I22-Small angle scattering & Diffraction
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Kiranjit K.
Bains
,
James
Bell
,
Robert D.
Young
,
Qian
Ma
,
Sally
Hayes
,
Laura
Howard
,
Olga
Shebanova
,
Nick J.
Terrill
,
Keith M.
Meek
,
Justyn W.
Regini
,
Andrew J.
Quantock
Diamond Proposal Number(s):
[34903, 40168]
Open Access
Abstract: Purpose: To study the structural arrangement of crystallin proteins in the human lens during development.
Methods: Fetal human lenses were acquired from the UK Human Developmental Biology Resource and examined at four developmental stages; postconception weeks (pcw) 8 to 9 (n = 5), 12 to 13 (n = 3), 16 to 17 (n = 6), and 20 to 21 (n = 3). Small-angle X-ray scattering patterns were obtained as raster scans across the entirety of each lens using a 0.1 nm-wavelength, synchrotron X-ray beam measuring 200 × 150 µm at the specimen. Analysis of each small-angle X-ray scattering pattern provided a measure of the average nearest neighbor spacing and the extent of spatial order in the crystallin protein array.
Results: Crystallins in the lens center became compacted as development progressed, with the average spacing measuring 19.9 nm at 8 to 9 pcw, 19.6 nm at 12 to 13 pcw, 18.7 nm at 16 to 17 pcw, and 17.7 nm at 20 to 21 pcw. The spatial order of the crystallin proteins in the lens center also decreased with time as indicated by a parameter called the coherence distance, which measured 26.9 nm at 8 to 9 pcw, 24.7 nm at 12 to 13 pcw, 24.6 nm at 16 to 17 pcw, and 24.9 nm at 20 to 21 pcw. Spacing and spatial order were consistently higher at the lens periphery, compared with the center, at all developmental stages studied.
Conclusions: Spatiotemporal modifications in the array of crystallin proteins occur as the human lens develops. These are perhaps reflective of a shift in the relative proportions of crystallin subtypes present and have potential implications for the lens's developing refractive index.
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Jan 2026
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I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[35981]
Open Access
Abstract: The mechanism of nanoparticle formation during reverse sequence polymerization-induced self-assembly (PISA) is studied by small-angle X-ray scattering (SAXS). More specifically, N,N′-dimethylacrylamide (DMAC) monomer is added to a trithiocarbonate-capped poly(ɛ-caprolactone) (PCL) precursor and initially polymerized in the bulk at 80 °C via reversible addition-fragmentation chain transfer (RAFT) polymerization. SAXS indicates the unexpected formation of molten PCL droplets dispersed within DMAC monomer. After 5 min (14% DMAC conversion) at 80 °C, the reaction mixture is diluted with water, and the aqueous milieu is analyzed using a flow cell. A transient lamellar phase is formed immediately after water addition that subsequently transforms into nascent spherical nanoparticles. During the remaining DMAC polymerization, the overall nanoparticle diameter remains essentially constant with a concomitant reduction in the PCL core radius and the aggregation number. This suggests that individual PCL-PDMAC chains are in equilibrium with the nanoparticles. SAXS analysis indicates that the amorphous PCL cores have a mean diameter of 8.8 nm at 80 °C: X-ray diffraction (XRD) studies confirm that such nanoscale confinement prevents their crystallization on cooling to 20 °C. Finally, this formulation can be combined with crystallization-driven self-assembly (CDSA): UV-initiated DMAC polymerization at 15 °C produces rod-like PCL-PDMAC nanoparticles with semicrystalline PCL cores.
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Nov 2025
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I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[34903]
Open Access
Abstract: Introduction: The mechanisms underpinning the stiffening and stabilising effect of riboflavin/UVA crosslinking on the corneal stroma are not well understood. We report the findings of a biomechanics and synchrotron X-ray scattering study aimed at quantifying hierarchical strain mechanisms in treated and untreated porcine corneas. We applied the same approach to specimens treated with human recombinant decorin core protein, in isolation and in conjunction with riboflavin/UVA.
Methods: Tensile testing was carried out in conjunction with simultaneous synchrotron X-ray scattering. Diffraction peaks associated with the interfibrillar spacing and D-period of collagen were fit to bespoke models to quantify fibril elongation and reorientation under load.
Results: Riboflavin/UVA crosslinking stiffened corneas by approximately 60% while decorin treatment did not significantly affect the mechanical properties. Correlations between fibril elongation caused by applied tensile strain and bulk stiffness were used to approximate fibril stiffness, values for which were relatively similar for control and treatment groups, compared with the magnitude of difference in the bulk stiffness alone.
Discussion: The results imply the bulk stiffening caused by crosslinking was not primarily due to increases in fibril stiffness. Instead, trends in bulk fibril reorientation and straightening/uncrimping imply the stiffening is attributable to enhanced interconnectivity of the fibrillar stroma, leading to greater fibril recruitment fraction. The techniques reported here are applicable to a wide range of tissues for the evaluation of new, existing and adjuvant therapies.
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Sep 2025
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I22-Small angle scattering & Diffraction
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Qian
Ma
,
Andri K.
Riau
,
Robert D.
Young
,
James S.
Bell
,
Olga
Shebanova
,
Nicholas J.
Terrill
,
Gary H. F.
Yam
,
Evelina
Han
,
Keith M.
Meek
,
Jodhbir S.
Mehta
,
Craig
Boote
Diamond Proposal Number(s):
[23514, 28285, 29862, 34903]
Open Access
Abstract: Purpose: Donor tissue shortfalls and postsurgical complications are driving novel corneal tissue regeneration approaches. Corneal stromal keratocytes (CSKs) have shown promise in promoting corneal repair and restoring transparency. We investigated the impact of intrastromal CSK injection on corneal ultrastructure and proteoglycan (PG) distribution in a rat injury model.
Methods: Rats were divided into four groups: normal (n = 12), injured (irregular phototherapeutic keratectomy centrally; n = 6), CSK (injured + human CSK intrastromal injection; n = 6), and PBS (injured + PBS injection; n = 6). Three weeks after treatment, corneas were examined by slit-lamp and optical coherence tomography. Corneal ultrastructure was analysed via small-angle x-ray scattering (collagen fibril diameter, interfibrillar spacing and matrix order), transmission electron microscopy with cuprolinic blue before and after chondroitinase digestion (CS/DS and KS PGs), and immunofluorescence staining (lumican and decorin).
Results: Irregular phototherapeutic keratectomy caused corneal opacity and significantly disrupted stromal ultrastructure, characterized by increased haze density (P < 0.0001), change in central corneal thickness (P = 0.0005), and interfibrillar spacing (P < 0.0001), along with decreased fibril diameter (P < 0.0001), matrix order (P < 0.0001), CS/DS (P < 0.0001) and KS (P < 0.0001) PGs, lumican, and decorin. CSK injection recovered corneal clarity and native stromal ultrastructure, with haze density (P = 0.8086), change in central corneal thickness (P = 0.9503), fibril diameter (P = 0.1139), interfibrillar spacing (P = 0.5879), matrix order (P = 0.9999), CS/DS (P = 0.9969) and KS (P = 0.2877) PGs, lumican, and decorin returning to normal. In contrast, the PBS group exhibited similar corneal injury responses to the injured group.
Conclusions: CSK injection resolved early stage corneal scarring by restoring stromal collagen arrangement and PG distribution, further endorsing its potential for treating corneal opacities.
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Feb 2025
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I22-Small angle scattering & Diffraction
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Adelaide
Lerebours
,
Justyn
Regini
,
Roy A.
Quinlan
,
Toshihiro
Wada
,
Barbara
Pierscionek
,
Martin
Devonshire
,
Alexia A.
Kalligeraki
,
Alice
Uwineza
,
Laura
Young
,
John M.
Girkin
,
Phil
Warwick
,
Kurt
Smith
,
Masato
Hoshino
,
Kentaro
Uesugi
,
Naoto
Yagi
,
Nick
Terrill
,
Olga
Shebanova
,
Tim
Snow
,
Jim T.
Smith
Diamond Proposal Number(s):
[17075]
Open Access
Abstract: Recent studies apparently finding deleterious effects of radiation exposure on cataract formation in birds and voles living near Chernobyl represent a major challenge to current radiation protection regulations. This study conducted an integrated assessment of radiation exposure on cataractogenesis using the most advanced technologies available to assess the cataract status of lenses extracted from fish caught at both Chernobyl in Ukraine and Fukushima in Japan. It was hypothesised that these novel data would reveal positive correlations between radiation dose and early indicators of cataract formation.
The structure, function and optical properties of lenses were analysed from atomic to millimetre length scales. We measured the short-range order of the lens crystallin proteins using Small Angle X-Ray Scattering (SAXS) at both the SPring-8 and DIAMOND synchrotrons, the profile of the graded refractive index generated by these proteins, the epithelial cell density and organisation and finally the focal length of each lens.
The results showed no evidence of a difference between the focal length, the epithelial cell densities, the refractive indices, the interference functions and the short-range order of crystallin proteins (X-ray diffraction patterns) in lens from fish exposed to different radiation doses. It could be argued that animals in the natural environment which developed cataract would be more likely, for example, to suffer predation leading to survivor bias. But the cross-length scale study presented here, by evaluating small scale molecular and cellular changes in the lens (pre-cataract formation) significantly mitigates against this issue.
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Aug 2023
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I22-Small angle scattering & Diffraction
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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.
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Dec 2022
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I02-Macromolecular Crystallography
I03-Macromolecular Crystallography
I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[11316, 8458]
Open Access
Abstract: The mechanical properties of connective tissues are tailored to their specific function, and changes can lead to dysfunction and pathology. In most mammalian tissues the mechanical environment is governed by the micro- and nano-scale structure of collagen and its interaction with other tissue components, however these hierarchical properties remain poorly understood. In this study we use the human cornea as a model system to characterise and quantify the dominant deformation mechanisms of connective tissue in response to cyclic loads of physiological magnitude. Synchronised biomechanical testing, x-ray scattering and 3D digital image correlation revealed the presence of two dominant mechanisms: collagen fibril elongation due to a largely elastic, spring-like straightening of tropocollagen supramolecular twist, and a more viscous straightening of fibril crimp that gradually increased over successive loading cycles. The distinct mechanical properties of the two mechanisms suggest they have separate roles in vivo. The elastic, spring-like mechanism is fast-acting and likely responds to stresses associated with the cardiac cycle, while the more viscous crimp mechanism will respond to slower processes, such as postural stresses. It is anticipated that these findings will have broad applicability to understanding the normal and pathological functioning of other connective tissues such as skin and blood vessels that exhibit both helical structures and crimp.
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Jan 2022
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I22-Small angle scattering & Diffraction
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Andrew
Smith
,
S. G.
Alcock
,
L. S.
Davidson
,
J. H.
Emmins
,
J. C.
Hiller Bardsley
,
P.
Holloway
,
M.
Malfois
,
A. R.
Marshall
,
C. L.
Pizzey
,
S. E.
Rogers
,
O.
Shebanova
,
T.
Snow
,
J. P.
Sutter
,
E. P.
Williams
,
N. J.
Terrill
Open Access
Abstract: Beamline I22 at Diamond Light Source is dedicated to the study of soft-matter systems from both biological and materials science. The beamline can operate in the range 3.7 keV to 22 keV for transmission SAXS and 14 keV to 20 keV for microfocus SAXS with beam sizes of 240 µm × 60 µm [full width half-maximum (FWHM) horizontal (H) × vertical (V)] at the sample for the main beamline, and approximately 10 µm × 10 µm for the dedicated microfocusing platform. There is a versatile sample platform for accommodating a range of facilities and user-developed sample environments. The high brilliance of the insertion device source on I22 allows structural investigation of materials under extreme environments (for example, fluid flow at high pressures and temperatures). I22 provides reliable access to millisecond data acquisition timescales, essential to understanding kinetic processes such as protein folding or structural evolution in polymers and colloids.
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May 2021
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I22-Small angle scattering & Diffraction
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Brian R.
Pauw
,
Andrew
Smith
,
Tim
Snow
,
Olga
Shebanova
,
John P.
Sutter
,
Jan
Ilavsky
,
Daniel
Hermida-Merino
,
Glen J.
Smales
,
Nicholas J.
Terrill
,
Andreas F.
Thünemann
,
Wim
Bras
Open Access
Abstract: Ultra-SAXS can enhance the capabilities of existing synchrotron SAXS/WAXS beamlines. A compact ultra-SAXS module has been developed, which extends the measurable q-range with 0.0015 ≤ q (nm−1) ≤ 0.2, allowing structural dimensions in the range 30 ≤ D (nm) ≤ 4000 to be probed in addition to the range covered by a high-end SAXS/WAXS instrument. By shifting the module components in and out on their respective motor stages, SAXS/WAXS measurements can be easily and rapidly interleaved with USAXS measurements. The use of vertical crystal rotation axes (horizontal diffraction) greatly simplifies the construction, at minimal cost to efficiency. In this paper, the design considerations, realization and synchrotron findings are presented. Measurements of silica spheres, an alumina membrane, and a porous carbon catalyst are provided as application examples.
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May 2021
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I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[20249]
Open Access
Abstract: A detailed understanding of the local dynamics in ionic liquids remains an important aspect in the design of new ionic liquids as advanced functional fluids. Here, we use small-angle X-ray scattering and quasi-elastic neutron spectroscopy to investigate the local structure and dynamics in a model ionic liquid as a function of temperature and pressure, with a particular focus on state points (P,T) where the macroscopic dynamics, i.e., conductivity, is the same. Our results suggest that the initial step of ion transport is a confined diffusion process, on the nanosecond timescale, where the motion is restricted by a cage of nearest neighbors. This process is invariant considering timescale, geometry, and the participation ratio, at state points of constant conductivity, i.e., state points of isoconductivity. The connection to the nearest-neighbor structure is underlined by the invariance of the peak in the structure factor corresponding to nearest-neighbor correlations. At shorter timescales, picoseconds, two localized relaxation processes of the cation can be observed, which are not directly linked to ion transport. However, these processes also show invariance at isoconductivity. This points to that the overall energy landscape in ionic liquids responds in the same way to density changes and is mainly governed by the nearest-neighbor interactions.
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Mar 2021
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