2024-03-28T09:49:14Z
https://eprints.whiterose.ac.uk/cgi/oai2
oai:eprints.whiterose.ac.uk:16
2014-06-05T20:54:45Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/16/
Recruitment, augmentation and apoptosis of rat osteoclasts in 1,25-(OH)2D3 response to short-term treatment with 1,25-dihydroxyvitamin D3in vivo
Miao, Dengshun
Scutt, Andrew
RC Internal medicine
Background
Although much is known about the regulation of osteoclast (OC) formation and activity, little is known about OC senescence. In particular, the fate of of OC seen after 1,25-(OH)2D3 administration in vivo is unclear. There is evidence that the normal fate of OC is to undergo apoptosis (programmed cell death). We have investigated the effect of short-term application of high dose 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) on OC apoptosis in an experimental rat model.
Methods
OC recruitment, augmentation and apoptosis was visualised and quantitated by staining histochemically for tartrate resistant acid phosphatase (TRAP), double staining for TRAP/ED1 or TRAP/DAPI, in situ DNA fragmentation end labelling and histomorphometric analysis.
Results
Short-term treatment with high-dose 1,25-(OH)2D3 increased the recruitment of OC precursors in the bone marrow resulting in a short-lived increase in OC numbers. This was rapidly followed by an increase in the number of apoptotic OC and their subsequent removal. The response of OC to 1,25-(OH)2D3 treatment was dose and site dependent; higher doses producing stronger, more rapid responses and the response in the tibiae being consistently stronger and more rapid than in the vertebrae.
Conclusions
This study demonstrates that (1) after recruitment, OC are removed from the resorption site by apoptosis (2) the combined use of TRAP and ED1 can be used to identify OC and their precursors in vivo (3) double staining for TRAP and DAPI or in situ DNA fragmentation end labelling can be used to identify apoptotic OC in vivo.
2002-06-07
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/16/1/1471-2474-3-16.pdf
Miao, Dengshun and Scutt, Andrew (2002) Recruitment, augmentation and apoptosis of rat osteoclasts in 1,25-(OH)2D3 response to short-term treatment with 1,25-dihydroxyvitamin D3in vivo. BMC Musculoskeletal Disorders, 3 (16). ISSN 1471-2474
http://www.biomedcentral.com/1471-2474/3/16
10.1186/1471-2474-3-16
oai:eprints.whiterose.ac.uk:38
2014-06-04T18:40:11Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/38/
EMD273316 & EMD95833, type 4 phosphodiesterase inhibitors, stimulate fibroblastic-colony formation by bone marrow cells via direct inhibition of PDE4 and the induction of endogenous prostaglandin synthesis
Scutt, Andrew
Beier, Norbert
Fittschen, Claus
BACKGROUND:
Type 4 phosphodiesterase (PDE4) inhibitors have been shown to stimulate bone formation in vivo and to stimulate osteoblastic differentiation in vitro. As one possible mechanism for the stimulation of bone formation is the recruitment of osteoprogenitor cells from the bone marrow, we have investigated the effect of the PDE4 inhibitors EMD273316, EMD95833, EMD249615 and EMD 219906 on fibroblastic colony formation by whole bone marrow cells and on the ability of these colonies to adopt an osteoblastic phenotype.
RESULTS:
All four agents stimulated colony formation in a concentration dependent manner, however, in the case of EMD273316 & EMD95833, the effect was evident at lower concentrations and the addition of prostaglandin E2 (PGE2) was not necessary for maximal stimulation. It was subsequently found that co-incubation with indomethacin reduced the stimulatory effects of EMD273316 & EMD95833 but had no effect on the actions of EMD249615 and EMD 219906 and that EMD273316 & EMD95833 stimulated the synthesis of endogenous PGE2 by whole bone marrow cells whereas EMD249615 and EMD 219906 had no significant effect.
CONCLUSIONS:
These data suggest that EMD249615, EMD 219906, EMD273316 & EMD95833 can promote the recruitment of bone marrow osteoprogenitor cells leading to a stimulation of bone formation via their direct inhibitory effects on PDE4. The actions of EMD273316 & EMD95833 however, are augmented by their ability to stimulate endogenous prostanoids synthesis which acts synergistically with their direct effects on PDE4.
2004-06-25
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/38/1/1471-2210-4-10.pdf
Scutt, Andrew, Beier, Norbert and Fittschen, Claus (2004) EMD273316 & EMD95833, type 4 phosphodiesterase inhibitors, stimulate fibroblastic-colony formation by bone marrow cells via direct inhibition of PDE4 and the induction of endogenous prostaglandin synthesis. BMC Pharmacology, 4 (10). ISSN 1471-2210
http://www.biomedcentral.com/1471-2210/4/10
10.1186/1471-2210-4-10
oai:eprints.whiterose.ac.uk:107
2014-06-05T17:24:53Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/107/
Supramolecular dendritic liquid quasicrystals
Zeng, X.
Ungar, G.
Liu, Y.
Percec, V.
Dulcey, A.E.
Hobbs, J.K.
2004-03-11
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/107/1/ungarg1.pdf
Zeng, X., Ungar, G., Liu, Y. et al. (3 more authors) (2004) Supramolecular dendritic liquid quasicrystals. Nature, 428 (6979). pp. 157-160. ISSN 0028-0836
http://www.nature.com/nature
doi:10.1038/nature02368
oai:eprints.whiterose.ac.uk:421
2014-06-04T16:21:13Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
756E69743D536865666669656C64:536865666669656C642E46434D:536865666669656C642E4D4544:536865666669656C642E435355:536865666669656C642E4D5059
756E69743D596F726B:596F726B2E46414332:596F726B2E594F5232
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434F4D
696E737469747574696F6E3D536865666669656C64
696E737469747574696F6E3D596F726B
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/421/
The Epitheliome: agent-based modelling of the social behaviour of cells
Walker, D.C.
Southgate, J.
Hill, G.
Holcombe, M.
Hose, D.R.
Wood, S.M.
Mac Neil, S.
Smallwood, R.H. [r.smallwood@shef.ac.uk]
We have developed a new computational modelling paradigm for predicting the emergent behaviour
resulting from the interaction of cells in epithelial tissue. As proof-of-concept, an agent-based model,
in which there is a one-to-one correspondence between biological cells and software agents, has been
coupled to a simple physical model. Behaviour of the computational model is compared with the
growth characteristics of epithelial cells in monolayer culture, using growth media with low and
physiological calcium concentrations. Results show a qualitative fit between the growth characteristics
produced by the simulation and the in vitro cell models.
2004-08
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/421/1/Walker_2003_The_epitheliome_-_agent_based_modelling_of_the_social_behaviour_of_cells.pdf
Walker, D.C., Southgate, J., Hill, G. et al. (5 more authors) (2004) The Epitheliome: agent-based modelling of the social behaviour of cells. BioSystems, 76 (1-3). pp. 89-100. ISSN 0303-2647
http://www.elsevier.com/wps/find/journaldescription.cws_home/506017/description#description
doi:10.1016/j.biosystems.2004.05.025
oai:eprints.whiterose.ac.uk:1090
2014-06-05T23:12:33Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/1090/
Differential effects of ERK and p38 signaling in BMP-2 stimulated hypertrophy of cultured chick sternal chondrocytes
Reilly, G.C.
Golden, E.B.
Grasso-Knight, G.
Leboy, P.S.
Background
During endochondral bone formation, the hypertrophy of chondrocytes is accompanied by selective expression of several genes including type X collagen and alkaline phosphatase. This expression is stimulated by inducers including BMPs and ascorbate. A 316 base pair region of the type X collagen (Col X) promoter has been previously characterized as the site required for BMP regulation. The intent of this study was to examine the role of Mitogen Activated Protein (MAP) and related kinase pathways in the regulation of Col X transcription and alkaline phosphatase activity in pre-hypertrophic chick chondrocytes.
Results
Using a luciferase reporter regulated by the BMP-responsive region of the type X collagen promoter, we show that promoter activity is increased by inhibition of extra-cellular signal regulated kinases 1 or 2 (ERK1/2). In contrast the ability of BMP-2 to induce alkaline phosphatase activity is little affected by ERK1/2 inhibition. The previously demonstrated stimulatory affect of p38 on Col X was shown to act specifically at the BMP responsive region of the promoter. The inhibitory effect of the ERK1/2 pathway and stimulatory effect of the p38 pathway on the Col X promoter were confirmed by the use of mutant kinases. Inhibition of upstream kinases: protein kinase C (PKC) and phosphatidylinositol 3-(PI3) kinase pathways increased basal Col X activity but had no effect on the BMP-2 induced increase. In contrast, ascorbate had no effect on the BMP-2 responsive region of the Col X promoter nor did it alter the increase in promoter activity induced by ERK1/2 inhibition. The previously shown increase in alkaline phosphatase activity induced by ascorbate was not affected by any kinase inhibitors examined. However some reduction in the alkaline phosphatase activity induced by the combination of BMP-2 and ascorbate was observed with ERK1/2 inhibition.
Conclusion
Our results demonstrate that ERK1/2 plays a negative role while p38 plays a positive role in the BMP-2 activated transcription of type X collagen. This regulation occurs specifically at the BMP-2 responsive promoter region of Col X. Ascorbate does not modulate Col X at this region indicating that BMP-2 and ascorbate exert their action on chondrocyte hypertrophy via different transcriptional pathways. MAP kinases seem to have only a modest effect on alkaline phosphatase when activity is induced by the combination of both BMP-2 and ascorbate.
2005-02-03
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/1090/1/bmc_1478-811X-3-3.pdf
Reilly, G.C., Golden, E.B., Grasso-Knight, G. et al. (1 more author) (2005) Differential effects of ERK and p38 signaling in BMP-2 stimulated hypertrophy of cultured chick sternal chondrocytes. Cell Communication and Signaling, 3 (3). ISSN 1478-811X
http://www.biosignaling.com/content/3/1/3
doi:10.1186/1478-811X-3-3
oai:eprints.whiterose.ac.uk:1894
2007-08-05T18:25:12Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
756E69743D596F726B:596F726B2E46414332:596F726B2E594F5238
696E737469747574696F6E3D536865666669656C64
696E737469747574696F6E3D596F726B
7072696D6F3D6E6F5F646F63756D656E74735F617661696C61626C65
https://eprints.whiterose.ac.uk/1894/
Comparison between the in-plane anisotropies and magnetostriction constants of thin epitaxial Fe films grown on GaAs and Ga0.8In0.2As substrates, with Cr overlayers
Morley, N.A.
Gibbs, M.R.J.
Ahmad, E.
Will, I.G.
Xu, Y.B.
Thin epitaxial Fe films grown on GaAs(100) and Ga0.8In0.2As(100) substrates were investigated to determine how tuning the lattice constant mismatch between the Fe and the substrate may change the in-plane anisotropies and the magnetostriction. Two sets of Fe films were grown using molecular-beam epitaxy, each capped with a Cr overlayer. For each film, the in-plane anisotropy constants were determined from the normalized magnetization loops measured using a magneto-optic Kerr effect magnetometer. The lattice mismatch was found to give no contribution to the in-plane anisotropies. For all the films the magnetostriction constants, determined by the Villari method, were negative and became more negative as the Fe thickness decreased.
© 2006 American Institute of Physics
American Institute of Physics
2006-04-15
Article
PeerReviewed
Morley, N.A., Gibbs, M.R.J., Ahmad, E. et al. (2 more authors) (2006) Comparison between the in-plane anisotropies and magnetostriction constants of thin epitaxial Fe films grown on GaAs and Ga0.8In0.2As substrates, with Cr overlayers. Journal of Applied Physics, 99 (8). Art no. 08N508. ISSN 1089-7550
http://dx.doi.org/10.1063/1.2158974
doi:10.1063/1.2158974
oai:eprints.whiterose.ac.uk:1958
2014-06-05T11:37:42Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E495343
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/1958/
Topologically disordered systems at the glass transition
Ojovan, M.I.
Lee, W.E.
The thermodynamic approach to the viscosity and fragility of amorphous oxides was used to determine the topological characteristics of the disordered network-forming systems. Instead of the disordered system of atoms we considered the congruent disordered system of interconnecting bonds. The Gibbs free energy of network-breaking defects (configurons) was found based on available viscosity data. Amorphous silica and germania were used as reference disordered systems for which we found an excellent agreement of calculated and measured glass transition temperatures. We reveal that the Hausdorff dimension of the system of bonds changes from Euclidian three-dimensional below to fractal 2.55 ± 0.05-dimensional geometry above the glass transition temperature.
Institute of Physics
2006-12-20
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/1958/1/ojovanmi1_Topologically2.pdf
Ojovan, M.I. and Lee, W.E. (2006) Topologically disordered systems at the glass transition. Journal of Physics: Condensed Matter, 18 (50). pp. 11507-11520. ISSN 1361-648X
http://dx.doi.org/10.1088/0953-8984/18/50/007
doi:10.1088/0953-8984/18/50/007
oai:eprints.whiterose.ac.uk:2639
2013-02-08T16:54:40Z
7374617475733D707562
74797065733D626F6F6B5F73656374696F6E
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/2639/
Microsegregation and inclusion development during the casting of steel
Howe, A.A.
The enrichment of composition in the residual liquid during solidification is of itself an important parameter regarding the fitness for purpose of the alloy and, furthermore, will have a major influence on the precipitates and oxide inclusions that can nucleate and/or grow in the mushy zone. Corus sought a relatively simple, rapid model for this microsegregation and its associated inclusion type and size, for predictions across the thickness of continuously cast steels, suitable for use in
conjunction with macro-models but demonstrably superior to the use of analytical equations. Notably, the analytical equations employ constant temperature equilibrium and diffusivity data for a process that can cover a very wide temperature range, and the assumed growth laws coupled with these data have an implied thermal history at odds with the environment of the macroscopic model within which the algorithm is to be used. The development and use of this model are described, along with its validation against a proven but time-consuming Finite Difference program for this purpose.
Department of Engineering Materials, University of Sheffield.
Jones, H.
2007
Book Section
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/2639/1/FP2639Howe.pdf
Howe, A.A. (2007) Microsegregation and inclusion development during the casting of steel. In: Jones, H., (ed.) SP07 Proceedings of the 5th Decennial International Conference on Solidification Processing. Department of Engineering Materials, University of Sheffield. , Sheffield , pp. 76-79. ISBN ISBN-13: 978-0-9522507-4-6
oai:eprints.whiterose.ac.uk:2641
2013-02-08T16:54:39Z
7374617475733D707562
74797065733D626F6F6B5F73656374696F6E
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/2641/
Preparation of Cu-based bulk metallic glasses by suction casting
Figueroa, I.A.
Carroll, P.A.
Davies, H.A.
Jones, H.
Todd, I.
A series of Cu-Hf-Ti alloys prepared by rapid solidification of the melt and by copper mould casting were studied in the present work. Alloy ingots were prepared by arc-melting mixtures of pure metals in an argon atmosphere. An indication of the cooling rate obtained was determined using an Al-4.5 wt%Cu alloy. Cooling rates varied from 540 K/s for the centre section of a 4 mm die to 885 K/s for the outside wall section of the 2 mm die. The glass-forming ability, structure and thermal stability of Cu-Hf-Ti glassy alloys were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and differential thermal analysis (DTA). Bulk glass formation was observed for the Cu64Hf36, Cu55Hf25Ti20 and Cu56Hf25Ti19 alloys, with critical diameters dc for a fully glassy structure of 1, 4 and 5 mm, respectively. The substitution of Hf by Ti increased the glassforming ability (GFA) and the thermal stability.
Department of Engineering Materials, University of Sheffield.
Jones, H.
2007
Book Section
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/2641/1/FP2641Figueroa.pdf
Figueroa, I.A., Carroll, P.A., Davies, H.A. et al. (2 more authors) (2007) Preparation of Cu-based bulk metallic glasses by suction casting. In: Jones, H., (ed.) SP07 Proceedings of the 5th Decennial International Conference on Solidification Processing. Department of Engineering Materials, University of Sheffield. , Sheffield , pp. 479-482. ISBN ISBN-13: 978-0-9522507-4-6
oai:eprints.whiterose.ac.uk:2642
2013-02-08T16:54:39Z
7374617475733D707562
74797065733D626F6F6B5F73656374696F6E
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/2642/
Cooling slope casting to obtain thixotropic feedstock
Cardoso Legoretta, E.
Atkinson, H.V.
Jones, H.
Thixoforming, and related semi-solid processing routes for metallic alloys, require feedstock with a non-dendritic microstructure in the semi-solid state. The material then behaves in a thixotropic way in that, when it is sheared it flows and can be forced to fill a die and, when it is allowed to stand it thickens again. The New Rheocasting (the NRC process) is a recently developed semi-solid processing route. There are two versions of this route. In one, molten alloy is poured directly into a tilted mould and, through careful temperature control during cooling, a spheroidal semi-solid microstructure is achieved. The material in the mould is then upended into a shot sleeve and hence forced into a die. Alternatively, the molten alloy is poured onto a cooling slope and thence into a mould before processing. The aim of the work described in this paper was to develop understanding of the microstructural development during the initial stages of this process. The results for pouring A356 aluminium alloy via a cooling slope into a mould are presented.
Department of Engineering Materials, University of Sheffield.
Jones, H.
2007
Book Section
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/2642/1/FP2642Legoretta.pdf
Cardoso Legoretta, E., Atkinson, H.V. and Jones, H. (2007) Cooling slope casting to obtain thixotropic feedstock. In: Jones, H., (ed.) SP07 Proceedings of the 5th Decennial International Conference on Solidification Processing. Department of Engineering Materials, University of Sheffield. , Sheffield , pp. 582-586. ISBN ISBN-13: 978-0-9522507-4-6
oai:eprints.whiterose.ac.uk:3366
2014-06-06T20:20:50Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434E54
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/3366/
Enhanced longitudinal magnetooptic Kerr effect contrast in nanomagnetic structures
Gibson, U.J.
Holiday, L.F.
Allwood, D.A.
Basu, S.
Fry, P.W.
We report on enhanced longitudinal magnetooptic Kerr effect signal contrast in thin-film nanomagnetic disks with in-plane magnetization when combined with dielectric layers that provide impedance matching to the structure and the underlying substrate. Kerr signals can increase by a factor of three, while substrate reflectance is almost completely suppressed. This leads to an increase in Kerr ellipticity relative to the background intensity and a subsequent improvement in the measured signal-to-noise ratio. Measurements using a beam focused on opaque 400-nm Ni disks yield contrast improvements of a factor of 8. Arrays of nanodisks demonstrate more complex behavior due to diffraction effects.
IEEE
2007-06
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/3366/1/allwoodd1.pdf
Gibson, U.J., Holiday, L.F., Allwood, D.A. et al. (2 more authors) (2007) Enhanced longitudinal magnetooptic Kerr effect contrast in nanomagnetic structures. IEEE Transactions on Magnetics, 43 (6). pp. 2740-2742. ISSN 0018-9464
http://dx.doi.org/10.1109/TMAG.2007.894003
doi:10.1109/TMAG.2007.894003
oai:eprints.whiterose.ac.uk:3401
2013-02-08T16:55:23Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/3401/
New parametrization method for dissipative particle dynamics
Travis, K.P.
Bankhead, M.
Good, K.
Owens, S.L.
We introduce an improved method of parameterizing the Groot-Warren version of Dissipative Particle Dynamics (DPD) by exploiting a correspondence between DPD and
Scatchard-Hildebrand regular solution theory. The new parameterization scheme widens the realm of applicability of DPD by first removing the restriction of equal repulsive
interactions between like beads, and second, by relating all conservative interactions between beads directly to cohesive energy densities.
We establish the correspondence by deriving an expression for the Helmoltz free energy of mixing obtaining a heat of mixing which is exactly the same form as that for a
regular mixture (quadratic in the volume fraction) and an entropy of mixing which reduces to the ideal entropy of mixing for equal molar volumes. We equate the conservative interaction parameters in the DPD force law to the cohesive energy densities of the pure fluids providing an alternative method of calculating the self-interaction
parameters as well as a route to the cross-interaction parameter.
We validate the new parameterization by modelling the binary system: SnI4/SiCl4, which displays liquid-liquid coexistence below an upper critical solution temperature
around 140°C. A series of DPD simulations were conducted at a set of temperatures ranging from 0°C to above the experimental upper critical solution temperature using
conservative parameters based on extrapolated experimental data. These simulations can be regarded as being equivalent to a quench from a high temperature to a lower one at constant volume.
Our simulations recover the expected phase behaviour ranging from solid-liquid coexistence to liquid-liquid co-existence and eventually leading to a homogeneous single
phase system. The results yield a binodal curve in close agreement with one predicted using regular solution theory, but, significantly, in closer agreement with actual solubility
measurements.
American Institute of Physics
2007-07-07
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/3401/1/traviskm1.pdf
Travis, K.P., Bankhead, M., Good, K. et al. (1 more author) (2007) New parametrization method for dissipative particle dynamics. Journal of Chemical Physics, 127 (014109). ISSN 1089-7690
http://dx.doi.org/10.1063/1.2746325
doi:10.1063/1.2746325
oai:eprints.whiterose.ac.uk:3527
2013-02-08T16:55:27Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/3527/
Terbium-activated heavy scintillating glasses
Fu, J.
Kobayashi, M.
Parker, J.M.
Tb-activated scintillating glasses with high Ln2O3 (Ln=Gd, Y, Lu) concentration up to 40mol% have been prepared. The effects of Ln3+ ions on the density, thermal properties, transmission and luminescence properties under both UV and X-ray excitation have been investigated. The glasses containing Gd2O3 or Lu2O3 exhibit a high density of more than 6.0g/cm3. Energy transfer from Gd3+ to Tb3+ takes place in Gd-containing glass and as a result the Gd-containing glass shows a light yield 2.5 times higher than the Y-or Lu-containing glass. The Effect of the substitution of fluorine for oxygen on the optical properties was also investigated.
Elsevier Science BV
2008-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/3527/1/parkerj.1.pdf
Fu, J., Kobayashi, M. and Parker, J.M. (2008) Terbium-activated heavy scintillating glasses. Journal of Luminescence, 128 (1). pp. 99-104. ISSN 0022-2313
http://dx.doi.org/10.1016/j.jlumin.2007.05.006
doi:10.1016/j.jlumin.2007.05.006
oai:eprints.whiterose.ac.uk:3613
2014-06-05T10:30:54Z
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/3613/
Materials optimization for magnetic MEMS
Gibbs, M.R.J.
By highlighting magnetomechanical effects such as the DeltaE-effect, and developing modeling code that integrates magnetoelasticity with microelectromechanical systems, it is shown that a simple cantilever system can have a sensitivity to mass loading at the attogram level. The requirements on the magnetoelastic materials for such devices are described, and progress towards achieving optimized material is reviewed. The possibility for deployment of such systems in security, healthcare, and bioscience is outlined
IEEE
2006-02
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/3613/1/gibbsm1.pdf
Gibbs, M.R.J. (2006) Materials optimization for magnetic MEMS. IEEE Transactions on Magnetics, 42 (2). pp. 283-288. ISSN 0018-9464
http://dx.doi.org/10.1109/TMAG.2007.893764
doi:10.1109/TMAG.2007.893764
oai:eprints.whiterose.ac.uk:3614
2014-06-05T13:56:58Z
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696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/3614/
Finite-element analysis on cantilever beams coated with magnetostrictive material
Dean, J.
Gibbs, M.R.J.
Schrefl, T.
The main focus of this paper is to highlight some of the key criteria in successful utilization of magnetostrictive materials within a cantilever based microelectromechanical system (MEMS). The behavior of coated cantilever beams is complex and many authors have offered solutions using analytical techniques. In this study, the FEMLAB finite-element multiphysics package was used to incorporate the full magnetostrictive strain tensor and couple it with partial differential equations from structural mechanics to solve simple cantilever systems. A wide range of geometries and material properties were solved to study the effects on cantilever deflection and the system resonance frequencies. The latter were found by the use of an eigen-frequency solver. The models have been tailored for comparison with other such data within the field and results also go beyond previous work.
IEEE
2006-02
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/3614/1/gibbsm2.pdf
Dean, J., Gibbs, M.R.J. and Schrefl, T. (2006) Finite-element analysis on cantilever beams coated with magnetostrictive material. IEEE Transactions on Magnetics, 42 (2 (par). pp. 283-288. ISSN 0018-9464
http://dx.doi.org/10.1109/TMAG.2005.861322
doi:10.1109/TMAG.2005.861322
oai:eprints.whiterose.ac.uk:3615
2014-06-05T00:01:26Z
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696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/3615/
Detailed study of the hysteresis loops for annealed amorphous alloy wires having vanishing magnetostriction
Confalonieri, G.A.B.
Davies, H.A.
Gibbs, M.R.J.
The evolution of Barkhausen events during the magnetization process in current and furnace annealed Co-based amorphous wire having vanishing magnetostriction, /spl lambda//sub s/, is reported. Their origin is explained using the core-shell model commonly accepted for this class of wire. It is argued that the application of stresses during the annealing process, in wire having slightly negative and slightly positive /spl lambda//sub s/, changes the internal magnetic domain structure. Anisotropy induced by anelastic creep can be used to avoid the formation of these Barkhausen events. The behavior of the coercivity and susceptibility is also reported.
IEEE
2004-07
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/3615/1/gibbsm3.pdf
Confalonieri, G.A.B., Davies, H.A. and Gibbs, M.R.J. (2004) Detailed study of the hysteresis loops for annealed amorphous alloy wires having vanishing magnetostriction. IEEE Transactions on Magnetics, 40 (4). pp. 2694-2696. ISSN 0018-9464
http://dx.doi.org/10.1109/TMAG.2004.832269
doi:10.1109/TMAG.2004.832269
oai:eprints.whiterose.ac.uk:3634
2013-02-08T16:55:42Z
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696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/3634/
Configurational temperature control for atomic and molecular systems
Travis, K.P.
Braga, C.
A new configurational temperature thermostat suitable for molecules with holonomic constraints is derived. This thermostat has a simple set of motion equations, can generate the canonical ensemble in both position and momentum space, acts homogeneously through the spatial
coordinates, and does not intrinsically violate the constraints. Our new configurational thermostat is
closely related to the kinetic temperature Nosé-Hoover thermostat with feedback coupled to the position variables via a term proportional to the net molecular force. We validate the thermostat by comparing equilibrium static and dynamic quantities for a fluid of n-decane molecules under
configurational and kinetic temperature control. Practical aspects concerning the implementation of the new thermostat in a molecular dynamics code and the potential applications are discussed.
American Institute of Physics
2008-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/3634/1/traviskm2.pdf
Travis, K.P. and Braga, C. (2008) Configurational temperature control for atomic and molecular systems. The Journal of Chemical Physics, 128 (1). 014111.
http://dx.doi.org/10.1063/1.2815768
doi:10.1063/1.2815768
oai:eprints.whiterose.ac.uk:3759
2013-02-08T16:56:00Z
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696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/3759/
The 'granite encapsulation' route to the safe disposal of Pu and other actinide
Gibb, F.G.F.
Taylor, K.J.
Burakov, B.E.
Waste actinides, including plutonium, present a long-term management problem and a serious security issue. Immobilisation in mineral or ceramic waste forms for interim storage is a widely proposed first step. The safest, most secure geological disposal for Pu is in very deep boreholes and we propose that the key step to combination of these immobilisation and disposal concepts is encapsulation of the waste form in cylinders of recrystallized granite. We discuss the underpinning science, focusing on experimental work, and consider implementation. Finally, we present and discuss analyses of zircon, UO2 and Ce-doped cubic zirconia from high pressure and temperature experiments in granitic melts that demonstrate the viability of this solution and that actinides can be isolated from the environment for millions, maybe hundreds of millions, of years.
Elsevier Science BV
2008-03
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/3759/1/gibbfgf2.pdf
Gibb, F.G.F., Taylor, K.J. and Burakov, B.E. (2008) The 'granite encapsulation' route to the safe disposal of Pu and other actinide. Journal of Nuclear Materials, 374 (3). pp. 364-369. ISSN 0022-3115
http://dx.doi.org/10.1016/j.jnucmat.2007.08.018
doi:10.1016/j.jnucmat.2007.08.018
oai:eprints.whiterose.ac.uk:3760
2013-02-08T16:56:00Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/3760/
High-density support matrices: Key to the deep borehole disposal of spent nuclear fuel
Gibb, F.G.F.
McTaggart, N.A.
Travis, K.P.
Burley, D.
Hesketh, K.W.
Deep (4–5 km) boreholes are emerging as a safe, secure, environmentally sound and potentially cost-effective option for disposal of high-level radioactive wastes, including plutonium. One reason this option has not been widely accepted for spent fuel is because stacking the containers in a borehole could create load stresses threatening their integrity with potential for releasing highly mobile radionuclides like 129I before the borehole is filled and sealed. This problem can be overcome by using novel high-density support matrices deployed as fine metal shot along with the containers. Temperature distributions in and around the disposal are modelled to show how decay heat from the fuel can melt the shot within weeks of disposal to give a dense liquid in which the containers are almost weightless. Finally, within a few decades, this liquid will cool and solidify, entombing the waste containers in a base metal sarcophagus sealed into the host rock.
Elsevier B.V.
2008-03
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/3760/1/gibbfgf1.pdf
Gibb, F.G.F., McTaggart, N.A., Travis, K.P. et al. (2 more authors) (2008) High-density support matrices: Key to the deep borehole disposal of spent nuclear fuel. Journal of Nuclear Materials, 374 (3). pp. 370-377. ISSN 0022-3115
http://dx.doi.org/10.1016/j.jnucmat.2007.08.017
doi:10.1016/j.jnucmat.2007.08.017
oai:eprints.whiterose.ac.uk:4058
2013-02-08T16:56:11Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/4058/
Thermodynamic parameters of bonds in glassy materials from viscosity-temperature relationships
Ojovan, M.I.
Travis, K.P.
Hand, R.J.
Doremus's model of viscosity assumes that viscous flow in amorphous materials is mediated by broken bonds (configurons). The resulting equation contains four coefficients, which are directly related to the entropies and enthalpies of formation and motion of the configurons. Thus by fitting this viscosity equation to experimental viscosity data these enthalpy and entropy terms can be obtained. The non-linear nature of the equation obtained means that the fitting process is non-trivial. A genetic algorithm based approach has been developed to fit the equation to experimental viscosity data for a number of glassy materials, including SiO2, GeO2, B2O3, anorthite, diopside, xNa2O–(1-x)SiO2, xPbO–(1-x)SiO2, soda-lime-silica glasses, salol, and α-phenyl-o-cresol. Excellent fits of the equation to the viscosity data were obtained over the entire temperature range. The fitting parameters were used to quantitatively determine the enthalpies and entropies of formation and motion of configurons in the analysed systems and the activation energies for flow at high and low temperatures as well as fragility ratios using the Doremus criterion for fragility. A direct anti-correlation between fragility ratio and configuron percolation threshold, which determines the glass transition temperature in the analysed materials, was found.
Institute of Physics
2007-10
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/4058/1/ojovanm1.pdf
Ojovan, M.I., Travis, K.P. and Hand, R.J. (2007) Thermodynamic parameters of bonds in glassy materials from viscosity-temperature relationships. Journal of Physics: Condensed Matter, 19 (415107). ISSN 1361-648X
http://dx.doi.org/10.1088/0953-8984/19/41/415107
doi:10.1088/0953-8984/19/41/415107
oai:eprints.whiterose.ac.uk:4059
2013-02-08T16:56:11Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/4059/
Characterisation of Al corrosion and its impact on the mechanical performance of composite cement wasteforms by the acoustic emission technique
Spasova, L.M.
Ojovan, M.I.
In this study acoustic emission (AE) non-destructive method was used to evaluate the mechanical performance of cementitious wasteforms with encapsulated Al waste. AE waves generated as a result of Al corrosion in small-size blast furnace slag/ordinary Portland cement wasteforms were recorded and analysed. The basic principles of the conventional parameter-based AE approach and signal-based analysis were combined to establish a relationship between recorded AE signals and different interactions between the Al and the encapsulating cement matrix. The AE technique was shown as a potential and valuable tool for a new area of application related to monitoring and inspection of the mechanical stability of cementitious wasteforms with encapsulated metallic wastes such as Al.
Elsevier B.V.
2008-04
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/4059/1/ojovanm2.pdf
Spasova, L.M. and Ojovan, M.I. (2008) Characterisation of Al corrosion and its impact on the mechanical performance of composite cement wasteforms by the acoustic emission technique. Journal of Nuclear Materials, 375 (3). pp. 347-358. ISSN 0022-3115
http://dx.doi.org/10.1016/j.jnucmat.2007.11.010
doi:10.1016/j.jnucmat.2007.11.010
oai:eprints.whiterose.ac.uk:4076
2013-02-08T16:56:13Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/4076/
ac hopping admittance in spinel manganate negative temperature coefficient thermistor electroceramics
Schmidt, R.
Brinkman, A.W.
In this work, the ac admittance of a thick film nickel manganate spinel negative temperature coefficient thermistor ceramic system containing a glass phase is investigated. The dominating relaxation process is a grain boundary (GB) effect and has been investigated comprehensively. We present double-logarithmic plots of the specific admittance vs and (/dc) vs , and specific impedance z vs −z/ and [(dc/z)−1] vs , in order to characterize GB charge transport. Using the complex admittance notation (*), an unusually low Jonscher exponent of frequency ~0.007 was obtained and the GB relaxation displayed close to ideal behavior.
American Institute Physics
2008-06
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/4076/1/schmidtr1.pdf
Schmidt, R. and Brinkman, A.W. (2008) ac hopping admittance in spinel manganate negative temperature coefficient thermistor electroceramics. Journal of Applied Physics, 103 (11). p. 113710.
http://dx.doi.org/10.1063/1.2938029
doi:10.1063/1.2938029
oai:eprints.whiterose.ac.uk:4460
2013-02-08T16:56:25Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/4460/
Comment on the power law in rheological equations
Kirkwood, D.H.
Ward, P.J.
In conformity with the principle of shear reversal, it is proposed that the power law index in the Cross equation relating steady state viscosity to shear rate in semisolid alloy slurries should have a value of 4/3, which is independent of alloy system and the fraction solid.
Elsevier
2008-09-15
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/4460/1/Dirkwood.pdf
Kirkwood, D.H. and Ward, P.J. (2008) Comment on the power law in rheological equations. Materials Letters, 62 (24). pp. 3981-3983. ISSN 0167-577X
http://dx.doi.org/10.1016/j.matlet.2008.05.059
doi:10.1016/j.matlet.2008.05.059
oai:eprints.whiterose.ac.uk:4691
2013-02-08T16:56:38Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/4691/
Numerical modeling of semisolid flow under processing conditions
Kirkwood, D.H.
Ward, P.J.
During the industrial process of Semisolid Forming (or Thixoforming) of alloy slurries, typically the operation of die filling takes around 0.1s. During this time period the alloy slug is transformed from a solid-like structure capable of maintaining its shape, into a liquid-like slurry able to fill a complex die cavity: this involves a decrease in viscosity of some 6 orders of magnitude. Many attempts to measure thixotropic breakdown experimentally in alloy slurries have relied on the use of concentric cylindrical viscometers in which viscosity changes have been followed after shear rate changes over times above 1s to in excess of 1000s, which have little relevance to actual processing conditions and therefore to modeling of flow in industrial practice. The present paper is an attempt to abstract thixotropic breakdown rates from rapid compression tests between parallel plates moving together at velocities of around 1m/s, similar to industrial conditions. From this analysis, a model of slurry flow has been developed in which rapid thixotropic breakdown of the slurry occurs at high shear rates.
Stahleisen GMBH
2004
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/4691/1/Kirkwood.pdf
Kirkwood, D.H. and Ward, P.J. (2004) Numerical modeling of semisolid flow under processing conditions. Steel Research International, 75 (8/9). pp. 519-524. ISSN 1611-3683
oai:eprints.whiterose.ac.uk:7922
2013-02-08T16:57:57Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/7922/
Novel optical imaging technique to determine the 3-D orientation of collagen fibers in cartilage: variable-incidence angle polarization-sensitive optical coherence tomography
Ugryumova, N.
Jacobs, J.
Bonesi, M.
Matcher, S.J.
Objective: To investigate a novel optical method to determine the three dimensional (3-D) structure of articular cartilage collagen non-destructively.
Methods: Polarization-sensitive optical coherence tomography was used to determine the apparent optical birefringence of articular cartilage for a number of different illumination directions. A quantitative method based on the theory of light propagation in uniaxial crystalline materials was validated on equine flexor tendon. Qualitative maps of fiber polar and azimuthal orientation at sites on the posterior and anterior segments of the equine third metacarpophalangeal (fetlock) joint were produced, and the azimuthal orientations compared with data from a split-line experiment.
Results: Polar and azimuthal angles of cut flexor tendon broadly agreed with the nominal values but suggested that the accuracy was limited by our method of determining the apparent birefringence. On intact equine fetlock joints we found a non-zero polar tilt that changed in direction at various points along the apex, moving from the sagittal ridge outwards. The azimuthal orientation changes from being parallel to the sagittal ridge in the posterior region to being inclined to the ridge in the anterior region. This broadly agrees with split-line data for the anterior region but differs in the posterior region, possibly reflecting depth-dependent orientation changes.
Conclusion: General quantitative agreement was found between our method and histology in validation experiments. Qualitative results for cartilage suggest a complicated 3-D structure that warrants further study. There is potential to develop this approach into a tool that can provide depth-resolved information on collagen orientation in near real-time, non-destructively and in vivo. (c) 2008 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
Elsevier
2009-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/7922/2/matcherS_Novel_optical.pdf
Ugryumova, N., Jacobs, J., Bonesi, M. et al. (1 more author) (2009) Novel optical imaging technique to determine the 3-D orientation of collagen fibers in cartilage: variable-incidence angle polarization-sensitive optical coherence tomography. Osteoarthritis and Cartilage, 17 (1). pp. 33-42. ISSN 1063-4584
http://dx.doi.org/10.1016/j.joca.2008.05.005
doi:10.1016/j.joca.2008.05.005
oai:eprints.whiterose.ac.uk:8525
2014-06-13T14:58:19Z
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/8525/
Configurons: thermodynamic parameters and symmetry changes at glass transition
Ojovan, M.I.
Thermodynamic parameters of configurons - elementary excitations resulting from broken bonds in amorphous materials - are found from viscosity-temperature relationships. Glass-liquid transition phenomena and most popular models are described along with the configuron model of glass transition. The symmetry breaking, which occurs as a change of Hausdorff dimension of bonds, is examined at glass-liquid transition. Thermal history effects in the glass-liquid transition are interpreted in terms of configuron relaxation.
Molecular Diversity Preservation International
2008-09
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/8525/2/e10030334.pdf
Ojovan, M.I. (2008) Configurons: thermodynamic parameters and symmetry changes at glass transition. Entropy, 10 (3). pp. 334-364. ISSN 1099-4300
http://dx.doi.org/10.3390/e10030334
10.3390/e10030334
oai:eprints.whiterose.ac.uk:8539
2014-06-07T03:23:44Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/8539/
Viscosity and glass transition in amorphous oxides
Ojovan, M.I.
An overview is given of amorphous oxide materials viscosity and glass-liquid transition phenomena. The viscosity is a continuous function of temperature, whereas the glass-liquid transition is accompanied by explicit discontinuities in the derivative parameters such as the specific heat or thermal expansion coefficient. A compendium of viscosity models is given including recent data on viscous flow model based on network defects in which thermodynamic parameters of configurons—elementary excitations resulting from broken bonds—are found from viscosity-temperature relationships. Glass-liquid transition phenomena are described including the configuron model of glass transition which shows a reduction of Hausdorff dimension of bonds at glass-liquid transition.
Hindawi Publishing Corporation
2008-12
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/8539/1/Ojovan_Viscosity%5Bpublished%5D.pdf
Ojovan, M.I. (2008) Viscosity and glass transition in amorphous oxides. Advances in Condensed Matter Physics, 2008. Art. No.817829. ISSN 1687-8108
http://dx.doi.org/10.1155/2008/817829
10.1155/2008/817829
oai:eprints.whiterose.ac.uk:8571
2013-02-08T16:58:21Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/8571/
Improving gas sensing properties of graphene by introducing dopants and defects: a first-principles study
Zhang, Y.H.
Chen, Y.B.
Zhou, K.G.
Liu, C.H.
Zeng, J.
Zhang, H.L.
Peng, Y.
The interactions between four different graphenes (including pristine, B- or N-doped and defective graphenes) and small gas molecules (CO, NO, NO2 and NH3) were investigated by using density functional computations to exploit their potential applications as gas sensors. The structural and electronic properties of the graphene-molecule adsorption adducts are strongly dependent on the graphene structure and the molecular adsorption configuration. All four gas molecules show much stronger adsorption on the doped or defective graphenes than that on the pristine graphene. The defective graphene shows the highest adsorption energy with CO, NO and NO2 molecules, while the B- doped graphene gives the tightest binding with NH3. Meanwhile, the strong interactions between the adsorbed molecules and the modified graphenes induce dramatic changes to graphene's electronic properties. The transport behavior of a gas sensor using B- doped graphene shows a sensitivity two orders of magnitude higher than that of pristine graphene. This work reveals that the sensitivity of graphene-based chemical gas sensors could be drastically improved by introducing the appropriate dopant or defect.
Institute of Physics
2009-05-06
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/8571/2/Peng_Improving_gas.pdf
Zhang, Y.H., Chen, Y.B., Zhou, K.G. et al. (4 more authors) (2009) Improving gas sensing properties of graphene by introducing dopants and defects: a first-principles study. Nanotechnology, 20 (18). Art. No.185504. ISSN 0957-4484
http://dx.doi.org/10.1088/0957-4484/20/18/185504
10.1088/0957-4484/20/18/185504
oai:eprints.whiterose.ac.uk:8730
2013-02-08T16:58:35Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/8730/
A review of some recent developments in polarization-sensitive optical imaging techniques for the study of articular cartilage
Matcher, S.J
This article reviews recent developments in the optical imaging of articular cartilage using polarized-light methods, with an emphasis on tools that could be of use in tissue engineering approaches to treatment. Both second-harmonic generation microscopy and polarization-sensitive optical coherence tomography are described and their potential role in the treatment of cartilage disorders such as osteoarthritis is suggested. Key results are reviewed and future developments are discussed.
American Institute of Physics
2009-05-15
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/8730/1/Matcher_Review.pdf
Matcher, S.J (2009) A review of some recent developments in polarization-sensitive optical imaging techniques for the study of articular cartilage. Journal of Applied Physics, 105 (10). Art. No.102041. ISSN 0021-8979
http://dx.doi.org/10.1063/1.3116620
10.1063/1.3116620
oai:eprints.whiterose.ac.uk:8900
2014-09-15T01:35:40Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4543
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/8900/
Thaumasite form of sulfate attack in limestone cement mortars: A study on long term efficiency of mineral admixtures
Skaropoulou, A.
Tsivilis, S.
Kakali, G.
Sharp, J.
Swamy, R.
Concrete and mortar made from limestone cement may exhibit a lack of durability due to the formation of thaumasite. The addition of minerals that improve the concrete durability is expected to slow down the formation of thaumasite. in this work the effect of natural pozzolana, fly ash, ground granulated blast-furnace slag and metakaolin on the thaumasite formation in limestone cement mortar is examined. A limestone cement, containing 15% w/w limestone, was used. Mortar specimens were prepared by replacing a part of limestone cement with the above minerals. The specimens were immersed in a 1.8% MgSO4 solution and cured at 5 and 25 degrees C. The status of the samples after a storage period of 5 years was reported based on visual inspection, compressive strength, mass measurements, ultrasonic pulse velocity measurements and analytical techniques. It is concluded that the use of specific minerals, as partial replacement of cement, inhibits thaumasite formation in limestone cement mortar. (C) 2008 Elsevier Ltd. All rights reserved.
Elsevier
2009-06
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/8900/2/Swamyrn1.pdf
Skaropoulou, A., Tsivilis, S., Kakali, G. et al. (2 more authors) (2009) Thaumasite form of sulfate attack in limestone cement mortars: A study on long term efficiency of mineral admixtures. Construction and Building Materials, 23 (6). pp. 2338-2345. ISSN 0950-0618
http://dx.doi.org/10.1016/j.conbuildmat.2008.11.004
10.1016/j.conbuildmat.2008.11.004
oai:eprints.whiterose.ac.uk:9000
2014-06-07T08:39:30Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/9000/
Comparisons of elastic and creep deformation linearly dependent upon stress
Greenwood, G.W
The theory of linear elasticity provides a complete description of reversible deformation under small stresses for both isotropic and anisotropic solids. At elevated temperatures, creep deformation sometimes occurs at a rate that is linearly dependent upon stress. When this form of creep arises from vacancy movement, there is possibility of anisotropic behaviour through the orientational dependence of average grain dimensions. This indicates that the elasticity theory may be utilised to provide comparable descriptions of such creep deformation, with creep strain built up of equal increments of strain occurring in equal intervals of time. The extent of this analogy is explored with the conclusion that its usefulness is substantial when grains are small in relation to geometrical features of the component but it is no longer applicable when the grains approach the size of these features and where there is a high gradient of stress.
INSTITUTE OF MATERIALS
2009-04
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/9000/1/Greenwood_1.pdf
Greenwood, G.W (2009) Comparisons of elastic and creep deformation linearly dependent upon stress. Materials Science and Technology -London-, 25 (4). pp. 533-541. ISSN 0267-0836
http://dx.doi.org/10.1179/174328408X322105
10.1179/174328408X322105
oai:eprints.whiterose.ac.uk:9040
2013-02-08T16:58:47Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434E54
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/9040/
Control of the switching behavior of ferromagnetic nanowires using magnetostatic interactions
Basu, S.
Fry, P.W.
Gibs, M.R.J.
Schrefl, T.
Allwood, D.A.
Magnetostatic interactions between two end-to-end Permalloy (Ni80Fe20) nanowires have been studied as a function of their separation, end shape, and width. The change in switching field increases as the wires become closer, with deviations from the switching field of an isolated wire of up to 40% observed. The sign of the change depends on the relative magnetization orientation of the two wires, with higher fields for parallel magnetization and lower fields for antiparallel magnetization. A wire end shape has a strong influence, with larger field variations being seen for flat-ended wires than wires with tapered ends. The micromagnetic modeling and experiments performed here were in good qualitative agreement. The experimental control of switching behavior of one nanowire with another was also demonstrated using magnetostatic interactions.
American Institute of Physics
2009-08-15
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/9040/1/Allwood_Control.pdf
Basu, S., Fry, P.W., Gibs, M.R.J. et al. (2 more authors) (2009) Control of the switching behavior of ferromagnetic nanowires using magnetostatic interactions. Journal of Applied Physics, 105 (8). Art no.083901. ISSN 0021-8979
http://dx.doi.org/10.1063/1.3098251
10.1063/1.3098251
oai:eprints.whiterose.ac.uk:9212
2014-09-15T01:35:26Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4543
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/9212/
Plasma deposition of constrained layer damping coatings
Rongong, J.A.
Goruppa, A.A.
Buravalla, V.R.
Tomlinson, G.R.
Jones, F.R.
Plasma techniques are used to generate constrained layer damping (CLD) coatings on metallic substrates. The process involves the deposition of relatively thick, hard ceramic layers on to soft polymeric damping materials while maintaining the integrity of both layers. Reactive plasma sputter-deposition from an aluminium alloy target is used to deposit alumina layers, with Young's modulus in the range 77-220GPa and thickness up to 335 μ, on top of a silicone film. This methodology is also used to deposit a 40 μ alumina layer on a conventional viscoelastic damping film to produce an integral damping coating. Plasma CLD systems are shown to give at least 50 per cent more damping than equivalent metal-foil-based treatments. Numerical methods for rapid prediction of the performance of such coatings are discussed and validated by comparison with experimental results.
Professional Engineering Publishing
2004
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/9212/2/rongongja9.pdf
Rongong, J.A., Goruppa, A.A., Buravalla, V.R. et al. (2 more authors) (2004) Plasma deposition of constrained layer damping coatings. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 218 (7). pp. 669-680. ISSN 0954-4062
http://dx.doi.org/10.1243/0954406041319581
doi:10.1243/0954406041319581
oai:eprints.whiterose.ac.uk:9877
2013-02-08T16:59:12Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434F4D
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E454545
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/9877/
Evaluation of a cheap ultrasonic stage for light source coherence function measurement, optical coherence tomography and dynamic focusing
Krstajic, N.
Matcher, S.J.
Childs, D.
Steenbergen, W.
Hogg, R.
Smallwood, R.
We evaluate the performance of a cheap ultrasonic stage in setups related to optical coherence tomography. The stage was used in several configurations: (1) optical delay line in an optical coherence tomography (OCT) setup; (2) as a delay line measuring coherence function of a low coherence source (e. g. superluminescent diode) and (3) in a dynamic focusing arrangement. The results are as follows: the stage is suitable for coherence function measurement (coherence length up to 70 mu m) of the light source and dynamic focusing. We found it unsuitable for OCT due to an unstable velocity profile. Despite this, the velocity profile has a repeatable shape (4% over 1000 A-scans) and slight modifications to the stage promise wider applications.
Institute of Physics
2009-10
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/9877/1/Krstajic1.pdf
Krstajic, N., Matcher, S.J., Childs, D. et al. (3 more authors) (2009) Evaluation of a cheap ultrasonic stage for light source coherence function measurement, optical coherence tomography and dynamic focusing. Measurement Science and Technology, 20 (10). Art No.107002. ISSN 0957-0233
http://dx.doi.org/10.1088/0957-0233/20/10/107002
10.1088/0957-0233/20/10/107002
oai:eprints.whiterose.ac.uk:10197
2013-02-08T16:59:36Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4543
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10197/
Fracture mechanisms and failure analysis of carbon fibre/toughened epoxy composites subjected to compressive loading
Jumahat, A.
Soutis, C.
Jones, F.R.
Hodzic, A.
This study investigates the failure mechanisms of unidirectional (UD) HTS40/977-2 toughened resin composites subjected to longitudinal compressive loading. A possible sequence of failure initiation and propagation was proposed based on SEM and optical microscopy observations of failed specimens. The micrographs revealed that the misaligned fibres failed in two points upon reaching maximum micro-bending deformation and two planes of fracture were created to form a kink band. Therefore, fibre microbuckling and fibre kinking models were implemented to predict the compressive strength of LID HTS40/977-2 composite laminate. The analysis identified several parameters that were responsible for the microbuckling and kinking failure mechanisms. The effects of these parameters on the compressive strength of the LID HTS40/977-2 composite systems were discussed. The predicted compressive strength using a newly developed combined modes model showed a very good agreement to the measured value (c) 2009 Elsevier Ltd. All rights reserved
Elsevier
2010-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/10197/1/Soutis1.pdf
text
en
https://eprints.whiterose.ac.uk/10197/2/Soutis2.pdf
text
en
https://eprints.whiterose.ac.uk/10197/3/Soutis3.pdf
Jumahat, A., Soutis, C., Jones, F.R. et al. (1 more author) (2010) Fracture mechanisms and failure analysis of carbon fibre/toughened epoxy composites subjected to compressive loading. Composite Structures, 92 (2). pp. 295-305. ISSN 0263-8223
http://dx.doi.org/10.1016/j.compstruct.2009.08.010
10.1016/j.compstruct.2009.08.010
oai:eprints.whiterose.ac.uk:10252
2013-02-08T16:59:41Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10252/
Structural and thermal study of mesomorphic dodecylammonium carrageenates
Vincekovic, M.
Pustak, A.
Tusek-Bozic, L.
Liu, F.
Ungar, G.
Bujan, M.
Smit, I.
Filipovic-Vincekovic, N.
Structural characteristics and thermal stability of a series of dodecylammonium carrageenates formed by stoichiometric complexation of dodecylammonium chloride and differently charged carrageenans (kappa-, iota- and lambda-carrageenan, respectively) were investigated. IR spectral analysis confirmed the electrostatic and hydrogen bond interactions between the dodecylammonium and carrageenan species. X-ray diffraction experiments show increased ordering in the complexes compared to that in the parent carrageenans. Dodecylammonium carrageenates have a layer structure, in which a polar sublayer contains layers of carrageenan chains and a nonpolar sublayer consists of conformationally disordered dodecylammonium chains electrostatically attached to the carrageenan backbone. The major factor that determines the dodecylammonium carrageenate structure is cationic surfactant, while the carrageenans moiety plays a major role in determining thermal properties. (C) 2009 Elsevier Inc. All rights reserved.
Elsevier
2010-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/10252/1/Ungar_10252.pdf
Vincekovic, M., Pustak, A., Tusek-Bozic, L. et al. (5 more authors) (2010) Structural and thermal study of mesomorphic dodecylammonium carrageenates. Journal of Colloid and Interface Science , 341 (1). pp. 117-123. ISSN 0021-9797
http://dx.doi.org/10.1016/j.jcis.2009.09.021
10.1016/j.jcis.2009.09.021
oai:eprints.whiterose.ac.uk:10262
2010-01-07T10:29:29Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6E6F5F646F63756D656E74735F617661696C61626C65
https://eprints.whiterose.ac.uk/10262/
Carbon nitride: Ab initio investigation of carbon-rich phases
Hart, J.N.
Claeyssens, F.
Allan, N.L.
May, P.W.
We have examined the potential energy hypersurfaces for the carbon-rich phases of carbon nitride, CN and C3N, and discovered low-energy structures different from those reported previously. Trends in the preferred local bonding environments have been analyzed as a function of nitrogen content. For each composition, several structures with similar energies were found, but they have very different equilibrium volumes; the structure produced during synthesis will strongly depend on the preparation conditions. When low densities are favored, conjugated planar-ring structures with sp(2) hybridized carbon are most likely to be formed. These structures are similar to those suggested as potential photocatalytic materials. At high pressures, the preferred structures contain three-coordinate nitrogen and sp(3) hybridized carbon, including the beta-InS structure, which we predict to be the thermodynamically preferred structure for CN under positive hydrostatic pressures. This structure has a moderately high bulk modulus with a lower formation energy than beta-C3N4 and so should be more easily synthesized.
American Physical Society
2009-11
Article
NonPeerReviewed
Hart, J.N., Claeyssens, F., Allan, N.L. et al. (1 more author) (2009) Carbon nitride: Ab initio investigation of carbon-rich phases. Physical Review B , 80 (17). Art No.174111. ISSN 1098-0121
http://dx.doi.org/10.1103/PhysRevB.80.174111
10.1103/PhysRevB.80.174111
oai:eprints.whiterose.ac.uk:10263
2010-01-07T10:29:13Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6E6F5F646F63756D656E74735F617661696C61626C65
https://eprints.whiterose.ac.uk/10263/
Differential patterning of neuronal, glial and neural progenitor cells on phosphorus-doped and UV irradiated diamond-like carbon
Regan, E.M.
Uney, J.B.
Dick, A.D.
Zhang, Y.W.
Nunez-Yanez, J.
McGeehan, J.P.
Claeyssens, F.
Kelly, S.
Diamond-like carbon (DLC) is an attractive biomaterial for coating human implantable devices. Our particular research interest is in developing DLC as a coating material for implants and electrical devices for the nervous system. We previously reported that DLC is not toxic to N2a neuroblastoma cells or primary cortical neurons and showed that phosphorus-doped DLC (P:DLC) could be used to produce patterned neuron networks. In the present study we complement and extend these findings by exploring patterning of dorsal root ganglion (DRG) explants, human neural progenitor cells (hNPC) and U-87 astroglioma cells on P:DLC. Further P:DLC data is provided to highlight that P:DLC can be used as an effective coating material for in vitro multi-electrode arrays (MEAs) with potential for patterning groups of neurons on selected electrodes. We also introduce ultraviolet (UV) irradiation as a simple treatment to render DLC neurocompatible. We show that UV:DLC can be used to support patterned and unpatterned cortical neuron growth. These findings strongly support the use of DLC as tailorable and tuneable substrate to study neural cell biology in vitro and in vivo. We conclude that DLC is a well-suited candidate material for coating implantable devices in the human nervous system. (C) 2009 Elsevier Ltd. All rights reserved.
Elsevier
2010-01
Article
NonPeerReviewed
Regan, E.M., Uney, J.B., Dick, A.D. et al. (5 more authors) (2010) Differential patterning of neuronal, glial and neural progenitor cells on phosphorus-doped and UV irradiated diamond-like carbon. Biomaterials, 31 (2). pp. 207-215. ISSN 0142-9612
http://dx.doi.org/10.1016/j.biomaterials.2009.09.042
10.1016/j.biomaterials.2009.09.042
oai:eprints.whiterose.ac.uk:10268
2014-06-10T18:32:36Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434F4D
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10268/
Exploring hypotheses of the actions of TGF-beta 1 in epidermal wound healing using a 3D computational multiscale model of the human epidermis
Sun, T.
Adra, S.
Smallwood, R.
Holcombe, M.
MacNeil, S.
In vivo and in vitro studies give a paradoxical picture of the actions of the key regulatory factor TGF-beta 1 in epidermal wound healing with it stimulating migration of keratinocytes but also inhibiting their proliferation. To try to reconcile these into an easily visualized 3D model of wound healing amenable for experimentation by cell biologists, a multiscale model of the formation of a 3D skin epithelium was established with TGF-beta 1 literature-derived rule sets and equations embedded within it. At the cellular level, an agent-based bottom-up model that focuses on individual interacting units ( keratinocytes) was used. This was based on literature-derived rules governing keratinocyte behavior and keratinocyte/ECM interactions. The selection of these rule sets is described in detail in this paper. The agent-based model was then linked with a subcellular model of TGF-beta 1 production and its action on keratinocytes simulated with a complex pathway simulator. This multiscale model can be run at a cellular level only or at a combined cellular/subcellular level. It was then initially challenged ( by wounding) to investigate the behavior of keratinocytes in wound healing at the cellular level. To investigate the possible actions of TGF-beta 1, several hypotheses were then explored by deliberately manipulating some of these rule sets at subcellular levels. This exercise readily eliminated some hypotheses and identified a sequence of spatial-temporal actions of TGF-beta 1 for normal successful wound healing in an easy-to-follow 3D model. We suggest this multiscale model offers a valuable, easy-to-visualize aid to our understanding of the actions of this key regulator in wound healing, and provides a model that can now be used to explore pathologies of wound healing.
Public Library Science
2009-12-31
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/10268/1/Smallwood_Exploring.pdf
Sun, T., Adra, S., Smallwood, R. et al. (2 more authors) (2009) Exploring hypotheses of the actions of TGF-beta 1 in epidermal wound healing using a 3D computational multiscale model of the human epidermis. Plos One, 4 (12). Art No.e8515. ISSN 1932-6203
http://dx.doi.org/10.1371/journal.pone.0008515
10.1371/journal.pone.0008515
oai:eprints.whiterose.ac.uk:10305
2014-06-05T03:28:55Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434F4D
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10305/
Agent based modelling helps in understanding the rules by which fibroblasts support keratinocyte colony formation
Sun, T.
McMinn, P.
Holcombe, M.
Smallwood, R.
MacNeil, S.
Background: Autologous keratincoytes are routinely expanded using irradiated mouse fibroblasts and bovine serum for clinical use. With growing concerns about the safety of these xenobiotic materials, it is desirable to culture keratinocytes in media without animal derived products. An improved understanding of epithelial/mesenchymal interactions could assist in this.
Methodology/Principal Findings: A keratincyte/fibroblast o-culture model was developed by extending an agent-based keratinocyte colony formation model to include the response of keratinocytes to both fibroblasts and serum. The model was validated by comparison of the in virtuo and in vitro multicellular behaviour of keratinocytes and fibroblasts in single and co-culture in Greens medium. To test the robustness of the model, several properties of the fibroblasts were changed to investigate their influence on the multicellular morphogenesis of keratinocyes and fibroblasts. The model was then used to generate hypotheses to explore the interactions of both proliferative and growth arrested fibroblasts with keratinocytes. The key predictions arising from the model which were confirmed by in vitro experiments were that 1) the ratio of fibroblasts to keratinocytes would critically influence keratinocyte colony expansion, 2) this ratio needed to be optimum at the beginning of the co-culture, 3) proliferative fibroblasts would be more effective than irradiated cells in expanding keratinocytes and 4) in the presence of an adequate number of fibroblasts, keratinocyte expansion would be independent of serum.
Conclusions: A closely associated computational and biological approach is a powerful tool for understanding complex biological systems such as the interactions between keratinocytes and fibroblasts. The key outcome of this study is the finding that the early addition of a critical ratio of proliferative fibroblasts can give rapid keratinocyte expansion without the use of irradiated mouse fibroblasts and bovine serum.
Public Library Science
2008-05-07
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/10305/1/Smallwood_Agent.pdf
Sun, T., McMinn, P., Holcombe, M. et al. (2 more authors) (2008) Agent based modelling helps in understanding the rules by which fibroblasts support keratinocyte colony formation. Plos One , 3 (5). Art No.e2129. ISSN 1932-6203
http://dx.doi.org/10.1371/journal.pone.0002129
10.1371/journal.pone.0002129
oai:eprints.whiterose.ac.uk:10361
2017-04-13T03:20:47Z
oai:eprints.whiterose.ac.uk:10367
2013-02-08T16:59:57Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10367/
Surface hydration and nanoindentation of silicate glasses
Tadjiev, D.R.
Hand, R.J.
The near-surface mechanical properties of glasses and differences in mechanical behaviour between high and low durability silicate glasses are investigated. Nanoindentation is used to examine the effect of hydration on the near-surface mechanical properties of silicate glasses with varying degrees of chemical durability. It is shown that hydration has little if any effect on high durability glasses even at long immersion times, whereas in low durable glasses hydration reduces the near-surface mechanical properties significantly and the thickness of hydrated layer may exceed the indentation depth. In addition an attempt is made to measure the thickness and mechanical properties of hydrated layer in low durability glasses where influence of the substrate is negligible. (C) 2009 Elsevier B.V. All rights reserved.
Elsevier
2010-01-15
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/10367/1/Hand_10367.pdf
Tadjiev, D.R. and Hand, R.J. (2010) Surface hydration and nanoindentation of silicate glasses. Journal of Non-Crystalline Solids, 356 (2). pp. 102-108. ISSN 0022-3093
http://dx.doi.org/10.1016/j.jnoncrysol.2009.10.005
10.1016/j.jnoncrysol.2009.10.005
oai:eprints.whiterose.ac.uk:10757
2014-06-24T01:23:57Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434E54
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10757/
Transverse field-induced nucleation pad switching modes during domain wall injection
Bryan, M.T.
Fry, P.W.
Schrefl, T.
Gibbs, M.R.J.
Allwood, D.A.
Im, M.Y.
Fischer, P.
We have used magnetic transmission soft X-ray microscopy (M-TXM) to image in-field magnetization configurations of patterned Ni80F20 domain wall "nucleation pads" with attached planar nanowires. Comparison with micromagnetic simulations suggests that the evolution of magnetic domains in rectangular injection pads depends on the relative orientation of closure domains in the remanent state. The magnetization reversal pathway is altered by the inclusion of transverse magnetic fields. These different modes explain previous results of domain wall injection into nanowires.
Institute of Electrical and Electronics Engineers
2010-04
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/10757/1/Allwood_Transverse.pdf
Bryan, M.T., Fry, P.W., Schrefl, T. et al. (4 more authors) (2010) Transverse field-induced nucleation pad switching modes during domain wall injection. IEEE Transactions on Magnetics, 46 (4). pp. 963-967. ISSN 0018-9464
http://dx.doi.org/10.1109/TMAG.2009.2034848
10.1109/TMAG.2009.2034848
oai:eprints.whiterose.ac.uk:10783
2013-02-08T17:00:26Z
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696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10783/
Generation of internal stress and its effects
Greenwood, G.W.
Internal stresses may be generated continually in many polycrystalline materials. Their existence is manifested by changes in crystal defect concentration and arrangement, by surface observations, by macroscopic shape changes and particularly by alteration of mechanical properties when external stresses are simultaneously imposed.
Maney Publishing
2010-04
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/10783/1/Greenwood_10783.pdf
text
en
https://eprints.whiterose.ac.uk/10783/2/Greenwood_10783Figures.pdf
Greenwood, G.W. (2010) Generation of internal stress and its effects. Materials Science and Technology, 26 (4). pp. 398-403. ISSN 0267-0836
http://dx.doi.org/10.1179/026708309X12506933872946
10.1179/026708309X12506933872946
oai:eprints.whiterose.ac.uk:10825
2013-02-08T17:00:28Z
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74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
756E69743D536865666669656C64:536865666669656C642E5F5243:536865666669656C642E434E54
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10825/
Direct imaging of domain-wall interactions in Ni80Fe20 planar nanowires
Hayward, T.J.
Bryan, M.T.
Fry, P.W.
Fundi, P.M.
Gibbs, M.R.J.
Allwood, D.A.
Im, M.Y.
Fischer, P.
We have investigated magnetostatic interactions between domain walls in Ni80Fe20 planar nanowires using magnetic soft x-ray microscopy and micromagnetic simulations. In addition to significant monopole-like attraction and repulsion effects we observe that there is coupling of the magnetization configurations of the walls. This is explained in terms of an interaction energy that depends not only on the distance between the walls, but also upon their internal magnetization structure.
American Physical Society
2010-01
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/10825/1/Allwood__10825.pdf
Hayward, T.J., Bryan, M.T., Fry, P.W. et al. (5 more authors) (2010) Direct imaging of domain-wall interactions in Ni80Fe20 planar nanowires. Physical Review B , 81 (2). Art no.020410. ISSN 1098-0121
http://dx.doi.org/10.1103/PhysRevB.81.020410
10.1103/PhysRevB.81.020410
oai:eprints.whiterose.ac.uk:10840
2017-08-01T01:20:06Z
oai:eprints.whiterose.ac.uk:10897
2013-02-08T17:00:36Z
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74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/10897/
The effect of trapping superparamagnetic beads on domain wall motion
Bryan, M.T.
Dean, J.
Schrefl, T.
Thompson, F.E.
Haycock, J.
Allwood, D.A.
Domain walls may act as localized field sources to trap and move superparamagnetic beads for manipulating biological cells and DNA. The interaction between beads of various diameters and a wall is investigated using a combination of micromagnetic and analytical models. Domain walls can transport beads under applied magnetic fields but the mutual attraction between the bead and wall causes drag forces affecting the bead to couple into the wall motion. Therefore, the interaction with the bead causes a fundamental change in the domain wall dynamics, reducing the wall mobility by five orders of magnitude. (C) 2010 American Institute of Physics. [doi:10.1063/1.3428775]
American Institute of Physics
2010-05-10
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/10897/1/Bryan_10897.pdf
Bryan, M.T., Dean, J., Schrefl, T. et al. (3 more authors) (2010) The effect of trapping superparamagnetic beads on domain wall motion. Applied Physics Letters, 96 (19). Art no.192503. ISSN 0003-6951
http://dx.doi.org/10.1063/1.3428775
10.1063/1.3428775
oai:eprints.whiterose.ac.uk:11246
2013-02-08T17:07:08Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4543:536865666669656C642E414552
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
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https://eprints.whiterose.ac.uk/11246/
Effect of silica nanoparticles on compressive properties of an epoxy polymer
Jumahat, A.
Soutis, C.
Jones, R.F.
Hodzic, A.
The effect of nanosilica on compressive properties of an Epikote 828 epoxy at room temperature was studied. A 40 wt% nanosilica/epoxy masterbatch (nanopox F400) was used to prepare a series of epoxy based nanocomposites with 5-25 wt% nanosilica content. Static uniaxial compression tests were conducted on cubic and cylindrical specimens to study the compressive stress-strain response, failure mechanisms and damage characteristics of the pure and nanomodified epoxy. It was found that the compressive stiffness and strength were improved with increasing nanosilica content without significant reduction in failure strain. The presence of nanosilica improved ductility and promoted higher plastic hardening behaviour after yielding in comparison with the unmodified resin system. This result suggested that nanoparticles introduced additional mechanisms of energy absorption to enhance the compressive properties without reducing the deformation to failure.
Springer
2010-11
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/11246/1/Soutis_11246.pdf
Jumahat, A., Soutis, C., Jones, R.F. et al. (1 more author) (2010) Effect of silica nanoparticles on compressive properties of an epoxy polymer. Journal of Materials Science, 45 (21). pp. 5973-5983. ISSN 0022-2461
http://dx.doi.org/10.1007/s10853-010-4683-1
10.1007/s10853-010-4683-1
oai:eprints.whiterose.ac.uk:42656
2014-06-09T02:02:31Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434F4D
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E454545
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42656/
Quantum dot superluminescent diodes for optical coherence tomography: device engineering
Greenwood, P.D.L.
Childs, D.T.D.
Kennedy, K.
Groom, K.M.
Hugues, M.
Hopkinson, M.
Hogg, R.A.
Krstajic, N.
Smith, L.E.
Matcher, S.J.
Bonesi, M.
MacNeil, S.
Smallwood, R.
We present a 18 m W fiber-coupled single-mode super-luminescent diode with 85 nm bandwidth for application in optical coherence tomography (OCT). First, we describe the effect of quantum dot (QD) growth temperature on optical spectrum and gain, highlighting the need for the optimization of epitaxy for broadband applications. Then, by incorporating this improved material into a multicontact device, we show how bandwidth and power can be controlled. We then go on to show how the spectral shape influences the autocorrelation function, which exhibits a coherence length of < 11 mu m, and relative noise is found to be 10 dB lower than that of a thermal source. Finally, we apply the optimum device to OCT of in vivo skin and show the improvement that can be made with higher power, wider bandwidth, and lower noise, respectively.
Institute of Electrical and Electronics Engineers
2010
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42656/1/Childs_Quantum.pdf
Greenwood, P.D.L., Childs, D.T.D., Kennedy, K. et al. (10 more authors) (2010) Quantum dot superluminescent diodes for optical coherence tomography: device engineering. IEEE Journal of Selected Topics in Quantum Electronics, 16 (4). pp. 1015-1022. ISSN 1077-260X
http://dx.doi.org/10.1109/JSTQE.2009.2038720
10.1109/JSTQE.2009.2038720
oai:eprints.whiterose.ac.uk:42719
2016-11-18T17:09:51Z
7374617475733D707562
74797065733D61727469636C65
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
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https://eprints.whiterose.ac.uk/42719/
Investigation into high-temperature corrosion in a large-scale municipal waste-to-energy plant
Phongphiphat, A.
Ryu, C.
Yang, Y.B.
Finney, K.N.
Leyland, A.
Sharifi, V.N.
Swithenbank, J.
High-temperature corrosion in the superheater of a large-scale waste-to-energy plant was investigated. A comparison of nickel-/iron-based alloys and austenitic stainless steel probes placed in the furnace demonstrated that temperature and particle deposition greatly influence corrosion. Nickel-based alloys performed better than the other metal alloys, though an aluminide coating further increased their corrosion resistance. Sacrificial baffles provided additional room for deposit accumulation, resulting in vigorous deposit-induced corrosion. Computational modelling (FLUENT code) was used to simulate flow characteristics and heat transfer. This study has shown that the use of aluminide coatings is a promising technique for minimising superheater corrosion in such facilities. (C) 2010 Elsevier Ltd. All rights reserved.
Elsevier
2010-12
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42719/2/Finney_42719.pdf
Phongphiphat, A., Ryu, C., Yang, Y.B. et al. (4 more authors) (2010) Investigation into high-temperature corrosion in a large-scale municipal waste-to-energy plant. Corrosion Science, 52 (12). pp. 3861-3874. ISSN 0010-938X
http://dx.doi.org/10.1016/j.corsci.2010.07.032
10.1016/j.corsci.2010.07.032
oai:eprints.whiterose.ac.uk:42945
2013-02-08T17:31:39Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/42945/
Long-term field and laboratory leaching tests of cemented radioactive wastes
Ojovan, M.I.
Varlackova, G.A.
Golubeva, Z.I.
Burlaka, O.N.
Experiments with real and simulated radioactive cementitious wasteforms were set up to compare the leaching behaviour of cementitious wasteforms containing nuclear power plant operational waste in field and laboratory test conditions. Experiments revealed that the average annual Cs-137 leach rate in deionised water was about thirty-five times greater compared with the measured average value for the 1st year of the field test. Cumulative leached fraction of Cs-137 for 1st year (3.74%) was close to values reported in literature for similar laboratory experiments in deionised water, however more than two orders of magnitude higher than the 1st year leached fraction of Cs-137 in the repository test (0.01%). Therefore, to compare field and laboratory test results, a scaling factor is required in order to account for surface to volume factor difference, multiplied by a temperature factor and a leach rate decrease coefficient related to the ground water composition. (C) 2011 Elsevier B.V. All rights reserved.
Elsevier
2011-03-15
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/42945/1/WRRO_42945.pdf
Ojovan, M.I., Varlackova, G.A., Golubeva, Z.I. et al. (1 more author) (2011) Long-term field and laboratory leaching tests of cemented radioactive wastes. Journal of Hazardous Materials, 187 (1-3). pp. 296-302. ISSN 0304-3894
http://dx.doi.org/10.1016/j.jhazmat.2011.01.004
10.1016/j.jhazmat.2011.01.004
oai:eprints.whiterose.ac.uk:43092
2014-06-14T13:53:22Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E454545
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/43092/
Common path Fourier domain optical coherence tomography based on multiple reflections within the sample arm
Krstajic, N.
Hogg, R.
Matcher, S.J.
We present a common path Fourier domain optical coherence tomography (FDOCT) setup where the reference signal arises from multiple reflections within the sample arm. Two configurations are demonstrated. The first is based on a reflective microscope objective while the second is based on a normal (refractive) microscope objective. The second configuration is effectively a Mireau interferometer. We present a sensitivity analysis of these setups and images of in vivo skin. Advantages of both common path arrangements include: 1) the reference surface is not close to the sample surface while keeping the optical path lengths matched (so the additional interferometer is not needed) and 2) the user can independently control reference and sample arm power. Additionally, the configuration using the refractive objective ensures that the coherence gate and focus gate always match. A disadvantage is that the reference arm power in certain circumstances is not optimal (i.e. close to saturating the CCD). However, this issue can be removed by a light source of sufficient output power. We believe the idea is scalable and therefore of interest to endoscopy applications. (C) 2011 Elsevier B.V. All rights reserved.
Elsevier
2011
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/43092/2/WRRO_43092.pdf
Krstajic, N., Hogg, R. and Matcher, S.J. (2011) Common path Fourier domain optical coherence tomography based on multiple reflections within the sample arm. Optics Communications, 284 (12). pp. 3168-3172. ISSN 0030-4018
http://dx.doi.org/10.1016/j.optcom.2011.02.073
10.1016/j.optcom.2011.02.073
oai:eprints.whiterose.ac.uk:43230
2013-02-08T17:33:39Z
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696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/43230/
A mathematical approach to transformation toughening in bulk metallic glasses
Corteen, J.
Rainforth, M.
Todd, I.
A mathematical framework used to describe transformation toughening in zirconia-based ceramics is adapted to apply to transformation toughening in bulk metallic glass matrix composites. The method is applied to the Cu(47.5)Zr(47.5)Al(5) bulk metallic glass, showing that the low volume change of transformation in this alloy leads to negligible toughening via the proposed mechanism. An alternative mechanism for toughening is presented, whereby shear bands propagate more easily in the early stages of advance. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Elsevier
2011
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/43230/2/WRRO_43230.pdf
text
en
https://eprints.whiterose.ac.uk/43230/3/WRRO_43230%282%29.pdf
Corteen, J., Rainforth, M. and Todd, I. (2011) A mathematical approach to transformation toughening in bulk metallic glasses. Scripta Materialia, 65 (6). pp. 524-527. ISSN 1359-6462
http://dx.doi.org/10.1016/j.scriptamat.2011.06.018
10.1016/j.scriptamat.2011.06.018
oai:eprints.whiterose.ac.uk:43681
2013-02-08T17:36:42Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/43681/
Transverse and vortex domain wall structure in magnetic nanowires with uniaxial in-plane anisotropy
Bryan, M.T.
Bance, S.
Dean, J.
Schrefl, T.
Allwood, D.A.
Micromagnetic and analytical models are used to investigate how in-plane uniaxial anisotropy affects transverse and vortex domain walls in nanowires where shape anisotropy dominates. The effect of the uniaxial anisotropy can be interpreted as a modification of the effective wire dimensions. When the anisotropy axis is aligned with the wire axis (theta(a) = 0), the wall width is narrower than when no anisotropy is present. Conversely, the wall width increases when the anisotropy axis is perpendicular to the wire axis (theta(a) = pi/2). The anisotropy also affects the nanowire dimensions at which transverse walls become unstable. This phase boundary shifts to larger widths or thicknesses when theta(a) = 0, but smaller widths or thicknesses when theta(a) = pi/2.
Institute of Physics
2012-01-18
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/43681/1/WRRO_43681.pdf
Bryan, M.T., Bance, S., Dean, J. et al. (2 more authors) (2012) Transverse and vortex domain wall structure in magnetic nanowires with uniaxial in-plane anisotropy. Journal of Physics -Condensed Matter, 24 (2). Art no. 024205. ISSN 0953-8984
http://dx.doi.org/10.1088/0953-8984/24/2/024205
10.1088/0953-8984/24/2/024205
oai:eprints.whiterose.ac.uk:43686
2013-02-08T17:36:44Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/43686/
Thermally-induced cation disorder in LiFePO(4)
Biendicho, J.J.
West, A.R.
LiFePO(4) has a fully ordered olivine structure in samples prepared by solid state reaction below similar to 800 degrees C but, with increasing temperature, a small amount of Li and Fe site exchange occurs reaching a value of about 4% just below melting at 975 degrees C. The disorder is reversible on annealing at lower temperatures and is detected by changes in lattice parameters and in cation site occupancies obtained by Rietveld refinement of X-ray powder diffraction data. (C) 2011 Elsevier B.V. All rights reserved.
Elsevier
2011-11-16
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/43686/1/WRRO_43686.pdf
Biendicho, J.J. and West, A.R. (2011) Thermally-induced cation disorder in LiFePO(4). Solid State Ionics, 203 (1). pp. 33-36. ISSN 0167-2738
http://dx.doi.org/10.1016/j.ssi.2011.08.006
10.1016/j.ssi.2011.08.006
oai:eprints.whiterose.ac.uk:43690
2013-02-08T17:36:47Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/43690/
The role of matrix cracks and fibre/matrix debonding on the stress transfer between fibre and matrix in a single fibre fragmentation test
Johnson, A.C.
Hayes, S.A.
Jones, F.R.
The single fibre fragmentation test is commonly used to characterise the fibre/matrix interface. During fragmentation, the stored energy is released resulting in matrix cracking and/or fibre/matrix debonding.
Axisymmetric finite element models were formulated to study the impact of matrix cracks and fibre/matrix debonding on the effective stress transfer efficiency (EST) and stress transfer length (STL). At high strains, plastic deformation in the matrix dominated the stress transfer mechanism. The combination of matrix cracking and plasticity reduced the EST and increased STL.
For experimental validation, three resins were formulated and the fragmentation of an unsized and uncoupled E-glass fibre examined as a function of matrix properties. Fibre failure was always accompanied by matrix cracking and debonding. With the stiff resin, debonding, transverse matrix cracking and conical crack initiation were observed. With a lower modulus and lower yield strength resin the transverse matrix crack length decreased while that of the conical crack increased. (C) 2011 Elsevier Ltd. All rights reserved.
Elsevier
2012-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/43690/1/WRRO_43690.pdf
Johnson, A.C., Hayes, S.A. and Jones, F.R. (2012) The role of matrix cracks and fibre/matrix debonding on the stress transfer between fibre and matrix in a single fibre fragmentation test. Composites Part A Applied Science and Manufacturing, 43 (1). pp. 65-72. ISSN 1359-835X
http://dx.doi.org/10.1016/j.compositesa.2011.09.005
10.1016/j.compositesa.2011.09.005
oai:eprints.whiterose.ac.uk:43898
2014-09-15T03:39:49Z
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7072696D6F3D6E6F5F646F63756D656E74735F617661696C61626C65
https://eprints.whiterose.ac.uk/43898/
Protein binding on stepped calcite surfaces: simulations of ovocleidin-17 on calcite {31.16} and {31.8}
Freeman, C. L.
Harding, J. H.
Quigley, D.
Rodger, P. M.
Simulations using classical molecular dynamics are reported on the binding of the protein Ovocleidin-17 to calcite stepped surfaces. vicinal surfaces ({31.8} and {31.16}) are used to obtain acute and obtuse steps. The simulations demonstrate that binding is greater at the obtuse step.
A range of analytical methods is used to show the importance of surface and local water structure
for protein binding. We discuss the general features of molecular binding in the light of these results. Our analysis shows that it is unlikely that Ovocleidin-17 is important in controlling crystal morphology; its main role is likely to be in controlling calcite nucleation.
Royal Society of Chemistry
2012
Article
PeerReviewed
Freeman, C. L., Harding, J. H., Quigley, D. et al. (1 more author) (2012) Protein binding on stepped calcite surfaces: simulations of ovocleidin-17 on calcite {31.16} and {31.8}. Physical Chemistry Chemical Physics, 14. pp. 7287-7295. ISSN 1463-9076
http://dx.doi.org/10.1039/c2cp23987f
10.1039/c2cp23987f
oai:eprints.whiterose.ac.uk:73424
2013-02-08T17:39:03Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/73424/
The nature of the hole states in Li doped NiO
Harding, John
Chen, Hungru
We have performed density functional calculations on Li0.125Ni0.875O using both the HSE06 hybrid functional and the DFT+U method. Contrary to previous calculations, both methods show that the system is better described with the hole localized on the nickel ion (which is thus formally Ni3+) rather than in the oxygen valence band. We discuss the experimental results in the light of this finding and show that it is consistent with the available data.
American Physical Society
2012-03-28
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/73424/1/WRRO_73424.pdf
Harding, John and Chen, Hungru (2012) The nature of the hole states in Li doped NiO. Physical Review B (PRB), 85 (11). p. 115127. ISSN 1098-0121
http://dx.doi.org/10.1103/PhysRevB.85.115127
10.1103/PhysRevB.85.115127
oai:eprints.whiterose.ac.uk:74868
2013-02-08T17:41:46Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/74868/
First principles study of intrinsic point defects in hexagonal barium titanate
Dawson, J.A.
Harding, J.H.
Chen , H.R.
Sinclair, D.C.
Density functional theory (DFT) calculations have been used to study the nature of intrinsic defects in the hexagonal polymorph of barium titanate. Defect formation energies are derived for multiple charge states and due consideration is given to finite-size effects (elastic and electrostatic) and the band gap error in defective cells. Correct treatment of the chemical potential of atomic oxygen means that it is possible to circumvent the usual errors associated with the inaccuracy of DFT calculations on the oxygen dimer. Results confirm that both mono- and di-vacancies exist in their nominal charge states over the majority of the band gap. Oxygen vacancies are found to dominate the system in metal-rich conditions with face sharing oxygen vacancies being preferred over corner sharing oxygen vacancies. In oxygen-rich conditions, the dominant vacancy found depends on the Fermi level. Binding energies also show the preference for metal-oxygen di-vacancy formation. Calculated equilibrium concentrations of vacancies in the system are presented for numerous temperatures. Comparisons are drawn with the cubic polymorph as well as with previous potential-based simulations and experimental results.
American Institute of Physics
2012-05-12
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/74868/1/WRRO_74868.pdf
Dawson, J.A., Harding, J.H., Chen , H.R. et al. (1 more author) (2012) First principles study of intrinsic point defects in hexagonal barium titanate. Journal of Applied Physics, 111 (9). Art no. 094108. ISSN 0021-8979
http://dx.doi.org/10.1063/1.4711099
10.1063/1.4711099
oai:eprints.whiterose.ac.uk:74869
2013-02-08T17:41:46Z
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74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/74869/
Nature of the hole states in Li-doped NiO
Chen, H.R.
Harding, J.H.
We have performed density functional calculations on Li0.125Ni0.875O using both the HSE06 hybrid functional and the density functional theory (DFT) + U method. Contrary to previous calculations, both methods show that the system is better described with the hole localized on the nickel ion (which is thus formally Ni3+) rather than in the oxygen valence band. We discuss the experimental results in the light of this finding and show that it is consistent with the available data.
American Physical Society
2012-03-28
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/74869/1/WRRO_74869.pdf
Chen, H.R. and Harding, J.H. (2012) Nature of the hole states in Li-doped NiO. Physical Review B (PRB), 85 (11). pp. 115-127. ISSN 1098-0121
http://dx.doi.org/10.1103/PhysRevB.85.115127
10.1103/PhysRevB.85.115127
oai:eprints.whiterose.ac.uk:74870
2013-02-08T17:41:47Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/74870/
Molecular dynamics studies of the bonding properties of amorphous silicon nitride coatings on crystalline silicon
Butler, K.T.
Lamers, M.P.W.E.
Weeber , A.W.
Harding, J.H.
In this paper we present molecular dynamics simulations of silicon nitride, both in bulk and as an interface to crystalline silicon. We investigate, in particular, the bonding structure of the silicon nitride and analyze the simulations to search for de- fective geometries which have been identified as potential charge carrier traps when silicon nitride forms an interface with silicon semiconductors. The simulations reveal how the bonding patterns in silicon nitride are dependent upon the stoichiometry of the system. Furthermore we demonstrate how having an “interphase”, where the nitrogen content in silicon gradually reduces towards pure silicon across a boundary region, as opposed to an interface where there is an abrupt drop in nitrogen con- centration at the boundary, can result in significantly different numbers of certain important carrier trap
American Institute of Physics
2011-12-11
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/74870/1/WRRO_74870.pdf
Butler, K.T., Lamers, M.P.W.E., Weeber , A.W. et al. (1 more author) (2011) Molecular dynamics studies of the bonding properties of amorphous silicon nitride coatings on crystalline silicon. Journal of Applied Physics, 84 (8). Art no. 085108. ISSN 0021-8979
http://dx.doi.org/10.1063/1.3670068
10.1063/1.3670068
oai:eprints.whiterose.ac.uk:74871
2013-02-08T17:41:47Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/74871/
Nature of the hole states in Li-doped NiO
Chen, H.R.
Harding, J.H.
We have performed density functional calculations on Li0.125Ni0.875O using both the HSE06 hybrid functional and the density functional theory (DFT) + U method. Contrary to previous calculations, both methods show that the system is better described with the hole localized on the nickel ion (which is thus formally Ni3+) rather than in the oxygen valence band. We discuss the experimental results in the light of this finding and show that it is consistent with the available data.
American Physical Society
2012-03-28
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/74871/2/WRRO_74871.pdf
Chen, H.R. and Harding, J.H. (2012) Nature of the hole states in Li-doped NiO. Physical Review B (PRB), 85 (11). pp. 115-127. ISSN 1098-0121
http://dx.doi.org/10.1103/PhysRevB.85.115127
10.1103/PhysRevB.85.115127
oai:eprints.whiterose.ac.uk:74872
2013-02-08T17:41:47Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/74872/
First principles study of intrinsic point defects in hexagonal barium titanate
Dawson, J.A.
Harding, J.H.
Chen , H.R.
Sinclair, D.C.
Density functional theory (DFT) calculations have been used to study the nature of intrinsic defects in the hexagonal polymorph of barium titanate. Defect formation energies are derived for multiple charge states and due consideration is given to finite-size effects (elastic and electrostatic) and the band gap error in defective cells. Correct treatment of the chemical potential of atomic oxygen means that it is possible to circumvent the usual errors associated with the inaccuracy of DFT calculations on the oxygen dimer. Results confirm that both mono- and di-vacancies exist in their nominal charge states over the majority of the band gap. Oxygen vacancies are found to dominate the system in metal-rich conditions with face sharing oxygen vacancies being preferred over corner sharing oxygen vacancies. In oxygen-rich conditions, the dominant vacancy found depends on the Fermi level. Binding energies also show the preference for metal-oxygen di-vacancy formation. Calculated equilibrium concentrations of vacancies in the system are presented for numerous temperatures. Comparisons are drawn with the cubic polymorph as well as with previous potential-based simulations and experimental results.
American Institute of Physics
2012-05-12
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/74872/1/WRRO_74872.pdf
Dawson, J.A., Harding, J.H., Chen , H.R. et al. (1 more author) (2012) First principles study of intrinsic point defects in hexagonal barium titanate. Journal of Applied Physics, 111 (9). Article number: 094108. ISSN 0021-8979
http://dx.doi.org/10.1063/1.4711099
10.1063/1.4711099
oai:eprints.whiterose.ac.uk:74873
2014-09-15T03:35:21Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/74873/
Stoichiometrically graded SiNx for improved surface passivation in high performance solar cells
Butler, K.T.
Harding, J.H.
Lamers, M.P.W.E.
Weeber, A.W.
The effects of an interface gradient in nitrogen concentration on a number of important properties of amorphous hydrogenated silicon nitride / crystalline silicon (a-SiNx:H/c-Si) interfaces in the context of solar cell devices are investigated using molecular dynamics simulations. We simulate interfaces with a gradient of nitrogen which goes from SiN1.2 to Si over widths from 2 9 nm, in the presence of 10 at % hydrogen, to recreate the conditions present when SiNx layers are deposited onto c-Si by plasma enhanced vapour deposition. We examine how changing the width of the nitrogen gradient can affect a number of atomic level structural properties which influence the optical and electrical performance of solar cells. We examine the trajectories of our simulations to search for certain geometries which have previously been identified as being important at this interface. Silicon- silicon and silicon hydrogen bonds, which are help to determine the refractive index of the interface are shown to increase with increasing N gradient width. The fixed charge in the interface is also shown to increase with the width of the gradient. The results demonstrate how altering the width of the N layer can affect the efficiency of a-SiNx:H as both an anti-reflective coating and a passivation layer, and we suggest an optimal gradient width of, in the region of, 2 nm
American Institute of Physics
2012-11-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/74873/2/WRRO_74873.pdf
Butler, K.T., Harding, J.H., Lamers, M.P.W.E. et al. (1 more author) (2012) Stoichiometrically graded SiNx for improved surface passivation in high performance solar cells. Journal of Applied Physics, 112 (9). Article number: 094303. ISSN 0021-8979
http://dx.doi.org/10.1063/1.4764012
10.1063/1.4764012
oai:eprints.whiterose.ac.uk:74889
2013-02-08T17:41:47Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/74889/
Charge disproportionation and Jahn-Teller distortion in LiNiO2 and NaNiO2: A density functional theory study
Chen, H.R.
Freeman, C.L.
Harding, J.H.
Density functional theory calculations have been performed on three potential ground-state configurations of LiNiO2 and NaNiO2. These calculations show that, whereas NaNiO2 shows the expected cooperative Jahn-Teller distortion (and therefore a crystal structure with C2/m symmetry), LiNiO2 shows at least two possible crystal structures very close in energy (within 3 meV/f.u.): P21/c and P2/c. Moreover, one of them (P2/c) shows charge disproportionation of the (expected) Ni3+ cations into Ni2+ and Ni4+. We discuss the implications of this complex ground state for the interpretation of the available electron and neutron structure data, its electronic and complex magnetic behaviour.
American Physical Society
2011-08-19
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/74889/1/WRRO_74889.pdf
Chen, H.R., Freeman, C.L. and Harding, J.H. (2011) Charge disproportionation and Jahn-Teller distortion in LiNiO2 and NaNiO2: A density functional theory study. Physical Review B (PRB), 84 (8). Article number: 085108. ISSN 1098-0121
http://dx.doi.org/ 10.1103/PhysRevB.84.085108
10.1103/PhysRevB.84.085108
oai:eprints.whiterose.ac.uk:74890
2013-02-08T17:41:47Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/74890/
Structural and electronic properties of silver/silicon interfaces and implications for solar cell performance
Butler, K.T.
Vollum, P.E.
Muggerud, A.M.
Cabrera, E
Harding, J.H.
We present the results of an experimental and atomistic modelling investigation of the Sili- con/Silver (Si/Ag) interfaces found in industrial solar cells. We use small ab initio calculations to parameterize a new interatomic potential for the Si/Ag interaction. This interatomic potential is then validated against larger ab initio calculations as well as the results of previous experimental and theoretical studies of Si/Ag systems. The interatomic potential allows us to perform a large- scale search of the conformational space of Si/Ag interfaces identified from transmission electron microscopy (TEM) studies. The most favourable geometries thus identified are then used as the input for more accurate ab initio calculations. We demonstrate that the two interfaces which we identify experimentally have significantly different geometric and electronic structures. We also demonstrate how these different structures result in significantly different Schottky barriers at the interfaces.
American Physical Society
2011-06-07
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/74890/1/WRRO_74890.pdf
Butler, K.T., Vollum, P.E., Muggerud, A.M. et al. (2 more authors) (2011) Structural and electronic properties of silver/silicon interfaces and implications for solar cell performance. Physical Review B (PRB), 83 (23). Article number: 235307. ISSN 1098-0121
http://dx.doi.org/10.1103/PhysRevB.83.235307
10.1103/PhysRevB.83.235307
oai:eprints.whiterose.ac.uk:76937
2013-11-05T12:39:23Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/76937/
Postulates on electromagnetic activity in biological systems and cancer
Pokorny, J
Pokorny, J
Kobilkova, J
A framework of postulates is formulated to define the existence, nature, and function of a coherent state far from thermodynamic equilibrium in biological systems as an essential condition for the existence of life. This state is excited and sustained by energy supply. Mitochondria producing small packets of energy in the form of adenosine and guanosine triphosphate and strong static electric field around them form boundary elements between biochemical-genetic and physical processes. The transformation mechanism of chemical energy into useful work for biological needs and the excitation of the coherent state far from thermodynamic equilibrium are fundamental problems. The exceptional electrical polarity of biological objects and long-range interactions suggest a basic role of the endogenous electromagnetic field generated by living cells. The formulated postulates encompass generation, properties and function of the electromagnetic field connected with biological activity and its pathological deviations. Excited longitudinal polar oscillations in microtubules in eukaryotic cells generate the endogenous electromagnetic field. The metabolic activity of mitochondria connected with water ordering forms conditions for excitation. The electrodynamic field plays an important role in the establishment of coherence, directional transport, organization of morphological structures, interactions, information transfer, and brain activity. An overview of experimental results and physical models supporting the postulates is included. The existence of the endogenous biological electromagnetic field, its generation by microtubules and supporting effects produced by mitochondria have a reasonable experimental foundation. Cancer transformation is a pathological reduction of the coherent energy state far from thermodynamic equilibrium. Malignancy, i.e. local invasion and metastasis, is a direct consequence of mitochondrial dysfunction, disturbed microtubule polar oscillations and the generated electromagnetic field.
The Royal Society of Chemistry
2013-10-14
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/76937/1/Full_Pokorny.pdf
Pokorny, J, Pokorny, J and Kobilkova, J (2013) Postulates on electromagnetic activity in biological systems and cancer. Integrative Biology. - .
http://dx.doi.org/10.1039/C3IB40166A
10.1039/C3IB40166A
oai:eprints.whiterose.ac.uk:78349
2014-04-22T12:55:10Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78349/
Oriented crystal growth on organic monolayers
Harding, JH
Freeman, CL
Duffy, DM
RSCPublishing
2014-02-28
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78349/1/Full_Harding.pdf
Harding, JH, Freeman, CL and Duffy, DM (2014) Oriented crystal growth on organic monolayers. CRYSTENGCOMM, 16 (8). 1430 - 1438. ISSN 1466-8033
http://dx.doi.org/10.1039/c3ce41677a
10.1039/c3ce41677a
oai:eprints.whiterose.ac.uk:78579
2014-04-17T14:26:52Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78579/
Dissolution of UK high-level waste glass under simulated hyperalkaline conditions of a colocated geological disposal facility
Corkhill, CL
Cassingham, NJ
Heath, PG
Hyatt, NC
We report analysis of chemical durability of UK HLW MW+25% simulant glass under model hyperalkaline conditions of a colocated geological disposal facility. Glass powders and monoliths were dissolved for 168 days in saturated Ca(OH). Dissolution in the presence of high concentrations of Ca (>200 mg/L) was an order of magnitude lower than dissolution in water. Dissolution of Si did not occur until a Ca:Si ratio of <2 was achieved. The mechanism of dissolution involved the incorporation of Ca into the hydrated surface (initial, incubation regime), the precipitation of C-S-H phases, including a range of compositions in the C-(N)-(A)-S-H and M-S-H systems (intermediate regime), and the precipitation of C-S-H phases (the residual regime). Thermodynamic analysis and consideration of the CaO-SiO-HO phase diagram suggest that the rate-limiting step of glass dissolution in Ca-rich solutions is Ca-Si equilibrium, involving the precipitation of C-S-H phases, which change in chemical composition as a function of solution chemistry. In low SA/V ratio experiments, the dissolution progressed only to the initial incubation regime, resulting from fewer surface sites for Ca incorporation. Overall, these results suggest that Ca and Si in solution play an important role in the long-term durability of UK HLW in Ca-rich solutions. © 2013 The Authors. International Journal of Applied Glass Science published by John Wiley & Sons Ltd on behalf of The American Ceramic Society and Wiley Periodicals, Inc.
Wiley
2013-12
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78579/1/Full_Corkhill.pdf
Corkhill, CL, Cassingham, NJ, Heath, PG et al. (1 more author) (2013) Dissolution of UK high-level waste glass under simulated hyperalkaline conditions of a colocated geological disposal facility. International Journal of Applied Glass Science, 4 (4). 341 - 356. ISSN 2041-1286
http://dx.doi.org/10.1111/ijag.12042
10.1111/ijag.12042
oai:eprints.whiterose.ac.uk:78686
2014-04-25T13:24:50Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78686/
Monitoring Fibrous Scaffold Guidance of Three-Dimensional Collagen Organisation Using Minimally-Invasive Second Harmonic Generation
Delaine-Smith, RM
Green, NH
Matcher, SJ
MacNeil, S
Reilly, GC
PLOS
2014-02-28
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78686/1/Monitoring_Fibrous.pdf
Delaine-Smith, RM, Green, NH, Matcher, SJ et al. (2 more authors) (2014) Monitoring Fibrous Scaffold Guidance of Three-Dimensional Collagen Organisation Using Minimally-Invasive Second Harmonic Generation. PLOS ONE, 9 (2). e89761. ISSN 1932-6203
http://dx.doi.org/10.1371/journal.pone.0089761
10.1371/journal.pone.0089761
oai:eprints.whiterose.ac.uk:78697
2014-04-25T14:32:26Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78697/
Real-Time Gamma Imaging of Technetium Transport through Natural and Engineered Porous Materials for Radioactive Waste Disposal
Corkhill, CL
Bridge, JW
Chen, XC
Hillel, P
Thornton, SF
Romero-Gonzalez, ME
Banwart, SA
Hyatt, NC
American Chemical Society
2013-12-03
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78697/1/Realtime_Gamma.pdf
Corkhill, CL, Bridge, JW, Chen, XC et al. (5 more authors) (2013) Real-Time Gamma Imaging of Technetium Transport through Natural and Engineered Porous Materials for Radioactive Waste Disposal. ENVIRONMENTAL SCIENCE & TECHNOLOGY, 47 (23). 13857 - 13864. ISSN 0013-936X
http://dx.doi.org/10.1021/es402718j
10.1021/es402718j
oai:eprints.whiterose.ac.uk:78735
2014-04-28T13:41:38Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78735/
Remediation of soils contaminated with particulate depleted uranium by multi stage chemical extraction
Crean, D.E
Livens, F.R
Sajih, M
Stennett, M.C
Grolimund, D
Borca, C.N
Hyatt, N.C
Contamination of soils with depleted uranium (DU) from munitions firing occurs in conflict zones and at
test firing sites. This study reports the development of a chemical extraction methodology for remediation
of soils contaminated with particulate DU. Uranium phases in soils from two sites at a UK firing range,
MOD Eskmeals, were characterised by electron microscopy and sequential extraction. Uranium rich particles
with characteristic spherical morphologies were observed in soils, consistent with other instances of
DU munitions contamination. Batch extraction efficiencies for aqueous ammonium bicarbonate (42–50%
total DU extracted), citric acid (30–42% total DU) and sulphuric acid (13–19% total DU) were evaluated.
Characterisation of residues from bicarbonate-treated soils by synchrotron microfocus X-ray diffraction
and X-ray absorption spectroscopy revealed partially leached U(IV)-oxide particles and some secondary
uranyl-carbonate phases. Based on these data, a multi-stage extraction scheme was developed utilising
leaching in ammonium bicarbonate followed by citric acid to dissolve secondary carbonate species. Site
specific U extraction was improved to 68–87% total U by the application of this methodology, potentially
providing a route to efficient DU decontamination using low cost, environmentally compatible reagents
Elsevier
2013-12-15
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78735/1/WRRO_78735.pdf
Crean, D.E, Livens, F.R, Sajih, M et al. (4 more authors) (2013) Remediation of soils contaminated with particulate depleted uranium by multi stage chemical extraction. Journal of Hazardous Materials, 263 (2). 382 - 390. ISSN 0304-3894
http://dx.doi.org/10.1016/j.jhazmat.2013.08.013
10.1016/j.jhazmat.2013.08.013
oai:eprints.whiterose.ac.uk:78748
2014-04-28T14:46:48Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78748/
Thermal treatment of simulant plutonium contaminated materials from the Sellafield site by vitrification in a blast-furnace slag
Hyatt, N.C
Schwarz, R.R
Bingham, P.A
Stennett, M.C
Corkhill, C.L
Heath, P.G
Hand, R.J
James, M
Pearson, A
Morgan, S
Four waste simulants, representative of Plutonium Contaminated Materials (PCMs) at the Sellafield site,
were vitrified through additions of Ground Granulated Blast-furnace Slag (GGBS). Ce (as a Pu surrogate)
was effectively partitioned into the slag product, enriched in an amorphous CaO–Fe2O3–Al2O3–SiO2 phase
when other crystalline phases were also present. Ce L3 edge XANES data demonstrated Ce to be present as
trivalent species in the slag fraction, irrespective of the waste type. Estimated volume reductions of ca.
80–95% were demonstrated, against a baseline of uncompacted 200 L PCM waste drums. The dissolution
behaviour of PCM slag wasteforms was investigated at 50 �C in saturated Ca(OH)2 solution under N2
atmosphere, to simulate the hyperalkaline anoxic environment of a cementitious UK Geological Disposal
Facility for Intermediate Level Waste (ILW). These experiments demonstrated the performance of the slag
wasteforms to be comparable to that of other vitrified ILW materials considered potentially suitable for
geological disposal
Elsevier
2014-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78748/1/WRRO_78748.pdf
Hyatt, N.C, Schwarz, R.R, Bingham, P.A et al. (7 more authors) (2014) Thermal treatment of simulant plutonium contaminated materials from the Sellafield site by vitrification in a blast-furnace slag. Journal of Nuclear Materials, 444 (1-3). 186 - 199. ISSN 0022-3115
http://dx.doi.org/10.1016/j.jnucmat.2013.08.019
10.1016/j.jnucmat.2013.08.019
oai:eprints.whiterose.ac.uk:78883
2014-05-08T15:08:00Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/78883/
Influence of Lubricants and Attrition Milling Parameters on the Quality of Zirconolite Ceramics, Consolidated by Hot Isostatic Pressing, for Immobilization of Plutonium
Squire, J
Maddrell, E.R
Hyatt, N.C
Stennett, M.C
The effect of attrition milling on the processing of precursor oxides was investigated, with reference to the fabrication of titanate ceramics for the immobilization of plutonium and actinides, consolidated by hot isostatic pressing. Difficulties encountered during the lubricant removal step masked any correlation between the milling conditions and the final product. Four lubricants were investigated zinc stearate, Ceridust™, polyethylene glycol and oleic acid. The precursor blends were added to these lubricants to ensure the powders remained free flowing while dry milling in an attrition mill. All except Ceridust™ allowed the milled powders to be freely discharged. Examination of the products showed that each sample was highly porous and all were below the target minimum of 92 % of theoretical density. XRD and SEM analysis showed the production of a multiphase ceramic (zirconolite, perovskite, ilmenite) rather than the single target phase zirconolite. The impact of incomplete lubricant burn out on the oxidation states of Ce and Fe was investigated by XANES and Mössbauer spectroscopy, respectively. Suggested modifications to the HIP processing line, including the addition of an in situ sintered metal filter, the use of fumed metal oxides and the introduction of electrical conductivity in the precursors, are presented. © 2014 The American Ceramic Society.
Wiley
2014-02-20
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/78883/1/WRRO_78883.pdf
Squire, J, Maddrell, E.R, Hyatt, N.C et al. (1 more author) (2014) Influence of Lubricants and Attrition Milling Parameters on the Quality of Zirconolite Ceramics, Consolidated by Hot Isostatic Pressing, for Immobilization of Plutonium. International Journal of Applied Ceramic Technology. ISSN 1546-542X
http://dx.doi.org/10.1111/ijac.12239
10.1111/ijac.12239
oai:eprints.whiterose.ac.uk:78887
2014-05-08T15:57:43Z
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756E69743D536865666669656C64:536865666669656C642E464353:536865666669656C642E494E46
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6E6F5F646F63756D656E74735F617661696C61626C65
https://eprints.whiterose.ac.uk/78887/
Query transformations and their role in Web searching by the general public
Whittle, M.
Eaglestone, B.
Ford, N.
Gillet, V.J.
Madden, A.
Introduction - This paper reports preliminary research in a primarily experimental study of how the general public search for information on the Web. The focus is on the query transformation patterns that characterise searching.
Method - In this work, we have used transaction logs from the Excite search engine to develop methods for analysing query transformations that should aid the analysis of our ongoing experimental work. Our methods involve the use of similarity techniques to link queries with the most similar previous query in a train. The resulting query transformations are represented as a list of codes representing a whole search.
Analysis - It is shown how query transformation sequences can be represented as graphical networks and some basic statistical results are shown. A correlation analysis is performed to examine the co-occurrence of Boolean and quotation mark changes with the syntactic changes.
Results - A frequency analysis of the occurrence of query transformation codes is presented. The connectivity of graphs obtained from the query transformation is investigated and found to follow an exponential scaling law. The correlation analysis reveals a number of patterns that provide some interesting insights into Web searching by the general public.
Conclusion - We have developed analytical methods based on query similarity that can be applied to our current experimental work with volunteer subjects. The results of these will form part of a database with the aim of developing an improved understanding of how the public search the Web.
Professor T.D. Wilson
2006-10
Article
NonPeerReviewed
Whittle, M., Eaglestone, B., Ford, N. et al. (2 more authors) (2006) Query transformations and their role in Web searching by the general public. Information Research, 12 (1). ISSN 1368-1613
http://www.informationr.net/ir/12-1/paper276.html
oai:eprints.whiterose.ac.uk:79361
2014-06-16T09:03:43Z
7374617475733D707562
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E434956
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/79361/
Technetium-99m transport and immobilisation in porous media: Development of a novel nuclear imaging technique
Corkhill, C.L.
Gardner, L.J.
Hyatt, N.C.
Bridge, J.W.
Banwart, S.A.
Hillel, P.
Technetium-99, a β-emitting radioactive fission product of U, formed in nuclear reactors, presents a major challenge to nuclear waste disposal strategies. Its long half-life (2.1 × 10 years) and high solubility under oxic conditions as the pertechnetate anion [Tc(VII)O] is particularly problematic for long-term disposal of radioactive waste in geological repositories. In this study, we demonstrate a novel technique for quantifying the transport and immobilisation of technetium-99m, a γ-emitting metastable isomer of technetium-99 commonly used in medical imaging. A standard medical gamma camera was used for non-invasive quantitative imaging of technetium-99m during co-advection through quartz sand and various cementitious materials commonly used in nuclear waste disposal strategies. Spatial moments analysis of the resulting Tc plume provided information about the relative changes in mass distribution of the radionuclide in the various test materials. Tc advected through quartz sand demonstrated typical conservative behaviour, while transport through the cementitious materials produced a significant reduction in radionuclide centre of mass transport velocity over time. Gamma camera imaging has proven an effective tool for helping to understand the factors which control the migration of radionuclides for surface, near-surface and deep geological disposal of nuclear waste. © 2013 Materials Research Society.
Materials Research Society
2013
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/79361/1/SAB4.pdf
Corkhill, C.L., Gardner, L.J., Hyatt, N.C. et al. (3 more authors) (2013) Technetium-99m transport and immobilisation in porous media: Development of a novel nuclear imaging technique. Materials Research Society Symposium Proceedings, 1518. 123 - 129. ISSN 0272-9172
http://dx.doi.org/10.1557/opl.2013.111
10.1557/opl.2013.111
oai:eprints.whiterose.ac.uk:79363
2014-06-13T13:26:42Z
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696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/79363/
Non-stoichiometry in "CaCu3Ti4O12" (CCTO) ceramics
Schmidt, R
Pandey, S
Fiorenza, P
Sinclair, D.C
A combined powder X-ray lattice parameter and ceramic impedance spectroscopy study is presented on
materials within the CaO–CuO–TiO2 ternary phase diagram. Several compositions containing CaCu3Ti4O12
(CCTO) and small amounts of secondary phases such as TiO2, CaTiO3 and CuO are analysed and two
different defect mechanisms are identified as the cause of the non-stoichiometry in CCTO. The first
mechanism involves a variation in the Cu content, which explains the large differences in the intrinsic bulk
and extrinsic grain boundary (GB) resistance, and the formation of the ceramic internal barrier layer
capacitor (IBLC) structure. The second mechanism is associated with Ca–Cu anti-site disorder causing an
unusually high intrinsic bulk permittivity above that predicted from Clausius–Mossotti calculations.
RSC
2013-05-24
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/79363/1/WRRO_79363.pdf
Schmidt, R, Pandey, S, Fiorenza, P et al. (1 more author) (2013) Non-stoichiometry in "CaCu3Ti4O12" (CCTO) ceramics. RSC Advances, 3 (34). 14580 - 14589. ISSN 2046-2069
http://dx.doi.org/10.1039/c3ra41319e
10.1039/c3ra41319e
oai:eprints.whiterose.ac.uk:79387
2018-03-20T23:46:16Z
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/79387/
A family of oxide ion conductors based on the ferroelectric perovskite Na0.5Bi0.5TiO3
Li, M.
Pietrowski, M.J.
De Souza, R.A.
Zhang, H.
Reaney, I.M.
Cook, S.N.
Kilner, J.A.
Sinclair, D.C.
Oxide ion conductors find important technical applications in electrochemical devices such as solid-oxide fuel cells (SOFCs), oxygen separation membranes and sensors1, 2, 3, 4, 5, 6, 7, 8, 9. Na0.5Bi0.5TiO3 (NBT) is a well-known lead-free piezoelectric material; however, it is often reported to possess high leakage conductivity that is problematic for its piezo- and ferroelectric applications10, 11, 12, 13, 14, 15. Here we report this high leakage to be oxide ion conduction due to Bi-deficiency and oxygen vacancies induced during materials processing. Mg-doping on the Ti-site increases the ionic conductivity to ~0.01 S cm−1 at 600 °C, improves the electrolyte stability in reducing atmospheres and lowers the sintering temperature. This study not only demonstrates how to adjust the nominal NBT composition for dielectric-based applications, but also, more importantly, gives NBT-based materials an unexpected role as a completely new family of oxide ion conductors with potential applications in intermediate-temperature SOFCs and opens up a new direction to design oxide ion conductors in perovskite oxides.
Nature Publishing Group
2014-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/79387/1/Sinclair-AFC.pdf
Li, M., Pietrowski, M.J., De Souza, R.A. et al. (5 more authors) (2014) A family of oxide ion conductors based on the ferroelectric perovskite Na0.5Bi0.5TiO3. Nature Materials, 13 (1). 31 - 35. ISSN 1476-1122
http://dx.doi.org/10.1038/NMAT3782
10.1038/NMAT3782
oai:eprints.whiterose.ac.uk:79425
2014-06-18T14:32:34Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/79425/
Simulation of impedance spectra for a full three-dimensional ceramic microstructure using a finite element model
Dean, J.S
Harding, J.H
Sinclair, D.C
A method of characterizing electrically heterogeneous electroceramics for a full three-dimensional collection of randomly shaped grains is presented. Finite element modeling, solving Maxwell's equations in space and time is used to simulate impedance spectroscopy (IS) data. This technique overcomes several deficiencies associated with previous methods used to simulate IS data and allows comprehensive treatment of a full three-dimensional granular representation of ceramic microstructure without the requirement for equivalent circuits based on the Brickwork layer model (BLM) or the introduction of constant phase elements to describe any nonideality of the IS response. This is applied to a full three-dimensional ceramic microstructure with varying grain size and electrical properties to generate IS plots that highlight limitations of the BLM in data analysis. © 2013 The American Ceramic Society.
2014-03
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/79425/1/Paper_for_open_access.docx
Dean, J.S, Harding, J.H and Sinclair, D.C (2014) Simulation of impedance spectra for a full three-dimensional ceramic microstructure using a finite element model. Journal of the American Ceramic Society, 97 (3). 885 - 891. ISSN 0002-7820
http://dx.doi.org/10.1111/jace.12750
10.1111/jace.12750
oai:eprints.whiterose.ac.uk:79459
2014-06-20T13:08:25Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/79459/
Effects of cationic substitution on structural defects in layered cathode materials LiNiO2
Chen, H.
Dawson, J.A.
Harding, J.H.
The electrochemical properties of layered rock salt cathode materials are strongly influenced by defects.
The three most common defects in LiNiO2-based compounds, namely extra Ni, Li–Ni anti-site and
oxygen vacancy defects have been investigated. The calculated defect formation energies are very low in
LiNiO2, consistent with the difficulty in synthesizing stoichiometric defect-free LiNiO2. A systematic study
is conducted to examine the effect of Co, Mn and Al substitution on defect formation. It is shown that
the presence of Ni2+ in the Li layer can be rationalized using ideas of superexchange interactions. In
addition, a correlation between oxygen vacancy formation energy and oxygen charge is noted. This
explains the better thermal stability obtained by early transition metal or Al substitutions.
RSC Publishing
2014-04-08
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/79459/1/WRRO_79459.pdf
Chen, H., Dawson, J.A. and Harding, J.H. (2014) Effects of cationic substitution on structural defects in layered cathode materials LiNiO2. Journal of Materials Chemistry A, 2 (21). 7988 - 7996. ISSN 2050-7488
http://dx.doi.org/10.1039/c4ta00637b
10.1039/c4ta00637b
oai:eprints.whiterose.ac.uk:79462
2014-06-20T13:38:18Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/79462/
Hole conductivity in oxygen-excess BaTi(1-x)CaxO(3-x+d)
Ren, P.
Maso, N.
West, A.R.
BaTiO3 containing Ca substituted for Ti as an acceptor dopant, with oxygen vacancies for charge compensation
and processed in air, is a p-type semiconductor. The hole conductivity is attributed to uptake of a small
amount of oxygen which ionises by means of electron transfer from lattice oxide ions, generating O�
ions as the source of p-type semiconductivity. Samples heated in high pressure O2, up to 80 atm, absorb
up to twice the amount expected from the oxygen vacancy concentration. This is attributed to
incorporation of superoxide, O2
�, ions in oxygen vacancies associated with the Ca2+ dopant and is
supported by Raman spectroscopy results.
RSC Publishing
2013-11-08
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/79462/1/WRRO_79462.pdf
Ren, P., Maso, N. and West, A.R. (2013) Hole conductivity in oxygen-excess BaTi(1-x)CaxO(3-x+d). Physical Chemistry Chemical Physics, 15 (48). 20943 - 20950. ISSN 1463-9076
http://dx.doi.org/10.1039/c3cp52475b
10.1039/c3cp52475b
oai:eprints.whiterose.ac.uk:79465
2014-06-20T14:03:48Z
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756E69743D536865666669656C64:536865666669656C642E464350:536865666669656C642E43484D
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/79465/
Long-lived metal complexes open up microsecond lifetime imaging microscopy under multiphoton excitation: from FLIM to PLIM and beyond
Baggaley, E.
Botchway, S.W.
Haycock, J.W.
Morris, H.
Sazanovich, I.V.
Williams, J.A.G.
Weinstein, J.A.
Lifetime imaging microscopy with sub-micron resolution provides essential understanding of living systems by
allowing both the visualisation of their structure, and the sensing of bio-relevant analytes in vivo using external
probes. Chemistry is pivotal for the development of the next generation of bio-tools, where contrast,
sensitivity, and molecular specificity facilitate observation of processes fundamental to life. A fundamental
limitation at present is the nanosecond lifetime of conventional fluorescent probes which typically confines
the sensitivity to sub-nanosecond changes, whilst nanosecond background autofluorescence compromises
the contrast. High-resolution visualization with complete background rejection and simultaneous mapping of
bio-relevant analytes including oxygen – with sensitivity orders of magnitude higher than that currently
attainable – can be achieved using time-resolved emission imaging microscopy (TREM) in conjunction with
probes with microsecond (or longer) lifetimes. Yet the microsecond timescale has so far been incompatible
with available multiphoton excitation/detection technologies. Here we realize for the first time microsecondimaging
with multiphoton excitation whilst maintaining the essential sub-micron spatial resolution. The new
method is background-free and expands available imaging and sensing timescales 1000-fold. Exploiting the
first engineered water-soluble member of a family of remarkably emissive platinum-based, microsecond-lived
probes amongst others, we demonstrate (i) the first instance of background-free multiphoton-excited
microsecond depth imaging of live cells and histological tissues, (ii) over an order-of-magnitude variation in
the probe lifetime in vivo in response to the local microenvironment. The concept of two-photon TREM can
be seen as “FLIM + PLIM” as it can be used on any timescale, from ultrafast fluorescence of organic molecules
to slower emission of transition metal complexes or lanthanides/actinides, and combinations thereof. It brings
together transition metal complexes as versatile emissive probes with the new multiphoton-excitation/
microsecond-detection approach to create a transformative framework for multiphoton imaging and sensing
across biological, medicinal and material sciences.
RSC Publishing
2013-10-16
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/79465/1/WRRO_79465.pdf
Baggaley, E., Botchway, S.W., Haycock, J.W. et al. (4 more authors) (2013) Long-lived metal complexes open up microsecond lifetime imaging microscopy under multiphoton excitation: from FLIM to PLIM and beyond. Chemical Science, 5 (3). 879 - 886. ISSN 2041-6520
http://dx.doi.org/10.1039/c3sc51875b
10.1039/c3sc51875b
oai:eprints.whiterose.ac.uk:79511
2014-06-24T13:21:29Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/79511/
Investigating the rheological properties of native plant latex
Bauer, G.
Friedrich, C.
Gillig, C.
Vollrath, F.
Speck, T.
Holland, C.
Plant latex, the source of natural rubber, has been of interest to mankind for millennia,
with much of the research on its rheological (flow) properties focused
towards industrial application. However, little is known regarding the rheology
of the nativematerial as produced by the plant, a key factor in determining latex’s
biological functions. In this study, we outline a method for rheological comparison
between native latices that requires a minimum of preparatory steps. Our
approach provides quantitative insights into the coagulation mechanisms of
Euphorbia and Ficus latex allowing interpretation within a comparative evolutionary
framework. Our findings reveal that in laboratory conditions both
latices behave like non-Newtonian materials with the coagulation of Euphorbia
latex being mediated by a slowevaporative process (more than 60 min),whereas
Ficus appears to use additional biochemical components to increase the rate of
coagulation (more than 30 min). Based on these results,we propose two different
primary defensive roles for latex in these plants: the delivery of anti-herbivory
compounds (Euphorbia) and rapid wound healing (Ficus).
Royal Society Publishing
2014-01-06
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/79511/1/WRRO_79511.pdf
Bauer, G., Friedrich, C., Gillig, C. et al. (3 more authors) (2014) Investigating the rheological properties of native plant latex. Journal of The Royal Society Interface, 11 (90). 20130847. ISSN 1742-5689
http://dx.doi.org/10.1098/rsif.2013.0847
10.1098/rsif.2013.0847
oai:eprints.whiterose.ac.uk:79552
2014-06-26T12:35:44Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/79552/
Simulation of impedance spectra for a full three-dimensional ceramic microstructure using a finite element model
Dean, J.S.
Harding, J.H.
Sinclair, D.C.
A method of characterizing electrically heterogeneous electroceramics for a full three-dimensional collection of randomly shaped grains is presented. Finite element modeling, solving Maxwell's equations in space and time is used to simulate impedance spectroscopy (IS) data. This technique overcomes several deficiencies associated with previous methods used to simulate IS data and allows comprehensive treatment of a full three-dimensional granular representation of ceramic microstructure without the requirement for equivalent circuits based on the Brickwork layer model (BLM) or the introduction of constant phase elements to describe any nonideality of the IS response. This is applied to a full three-dimensional ceramic microstructure with varying grain size and electrical properties to generate IS plots that highlight limitations of the BLM in data analysis. © 2013 The American Ceramic Society.
2014-03
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/79552/3/WRRO_79552.pdf
Dean, J.S., Harding, J.H. and Sinclair, D.C. (2014) Simulation of impedance spectra for a full three-dimensional ceramic microstructure using a finite element model. Journal of the American Ceramic Society, 97 (3). 885 - 891. ISSN 0002-7820
http://dx.doi.org/10.1111/jace.12750
10.1111/jace.12750
oai:eprints.whiterose.ac.uk:79554
2014-06-26T13:20:05Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/79554/
The Speed of Sound in Silk: Linking Material Performance to Biological Function.
Mortimer, B.
Gordon, S.D.
Holland, C.
Siviour, C.R.
Vollrath, F.
Windmill, J.F.
Sonic properties of spider silks are measured independent of the web using laser vibrometry and ballistic impact providing insights into Nature's design of functionalized high-performance materials. Through comparison to cocoon silk and other industrial fibers, we find that major ampullate silk has the largest wavespeed range of any known material.
John Wiley & Sons
2014-06-06
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/79554/1/WRRO_79554.pdf
Mortimer, B., Gordon, S.D., Holland, C. et al. (3 more authors) (2014) The Speed of Sound in Silk: Linking Material Performance to Biological Function. Advanced Materials. ISSN 0935-9648
http://dx.doi.org/10.1002/adma.201401027
10.1002/adma.201401027
oai:eprints.whiterose.ac.uk:79735
2018-03-21T11:00:07Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/79735/
Effect of plutonium doping on radiation damage in zirconolite: A computer simulation study
Foxhall, H.R.
Travis, K.P.
Owens, S.L.
We present the results of extensive Molecular Dynamics (MD) simulations of alpha-recoil radiation damage in a range of crystalline zirconolites, CaZrTi2O7. Our studied systems include pure zirconolite, which we use as a reference material and the first ever simulations of damage in Pu-doped zirconolite, where plutonium is doped onto both of the M1 sites in the material, i.e. (Ca0.7Pu0.3)ZrTi2O7 and Ca(Zr0.7Pu0.3)(Ti1.7Fe0.3)O7. Our goal was to determine the extent of local damage caused by a plutonium primary knock on atom (PKA) interacting with the crystal lattice. Recoil energies of up to 34.7 keV have been simulated. The damage is characterised using a number of analysis tools including: site specific radial distribution functions; defect statistics; and the asphericity parameter at various times during the annealing process. Our results show that there is much information to be gained by the use of novel techniques for radiation damage analysis. Also, we show inclusion of actinides in radiation damage simulations can significantly increase the extent of damage observed and should be considered carefully when describing radiation damage behaviour in future.
Elsevier
2014-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/79735/1/Zirc_paper_submission_final.pdf
Foxhall, H.R., Travis, K.P. and Owens, S.L. (2014) Effect of plutonium doping on radiation damage in zirconolite: A computer simulation study. Journal of Nuclear Materials, 444 (1-3). 220 - 228. ISSN 0022-3115
http://dx.doi.org/10.1016/j.jnucmat.2013.09.036
10.1016/j.jnucmat.2013.09.036
oai:eprints.whiterose.ac.uk:79827
2018-03-29T12:09:32Z
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/79827/
Chemical characterisation of metakaolin and fly ash based geopolymers during exposure to solvents used in carbon capture
Gordon, L.E.
San Nicolas, R.
Provis, J.L.
This paper presents an investigation into the chemical resistance of blended alkali activated aluminosilicate materials, specifically under exposure to two solvents used in post-combustion carbon capture, monoethanolamine (MEA) and potassium carbonate, as well as during immersion in distilled water. Geopolymers are formulated based on metakaolin and aon fly ash as aluminosilicate precursors, with the addition of ground granulated blast furnace slag (GGBFS) as a source of Ca. The samples are subjected to mineralogical and chemical characterisation in this paper, with data obtained through leaching analysis and X-ray diffraction, supported by compressive strength data. Exposure to solvents generally results in significant alteration of the geopolymer microstructure. The zeolitic phases formed in undamaged metakaolin-based binders are reduced to undetectable levels after 28 days of solvent exposure, although the hydrosodalite formed in the fly ash binders does persist. Leaching analysis indicates that resistance to structural damage in MEA is quite high, due to the low solubility of Na and hydroxides upon immersion. KCO solutions are aggressive towards geopolymers via alteration of the binder structure and dissolution of network-forming species (Si and Al), leading to the loss of binder strength. This is most marked in the fly ash/GGBFS formulations. Despite the low to intermediate level of Ca present in these geopolymer binders, significant formation of Ca-containing carbonate phases occurs upon exposure to KCO. The limited curing duration of the specimens tested here is certainly contributing to the degradation taking place under KCO exposure, whereas the low water activity in the MEA solutions used means that bond hydrolysis in the aluminosilicate geopolymer framework is restricted, and the materials perform much better than in a more water-rich environment. © 2014 Elsevier Ltd.
Elsevier
2014-06-27
Article
PeerReviewed
text
en
cc_by_nc_nd_4
https://eprints.whiterose.ac.uk/79827/1/Gordon%20et%20al.%20IJGGC%202014%20as%20accepted.pdf
Gordon, L.E., San Nicolas, R. and Provis, J.L. orcid.org/0000-0003-3372-8922 <https://orcid.org/0000-0003-3372-8922> (2014) Chemical characterisation of metakaolin and fly ash based geopolymers during exposure to solvents used in carbon capture. International Journal of Greenhouse Gas Control , 27. pp. 255-266. ISSN 1750-5836
https://dx.doi.org/10.1016/j.ijggc.2014.06.005
10.1016/j.ijggc.2014.06.005
oai:eprints.whiterose.ac.uk:80393
2016-01-27T15:17:44Z
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https://eprints.whiterose.ac.uk/80393/
Development of a Three Dimensional Multiscale Computational Model of the Human Epidermis
Adra, S.
Sun, T.
MacNeil, S.
Holcombe, M.
Smallwood, R.
We report results from studies using four different protocols to prepare hydrated amorphous calcium carbonate,
ranging from random initial structures to melting hydrated mineral structures. All protocols give
good agreement with experimental X-ray structure factors. However, the thermodynamic properties, ion
coordination environments, and distribution of water for the structures produced by the protocols show
statistically significant variation depending on the protocols used. We discuss the diffusivity of water
through the various structures and its relation to experiments. We show that one protocol (based on melting
ikaite) gives a structure where the water is mobile, due to the presence of porosity in the amorphous
structure. We conclude that our models of hydrated amorphous calcium carbonate do give a range of
behaviour that resembles that observed experimentally, although the variation is less marked in the simulations
than in experiments.
Public Library of Science
2010-01-14
Article
PeerReviewed
text
en
cc_by_3
https://eprints.whiterose.ac.uk/80393/1/Development%20of%20a%20three%20dimensional%20multiscale%20computational%20model%20of%20the%20human%20epidermis..pdf
Adra, S., Sun, T., MacNeil, S. et al. (2 more authors) (2010) Development of a Three Dimensional Multiscale Computational Model of the Human Epidermis. PLoS One, 5 (1). e8511. ISSN 1932-6203
http://dx.doi.org/10.1371/journal.pone.0008511
oai:eprints.whiterose.ac.uk:80685
2023-06-23T21:41:53Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/80685/
Development and Characterization of Novel Polyurethane Films Impregnated with Tolfenamic Acid for Therapeutic Applications
Istanbullu, H.
Ahmed, S.
Sheraz, M.A.
Rehman, I.U.
The present study deals with the preparation of polyurethane (PU) films impregnated with a nonsteroidal anti-inflammatory drug, tolfenamic acid (TA). Solvent evaporation technique has been employed for the preparation of TA-PU films in two different ratios of 1 : 2 and 1 : 5 in Tetrahydrofuran (THF) or THF-ethanol mixtures. The prepared films were characterized using X-Ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and release studies. The results indicate transformation of crystalline TA to its amorphous form. The degree of crystallinity changes both by increasing the polymer concentration and solvent used for the film preparations. The release profiles of TA were also found to be affected, showing a decrease from approximately 50% to 25% from 1 : 2 to 1 : 5 ratios, respectively.
Hindawi Publishing Corporation
2013
Article
PeerReviewed
text
en
cc_by_3
https://eprints.whiterose.ac.uk/80685/1/Development%20and%20characterization%20of%20novel%20polyurethane%20films%20impregnated%20with%20tolfenamic%20acid%20for%20therapeutic%20applications..pdf
Istanbullu, H., Ahmed, S., Sheraz, M.A. et al. (1 more author) (2013) Development and Characterization of Novel Polyurethane Films Impregnated with Tolfenamic Acid for Therapeutic Applications. BioMed Research International. 178973. ISSN 2314-6133
http://dx.doi.org/10.1155/2013/178973
10.1155/2013/178973
oai:eprints.whiterose.ac.uk:80773
2023-06-23T21:41:59Z
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74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
756E69743D536865666669656C64:536865666669656C642E46434D:536865666669656C642E4D4544:536865666669656C642E47454D:536865666669656C642E4F4350
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/80773/
Acute In Vivo Response to an Alternative Implant for Urogynecology
Regueros, S.R.
Albersen, M.
Manodoro, S.
Zia, S.
Osman, N.I.
Bullock, A.J.
Chapple, C.R.
Deprest, J.
MacNeil, S.
Purpose. To investigate in vivo the acute host response to an alternative implant designed for the treatment of stress urinary incontinence (SUI) and pelvic organ prolapse (POP).
Methods. A biodegradable scaffold was produced from poly-L-lactic acid (PLA) using the electrospinning technique. Human and rat adipose-derived stem cells (ADSCs) were isolated and characterized by fluorescence-activated cell sorting and differentiation assays. PLA scaffolds were seeded and cultured for 2 weeks with human or rat ADSCs. Scaffolds with and without human or rat ADSCs were implanted subcutaneously on the abdominal wall of rats. After 3 and 7 days, 6 animals from each group were sacrificed. Sections from each sample were analyzed by Haematoxylin and Eosin staining, Sirius red staining, and immunohistochemistry for CD68, PECAM-1, and collagen I and III.
Results. Animals responded to the scaffolds with an acute macrophage response. After 7 days of implantation, there was extensive host cell penetration, new blood vessel formation, and new collagen deposition throughout the full thickness of the samples without obvious differences between cell-containing and cell-free scaffolds.
Conclusions. The acute in vivo response to an alternative implant (both with and without cells) for the treatment of SUI and POP showed good acute integration into the host tissues.
Hindawi Publishing Corporation
2014-07-17
Article
PeerReviewed
text
en
cc_by_3
https://eprints.whiterose.ac.uk/80773/7/Acute%20in%20vivo%20response%20to%20an%20alternative%20implant%20for%20urogynecology.pdf
Regueros, S.R., Albersen, M., Manodoro, S. et al. (6 more authors) (2014) Acute In Vivo Response to an Alternative Implant for Urogynecology. BioMed Research International, 2014. 853610. ISSN 2314-6133
http://dx.doi.org/10.1155/2014/853610
10.1155/2014/853610
oai:eprints.whiterose.ac.uk:81381
2014-11-10T13:48:54Z
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756E69743D536865666669656C64:536865666669656C642E464350:536865666669656C642E424953:536865666669656C642E424D53
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E414353
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/81381/
Time-Lapse Analysis of Human Embryonic Stem Cells Reveals Multiple Bottlenecks Restricting Colony Formation and Their Relief upon Culture Adaptation
Barbaric, I.
Biga, V.
Gokhale, P.J.
Jones, M.
Stavish, D.
Glen, A.
Coca, D.
Andrews, P.W.
Summary Using time-lapse imaging, we have identified a series of bottlenecks that restrict growth of early-passage human embryonic stem cells (hESCs) and that are relieved by karyotypically abnormal variants that are selected by prolonged culture. Only a minority of karyotypically normal cells divided after plating, and these were mainly cells in the later stages of cell cycle at the time of plating. Furthermore, the daughter cells showed a continued pattern of cell death after division, so that few formed long-term proliferating colonies. These colony-forming cells showed distinct patterns of cell movement. Increasing cell density enhanced cell movement facilitating cell:cell contact, which resulted in increased proportion of dividing cells and improved survival postplating of normal hESCs. In contrast, most of the karyotypically abnormal cells reentered the cell cycle on plating and gave rise to healthy progeny, without the need for cell:cell contacts and independent of their motility patterns.
Cell Press
2014-07-08
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/81381/13/BarbaricBiga_StemCellReports2014.pdf
Barbaric, I., Biga, V., Gokhale, P.J. et al. (5 more authors) (2014) Time-Lapse Analysis of Human Embryonic Stem Cells Reveals Multiple Bottlenecks Restricting Colony Formation and Their Relief upon Culture Adaptation. Stem Cell Reports, 3 (1). 142 - 155. ISSN 2213-6711
http://dx.doi.org/10.1016/j.stemcr.2014.05.006
10.1016/j.stemcr.2014.05.006
oai:eprints.whiterose.ac.uk:81468
2016-07-28T14:04:00Z
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756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
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https://eprints.whiterose.ac.uk/81468/
Anti-inflammatory and anti-invasive effects of alpha-melanocyte-stimulating hormone in human melanoma cells
Eves, P.
Haycock, J.
Layton, C.
Wagner, M.
Kemp, H.
Szabo, M.
Morandini, R.
Ghanem, G.
Garcia-Borron, J.C.
Jimenez-Cervantes, C.
Mac Neil, S.
α-Melanocyte stimulating hormone (α-MSH) is known to have pleiotrophic functions including pigmentary, anti-inflammatory, antipyretic and immunoregulatory roles in the mammalian body. It is also reported to influence melanoma invasion with levels of α-, β- and γ-MSH correlated clinically with malignant melanoma development, but other studies suggest α-MSH acts to retard invasion. In the present study, we investigated the action of α-MSH on three human melanoma cell lines (HBL, A375-SM and C8161) differing in metastatic potential. α-melanocyte-simulating hormone reduced invasion through fibronectin and also through a human reconstructed skin composite model for the HBL line, and inhibited proinflammatory cytokine-stimulated activation of the NF-κB transcription factor. However, A375-SM and C8161 cells did not respond to α-MSH. Immunofluorescent microscopy and Western blotting identified melanocortin-1 receptor (MC-1R) expression for all three lines and MC-2R on HBL and A375-SM lines. Receptor binding identified a similar affinity for α-MSH for all three lines with the highest number of binding sites on HBL cells. Only the HBL melanoma line demonstrated a detectable cyclic adenosine monophosphate (cAMP) response to α-MSH, although all three lines responded to acute α-MSH addition (+(−)-N6-(2-phenylisopropyl)-adenosine (PIA)) with an elevation in intracellular calcium. The nonresponsive lines displayed MC-1R polymorphisms (C8161, Arg (wt) 151/Cys 151; A375-SM, homozygous Cys 151), whereas the HBL line was wild type. Stable transfection of the C8161 line with wild-type MC-1R produced cells whose invasion was significantly inhibited by α-MSH. From this data, we conclude that α-MSH can reduce melanoma cell invasion and protect cells against proinflammatory cytokine attack in cells with the wild-type receptor (HBL).
Cancer Research UK
2003-11-11
Article
PeerReviewed
text
en
cc_by_nc_sa_3
https://eprints.whiterose.ac.uk/81468/7/Anti-inflammatory%20and%20anti-invasive%20effects%20of%20alpha-melanocyte-stimulating%20hormone%20in%20human%20melanoma%20cells..pdf
Eves, P., Haycock, J. orcid.org/0000-0002-3950-3583 <https://orcid.org/0000-0002-3950-3583>, Layton, C. et al. (8 more authors) (2003) Anti-inflammatory and anti-invasive effects of alpha-melanocyte-stimulating hormone in human melanoma cells. British Journal of Cancer, 89 (10). pp. 2004-2015. ISSN 0007-0920
http://dx.doi.org/10.1038/sj.bjc.6601349
10.1038/sj.bjc.6601349
oai:eprints.whiterose.ac.uk:81469
2016-11-03T01:47:36Z
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756E69743D536865666669656C64:536865666669656C642E46434D:536865666669656C642E484D43
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/81469/
Melanoma cell migration is upregulated by tumour necrosis factor-alpha and suppressed by alpha-melanocyte-stimulating hormone
Zhu, N.
Lalla, R.
Eves, P.
Brown, T.L.
King, A.
Kemp, E.H.
Haycock, J.W.
MacNeil, S.
We reported recently that the inflammatory cytokine tumour necrosis factor α (TNF-α) can upregulate integrin expression, cell attachment and invasion of cells through fibronectin in a human melanoma cell line (HBL). Furthermore, the actions of TNF-α were suppressed by the addition of an anti-inflammatory peptide α-melanocyte-stimulating hormone (α-MSH). In the current study, we extend this work investigating to what extent TNF-α might stimulate melanoma invasion by promoting cell migration and whether α-MSH is also inhibitory. Two human melanoma cell lines were examined in vitro (HBL and C8161) using a scratch migration assay. Analysis using either time-lapse video microscopy or imaging software analysis of migrating ‘fronts’ of cells revealed that C8161 cells migrated more rapidly than HBL cells. However, when cells were stimulated with TNF-α both cell types responded with a significant increase in migration distance over a 16–26 h incubation time. α-Melanocyte-stimulating hormone had an inhibitory effect on TNF-α-stimulated migration for HBL cells, completely blocking migration at 10−9 m. In contrast, C8161 cells did not respond to α-MSH (as these cells have a loss-of-function melanocortin-1 receptor). However, stable transfection of C8161 cells with the wild-type melanocortin-1 receptor produced cells whose migration was significantly inhibited by α-MSH. In addition, the use of a neutralising antibody to the β1-integrin subunit significantly reduced migration in both cell types. This data therefore supports an inflammatory environment promoting melanoma cell migration, and in addition shows that α-MSH can inhibit inflammatory stimulated migration. The data also support a fundamental role of the β1-integrin receptor in melanoma cell migration.
Nature Publishing Group
2004-04-05
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/81469/7/WRRO_81469.pdf
Zhu, N., Lalla, R., Eves, P. et al. (5 more authors) (2004) Melanoma cell migration is upregulated by tumour necrosis factor-alpha and suppressed by alpha-melanocyte-stimulating hormone. British Journal of Cancer, 90 (7). 1457 - 1463. ISSN 0007-0920
http://dx.doi.org/10.1038/sj.bjc.6601698
10.1038/sj.bjc.6601698
oai:eprints.whiterose.ac.uk:81594
2018-01-23T21:28:17Z
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74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
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https://eprints.whiterose.ac.uk/81594/
Wear and degradation on retrieved zirconia femoral heads
Nogiwa-Valdez, AA
Rainforth, WM
Stewart, TD
Zirconia femoral heads retrieved from patients after different implantation periods (up to 13 years) were analysed using vertical scanning interferometry, atomic force microscopy and Raman microspectroscopy. A range of topographical and compositional changes on the surface of the retrievals are reported in this work. The study revealed that changes in roughness are the result of a combination of factors, i.e. scratching, surface upheaval due to transformation to the monoclinic phase and grain pull-out. Clusters of transformed monoclinic grains were observed on heads implanted for more than 3 years. The phase composition of these clusters was confirmed by Raman microspectroscopy. Increased abrasive wear and a higher monoclinic phase content concentrated on the pole of the femoral heads, confirming that the tetragonal to monoclinic phase transformation was not only induced by the tetragonal phase metastability and environmental conditions but mechanical and tribological factors, also affected the transformation kinetics. Additionally, the head implanted for 13 years showed evidence of a self-polishing mechanism leading to a considerable smoothening of the surface. These observations provide an insight into the interrelated mechanisms underlying the wear and transformation process on zirconia ceramics during implantation.
Elsevier
2014-03
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/81594/1/Akemi%20zirconia%20retrievals%20paper%20JMMMB.pdf
Nogiwa-Valdez, AA, Rainforth, WM and Stewart, TD (2014) Wear and degradation on retrieved zirconia femoral heads. Journal of the Mechanical Behavior of Biomedical Materials, 31. 145 - 151. ISSN 1751-6161
http://dx.doi.org/10.1016/j.jmbbm.2013.09.019
10.1016/j.jmbbm.2013.09.019
oai:eprints.whiterose.ac.uk:81689
2018-03-29T18:24:39Z
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/81689/
Extremely Large Magnetic Entropy Changes, Quantum Phases, Transitions and Diagram in Gd(OH)3 Single Crystal Nanowires - Quasi-1D Large Spin (S = -7/2) Chain Antiferromagnet
Zeng, R.
Zhang, C.F.
Debnath, J.C.
Shamba, P.
Wang, J.L.
Chen, Z.X.
Guo, Z.P.
Dou, S.X.
Systematically magnetic and magnetothermal measurements at temperatures down to 2 K and magnetic fields up to 13.5 Tesla for Gd(OH)3 Single Crystal Nanowires - Quasi-1D Large Spin (S = -7/2) Chain Antiferromagnet have been conducted. We find that, (1) magnetic field enhances the thermal and local spin fluctuations which suppress long-range spin ordering (LRO) within the measured temperature range, and close to 0 K at the quantum critical point (QCP); (2) possible field-induced exotic local spin-liquid-like, aligned-spin, and spin-flip exotic paramagnetic phases, and transitions in the low temperature and high field range have been observed, allowing us to identify a possible quantum critical point; (3) there is extremely large, fully reversible MCE (magnetic entropy change (-{\Delta}SM) = 27.8, 66, and 88 J / kg K, adiabatic temperature change ({\Delta}Tad) = 6.7, 17.6, and 36.4 K at 2.55 K for field changes of 2, 5, and 11 T, respectively in the continuum of quantum phase transitions in this system; (4) moreover, careful experiments and analysis may allow experimental determination and set up a quantum phase diagram of this system. The magnetic-entropy change monotonically increases with decreasing temperature, and it exceeds the magnetocaloric effect (MCE) in any other known low temperature reversible MCE material by at least a factor of 3. The extremely large magnetic entropy change may be attributed to the large amount of weakly interacting spins that can be easily aligned at low-lying energy in the quantum critical regime of our nanosized materials, since there is large MCE in the local spin-liquid-like (low energy excitation and even gapless state) range. These indicate that the material is a promising MCE candidate for low temperature application, and possibly could make ultra-low temperatures easily achievable for most laboratories and for space application as well.
2012-07-13
Article
NonPeerReviewed
text
en
https://eprints.whiterose.ac.uk/81689/1/1207.3239v1.pdf
Zeng, R., Zhang, C.F., Debnath, J.C. et al. (5 more authors) (2012) Extremely Large Magnetic Entropy Changes, Quantum Phases, Transitions and Diagram in Gd(OH)3 Single Crystal Nanowires - Quasi-1D Large Spin (S = -7/2) Chain Antiferromagnet.
oai:eprints.whiterose.ac.uk:82528
2014-12-11T10:10:59Z
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/82528/
Electrospun polyurethane/hydroxyapatite bioactive Scaffolds for bone tissue engineering: The role of solvent and hydroxyapatite particles
Tetteh, G.
Khan, A.S.
Delaine-Smith, R.M.
Reilly, G.C.
Rehman, I.U.
Abstract Polyurethane (PU) is a promising polymer to support bone–matrix producing cells due to its durability and mechanical resistance. In this study two types of medical grade poly-ether urethanes Z3A1 and Z9A1 and PU-Hydroxyapatite (PU–HA) composites were investigated for their ability to act as a scaffold for tissue engineered bone. PU dissolved in varying concentrations of dimethylformamide (DMF) and tetrahydrofuran (THF) solvents were electrospun to attain scaffolds with randomly orientated non-woven fibres. Bioactive polymeric composite scaffolds were created using 15 wt% Z3A1 in a 70/30 DMF/THF PU solution and incorporating micro- or nano-sized HA particles in a ratio of 3:1 respectively, whilst a 25 wt% Z9A1 PU solution was doped in ratio of 5:1. Chemical properties of the resulting composites were evaluated by FTIR and physical properties by SEM. Tensile mechanical testing was carried out on all electrospun scaffolds. MLO-A5 osteoblastic mouse cells and human embryonic mesenchymal progenitor cells, hES-MPs were seeded on the scaffolds to test their biocompatibility and ability to support mineralised matrix production over a 28 day culture period. Cell viability was assayed by MTT and calcium and collagen deposition by Sirius red and alizarin red respectively. SEM images of both electrospun PU scaffolds and PU–HA composite scaffolds showed differences in fibre morphology with changes in solvent combinations and size of HA particles. Inclusion of THF eliminated the presence of beads in fibres that were present in scaffolds fabricated with 100% DMF solvent, and resulted in fibres with a more uniform morphology and thicker diameters. Mechanical testing demonstrated that the Young׳s Modulus and yield strength was lower at higher THF concentrations. Inclusion of both sizes of HA particles in PU–HA solutions reinforced the scaffolds leading to higher mechanical properties, whilst FTIR characterisation confirmed the presence of HA in all composite scaffolds. Although all scaffolds supported proliferation of both cell types and deposition of calcified matrix, PU–HA composite fibres containing nano-HA enabled the highest cell viability and collagen deposition. These scaffolds have the potential to support bone matrix formation for bone tissue engineering.
Elsevier
2014-11
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/82528/1/WRRO_82528.pdf
Tetteh, G., Khan, A.S., Delaine-Smith, R.M. et al. (2 more authors) (2014) Electrospun polyurethane/hydroxyapatite bioactive Scaffolds for bone tissue engineering: The role of solvent and hydroxyapatite particles. Journal of the Mechanical Behavior of Biomedical Materials, 39. 95 - 110. ISSN 1751-6161
http://dx.doi.org/10.1021/ol5016702
10.1016/j.jmbbm.2014.06.019
oai:eprints.whiterose.ac.uk:83443
2018-03-21T20:56:54Z
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/83443/
Magnetic and structural characterization of NiFe/Fe30Co70 Bilayers
Morley, N.A.
Finkel, A.C.
Yang, W.
Reeves-Mclaren, N.
Magnetostrictive films are required for a wide range of device applications; by increasing the magnetostriction constant and decreasing the anisotropy field, the devices will become more efficient. This paper has studied Fe30Co70 films on different thicknesses of the soft magnetic underlayer Ni81Fe19, to determine how the structural and magnetic properties change. It was found that the anisotropy field of the Fe30Co70 film could be reduced by 50% to 10 kA/m and the magnetostriction constant increased by a factor 4 to 65 ppm when grown on 30 nm Ni81Fe19. This was due to the NiFe underlayer inducing a BCC(110) texture within the Fe30Co70 film and reducing the in-plane stress.
IEEE
2014-11-01
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/83443/7/feco%20paper%20%20final.pdf
Morley, N.A., Finkel, A.C., Yang, W. et al. (1 more author) (2014) Magnetic and structural characterization of NiFe/Fe30Co70 Bilayers. IEEE Transactions on Magnetics, 50 (11). 2503704. ISSN 0018-9464
http://dx.doi.org/10.1109/TMAG.2014.2330001
10.1109/TMAG.2014.2330001
oai:eprints.whiterose.ac.uk:83444
2015-02-18T15:49:42Z
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7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/83444/
Measurement of hyperfine coupling constants of muoniated radicals in small molecule semiconductors
Schulz, L.
Wang, K.
Willis, M.
Nuccio, L.
Murahari, P.
Zhang, S.
Pratt, F.L.
Lord, J.S.
Morley, N.A.
Bernhard, C.
Drew, A.J.
We report the hyperfine coupling constants of muoniated radicals formed in a number of organic semiconductors, via transverse field measurements taken in the Paschen Back limit, and compare the results to avoided level crossing resonances. Five muoniated radicals are found in tetracene, despite there only being three potential non-equivalent bonding sites, and we suggest that this might be down to crystal packing effects. For 6,13-bis(triisopropylsilylethynyl) pentacene and 6,13-bis(trimethlsilylethynyl)-pentacene, we demonstrate that the transverse field data supports the previously published avoided level crossing resonances.
Institute of Physics Publishing
2014
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/83444/1/Schulz%20IoP%202014%20muons.pdf
Schulz, L., Wang, K., Willis, M. et al. (8 more authors) (2014) Measurement of hyperfine coupling constants of muoniated radicals in small molecule semiconductors. Journal of Physics: Conference Series, 551. 012042. ISSN 1742-6588
http://dx.doi.org/10.1088/1742-6596/551/1/012042
10.1088/1742-6596/551/1/012042
oai:eprints.whiterose.ac.uk:83451
2018-03-22T04:17:12Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/83451/
Study of the magnetic-Alq3 interface in organic spin-valves
Morley, N.A.
Drew, A.J.
Zhang, H.
Scott, K.
Hudziak, S.
Morgan, D.J.
The interface between the organic semiconductor tris(8-hydrixyquinolate) aluminium (Alq3) and two different magnetic electrodes has been investigated using X-ray photoelectron spectroscopy (XPS), Kelvin Probe, atomic force microscopy (AFM) and magneto-optic Kerr effect (MOKE) magnetometry. The transition metal magnetic electrode/Alq3 films were first measured using a XPS, and then washed and remeasured. It was found that Alq3 still existed on the magnetic electrode after washing. This suggests that the Alq3 chemisorbs onto the transition metal electrode surfaces. Using MOKE magnetometry, the surface magnetisation of the transition metal electrodes was studied. It was found that the surface magnetisation of the NiFe electrode changed with the Alq3 layer on top, which was taken to be due to the Alq3 chemisorption onto the NiFe electrode, so changing the electronic states at the interface. © 2014 Elsevier B.V. All rights reserved.
Elsevier
2014-09-15
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/83451/8/morley%20nonedited%202014.pdf
Morley, N.A., Drew, A.J., Zhang, H. et al. (3 more authors) (2014) Study of the magnetic-Alq3 interface in organic spin-valves. Applied Surface Science, 313. 850 - 857. ISSN 0169-4332
http://dx.doi.org/10.1016/j.apsusc.2014.06.088
10.1016/j.apsusc.2014.06.088
oai:eprints.whiterose.ac.uk:83636
2023-06-23T21:44:56Z
7374617475733D707562
74797065733D61727469636C65
756E69743D536865666669656C64:536865666669656C642E464350:536865666669656C642E424953:536865666669656C642E424D53
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E414353
756E69743D536865666669656C64:536865666669656C642E464345:536865666669656C642E4D4154
696E737469747574696F6E3D536865666669656C64
7072696D6F3D6861735F7075626C6963
https://eprints.whiterose.ac.uk/83636/
Time-Lapse Analysis of Human Embryonic Stem Cells Reveals Multiple Bottlenecks Restricting Colony Formation and Their Relief upon Culture Adaptation
Barbaric, I.
Biga, V.
Gokhale, P.J.
Jones, M.
Stavish, D.
Glen, A.
Coca, D.
Andrews, P.W.
Summary Using time-lapse imaging, we have identified a series of bottlenecks that restrict growth of early-passage human embryonic stem cells (hESCs) and that are relieved by karyotypically abnormal variants that are selected by prolonged culture. Only a minority of karyotypically normal cells divided after plating, and these were mainly cells in the later stages of cell cycle at the time of plating. Furthermore, the daughter cells showed a continued pattern of cell death after division, so that few formed long-term proliferating colonies. These colony-forming cells showed distinct patterns of cell movement. Increasing cell density enhanced cell movement facilitating cell:cell contact, which resulted in increased proportion of dividing cells and improved survival postplating of normal hESCs. In contrast, most of the karyotypically abnormal cells reentered the cell cycle on plating and gave rise to healthy progeny, without the need for cell:cell contacts and independent of their motility patterns.
Cell Press
2014-07-08
Article
PeerReviewed
text
en
https://eprints.whiterose.ac.uk/83636/20/Time-lapse%20analysis%20of%20human%20embryonic%20stem%20cells%20reveals%20multiple%20bottlenecks%20restricting%20colony%20formation%20and%20their%20relief%20upon%20culture%20adaptation..pdf
Barbaric, I., Biga, V., Gokhale, P.J. et al. (5 more authors) (2014) Time-Lapse Analysis of Human Embryonic Stem Cells Reveals Multiple Bottlenecks Restricting Colony Formation and Their Relief upon Culture Adaptation. Stem Cell Reports, 3 (1). 142 - . ISSN 2213-6711
http://dx.doi.org/10.1016/j.stemcr.2014.05.006
10.1016/j.stemcr.2014.05.006
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