ORCID Profile
0000-0002-3898-8881
Current Organisation
University College London
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Aerospace Materials | Automotive Engineering Materials | Manufacturing Processes and Technologies (excl. Textiles) | Materials Engineering | Metals and Alloy Materials |
Basic Iron and Steel Products | Basic Metal Products (incl. Smelting, Rolling, Drawing and Extruding) not elsewhere classified | Basic Aluminium Products | Basic Copper Products
Publisher: SPIE
Date: 28-08-2008
DOI: 10.1117/12.795558
Publisher: Elsevier BV
Date: 02-2015
Publisher: Springer Science and Business Media LLC
Date: 10-10-2009
DOI: 10.1007/S10856-009-3888-9
Abstract: X-ray microtomography (microCT) is a popular tool for imaging scaffolds designed for tissue engineering applications. The ability of synchrotron microCT to monitor tissue response and changes in a bioactive glass scaffold ex vivo were assessed. It was possible to observe the morphology of the bone soft tissue ingrowth and the calcium distribution within the scaffold. A second aim was to use two newly developed compression rigs, one designed for use inside a laboratory based microCT machine for continual monitoring of the pore structure and crack formation and another designed for use in the synchrotron facility. Both rigs allowed imaging of the failure mechanism while obtaining stress-strain data. Failure mechanisms of the bioactive glass scaffolds were found not to follow classical predictions for the failure of brittle foams. Compression strengths were found to be 4.5-6 MPa while maintaining an interconnected pore network suitable for tissue engineering applications.
Publisher: Elsevier BV
Date: 08-2017
Publisher: Wiley
Date: 2010
DOI: 10.1111/J.1549-8719.2009.00009.X
Abstract: To quantitatively assess microvascular dimensions in the eyes of neonatal wild-type and VEGF(120)-tg mice, using a novel combination of techniques which permit three-dimensional (3D) image reconstruction. A novel combination of techniques was developed for the accurate 3D imaging of the microvasculature and demonstrated on the hyaloid vasculature of the neonatal mouse eye. Vascular corrosion casting is used to create a stable replica of the vascular network and X-ray microcomputed tomography (muCT) to obtain the 3D images. In-house computer-aided image analysis techniques were then used to perform a quantitative morphological analysis of the images. With the use of these methods, differences in the numbers of vessel segments, their diameter, and volume of vessels in the vitreous compartment were quantitated in wild-type neonatal mice or littermates over-expressing a labile (nonheparin binding) isoform of vascular endothelial growth factor (VEGF(120)) from the developing lens. This methodology was instructive in demonstrating that hyaloid vascular networks in VEGFA(120) over-expressing mice have a 10-fold increase in blind-ended, a six-fold increase in connected vessel segments, in addition to a sixfold increase (0.0314 versus 0.0051 mm(3)) in total vitreous vessel volume compared with wild type. These parameters are not readily quantified via histological, ultrastructural, or stereological analysis. The combination of techniques described here provides the first 3D quantitative characterization of vasculature in an organ system i.e., the neonatal murine intra-ocular vasculature in both wild-type mice and a transgenic model of lens-specific over-expression of VEGF.
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.ACTBIO.2013.07.014
Abstract: Bioactive glass scaffolds (70S30C 70% SiO2 and 30% CaO) produced by a sol-gel foaming process are thought to be suitable matrices for bone tissue regeneration. Previous in vitro data showed bone matrix production and active remodelling in the presence of osteogenic cells. Here we report their ability to act as scaffolds for in vivo bone regeneration in a rat tibial defect model, but only when preconditioned. Pretreatment methods (dry, pre-wetted or preconditioned without blood) for the 70S30C scaffolds were compared against commercial synthetic bone grafts (NovaBone® and Actifuse®). Poor bone ingrowth was found for both dry and wetted sol-gel foams, associated with rapid increase in pH within the scaffolds. Bone ingrowth was quantified through histology and novel micro-CT image analysis. The percentage bone ingrowth into dry, wetted and preconditioned 70S30C scaffolds at 11 weeks were 10±1%, 21±2% and 39±4%, respectively. Only the preconditioned s le showed above 60% material-bone contact, which was similar to that in NovaBone and Actifuse. Unlike the commercial products, preconditioned 70S30C scaffolds degraded and were replaced with new bone. The results suggest that bioactive glass compositions should be redesigned if sol-gel scaffolds are to be used without preconditioning to avoid excess calcium release.
Publisher: Elsevier BV
Date: 05-2022
Publisher: Elsevier BV
Date: 07-2017
DOI: 10.1016/J.ACTBIO.2017.04.030
Abstract: A challenge in using bioactive melt-derived glass in bone regeneration is to produce scaffolds with interconnected pores while maintaining the amorphous nature of the glass and its associated bioactivity. Here we introduce a method for creating porous melt-derived bioactive glass foam scaffolds with low silica content and report in vitro and preliminary in vivo data. The gel-cast foaming process was adapted, employing temperature controlled gelation of gelatin, rather than the in situ acrylic polymerisation used previously. To form a 3D construct from melt derived glasses, particles must be fused via thermal processing, termed sintering. The original Bioglass® 45S5 composition crystallises upon sintering, altering its bioactivity, due to the temperature difference between the glass transition temperature and the crystallisation onset being small. Here, we optimised and compared scaffolds from three glass compositions, ICIE16, PSrBG and 13-93, which were selected due to their widened sintering windows. Amorphous scaffolds with modal pore interconnect diameters between 100-150µm and porosities of 75% had compressive strengths of 3.4±0.3MPa, 8.4±0.8MPa and 15.3±1.8MPa, for ICIE16, PSrBG and 13-93 respectively. These porosities and compressive strength values are within the range of cancellous bone, and greater than previously reported foamed scaffolds. Dental pulp stem cells attached to the scaffold surfaces during in vitro culture and were viable. In vivo, the scaffolds were found to regenerate bone in a rabbit model according to X-ray micro tomography imaging. This manuscript describes a new method for making scaffolds from bioactive glasses using highly bioactive glass compositions. The glass compositions have lower silica content that those that have been previously made into amorphous scaffolds and they have been designed to have similar network connectivity to that of the original (and commercially used) 45S5 Bioglass. The aim was to match Bioglass' bioactivity. The scaffolds retain the amorphous nature of bioactive glass while having an open pore structure and compressive strength similar to porous bone (the original 45S5 Bioglass crystallises during sintering, which can cause reduced bioactivity or instability). The new scaffolds showed unexpectedly rapid bone regeneration in a rabbit model.
Publisher: Oxford University Press (OUP)
Date: 24-01-2014
Publisher: Elsevier BV
Date: 05-2021
Publisher: Trans Tech Publications, Ltd.
Date: 08-2015
DOI: 10.4028/WWW.SCIENTIFIC.NET/MSF.828-829.461
Abstract: The Interdependence model currently uses an analytical expression for a moving planar interface to calculate the solute diffusion length designated as x’ dl in the model. Upon nucleation within an alloy melt (i.e. when the solid embryo starts to grow), the interface grows with a spherical front which then breaks down into a dendritic interface. The time required for this breakdown is a subject for separate research. In this paper, we explore the validity of using a planar interface in the early stages of nucleation and growth of metal alloys as used in the Interdependence model. The diffusion field ahead of a planar interface, in theory, has an exponentially changing composition of infinite length. In the Interdependence model, x’ dl is assumed to be where this exponentially decreasing composition profile in the liquid ahead of the interface (for k 1) reduces to within 1% of a quantity proportional to the nominal alloy composition, C 0 , far from the interface. A numerical solidification model, μMatIC, is used to simulate the growth of a single grain with a dendritic interface in 2D and 3D. The numerical model is capable of generating the solute profile ahead of the growing grain which is used to evaluate the solute diffusion length that can be compared with the results obtained from the planar interface model. The comparisons were made with both 1% and 0.1% cut-off criteria. The results indicate that the 1% assumption being used in the planar front diffusion length calculation is a good approximation for the Interdependence model.
Publisher: Trans Tech Publications, Ltd.
Date: 10-2012
DOI: 10.4028/WWW.SCIENTIFIC.NET/SSP.192-193.179
Abstract: Optimising semi-solid processing and accurately modelling semi-solid deformation requires a fundamental understanding of the globule-scale mechanisms that cause the macroscopic rheological response. In this work, apparatus and analysis techniques are being developed for the time-resolved, three-dimensional imaging of semi-solid alloy deformation. This paper overviews synchrotron X-ray tomography results on globular Al-15wt%Cu deformed at 0.7 solid fraction using extrusion. The globule-globule interactions in response to load were quantified in terms of the response of in idual globules with respect to globule translation, rotation, and deformation. The potential of time-resolved X-ray tomography in the study of semi-solid alloy deformation is then discussed.
Publisher: Elsevier BV
Date: 12-2020
Publisher: Springer Science and Business Media LLC
Date: 06-05-2016
Publisher: American Chemical Society (ACS)
Date: 16-06-2017
Abstract: Antimicrobial silver nanoparticle coatings have attracted interest for reducing prosthetic joint infection. However, few studies report in vivo investigations of the biotransformation of silver nanoparticles within the regenerating tissue and its impact on bone formation. We present a longitudinal investigation of the osseointegration of silver nanoparticle-coated additive manufactured titanium implants in rat tibial defects. Correlative imaging at different time points using nanoscale secondary ion mass spectrometry, transmission electron microscopy (TEM), histomorphometry, and 3D X-ray microcomputed tomography provided quantitative insight from the nano- to macroscales. The quality and quantity of newly formed bone is comparable between the uncoated and silver coated implants. The newly formed bone demonstrates a trabecular morphology with bone being located at the implant surface, and at a distance, at two weeks. Nanoscale elemental mapping of the bone-implant interface showed that silver was present primarily in the osseous tissue and colocalized with sulfur. TEM revealed silver sulfide nanoparticles in the newly regenerated bone, presenting strong evidence that the previously in vitro observed biotransformation of silver to silver sulfide occurs in vivo.
Publisher: Elsevier BV
Date: 02-2019
DOI: 10.1016/J.MSEC.2018.10.033
Abstract: There is increasing demand for synthetic bone scaffolds for bone tissue engineering as they can counter issues such as potential harvesting morbidity and restrictions in donor sites which h er autologous bone grafts and address the potential for disease transmission in the case of allografts. Due to their excellent biocompatibility, titanium scaffolds have great potential as bone graft substitutes as they mimic the structure and properties of human cancellous bone. Here we report on a new thermoset bio-polymer which can act as a binder for Direct Ink Writing (DIW) of titanium artificial bone scaffolds. We demonstrate the use of the binder to manufacture porous titanium scaffolds with evenly distributed and highly interconnected porosity ideal for orthopaedic applications. Due to their porous structure, the scaffolds exhibit an effective Young's modulus similar to human cortical bone, alleviating undesirable stress-shielding effects, and possess superior strength. The biocompatibility of the scaffolds was investigated in vitro by cell viability and proliferation assays using human bone-marrow-derived Mesenchymal stem cells (hMSCs). The hMSCs displayed well-spread morphologies, well-organized F-actin and large vinculin complexes confirming their excellent biocompatibility. The vinculin regions had significantly larger Focal Adhesion (FA) area and equivalent FA numbers compared to that of tissue culture plate controls, showing that the scaffolds support cell viability and promote attachment. In conclusion, we have demonstrated the excellent potential of the thermoset bio-polymer as a Direct Ink Writing ready binder for manufacture of porous titanium scaffolds for hard tissue engineering.
Publisher: Springer Science and Business Media LLC
Date: 18-07-2014
DOI: 10.1038/NCOMMS5464
Abstract: The behaviour of granular solid–liquid mixtures is key when deforming a wide range of materials from cornstarch slurries to soils, rock and magma flows. Here we demonstrate that treating semi-solid alloys as a granular fluid is critical to understanding flow behaviour and defect formation during casting. Using synchrotron X-ray tomography, we directly measure the discrete grain response during uniaxial compression. We show that the stress–strain response at 64–93% solid is due to the shear-induced dilation of discrete rearranging grains. This leads to the counter-intuitive result that, in unfed s les, compression can open internal pores and draw the free surface into the liquid, resulting in cracking. A soil mechanics approach shows that, irrespective of initial solid fraction, the solid packing density moves towards a constant value during deformation, consistent with the existence of a critical state in mushy alloys analogous to soils.
Publisher: Elsevier BV
Date: 10-2014
Publisher: IOP Publishing
Date: 03-2016
Publisher: Elsevier BV
Date: 11-2014
Publisher: Elsevier BV
Date: 06-2016
Publisher: Elsevier BV
Date: 2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0JM01072C
Publisher: Elsevier BV
Date: 07-2023
Publisher: Wiley
Date: 22-10-2012
Abstract: Remodelling of scaffolds and new bone formation is critical for effective bone regeneration. Herein is reported the first demonstration of resorption pits due to osteoclast activity on the surface of sol-gel bioactive glass foam scaffolds. Bioactive glass foam scaffolds are known to have osteogenic potential and suitable pore networks for bone regeneration. Degradation of the scaffolds is known to be initially solution mediated, but for effective bone regeneration, remodelling of the scaffold by osteoclasts and vascularisation of the scaffold is necessary. The culture of C7 macrophages on a bioactive glass scaffold induces the cells to differentiate into (TRAP(+ve) ) osteoclasts. They then form distinctive resorption pits within 3 weeks, while MC3T3-E1 pre-osteoblasts deposit mineralized osteoid on their surfaces in co-culture. The scaffolds are of the 70S30C (70 mol% SiO2 , 30 mol% CaO) composition, with modal pore and interconnect diameters of 373 μm and 172 μm respectively (quantified by X-ray micro-tomography and 3D image analysis). The release of soluble silica and calcium ions from 70S30C scaffolds induces an increase in osteoblast numbers as determined via the MTT assay. Scaffolds also support growth of endothelial cells on their surface and tube formation (characteristic of functional microvasculature) following 4 days in culture. This data supports the hypothesis that 70S30C bioactive glass scaffolds promote the differentiation of the 3 main cell types involved in vascularized bone regeneration.
Publisher: IOP Publishing
Date: 03-07-2012
Publisher: Elsevier BV
Date: 08-2020
Publisher: EAGE Publications BV
Date: 06-2015
Publisher: Elsevier BV
Date: 03-2021
Publisher: Mineralogical Society of America
Date: 11-2018
DOI: 10.2138/AM-2018-6419
Publisher: Elsevier BV
Date: 10-2016
Publisher: Wiley
Date: 02-05-2014
Abstract: X-ray microtomography and serial block face scanning electron microscopy are used to reveal independent clusters of inorganic particles embedded within a polymer. These clusters are interpenetrating, of varying size, and have fractal dimensions that strongly influence transport and structure-property relations. This interpretation forms a baseline for designing hybrid materials for applications in self-healing, drug delivery, and membranes.
Publisher: Springer Science and Business Media LLC
Date: 20-06-2019
DOI: 10.1038/S41598-019-45561-W
Abstract: High energy X-ray phase contrast tomography is tremendously beneficial to the study of thick and dense materials with poor attenuation contrast. Recently, the X-ray speckle-based imaging technique has attracted widespread interest because multimodal contrast images can now be retrieved simultaneously using an inexpensive wavefront modulator and a less stringent experimental setup. However, it is time-consuming to perform high resolution phase tomography with the conventional step-scan mode because the accumulated time overhead severely limits the speed of data acquisition for each projection. Although phase information can be extracted from a single speckle image, the spatial resolution is deteriorated due to the use of a large correlation window to track the speckle displacement. Here we report a fast data acquisition strategy utilising a fly-scan mode for near field X-ray speckle-based phase tomography. Compared to the existing step-scan scheme, the data acquisition time can be significantly reduced by more than one order of magnitude without compromising spatial resolution. Furthermore, we have extended the proposed speckle-based fly-scan phase tomography into the previously challenging high X-ray energy region (120 keV). This development opens up opportunities for a wide range of applications where exposure time and radiation dose are critical.
Publisher: Elsevier BV
Date: 06-2016
Publisher: Springer Science and Business Media LLC
Date: 08-07-2016
DOI: 10.1007/S11661-016-3618-0
Abstract: Dendritic morphology was investigated in a directionally solidified magnesium-zinc alloy using synchrotron X-ray tomography and electron backscattered diffraction. Unexpectedly, primary dendrites grew along $$ {\\langle}21\\overline{3}1 {\\rangle}$$ ⟨ 21 3 ¯ 1 ⟩ , rather than the previously reported $${\\langle} 11\\overline{2} 0{\\rangle} $$ ⟨ 11 2 ¯ 0 ⟩ and $${\\langle} 22\\overline{4}5 {\\rangle}$$ ⟨ 22 4 ¯ 5 ⟩ directions. Further, seven asymmetric sets of side branches formed, instead of six-fold symmetric arms, evolving with three coexisting morphologies per trunk of: traditional, seaweed structure, and free growth. The anomalous growth is attributed to the imposed thermal gradient and zinc-induced interfacial energy anisotropy variations.
Publisher: Wiley
Date: 21-03-2017
Abstract: Joint replacement surgery is associated with significant morbidity and mortality following infection with either methicillin-resistant Staphylococcus aureus (MRSA) or Staphylococcus epidermidis. These organisms have strong biofilm-forming capability in deep wounds and on prosthetic surfaces, with 10
Publisher: MDPI AG
Date: 29-11-2022
DOI: 10.3390/CMD3040037
Abstract: Machine learning (ML) is providing a new design paradigm for many areas of technology, including corrosion inhibition. However, ML models require relatively large and erse training sets to be most effective. This paper provides an overview of developments in corrosion inhibitor research, focussing on how corrosion performance data can be incorporated into machine learning and how large sets of inhibitor performance data that are suitable for training robust ML models can be developed through various corrosion inhibition testing approaches, especially high-throughput performance testing. It examines different types of environments where corrosion by-products and electrolytes operate, with a view to understanding how conventional inhibitor testing methods may be better designed, chosen, and applied to obtain the most useful performance data for inhibitors. The authors explore the role of modern characterisation techniques in defining corrosion chemistry in occluded structures (e.g., lap joints) and examine how corrosion inhibition databases generated by these techniques can be exemplified by recent developments. Finally, the authors briefly discuss how the effects of specific structures, alloy microstructures, leaching structures, and kinetics in paint films may be incorporated into machine learning strategies.
Publisher: International Union of Crystallography (IUCr)
Date: 12-06-2018
DOI: 10.1107/S1600577518005623
Abstract: X-ray phase-contrast imaging can substantially enhance image contrast for weakly absorbing s les. The fabrication of dedicated optics remains a major barrier, especially in high-energy regions ( i.e. over 50 keV). Here, the authors perform X-ray phase-contrast imaging by using engineered porous materials as random absorption masks, which provides an alternative solution to extend X-ray phase-contrast imaging into previously challenging higher energy regions. The authors have measured various s les to demonstrate the feasibility of the proposed engineering materials. This technique could potentially be useful for studying s les across a wide range of applications and disciplines.
Publisher: Elsevier BV
Date: 09-2023
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2012
End Date: 03-2016
Amount: $420,000.00
Funder: Australian Research Council
View Funded Activity