B07-B-Versatile Soft X-ray beamline: High Throughput
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Diamond Proposal Number(s):
[31119]
Open Access
Abstract: Tin-containing layers with different degrees of oxidation are uniformly distributed along the length of silicon nanowires formed by a top-down method by applying metalorganic chemical vapor deposition. The electronic and atomic structure of the obtained layers is investigated by applying nondestructive surface-sensitive X-ray absorption near edge spectroscopy using synchrotron radiation. The results demonstrated, for the first time, a distribution effect of the tin-containing phases in the nanostructured silicon matrix compared to the results obtained for planar structures at the same deposition temperatures. The amount and distribution of tin-containing phases can be effectively varied and controlled by adjusting the geometric parameters (pore diameter and length) of the initial matrix of nanostructured silicon. Due to the occurrence of intense interactions between precursor molecules and decomposition by-products in the nanocapillary, as a consequence of random thermal motion of molecules in the nanocapillary, which leads to additional kinetic energy and formation of reducing agents, resulting in effective reduction of tin-based compounds to a metallic tin state for molecules with the highest penetration depth in the nanostructured silicon matrix. This effect will enable clear control of the phase distributions of functional materials in 3D matrices for a wide range of applications.
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Jan 2023
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I15-Extreme Conditions
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Diamond Proposal Number(s):
[24144]
Open Access
Abstract: BiFeO3-BaTiO3 (BF-BT) solid solutions exhibit great promise as the basis for high temperature piezoelectric transducers and energy storage dielectrics, but the fundamental mechanisms governing their functional properties require further clarification. In the present study, both pure and niobium-doped 0.7BF-0.3BT ceramics are synthesized by solid state reaction and their structure-property relationships are systematically investigated. It is shown that substituting a low concentration of Ti with Nb at a level of 0.5 at% increases the resistivity of BF-BT ceramics and facilitates ferroelectric switching at high electric field levels. Stable planar piezoelectric coupling factor values are achieved with a variation from 0.35 to 0.45 over the temperature range from 100 to 430 °C. In addition to the ferroelectric-paraelectric phase transformation at the Curie point (~ 430 °C), a frequency-dependent relaxation of the dielectric permittivity and associated loss peak are observed over the temperature range from -50 to +150 °C. These effects are correlated with anomalous enhancement of the remanent polarization and structural (rhombohedral) distortion with increasing temperature, indicating the occurrence of a re-entrant relaxor ferroelectric transformation on cooling. The results of the study provide new insight into the thermal evolution of structure and the corresponding functional properties in BF-BT and related solid solutions.
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Jan 2023
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I22-Small angle scattering & Diffraction
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Mario
Gonzalez-Jimenez
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Trent
Barnard
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Ben A.
Russell
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Nikita V.
Tukachev
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Uroš
Javornik
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Laure-Anne
Hayes
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Andrew J.
Farrell
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Sarah
Guinane
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Hans M.
Senn
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Andrew J.
Smith
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Martin
Wilding
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Gregor
Mali
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Motohiro
Nakano
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Yuji
Miyazaki
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Paul
Mcmillan
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Gabriele C.
Sosso
,
Klaas
Wynne
Diamond Proposal Number(s):
[28529]
Open Access
Abstract: A common feature of glasses is the “boson peak”, observed as an excess in the heat capacity over the crystal or as an additional peak in the terahertz vibrational spectrum. The microscopic origins of this peak are not well understood; the emergence of locally ordered structures has been put forward as a possible candidate. Here, we show that depolarised Raman scattering in liquids consisting of highly symmetric molecules can be used to isolate the boson peak, allowing its detailed observation from the liquid into the glass. The boson peak in the vibrational spectrum matches the excess heat capacity. As the boson peak intensifies on cooling, wide-angle x-ray scattering shows the simultaneous appearance of a pre-peak due to molecular clusters consisting of circa 20 molecules. Atomistic molecular dynamics simulations indicate that these are caused by over-coordinated molecules. These findings represent an essential step toward our understanding of the physics of vitrification.
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Jan 2023
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Detectors
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J.
Correa
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M.
Mehrjoo
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R.
Battistelli
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F.
Lehmkühler
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A.
Marras
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C. B.
Wunderer
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T.
Hirono
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V.
Felk
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F.
Krivan
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S.
Lange
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I.
Shevyakov
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V.
Vardanyan
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M.
Zimmer
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M.
Hoesch
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K.
Bagschik
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N.
Guerrini
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B.
Marsh
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I.
Sedgwick
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G.
Cautero
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L.
Stebel
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D.
Giuressi
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R. H.
Menk
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A.
Greer
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T.
Nicholls
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W.
Nichols
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U.
Pedersen
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P.
Shikhaliev
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N.
Tartoni
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H. J.
Hyun
,
S. H.
Kim
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S. Y.
Park
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K. S.
Kim
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F.
Orsini
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F. J.
Iguaz
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F.
Büttner
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B.
Pfau
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E.
Plönjes
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K.
Kharitonov
,
M.
Ruiz-Lopez
,
R.
Pan
,
S.
Gang
,
B.
Keitel
,
H.
Graafsma
Open Access
Abstract: The PERCIVAL detector is a CMOS imager designed for the soft X-ray regime at photon sources. Although still in its final development phase, it has recently seen its first user experiments: ptychography at a free-electron laser, holographic imaging at a storage ring and preliminary tests on X-ray photon correlation spectroscopy. The detector performed remarkably well in terms of spatial resolution achievable in the sample plane, owing to its small pixel size, large active area and very large dynamic range; but also in terms of its frame rate, which is significantly faster than traditional CCDs. In particular, it is the combination of these features which makes PERCIVAL an attractive option for soft X-ray science.
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Jan 2023
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B21-High Throughput SAXS
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Diamond Proposal Number(s):
[29806]
Open Access
Abstract: Small-angle X-ray scattering (SAXS) can be used for structural determination of biological macromolecules and polymers in their native states (e.g. liquid phase). This means that the structural changes of (bio-)polymers, such as proteins and DNA, can be monitored in situ to understand their sensitivity to changes in chemical environments. In an attempt to improve the reliability of such experiments, the reduction of radiation damage occurring from exposure to X-rays is required. One such method, is to use scavenger molecules to protect macromolecules against radicals produced during radiation exposure, such as reactive oxygen species (ROS). In this study we investigate the feasibility of applying the compatible solute, osmolyte and radiation protector Ectoine (THP(B)), as a scavenger molecule during SAXS measurements of the single-stranded DNA-binding protein Gene-V Protein (G5P/GVP). In this case, we monitor the radiation induced changes of G5P during bio-SAXS measurments and the resulting microscopic energy-damage relation was determined from microdosimetric calculations by Monte-Carlo based particle scattering simulations with TOPAS/Geant4 and a custom target-model. This resulted in a median-lethal energy deposit of pure G5P at 4 mg mL−1 of E1/2 = 7 ± 5 eV, whereas a threefold increase of energy-deposit was needed under the presence of Ectoine to reach the same level of damage. This indicates that Ectoine increases the possible exposure time before radiation-damage to G5P is observed. Furthermore, the dominant type of damage shifted from aggregation in pure solutions towards a fragmentation for solutions containing Ectoine as a cosolute. These results are interpreted in terms of indirect radiation damage by reactive secondary species, as well as post-irradiation effects, related to preferential-exclusion of the cosolute from the protein surface. Hence, Ectoine is shown to provide a non-disturbing way to improve structure-determination of proteins via bio-SAXS in future studies.
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Jan 2023
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I03-Macromolecular Crystallography
I04-Macromolecular Crystallography
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Diamond Proposal Number(s):
[28534]
Open Access
Abstract: N-Acyl indolines 4 are potent, non-covalent Notum inhibitors developed from a covalent virtual screening hit 2a. The lead compounds were simple to synthesise, achieved excellent potency in a biochemical Notum-OPTS assay and restored Wnt signalling in a cell-based TCF/LEF reporter assay. Multiple high resolution X-ray structures established a common binding mode of these inhibitors with the indoline bound centred in the palmiteolate pocket with key interactions being aromatic stacking and a water mediated hydrogen bond to the oxyanion hole. These N-acyl indolines 4 will be useful tools for use in vitro studies to investigate the role of Notum in disease models, especially when paired with a structurally related covalent inhibitor (e.g. 4w and 2a). Overall, this study highlights the designed switch from covalent to non-covalent Notum inhibitors and so illustrates a complementary approach for hit generation and target inhibition.
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Jan 2023
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Stefan
Gahbauer
,
Galen J.
Correy
,
Marion
Schuller
,
Matteo P.
Ferla
,
Yagmur Umay
Doruk
,
Moira
Rachman
,
Taiasean
Wu
,
Morgan
Diolaiti
,
Siyi
Wang
,
R. Jeffrey
Neitz
,
Daren
Fearon
,
Dmytro S.
Radchenko
,
Yurii S.
Moroz
,
John J.
Irwin
,
Adam R.
Renslo
,
Jenny C.
Taylor
,
Jason E.
Gestwicki
,
Frank
Von Delft
,
Alan
Ashworth
,
Ivan
Ahel
,
Brian K.
Shoichet
,
James S.
Fraser
Open Access
Abstract: The nonstructural protein 3 (NSP3) of the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) contains a conserved macrodomain enzyme (Mac1) that is critical for pathogenesis and lethality. While small-molecule inhibitors of Mac1 have great therapeutic potential, at the outset of the COVID-19 pandemic, there were no well-validated inhibitors for this protein nor, indeed, the macrodomain enzyme family, making this target a pharmacological orphan. Here, we report the structure-based discovery and development of several different chemical scaffolds exhibiting low- to sub-micromolar affinity for Mac1 through iterations of computer-aided design, structural characterization by ultra-high-resolution protein crystallography, and binding evaluation. Potent scaffolds were designed with in silico fragment linkage and by ultra-large library docking of over 450 million molecules. Both techniques leverage the computational exploration of tangible chemical space and are applicable to other pharmacological orphans. Overall, 160 ligands in 119 different scaffolds were discovered, and 153 Mac1-ligand complex crystal structures were determined, typically to 1 Å resolution or better. Our analyses discovered selective and cell-permeable molecules, unexpected ligand-mediated conformational changes within the active site, and key inhibitor motifs that will template future drug development against Mac1.
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Jan 2023
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I15-Extreme Conditions
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Open Access
Abstract: Geothermal heat from the Earth`s crust is a source of natural and renewable energy. This energy can be extracted and used for generating electricity and heating of houses in the winter months. However, in order to extract energy from a well, we need to use material that can sustain contact with geothermal steam and is resistant to corrosion of the geothermal fluid and non-condensing gases such as hydrogen sulfide (H2S) and carbon dioxide (CO2), chloride ions (Cl−), and hydrogen fluoride (HF). An interesting alternative to today's materials are bimetals, composed of two different materials where the layer in contact with the aggressive environment is made of a noble material, while the outer layer (typically low-carbon steel) strengthens the composite and additionally provides good weldability.
This paper presents the microstructure, phase composition, and distribution of residual stresses of the bimetallic system nickel-chromium-molybdenum alloy (Alloy 625) cladded on the ferritic pressure vessel steel P355NH base material.
The bimetal has been prepared by explosion welding and is its use is geared for transport of highly corrosive media and as a material for heat exchangers, condensers, etc.
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Jan 2023
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Open Access
Abstract: Sb- and Nb-doped Zr and Sn-umbites have been prepared using hydrothermal synthesis with both high purity and yield. All four materials display excellent removal of Cs+ cations from acidic, neutral, and basic solutions, abating at least 80% of the Cs present. This performance is retained in the presence of competing Na+ cations as well as across the pH range. The most sustained selectivity is observed in acidic media, with evidence of a minor reduction in selectivity under basic conditions. The umbites have successfully been shaped into pellets, introducing macroporosity and retaining the selective uptake of Cs in the presence of excess Na. Through thermal treatment, samples of partially Cs-exchanged umbite can be converted into dense silicate phases where radioactive Cs can be immobilized in a potential wasteform for long term storage. These findings present doped umbites as prospective materials for industrial use with selective abatement properties and capabilities for deployment followed by end of life geological disposal.
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Jan 2023
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[28087, 26608]
Abstract: Ti40Zr10Cu32Pd14Ga4 and Ti40Zr10Cu32Pd14Sn4 (in at.%) bulk metallic glasses (BMGs) with different geometries (wedges, rods, ribbons and discs) were prepared by suction casting, melt spinning and splat quenching, respectively. For comparison, the reference Ti40Zr10Cu36Pd14 BMG was cast as a rod with 2 mm diameter and in wedge-shaped form. High-energy X-ray diffraction measurements yielded a critical casting thickness of 2.4, 2.1 and at least 4 mm for the reference, Ga-containing, and Sn-containing BMGs, respectively. The extension of the supercooled liquid region of about 50 K, measured for the glassy rods and ribbons by differential scanning calorimetry, is larger than that of only 20 K found for the splat-quenched discs. As to the alloys’ mechanical properties, the Ti40Zr10Cu36Pd14 glassy rods deform plastically in compression up to a strain of 3.8% and possess a Young’s modulus of 78 GPa. The Sn- and Ga- containing BMG rods reach respectively a plastic strain of 6.1% and 4.7%, and a Young’s modulus of 72 and 63 GPa. Corrosion tests were performed by electrochemical experiments, and the highest pitting resistance was observed for Ti40Zr10Cu32Pd14Sn4 (pitting overpotential ηpit = 446 mV) compared to Ti40Zr10Cu32Pd14Ga4 (379 mV) and Ti40Zr10Cu36Pd14 (183 mV). The results of live/dead assay and cell viability revealed excellent biocompatibility for the Ga-containing BMGs.
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Jan 2023
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