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12,025 items found (0 items not approved), displaying 1 to 10.[First/Prev] 1, 2, 3, 4, 5, 6, 7, 8 [Next/Last]

Instruments / Technical Area	Publication Details	Published
I13-2-Diamond Manchester Imaging	Evaluating the morphology of the degradation layer of pure magnesium via 3D imaging at resolutions below 40 nm Berit Zeller-Plumhoff , Daniel Laipple , Hanna Slominska , Kamila Iskhakova , Elena Longo , Alexander Hermann , Silja Flenner , Imke Greving , Malte Storm , Regine Willumeit-Römer Bioactive Materials 6, 4368 - 4376 DOI: 10.1016/j.bioactmat.2021.04.009 Diamond Proposal Number(s): [22346, 21697] Open Access Show Abstract ▼ Abstract: Magnesium is attractive for the application as a temporary bone implant due to its inherent biodegradability, non-toxicity and suitable mechanical properties. The degradation process of magnesium in physiological environments is complex and is thought to be a diffusion-limited transport problem. We use a multi-scale imaging approach using micro computed tomography and transmission X-ray microscopy (TXM) at resolutions below 40 nm. Thus, we are able to evaluate the nanoporosity of the degradation layer and infer its impact on the degradation process of pure magnesium in two physiological solutions. Magnesium samples were degraded in simulated body fluid (SBF) or Dulbecco's modified Eagle's medium (DMEM) with 10% fetal bovine serum (FBS) for one to four weeks. TXM reveals the three-dimensional interconnected pore network within the degradation layer for both solutions. The pore network morphology and degradation layer composition are similar for all samples. By contrast, the degradation layer thickness in samples degraded in SBF was significantly higher and more inhomogeneous than in DMEM+10%FBS. Distinct features could be observed within the degradation layer of samples degraded in SBF, suggesting the formation of microgalvanic cells, which are not present in samples degraded in DMEM+10%FBS. The results suggest that the nanoporosity of the degradation layer and the resulting ion diffusion processes therein have a limited influence on the overall degradation process. This indicates that the influence of organic components on the dampening of the degradation rate by the suppression of microgalvanic degradation is much greater in the present study.	Dec 2021
I12-JEEP: Joint Engineering, Environmental and Processing	Preferential wheat (Triticum aestivum. L cv. Fielder) root growth in different sized aggregates Tinashe Mawodza , Manoj Menon , Harriet Brooks , Oxana V. Magdysyuk , Genoveva Burca , Stuart Casson Soil And Tillage Research 212 DOI: 10.1016/j.still.2021.105054 Diamond Proposal Number(s): [22992] Show Abstract ▼ Abstract: Soil structure is one of the most important environmental factors affecting root architectural development and consequently plant yield. Understanding how plant roots respond to soils with variable soil structure is important as it enables soil management practices that promote optimal root growth. Many contemporary, non-invasive experiments investigating how plant root architecture responds to soil structural variations have often focused on compaction, often neglecting the role of soil aggregate size in determining root configuration. To better understand this, in this study, we used non-invasive neutron and X-Ray imaging to investigate how variable aggregate size affects the early root architectural establishment in wheat plants. Sandy loam soil derived macro-aggregates of two distinct sizes (0.25−0.5 and 2−4 mm) were used to infer the suitability of each aggregate size for use in wheat seedbeds. We also grew wheat seedlings in partitioned containers with the two different aggregate size classes filled side by side to establish whether there would be preferential growth of roots in either aggregate size class. Our results showed significantly increased root growth in the smaller 0.25−0.5 mm aggregates as compared to the larger 2−4 mm aggregates. This was mainly as a result of enhanced lateral root growth when the wheat plants were grown in the finer aggregates. On the other hand, coarser aggregates induced significantly increased seminal root axes which partially offset the differences in total root length between the two aggregate sizes. Plants growing in partitioned containers similarly indicated preferential root growth in smaller aggregate with an even more pronounced difference in root growth in the smaller aggregates. As inferred from our results, seedbeds dominated by smaller macro-aggregates (finer soil tilth) may be optimal to enhance wheat seedling root growth in sandy loam soils.	Aug 2021
I13-2-Diamond Manchester Imaging	The importance of particle dispersion in electrical treeing and breakdown in nano-filled epoxy resin Siyuan Chen , Simon Rowland , James Carr , Malte Storm , Kwang-Leong Choy , Adam J. Clancy International Journal Of Electrical Power & Energy Systems 129 DOI: 10.1016/j.ijepes.2021.106838 Diamond Proposal Number(s): [18215] Show Abstract ▼ Abstract: The addition of nano-fillers has been widely proposed as a method to enhance the dielectric properties of high voltage polymeric insulation, though there are mixed reports in the literature. Here the potential of silica nano-particles to extend the time to failure specifically through resistance to electrical tree growth in epoxy resin is determined. The benefit of silane treating the nano-particles before compounding is clearly established with regard to slowing tree growth and subsequent time to failure. The growth of trees in needle-plane samples is measured in the laboratory with loadings of 1, 3 and 5 wt% nano-filler. In all cases the average times to failure are extended, but silane treatment of the nano-particles prior to compounding yields much superior results. The emergence of a pronounced inception time before tree growth is also noted for the higher-filled, silane-treated cases. The average time to failure of silane-treated 5 wt% filled material was 28 times that of the unfilled resin. The improvement in performance between the nanocomposites with untreated and treated fillers is attributed to fewer agglomerations and improved dispersion of the filler in the treated cases. Measurements of Partial Discharge (PD) indicated significant differences in PD patterns during the growth of trees in the treated and untreated cases. This distinction may provide a quality control method for monitoring materials. In particular, long periods in which PDs were not measured were observed in the silane-treated cases. Visual imaging of tree growth in the unfilled material allowed the changing nature of the tree from fine to tree to dark tree to be observed as it grew. Corresponding PD measurements suggest the dark tree is gradually becoming conductive, and that growth of maximum PD measured is dependent on the relative rates of the growth of the tree and its carbonization. X-ray computer tomography identified significant differences in average tree channel diameters (a reduction from 2.8 µm to 2.0 µm for 1 wt% and 3 wt% cases). This implies that in addition to tree length changes, evaporated tree volumes also change and may explain the change in partial discharge characteristics observed.	Jul 2021
I11-High Resolution Powder Diffraction	Size-distribution of irradiation-induced dislocation-loops in materials used in the nuclear industry Tamás Ungár , Philipp Frankel , Gábor Ribárik , Christopher P. Race , Michael Preuss Journal Of Nuclear Materials 550 DOI: 10.1016/j.jnucmat.2021.152945 Diamond Proposal Number(s): [8395, 10006] Show Abstract ▼ Abstract: Neutron or proton irradiation induced dislocation loops in Zr and its alloys are usually characterized by electron microscopy methods. In plastically deformed materials X-ray line profile analysis (XLPA) is now a well-established tool to determine dislocation densities (DDs) with excellent agreement between XLPA and TEM analysis. In irradiated zirconium alloys, however, XLPA determined DDs are often considerably larger than those obtained by TEM. In ion irradiated Cu and W it was shown that X-ray diffraction or MD simulations give significantly larger dislocation loop densities than conventional TEM analysis, which suggests that the smallest loops remain undetected by TEM. Based on these results we developed a new methodology to determine power-law size-distributions of irradiation-induced dislocation loops. We assume that only loops larger than a certain threshold are fully counted in TEM micrographs, whereas XLPA detects all the loops in the entire size range. This new analysis procedure shows that in neutron irradiated Zircaloy-2 in the channel-box materials the total DD is larger than in the cladding materials, even though TEM counting shows the opposite. We also found that there is a correlation between the reciprocal square-root of loop DDs and the diameter of loops. Our work shows that irradiation induced loop-formation and irradiation-damage in general can be better determined when we combine TEM investigations with XLPA.	Jul 2021
I03-Macromolecular Crystallography	Structural properties and peptide ligand binding of the capsid homology domains of human Arc Erik I. Hallin , Clive R. Bramham , Petri Kursula Biochemistry And Biophysics Reports 26 DOI: 10.1016/j.bbrep.2021.100975 Diamond Proposal Number(s): [13440] Open Access Show Abstract ▼ Abstract: The activity-regulated cytoskeleton-associated protein (Arc) is important for synaptic plasticity and the normal function of the brain. Arc interacts with neuronal postsynaptic proteins, but the mechanistic details of its function have not been fully established. The C-terminal domain of Arc consists of tandem domains, termed the N- and C-lobe. The N-lobe harbours a peptide binding site, able to bind multiple targets. By measuring the affinity of human Arc towards various peptides from stargazin and guanylate kinase-associated protein (GKAP), we have refined its specificity determinants. We found two sites in the GKAP repeat region that bind to Arc and confirmed these interactions by X-ray crystallography. Phosphorylation of the stargazin peptide did not affect binding affinity but caused changes in thermodynamic parameters. Comparison of the crystal structures of three high-resolution human Arc-peptide complexes identifies three conserved C–H…π interactions at the binding cavity, explaining the sequence specificity of short linear motif binding by Arc. We further characterise central residues of the Arc lobe fold, show the effects of peptide binding on protein dynamics, and identify acyl carrier proteins as structures similar to the Arc lobes. We hypothesise that Arc may affect protein-protein interactions and phase separation at the postsynaptic density, affecting protein turnover and re-modelling of the synapse. The present data on Arc structure and ligand binding will help in further deciphering these processes.	Jul 2021
I22-Small angle scattering & Diffraction	Ordered mesoporous carbons with body centred cubic pore structure F. Sakina , R. T. Baker Carbon Trends 4 DOI: 10.1016/j.cartre.2021.100051 Open Access Show Abstract ▼ Abstract: The preparation of mesoporous carbons possessing a highly ordered body centred cubic (bcc) arrangement of pores by employing a halide- and metal-free synthesis method is reported. Products were characterised using gas physisorption, Small Angle X-ray Diffraction and X-ray Scattering, Raman spectroscopy and High Resolution Transmission Electron Microscopy (TEM). The materials produced in this work had Specific Surface Areas of between 422 and 988 m2g−1 and pore diameters of around 7 nm. From the TEM images, high quality Digital Diffraction Patterns, relating to the ordered mesopore structure, were obtained. On increasing calcination temperature from 350 to 1000°C the bcc structure was retained but its dimensions decreased progressively as the mesopore structure shrank. The effects on the structure and texture of the materials of the three key parameters of polymerisation time and the concentrations of the two catalysts employed, NH4OH and oxalic acid, were studied. Shorter polymerisation times and lower catalyst concentrations gave rise to the most well-ordered products whereas longer polymerisation times with higher concentrations of base and acid catalyst resulted in disordered pore structures.	Jul 2021
I13-2-Diamond Manchester Imaging	Enhanced near-infrared absorption for laser powder bed fusion using reduced graphene oxide Chu Lun Alex Leung , Iuliia Elizarova , Mark Isaacs , Shashidhara Marathe , Eduardo Saiz , Peter D. Lee Applied Materials Today 23 DOI: 10.1016/j.apmt.2021.101009 Diamond Proposal Number(s): [19354] Open Access Show Abstract ▼ Abstract: Laser powder bed fusion (LPBF) is a revolutionary manufacturing technology that fabricates parts with unparalleled complexity, layer-by-layer. However, there are limited choices of commercial powders for LPBF, constrained partly by the laser absorbance, an area that is not well investigated. Carbon additives are commonly used to promote near infra-red (NIR) absorbance of the powders but their efficiency is limited. Here, we combine operando synchrotron X-ray imaging with chemical characterisation techniques to elucidate the role of additives on NIR absorption, melt track and defect evolution mechanisms during LPBF. We employ a reduced graphene oxide (rGO) additive to enable LPBF of low NIR absorbance powder, SiO2, under systematic build conditions. This work successfully manufactured glass tracks with a high relative density (99.6%) and overhang features (> 5 mm long) without pre/post heat treatment. Compared to conventional carbon additives, the rGO increases the powder's NIR absorbance by ca. 3 times and decreases the warpage and porosity in LPBF glass tracks. Our approach will dramatically widen the palette of materials for laser processing and enable existing LPBF machines to process low absorbance powder, such as SiO2, using a NIR beam.	Jun 2021
I22-Small angle scattering & Diffraction	Separating effects of bone-quality changes at multiple scales in steroid-induced osteoporosis: Combining multiscale experimental and modelling approaches Li Xi , Ettore Barbieri , Pan Wang , Wenwang Wu , Himadri Gupta Mechanics Of Materials 157 DOI: 10.1016/j.mechmat.2021.103821 Diamond Proposal Number(s): [9893, 11806, 12483] Show Abstract ▼ Abstract: Metabolic bone diseases have an impact on the multi-scale structure of bone and its mechanical properties. This study aims to conduct quantitative analysis of the link between specific material-level changes and mechanical alterations of bone tissue. We combine several scanning probe methods with an analytical multiscale model to investigate these links in a mouse model (𝐶𝑟h−120∕+) with endogenous steroid production. Experimental results from our prior study are used, which showed significant changes in spatial maps of nano-scale orientation, mineralization, and microporosity in 𝐶𝑟h−120∕+ mice bone. An analytical composite/continuum mechanical model is incorporated with these experimental parameters to predict the progressive reduction in elastic moduli. The largest fractional reduction in elastic modulus is found to arise from incorporation of microscale porosity, followed by the reduced nanoscale degree of orientation. Our work provides both insights into the altered structure-performance relations and a systematic analytical framework for linking scanning micro- and nanoprobe experimental data on hierarchical structural materials to macroscopic biomechanical outcomes.	Jun 2021
I03-Macromolecular Crystallography I04-Macromolecular Crystallography	The development of highly potent and selective small molecule correctors of Z α1-antitrypsin misfolding John Liddle , Andrew C. Pearce , Christopher Arico-Muendel , Svetlana Belyanskaya , Andrew Brewster , Murray Brown , Chun-Wa Chung , Alexis Denis , Nerina Dodic , Anthony Dossang , Peter Eddershaw , Diana Klimaszewska , Imran Haq , Duncan S. Holmes , Alistair Jagger , Toral Jakhria , Emilie Jigorel , Ken Lind , Jeff Messer , Margaret Neu , Allison Olszewski , Riccardo Ronzoni , James Rowedder , Martin Rüdiger , Steve Skinner , Kathrine J. Smith , Lionel Trottet , Iain Uings , Zhengrong Zhu , James A. Irving , David A. Lomas Bioorganic & Medicinal Chemistry Letters 41 DOI: 10.1016/j.bmcl.2021.127973 Diamond Proposal Number(s): [23853, 17201] Show Abstract ▼ Abstract: α1-antitrypsin deficiency is characterised by the misfolding and intracellular polymerisation of mutant α1-antitrypsin protein within the endoplasmic reticulum (ER) of hepatocytes. Small molecules that bind and stabilise Z α1-antitrypsin were identified via a DNA-encoded library screen. A subsequent structure based optimisation led to a series of highly potent, selective and cellular active α1-antitrypsin correctors.	Jun 2021
I22-Small angle scattering & Diffraction	Effects of ethylene oxide chain length on crystallization of polysorbate 80 and its related compounds Tania K. Lind , Emelie J. Nilsson , Benjamin Wyler , Dieter Scherer , Tatyana Skansberger , Maxim Morin , Vitaly Kocherbitov , Johan Engblom Journal Of Colloid And Interface Science 592, 468 - 484 DOI: 10.1016/j.jcis.2021.01.065 Diamond Proposal Number(s): [22299] Open Access Show Abstract ▼ Abstract: As a result of the synthesis protocol polyoxyethylene sorbitan monooleate (polysorbate 80, PS80) is a highly complex mixture of compounds. PS80 was therefore separated into its main constituents, e.g. polyoxyethylene isosorbide esters and polyoxyethylene esters, as well as mono- di- and polyesters using preparative high-performance liquid chromatography. In this comprehensive study the individual components and their ethoxylation level were verified by matrix assisted laser desorption/ionization time-of-flight and their thermotropic behavior was analyzed using differential scanning calorimetry and X-ray diffraction. A distinct correlation was found between the average length of the ethylene oxide (EO) chains in the headgroup and the individual compounds’ ability to crystallize. Importantly, a critical number of EO units required for crystallization of the headgroup was determined (6 EO units per chain or 24 per molecule). The investigation also revealed that the hydrocarbon tails only crystallize for polyoxyethylene sorbitan esters if saturated. PS80 is synthesized by reacting with approximately 20 mol of EO per mole of sorbitol, however, the number of EO units in the sorbitan ester in commercial PS80 products is higher than the expected 20 (5 EO units per chain). The complex behavior of all tested compounds revealed that if the amount of several of the linear by-products is reduced, the number of EO units in the chains will stay below the critical number and the product will not be able to crystallize by the EO chains.	Jun 2021

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