ORCID Profile
0000-0002-4405-6677
Current Organisations
University of Southampton
,
Westmead Hospital
,
University of St Andrews
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Publisher: Public Library of Science (PLoS)
Date: 13-10-2014
Publisher: Oxford University Press (OUP)
Date: 04-2011
Publisher: Informa UK Limited
Date: 25-08-2015
Publisher: Frontiers Media SA
Date: 22-08-2022
DOI: 10.3389/FMARS.2022.903035
Abstract: Krill are the subject of growing commercial fisheries and therefore fisheries management is necessary to ensure long-term sustainability. Krill catch limits, set by Commission for the Conservation of Antarctic Marine Living Resources, are based on absolute krill biomass, estimated from acoustic-trawl surveys. In this work, we develop a method for determining an error budget for acoustic-trawl surveys of krill which includes s ling and measurement variability. We use our error budget method to examine the sensitivity of biomass estimates to parameters in acoustic target strength (TS) models, length frequency distribution and length to wetmass relationships derived from net data. We determined that the average coefficient of variation ( CV ) of estimated biomass was 17.7% and the average CV due from scaling acoustic observations to biomass density was 5.3%. We found that a large proportion of the variability of biomass estimates is due to the krill orientation distribution, a parameter in the TS model. Orientation distributions with narrow standard deviations were found to emphasise the results of nulls in the TS to length relationship, which has to potential to lead to biologically implausible results.
Publisher: Elsevier BV
Date: 06-2017
DOI: 10.1016/J.MSEC.2017.02.116
Abstract: Tooth hypersensitivity is a growing problem affecting both the young and ageing population worldwide. Since an effective and permanent solution is not yet available, we propose a new methodology for the restoration of dental enamel using femtosecond lasers and novel calcium phosphate biomaterials. During this procedure the irradiated mineral transforms into a densified layer of acid resistant iron doped β-pyrophosphate, bonded with the surface of eroded enamel. Our aim therefore is to evaluate this densified mineral as a potential replacement material for dental hard tissue. To this end, we have tested the hardness of β-pyrophosphate pellets (sintered at 1000°C) and its mineral precursor (brushite), the wear rate during simulated tooth-brushing trials and the cytocompatibility of these minerals in powder form. It was found that the hardness of the β-pyrophosphate pellets is comparable with that of dental enamel and significantly higher than dentine while, the brushing trials prove that the wear rate of β-pyrophosphate is much slower than that of natural enamel. Finally, cytotoxicity and genotoxicity tests suggest that iron doped β-pyrophosphate is cytocompatible and therefore could be used in dental applications. Taken together and with the previously reported results on laser irradiation of these materials we conclude that iron doped β-pyrophosphate may be a promising material for restoring acid eroded and worn enamel.
Publisher: IOP Publishing
Date: 23-08-2013
Publisher: Oxford University Press (OUP)
Date: 04-2011
Publisher: Frontiers Media SA
Date: 07-04-2021
DOI: 10.3389/FMARS.2021.658384
Abstract: Antarctic krill are subject to precautionary catch limits, based on biomass estimates, to ensure human activities do not adversely impact their important ecological role. Accurate target strength models of in idual krill underpin biomass estimates. These models are scaled using measured and estimated distributions of length and orientation. However, while the length distribution of a krill swarm is accessible from net s les, there is currently limited consensus on the method for estimating krill orientation distribution. This leads to a limiting factor in biomass calculations. In this work, we consider geometric shape as a variable in target strength calculations and describe a practical method for generating a catalog of krill shapes. A catalog of shapes produces a more variable target strength response than an equivalent population of a scaled generic shape. Furthermore, using a shape catalog has the greatest impact on backscattering cross-section (linearized target strength) where the dominant scattering mechanism is mie scattering, irrespective of orientation distribution weighting. We suggest that shape distributions should be used in addition to length and orientation distributions to improve the accuracy of krill biomass estimates.
Publisher: SAGE Publications
Date: 26-08-2013
DOI: 10.1111/IJS.12132
Abstract: No evidence-based acute therapies exist for intracerebral hemorrhage. Intracerebral hemorrhage growth is an important determinant of patient outcome. Tranexamic acid is known to reduce hemorrhage in other conditions. The study aims to test the hypothesis that intracerebral hemorrhage patients selected with computed tomography angiography contrast extravasation ‘spot sign’ will have lower rates of hematoma growth when treated with intravenous tranexamic acid within 4·5-hours of stroke onset compared with placebo. The Spot sign and Tranexamic acid On Preventing ICH growth – AUStralasia Trial is a multicenter, prospective, 1:1 randomized, double-blind, placebo-controlled, investigator-initiated, academic Phase II trial. Intracerebral hemorrhage patients fulfilling clinical criteria (e.g. Glasgow Coma Scale , intracerebral hemorrhage volume ml, no identified secondary cause of intracerebral hemorrhage, no thrombotic events within the previous 12 months, no planned surgery) and demonstrating contrast extravasation on computed tomography angiography will receive either intravenous tranexamic acid 1 g 10-min bolus followed by 1 g eight-hour infusion or placebo. A second computed tomography will be performed at 24 ± 3 hours to evaluate intracerebral hemorrhage growth and patients followed up for three-months. The primary outcome measure is presence of intracerebral hemorrhage growth by 24 ± 3 hours, defined as either % or ml increase from baseline, and will be adjusted for baseline intracerebral hemorrhage volume. Secondary outcome measures include growth as a continuous measure, thromboembolic events, and the three-month modified Rankin Scale score. This is the first trial to evaluate the efficacy of tranexamic acid in intracerebral hemorrhage patients selected based on an imaging biomarker of high likelihood of hematoma growth. The trial is registered as NCT01702636.
Publisher: The Optical Society
Date: 13-08-2013
DOI: 10.1364/OE.21.019608
Publisher: Optica Publishing Group
Date: 05-02-2009
DOI: 10.1364/OE.17.002375
Abstract: Common-path optical coherence tomography (CPOCT) is known to reduce group velocity dispersion and polarization mismatch between the reference and the s le arm as both arms share the same physical path. Existing implementations of CPOCT typically require one to incorporate an additional cover glass within the beam path of the s le arm to provide a reference signal. In this paper, we aim to further reduce this step by directly making use of the back-reflected signal, arising from a conical lens-tip fiber, as a reference signal. The conical lens, which is directly manufactured onto the optical fiber tip via a simple selective-chemical etching process, fulfils two functions acting as both the imaging lens and the self-aligning reference plane. We use a Fourier-domain OCT system to demonstrate the feasibility of this technique upon biological tissue. An in-fiber CPOCT technique may prove potentially useful in endoscopic OCT imaging.
Publisher: OSA
Date: 2014
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.PARKRELDIS.2019.11.004
Abstract: Dystonia is a clinically and genetically heterogeneous disorder and a genetic cause is often difficult to elucidate. This is the first study to use whole genome sequencing (WGS) to investigate dystonia in a large s le of affected in iduals. WGS was performed on 111 probands with heterogenous dystonia phenotypes. We performed analysis for coding and non-coding variants, copy number variants (CNVs), and structural variants (SVs). We assessed for an association between dystonia and 10 known dystonia risk variants. A genetic diagnosis was obtained for 11.7% (13/111) of in iduals. We found that a genetic diagnosis was more likely in those with an earlier age at onset, younger age at testing, and a combined dystonia phenotype. We identified pathogenic/likely-pathogenic variants in ADCY5 (n = 1), ATM (n = 1), GNAL (n = 2), GLB1 (n = 1), KMT2B (n = 2), PRKN (n = 2), PRRT2 (n = 1), SGCE (n = 2), and THAP1 (n = 1). CNVs were detected in 3 in iduals. We found an association between the known risk variant ARSG rs11655081 and dystonia (p = 0.003). A genetic diagnosis was found in 11.7% of in iduals with dystonia. The diagnostic yield was higher in those with an earlier age of onset, younger age at testing, and a combined dystonia phenotype. WGS may be particularly relevant for dystonia given that it allows for the detection of CNVs, which accounted for 23% of the genetically diagnosed cases.
Publisher: The Optical Society
Date: 19-10-2012
DOI: 10.1364/OL.37.004416
Publisher: IOP Publishing
Date: 22-10-2004
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Christian Thomas Alcuin Brown.