ORCID Profile
0000-0003-3094-9762
Current Organisation
Rutherford Appleton Laboratory
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Publisher: Elsevier BV
Date: 08-2012
DOI: 10.1016/J.JBIOMECH.2012.05.046
Abstract: Evidence concerning the alteration of knee function during landing suffers from a lack of consensus. This uncertainty can be attributed to methodological flaws, particularly in relation to the statistical analysis of variable human movement data. The aim of this study was to compare single-subject and group analyses in detecting changes in knee stiffness and coordination during step landing that occur independent of an experimental intervention. A group of healthy men (N=12) stepped-down from a knee-high platform for 60 consecutive trials, each trial separated by a 1-minute rest. The magnitude and within-participant variability of sagittal stiffness and coordination of the landing knee were evaluated with both group and single-subject analyses. The group analysis detected significant changes in knee coordination. However, the single-subject analyses detected changes in all dependent variables, which included increases in variability with task repetition. Between-in idual variation was also present in the timing, size and direction of alterations. The results have important implications for the interpretation of existing information regarding the adaptation of knee mechanics to interventions such as fatigue, footwear or landing height. It is proposed that a participant's natural variation in knee mechanics should be analysed prior to an intervention in future experiments.
Publisher: Springer Science and Business Media LLC
Date: 09-2007
DOI: 10.1039/B705801B
Abstract: Two photon ionisation of 2-aminopurine (2AP) has been monitored following 267 nm irradiation in neutral and acidic aqueous solutions using picosecond time-resolved infrared spectroscopy (ps-TRIR). The transient infrared spectra obtained in neutral and acidic conditions show significant differences that are consistent with the formation of different species, namely the 2AP radical cation, 2AP+*, in acidic conditions and the uncharged radical, 2AP*(-H+), in neutral conditions. The ps-TRIR data indicate that deprotonation of 2AP+* in neutral solution takes place within <2 ps following photoionisation. DFT calculations (EDF1/6-31+G*) were used to support the assignment of the intermediates observed in these spectroscopic experiments.
Publisher: Royal Society of Chemistry (RSC)
Date: 2008
DOI: 10.1039/B811357B
Abstract: Photoinduced Fe-to-bpy charge transfer in [{Cp(dppe)Fe}(mu-C[triple bond]CC[triple bond]N){Re(CO)(3)(bpy)}]PF(6) has been observed by ps-TRIR spectroscopy, supported by UV-Vis/IR spectroelectrochemistry and DFT calculations.
Publisher: Springer Science and Business Media LLC
Date: 12-01-2013
Abstract: The mammalian target of rapamycin (mTOR) signalling pathway has a key role in cellular regulation and several diseases. While it is thought that Rheb GTPase regulates mTOR, acting immediately upstream, while raptor is immediately downstream of mTOR, direct interactions have yet to be verified in living cells, furthermore the localisation of Rheb has been reported to have only a cytoplasmic cellular localization. In this study a cytoplasmic as well as a significant sub-cellular nuclear mTOR localization was shown , utilizing green and red fluorescent protein (GFP and DsRed) fusion and highly sensitive single photon counting fluorescence lifetime imaging microscopy (FLIM) of live cells. The interaction of the mTORC1 components Rheb, mTOR and raptor, tagged with EGFP/DsRed was determined using fluorescence energy transfer-FLIM. The excited-state lifetime of EGFP-mTOR of ~2400 ps was reduced by energy transfer to ~2200 ps in the cytoplasm and to 2000 ps in the nucleus when co-expressed with DsRed-Rheb, similar results being obtained for co-expressed EGFP-mTOR and DsRed-raptor. The localization and distribution of mTOR was modified by amino acid withdrawal and re-addition but not by rapamycin. The results illustrate the power of GFP-technology combined with FRET-FLIM imaging in the study of the interaction of signalling components in living cells, here providing evidence for a direct physical interaction between mTOR and Rheb and between mTOR and raptor in living cells for the first time.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9SC05717J
Abstract: Break down of the Born–Oppenheimer approximation is caused by mixing of electronic and vibrational transitions in the radical cations of some conjugated polymers, resulting in unusually intense vibrational bands known as infrared active vibrations (IRAVs).
Publisher: Royal Society of Chemistry (RSC)
Date: 2003
DOI: 10.1039/B307005K
Abstract: Picosecond time-resolved resonance Raman spectroscopy, TR3, reveals an intense acetylenic band in the S1 state of the prototypical molecular wire 1,4-bis(phenylethynyl)benzene.
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2AN00978A
Abstract: Two-Dimensional Infrared (2D-IR) spectroscopy is used to detect binding of paracetamol with proteins in blood serum. Quantitative peak patterns are observed indicating structural changes of the albumins' secondary structure when paracetamol bound.
Publisher: AIP Publishing
Date: 10-2005
DOI: 10.1063/1.2054486
Abstract: A method for obtaining resonance Raman spectra from microvolume (2–5μl) frozen s les is described. The procedure involves trapping and freezing a microdroplet in a specially designed s le holder using a cryostream. The method makes it possible to prepare numerous low-volume air-sensitive s les in a suitable environment for spectroscopic studies. We have demonstrated the potential of the setup measuring the resonance Raman spectra of 4-thiouracil and horse heart myoglobin.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8SC00130H
Abstract: We demonstrate that a photochromic spironaphthoxazine switch operates with excellent fatigue resistance and high conversion when irradiated at 405/561 nm in a range of media including living cells.
Publisher: Proceedings of the National Academy of Sciences
Date: 21-10-2008
Abstract: This work explores time-resolved emission imaging microscopy (TREM) for noninvasive imaging and mapping of live cells on a hitherto uncharted microsecond time scale. Simple robust molecules for this purpose have long been sought. We have developed highly emissive, synthetically versatile, and photostable platinum(II) complexes that make TREM a practicable reality. [PtLCl], {HL = 1,3-di(2-pyridyl)benzene and derivatives}, are charge-neutral, small molecules that have low cytotoxicity and accumulate intracellularly within a remarkably short incubation time of 5 min, apparently under diffusion control. Their microsecond lifetimes and emission quantum yields of up to 70% are exceptionally high for transition metal complexes and permit the application of TREM to be demonstrated in a range of live cell types—normal human dermal fibroblast, neoplastic C8161 and CHO cells. [PtLCl] are thus likely to be suitable emission labels for any eukaryotic cell types. The high photostability of [PtLCl] under intense prolonged irradiation has allowed the development of tissue-friendly NIR two-photon excitation (TPE) in conjunction with transition metal complexes in live cells. A combination of confocal one-photon excitation, nonlinear TPE, and microsecond time-resolved imaging has revealed ( i ) preferential localization of the complexes to intracellular nucleic acid structures, in particular the nucleoli and ( ii ) the possibility of measuring intracellular emission lifetimes in the microsecond range. The combination of TREM, TPE, and Pt(II) complexes will be a powerful tool for investigating intracellular processes in vivo , because the long lifetimes allow discrimination from autofluorescence and open up the use of commonplace technology.
Publisher: AIP Publishing
Date: 22-11-2022
DOI: 10.1063/5.0127680
Abstract: The ability of two-dimensional infrared (2D-IR) spectroscopy to measure the amide I band of proteins in H2O rather than D2O-based solvents by evading the interfering water signals has enabled in vivo studies of proteins under physiological conditions and in biofluids. Future exploitation of 2D-IR in analytical settings, from diagnostics to protein screening, will, however, require comparisons between multiple datasets, necessitating control of data collection protocols to minimize measurement-to-measurement inconsistencies. Inspired by analytical spectroscopy applications in other disciplines, we describe a workflow for pre-processing 2D-IR data that aims to simplify spectral cross-comparisons. Our approach exploits the thermal water signal that is collected simultaneously with, but is temporally separated from the amide I response to guide custom baseline correction and spectral normalization strategies before combining them with Principal Component noise reduction tools. Case studies show that application of elements of the pre-processing workflow to previously published data enables improvements in quantification accuracy and detection limits. We subsequently apply the complete workflow in a new pilot study, testing the ability of a prototype library of 2D-IR spectra to quantify the four major protein constituents of blood serum in a single, label-free measurement. These advances show progress toward the robust data handling strategies that will be necessary for future applications of 2D-IR to pharmaceutical or biomedical problems.
Publisher: American Chemical Society (ACS)
Date: 21-11-2002
DOI: 10.1021/JA026099M
Abstract: A series of substituted benzoyl radicals has been generated by laser flash photolysis of alpha-hydroxy ketones, alpha-amino ketones, and acyl and bis(acyl)phosphine oxides, all of which are used commercially as photoinitiators in free radical polymerizations. The benzoyl radicals have been studied by fast time-resolved infrared spectroscopy. The absolute rate constants for their reaction with n-butylacrylate, thiophenol, bromotrichloromethane and oxygen were measured in acetonitrile solution. The rate constants of benzoyl radical addition to n-butylacrylate range from 1.3 x 10(5) to 5.5 x 10(5) M(-1) s(-1) and are about 2 orders of magnitude lower than for the n-butylacrylate addition to the counterradicals that are produced by alpha-cleavage of the investigated ketones. Density functional theoretical calculations have been performed in order to rationalize the observed reactivities of the initiating radicals. Calculations of the phosphorus-centered radicals generated by photolysis of an acyl and bis(acyl)phosphine oxide suggest that P atom Mulliken spin populations are an indicator of the relative reactivities of the phosphorus-centered radicals. The alpha-cleavage of (2,4,6-trimethylbenzoyl)phosphine oxide was studied by picosecond pump-probe and nanosecond step-scan time-resolved infrared spectroscopy. The results support a mechanism in which the alpha-cleavage occurs from the triplet excited state that has a lifetime less than or equal to the singlet excited state.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9SC01590F
Abstract: 2D-IR spectroscopy is used to measure protein amide I bands in water, avoiding the need for deuteration. We show that H/D exchange affects protein vibrational relaxation dynamics and that the ability to perform 2D-IR in water enables blood serum protein analysis.
Publisher: American Chemical Society (ACS)
Date: 18-12-2014
DOI: 10.1021/JA510663Z
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Anthony Parker.