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14,078 items found (0 items not approved), displaying 51 to 60.[First/Prev] 2, 3, 4, 5, 6, 7, 8, 9 [Next/Last]

Instruments / Technical Area	Publication Details	Published
B22-Multimode InfraRed imaging And Microspectroscopy	Insights into methanol-to-hydrocarbon catalysis over ZSM-5 and SAPO-34 from operando synchrotron infrared microspectroscopy Ivalina B. Minova , Santhosh K. Matam , Mark D. Frogley , Gianfelice Cinque , Richard Catlow , Paul A. Wright , Russell F. Howe DOI: 10.1142/9781800612013_0011	Mar 2023
B23-Circular Dichroism	Mueller matrix polarimetry on cyanine dye J-aggregates Samuel R. Clowes , Dora M. Răsădean , Tiberiu-M. Gianga , Tamas Javorfi , Rohanah Hussain , Giuliano Siligardi , G. Dan Pantos Molecules 28 DOI: 10.3390/molecules28041523 Diamond Proposal Number(s): [29075, 31797] Open Access Show Abstract ▼ Abstract: Cyanine dyes are known to form H- and J-aggregates in aqueous solutions. Here we show that the cyanine dye, S0271, assembles in water into vortex induced chiral J-aggregates. The chirality of the J-aggregates depends on the directionality of the vortex. This study utilised both conventional benchtop CD spectropolarimeters and Mueller matrix polarimetry. It was found that J-aggregates have real chirality alongside linear dichroism and linear and circular birefringence. We identify the factors that are key to the formation of metastable chiral J-aggregates and propose a mechanism for their assembly.	Feb 2023
B16-Test Beamline	Determining the critical fracture stress of Al dendrites near the melting point via synchrotron X-ray imaging Ling Qin , Zhiguo Zhang , Baisong Guo , Wei Li , Jiawei Mi Acta Metallurgica Sinica (english Letters) 121 DOI: 10.1007/s40195-023-01531-w Diamond Proposal Number(s): [7440] Show Abstract ▼ Abstract: Dendrites are the most common microstructural features in the cast metals, significantly affecting the structure integrity and mechanical properties of the castings. In this study, the in situ synchrotron X-ray radiographic and tomographic imaging techniques were combined to evaluate the critical fracture stress of the growing dendrite tip during the solidification of an Al-15 wt% Cu alloy under an external electromagnetic force. Two dendritic 3D models have been proposed to simulate the dendrite 3D morphologic characteristics and thus revealed that the critical fracture stresses of the Al dendrites at temperatures close to its melting point were in the range of 0.5 kPa–0.05 MPa. The present results demonstrate the feasibility of measuring the high-temperature mechanical properties of the metallic dendrites.	Feb 2023
I21-Resonant Inelastic X-ray Scattering (RIXS)	Resonant inelastic x-ray scattering from U3O8 and UN Eleanor Lawrence Bright , Lei Xu , Lottie Harding , Ross Springell , Andrew Walters , Martin Sundermann , Mirian Garcia-Fernandez , Stefano Agrestini , Roberto Caciuffo , Gerrit Van Der Laan , Gerry H. Lander Journal Of Physics: Condensed Matter DOI: 10.1088/1361-648X/acb8f4 Diamond Proposal Number(s): [29274] Show Abstract ▼ Abstract: Resonant inelastic x-ray scattering (RIXS) using an incident energy tuned to the uranium N4,5 absorption edges is reported from epitaxial films of α-U3O8 and UN. Theory shows that for U3O8 the multiplets associated with a 5f1 configuration with a ground state of 2F5/2 and the excited state of 2F7/2 are observed. However, the strong transition predicted at a transfer energy of 1.67 eV is not observed. We assume this is a consequence of the intermediate state lifetime broadening due to interaction with continuum states when the transferred energy exceeds the onset of the continuum in the presence of the core hole. This hypothesis is supported by the results obtained for the 5f-itinerant system UN, where no sharp transitions have been observed, although the broad scattering response centered at ∼ 1 eV is considered a signature of a predominantly 5f3 configuration in this band-like semi-metallic system. These experiments and theory add important information on these materials, both of which have been investigated since the 1960s, as well as whether RIXS at the uranium N edge can become a valuable tool for actinide research.	Feb 2023
I04-Macromolecular Crystallography	Structural and biochemical analysis of human inositol monophosphatase-1 inhibition by ebselen Areej Abuhammad , Nicola Laurieri , Alistair Rice , Edward D. Lowe , Nisha Singh , Saleem M. Naser , Samer S. Ratrout , Grant C. Churchill Journal Of Biomolecular Structure And Dynamics 37, 1 - 13 DOI: 10.1080/07391102.2023.2176925 Show Abstract ▼ Abstract: Bipolar disorder is a major psychiatric disorder associated with cognitive impairment and a high suicide rate. Frontline therapy for this condition includes lithium (Li+)-containing treatments that can exert severe side effects. One target of Li+ is inositol monophosphatase-1 (IMPase1); inhibition of IMPase1 through small-molecule compounds may provide an alternative treatment for bipolar disorder. One such compound is the anti-inflammatory drug ebselen, which is well tolerated and safe; however, ebselen’s exact mechanism of action in IMPase1 inhibition is not fully understood, preventing rational design of IMPase1 inhibitors. To fill this gap, we performed crystallographic and biochemical studies to investigate how ebselen inhibits IMPase1. We obtained a structure of IMPase1 in space group P21 after treatment with ebselen that revealed three key active-site loops (residues 33–44, 70–79, and 161–165) that are either disordered or in multiple conformations, supporting a hypothesis whereby dynamic conformational changes may be important for catalysis and ebselen inhibition. Using the thermal shift assay, we confirmed that ebselen significantly destabilizes the enzyme. Molecular docking suggests that ebselen could bind in the vicinity of His217. Investigation of the role of IMPase1 residues His217 and Cys218 suggests that inhibition of IMPase1 by ebselen may not be mediated via covalent modification of the active-site cysteine (Cys218) and is not affected by the covalent modification of other cysteine residues in the structure. Our results suggest that effects previously ascribed to ebselen-dependent inhibition likely result from disruption of essential active-site architecture, preventing activation of the IMPase1–Mg2+ complex.	Feb 2023
I04-Macromolecular Crystallography	An unusual disulfide-linked dimerization in the fluorescent protein rsCherryRev1.4 Thi Yen Hang Bui , Peter Dedecker , Luc Van Meervelt Acta Crystallographica Section F Structural Biology Communications 79, 38 - 44 DOI: 10.1107/S2053230X23000572 Diamond Proposal Number(s): [19190] Show Abstract ▼ Abstract: rsCherryRev1.4 has been reported as one of the reversibly photoswitchable variants of mCherry, and is an improved version with a faster off-switching speed and lower switching fatigue at high light intensities than its precursor rsCherryRev. However, rsCherryRev1.4 still has some limitations such as a tendency to dimerize as well as complex photophysical properties. Here, the crystal structure of rsCherryRev1.4 was determined at a resolution of 2 Å and it was discovered that it forms a dimer that shows disulfide bonding between the protomers. Mutagenesis, gel electrophoresis and size-exclusion chromatography strongly implicate Cys24 in this process. Replacing Cys24 in rsCherryRev1.4 resulted in a much lower tendency towards dimerization, while introducing Cys24 into mCherry correspondingly increased its dimerization. In principle, this finding opens the possibility of developing redox sensors based on controlled dimerization via disulfide cross-linking in fluorescent proteins, even though the actual application of engineering such sensors still requires additional research.	Feb 2023
Krios II-Titan Krios II at Diamond Krios III-Titan Krios III at Diamond Krios IV-Titan Krios IV at Diamond	Structural basis for membrane attack complex inhibition by CD59 Emma C. Couves , Scott Gardner , Tomas B. Voisin , Jasmine K. Bickel , Phillip J. Stansfeld , Edward W. Tate , Doryen Bubeck Nature Communications 14 DOI: 10.1038/s41467-023-36441-z Diamond Proposal Number(s): [25127] Open Access Show Abstract ▼ Abstract: CD59 is an abundant immuno-regulatory receptor that protects human cells from damage during complement activation. Here we show how the receptor binds complement proteins C8 and C9 at the membrane to prevent insertion and polymerization of membrane attack complex (MAC) pores. We present cryo-electron microscopy structures of two inhibited MAC precursors known as C5b8 and C5b9. We discover that in both complexes, CD59 binds the pore-forming β-hairpins of C8 to form an intermolecular β-sheet that prevents membrane perforation. While bound to C8, CD59 deflects the cascading C9 β-hairpins, rerouting their trajectory into the membrane. Preventing insertion of C9 restricts structural transitions of subsequent monomers and indirectly halts MAC polymerization. We combine our structural data with cellular assays and molecular dynamics simulations to explain how the membrane environment impacts the dual roles of CD59 in controlling pore formation of MAC, and as a target of bacterial virulence factors which hijack CD59 to lyse human cells.	Feb 2023
I12-JEEP: Joint Engineering, Environmental and Processing	Functional fatigue during superelastic load cycling of Ti2448 (Ti-24Nb-4Zr-8Sn, wt%) N. I. Church , C. E. P. Talbot , L. D. Connor , S. Michalik , N. G. Jones Materialia 214 DOI: 10.1016/j.mtla.2023.101719 Diamond Proposal Number(s): [30411] Show Abstract ▼ Abstract: Superelastic alloys based on Ti-Nb have potential in the aerospace sector for vibration damping applications, due to their wide mechanical hysteresis and tuneable properties. However, their uptake is currently limited by functional fatigue, whereby a degradation in properties is seen on cyclic loading. To understand the mechanisms that underpin this change in behaviour, a combination of ex situ and in situ testing was used to characterise the evolution of the mechanical response in a commercial Ti-Nb based alloy. It was found that the behaviour of these materials changes via a two-step mechanism, driven by the accumulation of transformation related defects and their associated stress fields. This understanding rationalises many discrepancies within the literature and highlights how the overall shape of the load response of these alloys is dominated by changes occurring only in specific regions of the material.	Feb 2023
I04-1-Macromolecular Crystallography (fixed wavelength)	Concentration‐dependent inhibition of mesophilic PETases on poly(ethylene terephthalate) can be eliminated by enzyme engineering Luisana Avilan , Bruce R. Lichtenstein , Gerhard Koenig , Michael Zahn , Mark D. Allen , Liliana Oliveira , Matilda Clark , Victoria Bemmer , Rosie Graham , Harry P. Austin , Graham Dominick , Christopher W. Johnson , Gregg T. Beckham , John Mcgeehan , Andrew R. Pickford Chemsuschem DOI: 10.1002/cssc.202202277 Diamond Proposal Number(s): [17212] Show Abstract ▼ Abstract: Enzyme-based depolymerization is a viable approach for recycling of poly(ethylene terephthalate) (PET). PETase from Ideonella sakaiensis (IsPETase) is capable of PET hydrolysis under mild conditions but suffers from concentration-dependent inhibition. Here, we report that this inhibition is dependent on incubation time, the solution conditions and PET surface area. Furthermore, this inhibition is evident in other mesophilic PET-degrading enzymes to varying degrees, independent of the level of PET depolymerization activity. The inhibition has no clear structural basis, but moderately thermostable IsPETase variants exhibit reduced inhibition, and the property is completely absent in the highly thermostable HotPETase, previously engineered by directed evolution, which our simulations suggest results from reduced flexibility around the active site. This work highlights a limitation in applying natural mesophilic hydrolases for PET hydrolysis, and reveals an unexpected positive outcome of engineering these enzymes for enhanced thermostability.	Feb 2023
I15-Extreme Conditions	Relating microstructure to magnetocaloric properties in RE36Tb20Co20Al24 (RE = Gd, Dy or Ho) high-entropy metallic-glass microwires designed by binary eutectic clusters method Hangboce Yin , Jun-Qiang Wang , Yongjiang Huang , Hongxian Shen , Shu Guo , Hongbo Fan , Juntao Huo , Jianfei Sun Journal Of Materials Science & Technology 92 DOI: 10.1016/j.jmst.2022.12.008 Diamond Proposal Number(s): [17412] Show Abstract ▼ Abstract: The new high-entropy metallic glasses (HE-MGs) are designed by using Dy and Ho to replace Gd in Gd36Tb20Co20Al24 alloy based on the binary eutectic clusters method. Compared with the equiatomic Gd25Tb25Co25Al25 HE-MG, the non-equiatomic RE36Tb20Co20Al24 (RE = Gd, Dy, or Ho) alloys show better glass-forming ability, which is attributed to the deep binary eutectic compositions used for alloy design. All RE36Tb20Co20Al24 alloys undergo second-order magnetic transition. An extreme peak value of magnetic entropy change is obtained as 10.3 J kg–1 K–1 (5 T) for the Ho36Tb20Co20Al24 alloy. In-situ high-energy synchrotron X-ray diffraction was conducted to observe the microstructural difference among non-equiatomic samples at cryogenic temperatures. The results indicate that Gd36Tb20Co20Al24 alloy possesses a relatively large average value of the dispersion of local clusters at a low-temperature range. This, combined with the critical exponent β close to 0.5 of Gd36Tb20Co20Al24 alloy, leads to its widest working temperature span among non-equiatomic samples. This work successfully establishes the connection between microstructure and magnetocaloric properties of HE-MGs, which is beneficial for understanding the physical mechanism of the magnetocaloric behaviors of HE-MGs.	Feb 2023

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