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1,188 results on '"Bunce C"'

4. Laser induced magnetization switching in films with perpendicular anisotropy: a comparison between measurements and a multi-macrospin model

Author

Bunce, C., Wu, J., Ju, G., Lu, B., Hinzke, D., Kazantseva, N., Nowak, U., and Chantrell, R. W.

Subjects
Condensed Matter - Materials Science, Condensed Matter - Other Condensed Matter
Abstract

Thermally-assisted ultra-fast magnetization reversal in a DC magnetic field for magnetic multilayer thin films with perpendicular anisotropy has been investigated in the time domain using femtosecond laser heating. The experiment is set-up as an optically pumped stroboscopic Time Resolved Magneto-Optical Kerr Effect magnetometer. It is observed that a modest laser fluence of about 0.3 mJ/square-cm induces switching of the magnetization in an applied field much less than the DC coercivity (0.8 T) on the sub-nanosecond time-scale. This switching was thermally-assisted by the energy from the femtosecond pump-pulse. The experimental results are compared with a model based on the Landau Lifschitz Bloch equation. The comparison supports a description of the reversal process as an ultra-fast demagnetization and partial recovery followed by slower thermally activated switching due to the spin system remaining at an elevated temperature after the heating pulse., Comment: 8 pages, 10 figures, to be submitted to PRB

Published
2009
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11. Development of a core outcome set for effectiveness studies of breech birth at term (Breech-COS)-an international multi-stakeholder Delphi study: study protocol.

Author

Walker, S, Dasgupta, T, Shennan, A, Sandall, J, Bunce, C, Roberts, P, Walker, S, Dasgupta, T, Shennan, A, Sandall, J, Bunce, C, and Roberts, P

Abstract

BACKGROUND: Women pregnant with a breech-presenting foetus at term are at increased risk of adverse pregnancy outcomes. The most common intervention used to improve neonatal outcomes is planned delivery by caesarean section. But this is not always possible, and some women prefer to plan a vaginal birth. A number of providers have proposed alternative interventions, such as delivery protocols or specialist teams, but heterogeneity in reported outcomes and their measurements prevents meaningful comparisons. The aim of this paper is to present a protocol for a study to develop a Breech Core Outcome Set (Breech-COS) for studies evaluating the effectiveness of interventions to improve outcomes associated with term breech birth. METHODS: The development of a Breech-COS includes three phases. First, a systematic literature review will be conducted to identify outcomes previously used in effectiveness studies of breech birth at term. A focus group discussion will be conducted with the study's pre-established Patient and Public Involvement (PPI) group, to enable service user perspectives on the results of the literature review to influence the design of the Delphi survey instrument. Second, an international Delphi survey will be conducted to prioritise outcomes for inclusion in the Breech-COS from the point of view of key stakeholders, including perinatal care providers and families who have experienced a term breech pregnancy. Finally, a consensus meeting will be held with stakeholders to ratify the Breech-COS and disseminate findings for application in future effectiveness studies. DISCUSSION: The expectation is that the Breech-COS will always be collected in all clinical trials, audits of practice and other forms of observation research that concern breech birth at term, along with other outcomes of interest. This will facilitate comparing, contrasting and combining studies with the ultimate goal of improved maternal and neonatal outcomes. TRIAL REGISTRATION: Core Outcome

Published
2022

12. Randomised controlled trial of adjunctive triamcinolone acetonide in eyes undergoing vitreoretinal surgery following open globe trauma: The ASCOT study

Author

Casswell, EJ, Cro, S, Cornelius, VR, Banerjee, PJ, Zvobgo, TM, Tudor Edwards, R, Ezeofor, V, Anthony, B, Shahid, SM, Bunce, C, Kelly, J, Murphy, C, Robertson, E, Charteris, D, and ASCOT Investigator Study Group

Subjects
Cellular and Molecular Neuroscience, Ophthalmology, Sensory Systems
Abstract

Background/aimsTo investigate the clinical effectiveness of adjunctive triamcinolone acetonide (TA) given at the time of vitreoretinal surgery following open globe trauma (OGT).MethodsA phase 3, multicentre, double-masked randomised controlled trial of patients undergoing vitrectomy following OGT comparing adjunctive TA (intravitreal and subtenons) against standard care (2014–2020). The primary outcome was the proportion of patients with at least 10 Early Treatment Diabetic Retinopathy Study (ETDRS) letter improvement in corrected visual acuity (VA) at 6 months. Secondary outcomes included: change in ETDRS, retinal detachment (RD) secondary to PVR, retinal reattachment, macular reattachment, tractional RD, number of operations, hypotony, elevated intraocular pressure and quality of life.Results280 patients were randomised over 75 months, of which 259 completed the study. 46.9% (n=61/130) of patients in the treatment group had a 10-letter improvement in VA compared with 43.4% (n=56/129) of the control group (difference 3.5% (95% CI −8.6% to 15.6%), OR=1.03 (95% CI 0.61 to 1.75), p=0.908)). Secondary outcome measures also failed to show any treatment benefit. For two of the secondary outcome measures, stable complete retinal and macular reattachment, outcomes were worse in the treatment group compared with controls, respectively, 51.6% (n=65/126) vs 64.2% (n=79/123), OR=0.59 (95% CI 0.36 to 0.99), and 54.0% (n=68/126) vs 66.7% (n=82/123), OR=0.59 (95% CI 0.35 to 0.98), for TA vs control.ConclusionThe use of combined intraocular and sub-Tenons capsule TA is not recommended as an adjunct to vitrectomy surgery following OGT.Trial registration numberNCT02873026.

Published
2023
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15. Visual outcome following posterior capsule rupture during manual small incision cataract surgery

Author

Oladigbolu, KK, Bunce, C, Raji, LA, Abah, ER, Umar, MM, and Buchan, JC

Subjects
genetic structures, eye diseases
Abstract

BACKGROUND: The quality of cataract surgery can be measured by visual outcome, which is sometimes limited by intraoperative complications, most commonly posterior capsular rupture. AIMS: The aim of the study was to assess visual outcome at the last visit (≥8 weeks) following posterior capsule rupture (PCR) in patients who had manual small incision cataract surgery (MSICS) managed without access to an automated vitrector. METHODS: A review of medical records of all manual small incision cataract surgeries performed between January 2013 and December 2016 at the National Eye Centre, Kaduna, Nigeria was conducted. Descriptive statistics and logistic regression analysis were performed using STATA 14.0 to examine risk factors for the development of a poor visual outcome and to assess the impact of PCR on development of poor visual outcome. RESULTS: In total, 405 patients were operated on with MSICS (50.6% males). Mean age was 62.4 (SD 12.6) years. PCR was the most common complication (n = 19 (4.7%)). The proportion of good outcomes (≥6/18) rose from 12.4% non-PCR and 0.0% for those with PCR at day 1 postoperative review, to 71.5 and 26.3%, respectively, by final follow up (P = 0.001). Patients with PCR were 7.0 (P = 0.0001) times more likely to have borderline/poor visual outcome (60 years increased the odds of borderline/poor by 1.4 times (P = 0.002). CONCLUSION: PCR significantly affects the visual outcome of cataract patients in settings with no facilities for automated vitrectomy. Minimizing complications will improve visual outcome of cataract patients and increase uptake of cataract surgical services.

Published
2021

20. Remanence and coercivity measurements of perpendicular ECC media

Author

Deakin, T., Bunce, C., Wu, S.Z., and O'Grady, K.

Subjects
Magnetic fields -- Models, Magnetic fields -- Analysis, Magnetization -- Analysis, Business, Electronics, Electronics and electrical industries
Abstract

This work reports on advanced remanence and coercivity measurements undertaken on a set of perpendicular exchange-coupled composite (ECC) media, where the demagnetizing field, [H.sub.D], has been properly accounted for. We find that, on correction, the shape of the hysteresis loop, and hence the shape of the remanence curve, changes significantly. More importantly, the value of the measured remanent coercivity, [H.sub.cr], is reduced by between 10 and 15% when the correction for HD is implemented. Measurements of the remanence, Mr, indicate that the normalized [Mr.sub.y]/[M.sub.s] varies strongly in the uncorrected case as the thickness of the soft layer increases, whereas for the corrected case, [M.sub.r]/[M.sub.s] is almost constant, around 0.82 [+ or -] 0.03. From the data obtained, we have also been able to determine the reversal processes that take place in both the hard and soft layers. Above a soft layer thickness of ~ 12 nm, [M.sub.r]/[M.sub.s] becomes dominated by the [H.sub.D]. Insight has also been gained into the exchange coupling between the soft and hard layers for a low Ms soft layer. Index Terms--Demagnetizing field, ECC media, magnetization reversal, remanence curves.

Published
2008

21. Picosecond magnetization dynamics of single-crystal [Fe.sub.3][O.sub.4] thin films

Author

Bunce, C., Wu, J., Lu, Y.X., Xu, Y.B., and Chantrell, R.W.

Subjects
Anisotropy -- Analysis, Kerr effect -- Analysis, Magnetization -- Analysis, Dielectric films -- Magnetic properties, Dielectric films -- Analysis, Thin films -- Magnetic properties, Thin films -- Analysis, Business, Electronics, Electronics and electrical industries
Abstract

The time-resolved magnetization dynamics of epitaxial [Fe.sub.3][O.sub.4] ultra-thin films grown on GaAs were investigated for the first time using a field pumped TRMOKE (time-resolved magneto-optical Kerr effect) setup. The dynamic response of the sample to the field pulse was measured for different DC bias fields applied along two orthogonal crystalline directions for 3 and 6 nm films. The results show a heavily damped precessional response to the applied field pulses. By fitting the Landau-Lifshitz-Gilbert equation to the data the temporal evolution of the magnetisation can be reproduced and the damping constant determined to be around 0.1. Index Terms--Iron oxide, magnetic anisotropy.

Published
2008

22. British Oculoplastic Surgery Society (BOPSS) national ptosis survey

Author

Scoppettuolo, E., Chadha, V., Bunce, C., Olver, J.M., and Wright, M.

Subjects
Blepharoptosis -- Surveys, Blepharoptosis -- Care and treatment, Blepharoptosis -- Patient outcomes, Eye -- Surgery, Eye -- Patient outcomes, Eye -- Surveys, Health
Published
2008

23. Predicting visual outcome following retinectomy for retinal detachment

Author

De Silva, D.J., Kwan, A., Bunce, C., and Bainbridge, J.

Subjects
Retinal detachment -- Care and treatment, Retinal detachment -- Patient outcomes, Retinal detachment -- Research, Visual acuity -- Research, Eye -- Surgery, Eye -- Patient outcomes, Eye -- Research, Health
Published
2008

26. Biometric and systemic associations

Author

Bourne, R.R.A., Foster, P.J., Bunce, C., Peto, T., Hitchings, R.A., Khaw, P.T., Seah, S.K.L., and Garway-Heath, D.F.

Subjects
Glaucoma -- Physiological aspects, Glaucoma -- Demographic aspects, Glaucoma -- Research, Biometric research -- Reports, Optic nerve -- Demographic aspects, Optic nerve -- Research, Optic nerve -- Physiological aspects, Health
Published
2008

27. Optic nerve head morphology

Author

Bourne, R.R.A., Foster, P.J., Bunce, C., Peto, T., Hitchings, R.A., Khaw, P.T., Seah, S.K.L., and Garway-Heath, D.F.

Subjects
Optic nerve -- Physiological aspects, Optic nerve -- Demographic aspects, Optic nerve -- Research, Glaucoma -- Demographic aspects, Morphological variation -- Research, Health
Published
2008

35. Silicone oil concentrates fibrogenic growth factors in the retro-oil fluid

Author

Asaria, R.H.Y., Kon, C.H., Bunce, C., Sethi, C.S., Limb, G.A., Khaw, P.T., Aylward, G.W., and Charteris, D.G.

Subjects
Proteins -- Measurement, Silicones in medicine -- Observations, Growth factors -- Observations, Fibroblast growth factors -- Measurement, Eye -- Surgery, Eye -- Complications and side effects, Health
Published
2004

41. Aetiology and surgical treatment of childhood blepharoptosis. (Clinical Science)

Author

Lee, V., Konrad, H., Bunce, C., Nelson, C., and Collin, J.R.O.

Subjects
Practice, Care and treatment, Abnormalities, Methods, Ocular motility disorders -- Care and treatment, Birth defects -- Care and treatment, Eye surgery -- Methods, Eye abnormalities -- Care and treatment, Eye -- Methods, Pediatric ophthalmology -- Practice -- Methods, Plastic surgery -- Practice -- Methods, Blepharoptosis -- Care and treatment, Eye -- Methods -- Abnormalities -- Movement disorders -- Surgery, Surgery, Plastic -- Practice -- Methods
Abstract

Aims: To describe the aetiology, demography, surgical management, and outcome of a cohort of paediatric ptosis patients in a large tertiary referral oculoplastic centre. Methods: A case note review of [...]

Published
2002

42. Low vision services for vision rehabilitation in the United Kingdom. (Scientific Correspondence)

Author

Culham, L.E., Ryan, B., Jackson, A.J., Hill, A.R., Jones, B., Miles, C., Young, J.A., Bunce, C., and Bird, A.C.

Subjects
Analysis, Case studies, Services, Health surveys -- Analysis -- Case studies, Public health -- Case studies -- Analysis, Low vision -- Services -- Case studies -- Analysis
Abstract

Aim: Little is known about the distribution and methods of delivery of low vision services across the United Kingdom. The purpose of this study was to determine the type and [...]

Published
2002

43. Vascular endothelial growth factor is elevated in ocular fluids of eyes harbouring uveal melanoma: Identification of a potential therapeutic window. (Clinical Science)

Author

Boyd, S.R., Tan, D., Bunce, C., Gittos, A., Neale, M.H., Hungerford, J.L., Charnock-Jones, S., and Cree, I.A.

Subjects
Care and treatment, Physiological aspects, Endothelial growth factors -- Physiological aspects, Neovascularization -- Physiological aspects, Eye cancer -- Care and treatment
Abstract

Background: Improved local treatment of uveal melanoma makes it possible for many patients to retain the affected eye, but a proportion will develop secondary complications such as neovascularisation of the [...]

Published
2002

45. Systemic cyclosporin a in high risk penetrating keratoplasties: a case-control study

Author

Poon, A.C., Forbes, J.B., Dart, J.K.G., Subramaniam, S, Bunce, C., Madison, P., Ficker, L.A., Tuft, S.J., Gartry, D.S., and Buckley, R.J.

Subjects
Prevention, Research, Cornea -- Research, Surgery -- Research, Cyclosporins -- Research, Ophthalmology -- Research, Graft rejection -- Prevention -- Research, Cyclosporine -- Research
Abstract

Aim--To examine the efficacy of systemic cyclosporin A (CSA) in preventing rejection and graft failure in high risk keratoplasty (PK). Methods--A retrospective case-control study with 49 patients in both the [...]

Published
2001

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