I22-Small angle scattering & Diffraction
|
Diamond Proposal Number(s):
[22909]
Open Access
Abstract: The discovery and development of new adhesive materials is critical for real-world applications of polymeric composite materials. Herein, we report the design and synthesis of a library of structurally related phase-separated supramolecular polyurethanes whose mechanical properties and adhesive characteristics can be enhanced through minor structural modifications of the polymer end-group. The interplay between phase separation of the hard domain polar end-groups and soft polybutadiene domains, coupled with tuneable self-assembly afforded by the polar end-groups, gives rise to a class of materials with tuneable mechanical properties. Exceptionally strong supramolecular adhesives and mechanically robust self-healing elastomers were identified. The mechanical properties were investigated through tensile testing. Finally, rheological analysis of the supramolecular materials was used to identify suitable healing and adhesive temperatures in addition to elucidate the supramolecular polyurethanes' thermal-responsive nature.
|
Dec 2022
|
|
I18-Microfocus Spectroscopy
|
Diamond Proposal Number(s):
[23705]
Abstract: Background: Contrast agents (CA) are administered in magnetic resonance imaging (MRI) clinical exams to measure tissue perfusion, enhance image contrast between adjacent tissues, or provide additional biochemical information in molecular MRI. The efficacy of a CA is determined by the tissue distribution of the agent and its concentration in the extracellular space of all tissues. Methods: In this work, micro-synchrotron radiation x-ray fluorescence (µ-SRXRF) was used to examine and characterize a gadolinium-based zinc-sensitive agent (GdL2) currently under development for detection of prostate cancer (PCa) by MRI. Prostate tissue samples were collected from control mice and mice with known PCa after an MRI exam that included injection of GdL2. The samples were raster scanned to investigate trends in Zn, Gd, Cu, Fe, S, P, and Ca. Results: Significant Zn and Gd co-localization was observed in both healthy and malignant tissues. In addition, a marked decrease in Zn was found in the lateral lobe of the prostate obtained from mice with PCa. Conclusion: We demonstrate here that µ-SRXRF is a useful tool for monitoring the distribution of several elements including Zn and Gd in animal models of cancer. The optimized procedures for tissue preparation, processing, data collection, and analysis are described.
|
Dec 2022
|
|
I20-EDE-Energy Dispersive EXAFS (EDE)
|
Diamond Proposal Number(s):
[23645]
Abstract: An integrated carbon capture and utilization (ICCU) process present an ideal solution to address anthropogenic carbon dioxide (CO2) emissions from fossil fuel-driven electricity production, allowing for capturing and subsequent utilization of CO2 instead of current release into the atmosphere. Effective dual-functional materials (DFMs), through the combination of CO2 sorbents and catalysts, can not only capture CO2 but also convert it into higher-value chemicals, such as CH4 or CO, under isothermal conditions within a single reactor are highly desirable for ICCU processes. In this study, we investigate the mechanism of ICCU over 10 %NiCaO by the time-resolved operando XAS/DRIFTS/MS and the influence of a reduction pretreatment on the process and the products formed. During the 1st stage of the ICCU process (carbon capture), CaO adsorbs CO2 resulting in bicarbonate, carbonate, and formate species formation. At the same time, the Ni catalytic active species are oxidized by CO2, leading to the formation of NiO and CO. However, pre-treating the same DFM under hydrogen, during heating to operating temperature, resulted in a switch to CH4 production, suggesting the presence of high levels of surface adsorbed H2. During the 2nd stage of ICCU (CO2 conversion), the NiO generated during capture is reduced by H2 to metallic Ni, which facilitates the reduction of bicarbonates, carbonates, and formats, via H2 dissociation, to produce and liberate gaseous CO. Thus, both adsorption and catalytic sites are regenerated for the subsequent ICCU cycle.
|
Oct 2022
|
|
B21-High Throughput SAXS
|
Diamond Proposal Number(s):
[22113]
Abstract: This study aims to understand possible effects of flavour compounds on the structure and conformation of endogenous proteins. Using methyl anthranilate (a grape flavour compound added to drinks, confectionery, and vape-liquids) and bovine serum albumin (BSA, a model serum protein) we designed experimental investigations using analytical ultracentrifugation, size exclusion chromatography small angle X-ray scattering, and fluorescence spectroscopy to reveal that methyl anthranilate spontaneously binds to BSA (ΔG°, ca. −21 KJ mol−1) which induces a conformational compactness (ca. 10 %) in the monomer structure. Complementary molecular modelling and dynamics simulations suggested the binding occurs at Sudlow II of BSA via establishment of hydrogen bonds with arginine409, lysine413 and serine488 leading to an increased conformational order in domains IA, IIB and IIIB. This work aims to set the foundation for future research on flavour-protein interactions and offer new sets of opportunities for understanding the effects of small compounds on protein structure.
|
Sep 2022
|
|
I03-Macromolecular Crystallography
|
Diamond Proposal Number(s):
[20303]
Abstract: The global HIV/AIDS epidemic still currently affects approximately 38 million individuals globally. The protease enzyme of the human immunodeficiency virus is a major drug target in antiviral therapy, however, under the influence of reverse transcriptase and in the context of drug pressure, the rapid PR mutation rate contributes significantly to clinical failure. The set of cooperative non-active site mutations, I13V/I62V/V77I, have been associated with reduced inhibitor susceptibility and are the focus of the current study. When compared to the wild-type protease the mutant protease exhibited decreased binding affinities towards ATV and DRV by 64- and 12-fold, respectively, and decreased the overall favourable Gibbs free energy for ATV, DRV, RTV and SQV. Moreover, these mutations decreased the thermal stability of the protease when in complex with ATV and DRV by approximately 6.4 and 4.2 °C, respectively. The crystal structure of the mutant protease revealed that the location of these mutations and their effect on the hydrophobic sliding mechanism may be crucial in their role in resistance.
|
Sep 2022
|
|
|
|
Abstract: Manufacturing austenitic stainless steels (ASSs) using additive manufacturing is of great interest for cryogenic applications. Here, the mechanical and microstructural responses of a 316L ASS built by laser powder bed fusion were revealed by performing in situ neutron diffraction tensile tests at the low-temperature range (from 373 to 10 K). The stacking fault energy almost linearly decreased from 29.2 ± 3.1 mJm−2 at 373 K to 7.5 ± 1.7 mJm−2 at 10 K, with a slope of 0.06 mJm−2K−1, leading to the transition of the dominant deformation mechanism from strain-induced twinning to martensite formation. As a result, excellent combinations of strength and ductility were achieved at the low-temperature range.
|
Sep 2022
|
|
I24-Microfocus Macromolecular Crystallography
|
Tadeo
Moreno-Chicano
,
Leiah M.
Carey
,
Danny
Axford
,
John H.
Beale
,
R. Bruce
Doak
,
Helen M. E.
Duyvesteyn
,
Ali
Ebrahim
,
Robert W.
Henning
,
Diana C. F.
Monteiro
,
Dean A.
Myles
,
Shigeki
Owada
,
Darren A.
Sherrell
,
Megan L.
Straw
,
Vukica
Šrajer
,
Hiroshi
Sugimoto
,
Kensuke
Tono
,
Takehiko
Tosha
,
Ivo
Tews
,
Martin
Trebbin
,
Richard W.
Strange
,
Kevin L.
Weiss
,
Jonathan A. R.
Worrall
,
Flora
Meilleur
,
Robin L.
Owen
,
Reza A.
Ghiladi
,
Michael A.
Hough
Diamond Proposal Number(s):
[14493]
Open Access
Abstract: Room-temperature macromolecular crystallography allows protein structures to be determined under close-to-physiological conditions, permits dynamic freedom in protein motions and enables time-resolved studies. In the case of metalloenzymes that are highly sensitive to radiation damage, such room-temperature experiments can present challenges, including increased rates of X-ray reduction of metal centres and site-specific radiation-damage artefacts, as well as in devising appropriate sample-delivery and data-collection methods. It can also be problematic to compare structures measured using different crystal sizes and light sources. In this study, structures of a multifunctional globin, dehaloperoxidase B (DHP-B), obtained using several methods of room-temperature crystallographic structure determination are described and compared. Here, data were measured from large single crystals and multiple microcrystals using neutrons, X-ray free-electron laser pulses, monochromatic synchrotron radiation and polychromatic (Laue) radiation light sources. These approaches span a range of 18 orders of magnitude in measurement time per diffraction pattern and four orders of magnitude in crystal volume. The first room-temperature neutron structures of DHP-B are also presented, allowing the explicit identification of the hydrogen positions. The neutron data proved to be complementary to the serial femtosecond crystallography data, with both methods providing structures free of the effects of X-ray radiation damage when compared with standard cryo-crystallography. Comparison of these room-temperature methods demonstrated the large differences in sample requirements, data-collection time and the potential for radiation damage between them. With regard to the structure and function of DHP-B, despite the results being partly limited by differences in the underlying structures, new information was gained on the protonation states of active-site residues which may guide future studies of DHP-B.
|
Sep 2022
|
|
|
|
Abstract: This work outlines the development of a workflow that combines both informed and data-driven approaches to process and classify 4D-STEM data utilising signal dimensionality reduction obtained from unsupervised machine learning algorithms. Using these ‘latent space’ representations of the scanned region, we can then apply clustering algorithms to identify regions of similar character. By combining the results of multiple autonomous computations, we would be able to map domains within the crystal and associate a level of confidence to given classifications. This confidence is then used to iteratively improve the learning algorithms and the performance of their dimensionality reduction. Incorporating this as a pre-processing unsupervised workflow would drastically improve the ability to characterise the nano-scale structure of materials, both through production of significantly signal-boosted diffraction data and reduction in laborious manual investigation.
|
Aug 2022
|
|
E02-JEM ARM 300CF
|
Diamond Proposal Number(s):
[28449]
Abstract: Catalysis happens only at the surface of materials, this makes nanoparticles of particular interest in the field of catalysis because of their high surface-to-volume ratio. The exact atomic structure of nanoparticle surfaces is of particular importance in catalysis, and the expression of surface facets is largely governed by their overall structure. Typically, small metal nanoparticles will take one of three major structural isomers: decahedron, icosahedron or cuboctahedron. Determination of the structural isomer of a nanoparticle can be performed using high-angle annular dark field (HAADF) scanning transmission electron microscopy (STEM). In this study, we are investigating size-selected gas-condensation magnetron sputtered clusters. In particular, we are interested in so-called “magic number” nanoparticles, which have a complete closed outer “shell” of atoms. Previous studies have attempted to manually count the number of each structural isomer, to calculate the relative abundance of each structure and therefore determine their relative potential energies. This is of interest to understand the magnetron conditions required to make specific surface facets for catalytic applications.
|
Aug 2022
|
|
|
|
Nigel D.
Browning
,
William
Bryan
,
James
Clarke
,
Michael
Ellis
,
Angus I.
Kirkland
,
Simon
Maskell
,
Julian
Mckenzie
,
B. Layla
Mehdi
,
R. J. Dwayne
Miller
,
Yoshie
Murooka
,
Timothy C. Q.
Noakes
,
Ian
Robinson
,
Sven L. M.
Schroeder
,
Jasper
Van Thor
,
Carsten
Welsch
Abstract: Transformative innovations in the science and technology of personalized medicine, energy storage, and clean growth start from achieving atomic and molecular understanding, and then control, of the fundamental (bio)-chemical interactions that determine each process. To generate the required level of understanding and control, the UK is currently investing in the design of a new national facility centered on the unique measurement capabilities offered by relativistic ultrafast electron diffraction and imaging (RUEDI). The underlying science and technology for RUEDI – ultrafast measurements and electron diffraction/imaging - are areas where John Spence made seminal contributions over the course of his career, and his work in these areas continues to guide the development of the science program for this new facility. Should RUEDI be successful in its goals, it will permit the direct observation of atomic/electronic motions directing the very chemistry we must control for the advances listed above.
|
Aug 2022
|
|
