in the sample of <0.3 K mm−1. This new apparatus has been deployed in operando studies at the TOMCAT (Swiss Light Source), I12 JEEP (Diamond Light Source) and PSICHÉ (Synchrotron SOLEIL) beamlines for 4D X-ray microtomography with scan intervals of a few minutes. Heitt Mjölnir is portable and modular, allowing a wide range of 4D characterizations of low-grade metamorphism and deformational processes. It enables spatially and temporally resolved fluid–rock interaction studies at conditions of crustal reservoirs and is suitable for characterization of material properties in geothermal, carbonation or subsurface gas storage applications. Technical drawings and an operation guide are included in this publication.




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A thermal deformation optimization method for cryogenically cooled silicon crystal monochromators under high heat load

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.




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Enhancing electrospray ionization efficiency for particle transmission through an aerodynamic lens stack

This work investigates the performance of the electrospray aerosol generator at the European X-ray Free Electron Laser (EuXFEL). This generator is, together with an aerodynamic lens stack that transports the particles into the X-ray interaction vacuum chamber, the method of choice to deliver particles for single-particle coherent diffractive imaging (SPI) experiments at the EuXFEL. For these experiments to be successful, it is necessary to achieve high transmission of particles from solution into the vacuum interaction region. Particle transmission is highly dependent on efficient neutralization of the charged aerosol generated by the electrospray mechanism as well as the geometry in the vicinity of the Taylor cone. We report absolute particle transmission values for different neutralizers and geometries while keeping the conditions suitable for SPI experiments. Our findings reveal that a vacuum ultraviolet ionizer demonstrates a transmission efficiency approximately seven times greater than the soft X-ray ionizer used previously. Combined with an optimized orifice size on the counter electrode, we achieve >40% particle transmission from solution into the X-ray interaction region. These findings offer valuable insights for optimizing electrospray aerosol generator configurations and data rates for SPI experiments.




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Grazing-incidence synchrotron radiation diffraction studies on irradiated Ce-doped and pristine Y-stabilized ZrO2 at the Rossendorf beamline

In this work, Ce-doped yttria-stabilized zirconia (YSZ) and pure YSZ phases were subjected to irradiation with 14 MeV Au ions. Irradiation studies were performed to simulate long-term structural and microstructural damage due to self-irradiation in YSZ phases hosting alpha-active radioactive species. It was found that both the Ce-doped YSZ and the YSZ phases had a reasonable tolerance to irradiation at high ion fluences and the bulk crystallinity was well preserved. Nevertheless, local microstrain increased in all compounds under study after irradiation, with the Ce-doped phases being less affected than pure YSZ. Doping with cerium ions increased the microstructural stability of YSZ phases through a possible reduction in the mobility of oxygen atoms, which limits the formation of structural defects. Doping of YSZ with tetravalent actinide elements is expected to have a similar effect. Thus, YSZ phases are promising for the safe long-term storage of radioactive elements. Using synchrotron radiation diffraction, measurements of the thin irradiated layers of the Ce-YSZ and YSZ samples were performed in grazing incidence (GI) mode. A corresponding module for measurements in GI mode was developed at the Rossendorf Beamline and relevant technical details for sample alignment and data collection are also presented.




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A differentiable simulation package for performing inference of synchrotron-radiation-based diagnostics

The direction of particle accelerator development is ever-increasing beam quality, currents and repetition rates. This poses a challenge to traditional diagnostics that directly intercept the beam due to the mutual destruction of both the beam and the diagnostic. An alternative approach is to infer beam parameters non-invasively from the synchrotron radiation emitted in bending magnets. However, inferring the beam distribution from a measured radiation pattern is a complex and computationally expensive task. To address this challenge we present SYRIPY (SYnchrotron Radiation In PYthon), a software package intended as a tool for performing inference of synchrotron-radiation-based diagnostics. SYRIPY has been developed using PyTorch, which makes it both differentiable and able to leverage the high performance of GPUs, two vital characteristics for performing statistical inference. The package consists of three modules: a particle tracker, Lienard–Wiechert solver and Fourier optics propagator, allowing start-to-end simulation of synchrotron radiation detection to be carried out. SYRIPY has been benchmarked against SRW, the prevalent numerical package in the field, showing good agreement and up to a 50× speed improvement. Finally, we have demonstrated how SYRIPY can be used to perform Bayesian inference of beam parameters using stochastic variational inference.




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Optimization of synchrotron radiation parameters using swarm intelligence and evolutionary algorithms

Alignment of each optical element at a synchrotron beamline takes days, even weeks, for each experiment costing valuable beam time. Evolutionary algorithms (EAs), efficient heuristic search methods based on Darwinian evolution, can be utilized for multi-objective optimization problems in different application areas. In this study, the flux and spot size of a synchrotron beam are optimized for two different experimental setups including optical elements such as lenses and mirrors. Calculations were carried out with the X-ray Tracer beamline simulator using swarm intelligence (SI) algorithms and for comparison the same setups were optimized with EAs. The EAs and SI algorithms used in this study for two different experimental setups are the Genetic Algorithm (GA), Non-dominated Sorting Genetic Algorithm II (NSGA-II), Particle Swarm Optimization (PSO) and Artificial Bee Colony (ABC). While one of the algorithms optimizes the lens position, the other focuses on optimizing the focal distances of Kirkpatrick–Baez mirrors. First, mono-objective evolutionary algorithms were used and the spot size or flux values checked separately. After comparison of mono-objective algorithms, the multi-objective evolutionary algorithm NSGA-II was run for both objectives – minimum spot size and maximum flux. Every algorithm configuration was run several times for Monte Carlo simulations since these processes generate random solutions and the simulator also produces solutions that are stochastic. The results show that the PSO algorithm gives the best values over all setups.




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VerSoX B07-B: a high-throughput XPS and ambient pressure NEXAFS beamline at Diamond Light Source

The beamline optics and endstations at branch B of the Versatile Soft X-ray (VerSoX) beamline B07 at Diamond Light Source are described. B07-B provides medium-flux X-rays in the range 45–2200 eV from a bending magnet source, giving access to local electronic structure for atoms of all elements from Li to Y. It has an endstation for high-throughput X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine-structure (NEXAFS) measurements under ultrahigh-vacuum (UHV) conditions. B07-B has a second endstation dedicated to NEXAFS at pressures from UHV to ambient pressure (1 atm). The combination of these endstations permits studies of a wide range of interfaces and materials. The beamline and endstation designs are discussed in detail, as well as their performance and the commissioning process.




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High-pressure X-ray photon correlation spectroscopy at fourth-generation synchrotron sources

A new experimental setup combining X-ray photon correlation spectroscopy (XPCS) in the hard X-ray regime and a high-pressure sample environment has been developed to monitor the pressure dependence of the internal motion of complex systems down to the atomic scale in the multi-gigapascal range, from room temperature to 600 K. The high flux of coherent high-energy X-rays at fourth-generation synchrotron sources solves the problems caused by the absorption of diamond anvil cells used to generate high pressure, enabling the measurement of the intermediate scattering function over six orders of magnitude in time, from 10−3 s to 103 s. The constraints posed by the high-pressure generation such as the preservation of X-ray coherence, as well as the sample, pressure and temperature stability, are discussed, and the feasibility of high-pressure XPCS is demonstrated through results obtained on metallic glasses.




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Scattered high-energy synchrotron radiation at the KARA visible-light diagnostic beamline

To characterize an electron beam, visible synchrotron light is often used and dedicated beamlines at synchrotron sources are becoming a more common feature as instruments and methods for the diagnostics are, along with the accelerators, further developed. At KARA (Karlsruhe Research Accelerator), such a beamline exists and is based on a typical infrared/visible-light configuration. From experience at such beamlines no significant radiation was expected (dose rates larger than 0.5 µSv h−1). This was found not to be the case and a higher dose was measured which fortunately could be shielded to an acceptable level with 0.3 mm of aluminium foil or 2.0 mm of Pyrex glass. The presence of this radiation led to further investigation by both experiment and calculation. A custom setup using a silicon drift detector for energy-dispersive spectroscopy (Ketek GmbH) and attenuation experiments showed the radiation to be predominantly copper K-shell fluorescence and is confirmed by calculation. The measurement of secondary radiation from scattering of synchrotron and other radiation, and its calculation, is important for radiation protection, and, although a lot of experience exists and methods for radiation protection are well established, changes in machine, beamlines and experiments mean a constant appraisal is needed.




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Modelling the power threshold and optimum thermal deformation of indirectly liquid-nitro­gen cryo-cooled Si monochromators

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.




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Synchrotron infrared nanospectroscopy in fourth-generation storage rings

Fourth-generation synchrotron storage rings represent a significant milestone in synchrotron technology, offering outstandingly bright and tightly focused X-ray beams for a wide range of scientific applications. However, due to their inherently tight magnetic lattices, these storage rings have posed critical challenges for accessing lower-energy radiation, such as infrared (IR) and THz. Here the first-ever IR beamline to be installed and to operate at a fourth-generation synchrotron storage ring is introduced. This work encompasses several notable advancements, including a thorough examination of the new IR source at Sirius, a detailed description of the radiation extraction scheme, and the successful validation of our optical concept through both measurements and simulations. This optimal optical setup has enabled us to achieve an exceptionally wide frequency range for our nanospectroscopy experiments. Through the utilization of synchrotron IR nanospectroscopy on biological and hard matter samples, the practicality and effectiveness of this beamline has been successfully demonstrated. The advantages of fourth-generation synchrotron IR sources, which can now operate with unparalleled stability as a result of the stringent requirements for producing low-emittance X-rays, are emphasized.




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Evaluation of the X-ray/EUV Nanolithography Facility at AS through wavefront propagation simulations

Synchrotron light sources can provide the required spatial coherence, stability and control to support the development of advanced lithography at the extreme ultraviolet and soft X-ray wavelengths that are relevant to current and future fabricating technologies. Here an evaluation of the optical performance of the soft X-ray (SXR) beamline of the Australian Synchrotron (AS) and its suitability for developing interference lithography using radiation in the 91.8 eV (13.5 nm) to 300 eV (4.13 nm) range are presented. A comprehensive physical optics model of the APPLE-II undulator source and SXR beamline was constructed to simulate the properties of the illumination at the proposed location of a photomask, as a function of photon energy, collimation and monochromator parameters. The model is validated using a combination of experimental measurements of the photon intensity distribution of the undulator harmonics. It is shown that the undulator harmonics intensity ratio can be accurately measured using an imaging detector and controlled using beamline optics. Finally, the photomask geometric constraints and achievable performance for the limiting case of fully spatially coherent illumination are evaluated.




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A distributed data processing scheme based on Hadoop for synchrotron radiation experiments

With the development of synchrotron radiation sources and high-frame-rate detectors, the amount of experimental data collected at synchrotron radiation beamlines has increased exponentially. As a result, data processing for synchrotron radiation experiments has entered the era of big data. It is becoming increasingly important for beamlines to have the capability to process large-scale data in parallel to keep up with the rapid growth of data. Currently, there is no set of data processing solutions based on the big data technology framework for beamlines. Apache Hadoop is a widely used distributed system architecture for solving the problem of massive data storage and computation. This paper presents a set of distributed data processing schemes for beamlines with experimental data using Hadoop. The Hadoop Distributed File System is utilized as the distributed file storage system, and Hadoop YARN serves as the resource scheduler for the distributed computing cluster. A distributed data processing pipeline that can carry out massively parallel computation is designed and developed using Hadoop Spark. The entire data processing platform adopts a distributed microservice architecture, which makes the system easy to expand, reduces module coupling and improves reliability.