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Thomas AW, Wang XG, Williams AG. Sensitivity of Parity-Violating Electron Scattering to a Dark Photon. Phys Rev Lett 2022; 129:011807. [PMID: 35841575 DOI: 10.1103/physrevlett.129.011807] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/17/2022] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
We explore the sensitivity of the parity-violating electron scattering (PVES) asymmetry in both elastic and deep-inelastic scattering to the properties of a dark photon. Given advances in experimental capabilities in recent years, there are interesting regions of parameter space where PVES offers the chance to discover new physics in the near future. There are also cases where the existence of a dark photon could significantly alter our understanding of the structure of atomic nuclei and neutron stars as well as parton distribution functions.
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Affiliation(s)
- A W Thomas
- ARC Centre of Excellence for Dark Matter Particle Physics and CSSM, Department of Physics, University of Adelaide, South Australia 5005, Australia
| | - X G Wang
- ARC Centre of Excellence for Dark Matter Particle Physics and CSSM, Department of Physics, University of Adelaide, South Australia 5005, Australia
| | - A G Williams
- ARC Centre of Excellence for Dark Matter Particle Physics and CSSM, Department of Physics, University of Adelaide, South Australia 5005, Australia
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Cocuzza C, Keppel CE, Liu H, Melnitchouk W, Metz A, Sato N, Thomas AW. Isovector EMC Effect from Global QCD Analysis with MARATHON Data. Phys Rev Lett 2021; 127:242001. [PMID: 34951781 DOI: 10.1103/physrevlett.127.242001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 08/23/2021] [Accepted: 10/28/2021] [Indexed: 06/14/2023]
Abstract
We report the results of a Monte Carlo global QCD analysis of unpolarized parton distribution functions (PDFs), including for the first time constraints from ratios of ^{3}He to ^{3}H structure functions recently obtained by the MARATHON experiment at Jefferson Lab. Our simultaneous analysis of nucleon PDFs and nuclear effects in A=2 and A=3 nuclei reveals the first indication for an isovector nuclear EMC effect in light nuclei. We find that while the MARATHON data yield relatively weak constraints on the F_{2}^{n}/F_{2}^{p} neutron to proton structure function ratio and on the d/u PDF ratio, they suggest an enhanced nuclear effect on the d-quark PDF in the bound proton, questioning the assumptions commonly made in nuclear PDF analyses.
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Affiliation(s)
- C Cocuzza
- Department of Physics, SERC, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - C E Keppel
- Jefferson Lab, Newport News, Virginia 23606, USA
| | - H Liu
- Department of Physics, University of Massachusetts, Amherst, Massachusetts 01003, USA
| | | | - A Metz
- Department of Physics, SERC, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - N Sato
- Jefferson Lab, Newport News, Virginia 23606, USA
| | - A W Thomas
- CSSM and CoEPP, Department of Physics, University of Adelaide South Australia 5005, Australia
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Wang XG, Thomas AW, Melnitchouk W. Do Short-Range Correlations Cause the Nuclear EMC Effect in the Deuteron? Phys Rev Lett 2020; 125:262002. [PMID: 33449726 DOI: 10.1103/physrevlett.125.262002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 11/09/2020] [Accepted: 12/04/2020] [Indexed: 06/12/2023]
Abstract
The relative contributions to the valence nuclear European Muon Collaboration (EMC) effect in the deuteron arising from nucleon off-shell effects and Fermi motion are examined in models which include nuclear binding and off-shell effects. Contrary to expectations, the effect of Fermi motion overwhelms the off-shell effects for nucleons in short-range correlations (SRCs), calling into question the hypothesized causal connection between SRCs and the EMC effect.
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Affiliation(s)
- X G Wang
- CSSM and ARC Centre of Excellence for Particle Physics at the Terascale, Department of Physics, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - A W Thomas
- CSSM and ARC Centre of Excellence for Particle Physics at the Terascale, Department of Physics, University of Adelaide, Adelaide, South Australia 5005, Australia
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Abstract
Recent years continue to be an exciting time for the neutron star physics, providing many new observations and insights to these natural ‘laboratories’ of cold dense matter. To describe them, there are many models on the market but still none that would reproduce all observed and experimental data. The quark-meson coupling model stands out with its natural inclusion of hyperons as dense matter building blocks, and fewer parameters necessary to obtain the nuclear matter equation of state. The latest advances of the QMC model and its application to the neutron star physics will be presented, within which we build the neutron star’s outer crust from finite nuclei up to the neutron drip line. The appearance of different elements and their position in the crust of a neutron star is explored and compared to the predictions of various models, giving the same quality of the results for the QMC model as for the models when the nucleon structure is not taken into account.
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Ruffino JS, Davies NA, Morris K, Ludgate M, Zhang L, Webb R, Thomas AW. Moderate-intensity exercise alters markers of alternative activation in circulating monocytes in females: a putative role for PPARγ. Eur J Appl Physiol 2016; 116:1671-82. [PMID: 27339155 PMCID: PMC4983283 DOI: 10.1007/s00421-016-3414-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 06/06/2016] [Indexed: 02/07/2023]
Abstract
PURPOSE Monocytes may be primed towards differentiation into classically activated M1 macrophages or alternatively activated M2 macrophages. M1 macrophages greatly contribute to the inflammation which promotes insulin resistance, whereas M2 macrophages resolve inflammation. We have previously shown that exercise increases M2 marker expression in mixed mononuclear cells, possibly via activation of the nuclear transcription factor PPARγ. However, these effects have not been demonstrated specifically within monocytes. Thus, we aimed to investigate whether moderate-intensity exercise elicited similar effects on monocytic M1/M2 marker expression and PPARγ activity to those reported previously in mononuclear cells, so as to further elucidate the mechanisms by which exercise may alter inflammatory status and, accordingly, prevent insulin resistance. METHODS/RESULTS 19 sedentary females completed an 8 week moderate-intensity exercise programme (walking 45 min, thrice weekly). Monocytes were isolated from blood via immunomagnetic separation; monocyte expression of M2 markers (Dectin-1: 2.6 ± 1.9-fold; IL-10: 3.0 ± 2.8-fold) significantly increased, whilst the expression of the M1 marker MCP-1 significantly decreased (0.83 ± 0.2 cf. basal), over the duration of the programme. Serum PPARγ activity levels and PPARγ target-genes (CD36: 1.9 ± 1.5-fold; LXRα: 5.0 ± 4.7-fold) were significantly increased after the 8 week exercise programme. Associated with these effects were significant improvements in systemic insulin sensitivity (McAuley's ISI: Δ0.98 M/mU/L cf. basal). CONCLUSION Exercise participation suppressed M1 markers and induced M2 markers in monocytes, potentially via PPARγ-triggered signalling, and these effects may contribute (perhaps via priming of monocytes for differentiation into M2 tissue-macrophages) to improved systemic insulin sensitivity in exercising participants. These findings provide an alternative mechanism by which exercise may exert its anti-inflammatory effects in order to prevent insulin resistance and type 2 diabetes.
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Affiliation(s)
- J S Ruffino
- Centre for Biomedical Science, Cardiff Metropolitan University, Cardiff, CF5 2YB, UK
| | - N A Davies
- College of Medicine, Swansea University, Swansea, SA2 8PP, UK
| | - K Morris
- Centre for Endocrine & Diabetes Sciences, Cardiff University School of Medicine, Cardiff, CF14 4YU, UK
| | - M Ludgate
- Centre for Endocrine & Diabetes Sciences, Cardiff University School of Medicine, Cardiff, CF14 4YU, UK
| | - L Zhang
- Centre for Endocrine & Diabetes Sciences, Cardiff University School of Medicine, Cardiff, CF14 4YU, UK
| | - R Webb
- Centre for Biomedical Science, Cardiff Metropolitan University, Cardiff, CF5 2YB, UK
| | - A W Thomas
- Centre for Biomedical Science, Cardiff Metropolitan University, Cardiff, CF5 2YB, UK.
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Abstract
We report the first use of the effective quark-meson coupling (QMC) energy density functional (EDF), derived from a quark model of hadron structure, to study a broad range of ground state properties of even-even nuclei across the periodic table in the nonrelativistic Hartree-Fock+BCS framework. The novelty of the QMC model is that the nuclear medium effects are treated through modification of the internal structure of the nucleon. The density dependence is microscopically derived and the spin-orbit term arises naturally. The QMC EDF depends on a single set of four adjustable parameters having a clear physics basis. When applied to diverse ground state data the QMC EDF already produces, in its present simple form, overall agreement with experiment of a quality comparable to a representative Skyrme EDF. There exist, however, multiple Skyrme parameter sets, frequently tailored to describe selected nuclear phenomena. The QMC EDF set of fewer parameters, derived in this work, is not open to such variation, chosen set being applied, without adjustment, to both the properties of finite nuclei and nuclear matter.
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Affiliation(s)
- J R Stone
- Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - P A M Guichon
- SPhN-IRFU, CEA Saclay, F91191 Gif sur Yvette, France
| | - P G Reinhard
- Institut für Theoretische Physik II, Universität Erlangen, D-91058 Erlangen, Germany
| | - A W Thomas
- ARC Centre of Excellence in Particle Physics at the Terascale and CSSM, Department of Physics, University of Adelaide, SA 5005 Australia
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Webb R, Thompson JES, Ruffino JS, Davies NA, Watkeys L, Hooper S, Jones PM, Walters G, Clayton D, Thomas AW, Morris K, Llewellyn DH, Ward M, Wyatt-Williams J, McDonnell BJ. Evaluation of cardiovascular risk-lowering health benefits accruing from laboratory-based, community-based and exercise-referral exercise programmes. BMJ Open Sport Exerc Med 2016; 2:e000089. [PMID: 27900165 PMCID: PMC5117059 DOI: 10.1136/bmjsem-2015-000089] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 12/22/2015] [Accepted: 01/01/2016] [Indexed: 11/28/2022] Open
Abstract
Background To evaluate the ability of community-based exercise programmes to facilitate public participation in exercise and hence improved cardiovascular health, we assessed the respective impacts of: a continuously monitored exercise programme based within our university (study 1); a Valleys Regional Park-facilitated community-based outdoor exercise programme (study 2); a Wales National Exercise Referral Scheme-delivered exercise-referral programme (study 3). Methods Biomolecular (monocytic PPARγ target gene expression), vascular haemodynamic (central/peripheral blood pressure, arterial stiffness), clinical (insulin sensitivity, blood lipids) and anthropometric (body mass index, waist circumference, heart rate) parameters were investigated using RT-PCR, applanation tonometry, chemical analysis and standard anthropometric techniques. Results In studies 1–3, 22/28, 32/65 and 11/14 participants adhered to their respective exercise programmes, and underwent significant increases in physical activity levels. Importantly, beneficial effects similar to those seen in our previous studies (eg, modulations in expression of monocytic PPARγ target genes, decreases in blood pressure/arterial stiffness, improvements in blood lipids/insulin sensitivity) were observed (albeit to slightly differing extents) only in participants who adhered to their respective exercise programmes. While study 1 achieved more intense exercise and more pronounced beneficial effects, significant cardiovascular risk-lowering health benefits related to biomolecular markers, blood pressure, arterial stiffness and blood lipids were achieved via community/referral-based delivery modes in studies 2 and 3. Conclusions Because cardiovascular health benefits were observed in all 3 studies, we conclude that the majority of benefits previously reported in laboratory-based studies can also be achieved in community-based/exercise-referral settings. These findings may be of use in guiding policymakers with regard to introduction and/or continued implementation of community/referral-based exercise programmes.
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Affiliation(s)
- R Webb
- Department of Biomedical Sciences , Cardiff Metropolitan University , Cardiff , UK
| | - J E S Thompson
- Department of Biomedical Sciences , Cardiff Metropolitan University , Cardiff , UK
| | - J-S Ruffino
- Department of Biomedical Sciences , Cardiff Metropolitan University , Cardiff , UK
| | - N A Davies
- Department of Biomedical Sciences , Cardiff Metropolitan University , Cardiff , UK
| | - L Watkeys
- Department of Biomedical Sciences , Cardiff Metropolitan University , Cardiff , UK
| | - S Hooper
- Department of Biomedical Sciences , Cardiff Metropolitan University , Cardiff , UK
| | - P M Jones
- Department of Biomedical Sciences , Cardiff Metropolitan University , Cardiff , UK
| | - G Walters
- Department of Biomedical Sciences , Cardiff Metropolitan University , Cardiff , UK
| | - D Clayton
- Department of Biomedical Sciences , Cardiff Metropolitan University , Cardiff , UK
| | - A W Thomas
- Department of Biomedical Sciences , Cardiff Metropolitan University , Cardiff , UK
| | - K Morris
- Department of Biomedical Sciences , Cardiff Metropolitan University , Cardiff , UK
| | - D H Llewellyn
- Department of Biomedical Sciences , Cardiff Metropolitan University , Cardiff , UK
| | - M Ward
- Blaengad Ltd , Wales , UK
| | - J Wyatt-Williams
- Department of Public Health Wales , Hayden Ellis Building , Cardiff , UK
| | - B J McDonnell
- Department of Biomedical Sciences , Cardiff Metropolitan University , Cardiff , UK
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Shanahan PE, Horsley R, Nakamura Y, Pleiter D, Rakow PEL, Schierholz G, Stüben H, Thomas AW, Young RD, Zanotti JM. Determination of the strange nucleon form factors. Phys Rev Lett 2015; 114:091802. [PMID: 25793800 DOI: 10.1103/physrevlett.114.091802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Indexed: 06/04/2023]
Abstract
The strange contribution to the electric and magnetic form factors of the nucleon is determined at a range of discrete values of Q^{2} up to 1.4 GeV^{2}. This is done by combining a recent analysis of lattice QCD results for the electromagnetic form factors of the octet baryons with experimental determinations of those quantities. The most precise result is a small negative value for the strange magnetic moment: G_{M}^{s}(Q^{2}=0)=-0.07±0.03μ_{N}. At larger values of Q^{2} both the electric and magnetic form factors are consistent with zero to within 2 standard deviations.
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Affiliation(s)
- P E Shanahan
- ARC Centre of Excellence in Particle Physics at the Terascale and CSSM, Department of Physics, University of Adelaide, Adelaide, SA 5005, Australia
| | - R Horsley
- School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - Y Nakamura
- RIKEN Advanced Institute for Computational Science, Kobe, Hyogo 650-0047, Japan
| | - D Pleiter
- JSC, Forschungzentrum Jülich, 52425 Jülich, Germany
- Institut für Theoretische Physik, Universität Regensburg, 93040 Regensburg, Germany
| | - P E L Rakow
- Theoretical Physics Division, Department of Mathematical Sciences, University of Liverpool, Liverpool L69 3BX, United Kingdom
| | - G Schierholz
- Deutsches Elektronen-Synchrotron DESY, 22603 Hamburg, Germany
| | - H Stüben
- Regionales Rechenzentrum, Universität Hamburg, 20146 Hamburg, Germany
| | - A W Thomas
- ARC Centre of Excellence in Particle Physics at the Terascale and CSSM, Department of Physics, University of Adelaide, Adelaide, SA 5005, Australia
| | - R D Young
- ARC Centre of Excellence in Particle Physics at the Terascale and CSSM, Department of Physics, University of Adelaide, Adelaide, SA 5005, Australia
| | - J M Zanotti
- ARC Centre of Excellence in Particle Physics at the Terascale and CSSM, Department of Physics, University of Adelaide, Adelaide, SA 5005, Australia
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Thomas AW, Catania C, Garner LE, Bazan GC. Pendant ionic groups of conjugated oligoelectrolytes govern their ability to intercalate into microbial membranes. Chem Commun (Camb) 2015; 51:9294-7. [DOI: 10.1039/c5cc01724f] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The ionic groups of lipid membrane intercalating conjugated oligoelectrolytes affect their interaction with E. coli and application in microbial fuel cells.
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Affiliation(s)
- A. W. Thomas
- Center for Polymers and Organic Solids
- Department of Chemistry and Biochemistry
- University of California
- Santa Barbara
- USA
| | - C. Catania
- Materials Department
- University of California
- Santa Barbara
- USA
| | | | - G. C. Bazan
- Center for Polymers and Organic Solids
- Department of Chemistry and Biochemistry
- University of California
- Santa Barbara
- USA
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Davies NA, Watkeys L, Butcher L, Potter S, Hughes MG, Moir H, Morris K, Thomas AW, Webb R. The contributions of oxidative stress, oxidised lipoproteins and AMPK towards exercise-associated PPARγ signalling within human monocytic cells. Free Radic Res 2014; 49:45-56. [DOI: 10.3109/10715762.2014.978311] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Cullen T, Thomas AW, Webb R, Phillips T, Hughes MG. OC2 The Soluble Il-6 Receptor Is Related To Weekly Training Volume And Fatigue In Highly Trained Swimmers. Br J Sports Med 2014. [DOI: 10.1136/bjsports-2014-094245.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Thomas AW, Whittenbury DL, Carroll JD, Tsushima K, Stone JR. Equation of State of Dense Matter and Consequences for Neutron Stars. EPJ Web of Conferences 2013. [DOI: 10.1051/epjconf/20136303004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Strunz GM, Giguère P, Thomas AW. Synthesis of pungenin, a foliar constituent of some spruce species, and investigation of its efficacy as a feeding deterrent for spruce budworm [Choristoneura fumiferana (Clem.)]. J Chem Ecol 2013; 12:251-60. [PMID: 24306414 DOI: 10.1007/bf01045608] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/1985] [Accepted: 06/19/1985] [Indexed: 10/25/2022]
Abstract
Pungenin was synthesized from 3,4-dihydroxyacetophenone by a short sequence involving manipulation of protecting groups on the 3 and 4 hydroxyl functions. Bioassays indicated that the glucoside is a modest feeding deterrent for sixth-instar spruce budworm larvae, but it does not appear to retard the development of small larvae or lead to increased mortality.
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Affiliation(s)
- G M Strunz
- Canadian Forestry Service, Maritimes Forest Research Centre, P. O. Box 4000, E3B 5P7, Fredericton, New Brunswick, Canada
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Shanahan PE, Thomas AW, Young RD. Charge symmetry breaking from a chiral extrapolation of moments of quark distribution functions. Int J Clin Exp Med 2013. [DOI: 10.1103/physrevd.87.094515] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Shanahan PE, Thomas AW, Tsushima K, Young RD, Myhrer F. Octet spin fractions and the proton spin problem. Phys Rev Lett 2013; 110:202001. [PMID: 25167398 DOI: 10.1103/physrevlett.110.202001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Indexed: 06/03/2023]
Abstract
The relatively small fraction of the spin of the proton carried by its quarks presents a major challenge to our understanding of the strong interaction. Traditional efforts to explore this problem have involved new and imaginative experiments and QCD based studies of the nucleon. We propose a new approach to the problem that exploits recent advances in lattice QCD. In particular, we extract values for the spin carried by the quarks in other members of the baryon octet in order to see whether the suppression observed for the proton is a general property or depends significantly on the baryon structure. We compare these results with the values for the spin fractions calculated within a model that includes the effects of confinement, relativity, gluon exchange currents, and the meson cloud required by chiral symmetry, finding a very satisfactory level of agreement given the precision currently attainable.
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Affiliation(s)
- P E Shanahan
- CSSM and ARC Centre of Excellence for Particle Physics at the Tera-scale, School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - A W Thomas
- CSSM and ARC Centre of Excellence for Particle Physics at the Tera-scale, School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - K Tsushima
- CSSM and ARC Centre of Excellence for Particle Physics at the Tera-scale, School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - R D Young
- CSSM and ARC Centre of Excellence for Particle Physics at the Tera-scale, School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia 5005, Australia
| | - F Myhrer
- Department of Physics, University of South Carolina, Columbia, South Carolina, USA
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Modolo J, Thomas AW, Legros A. Neural mass modeling of power-line magnetic fields effects on brain activity. Front Comput Neurosci 2013; 7:34. [PMID: 23596412 PMCID: PMC3622877 DOI: 10.3389/fncom.2013.00034] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 03/25/2013] [Indexed: 11/13/2022] Open
Abstract
Neural mass models are an appropriate framework to study brain activity, combining a high degree of biological realism while being mathematically tractable. These models have been used, with a certain success, to simulate brain electric (electroencephalography, EEG) and metabolic (functional magnetic resonance imaging, fMRI) activity. However, concrete applications of neural mass models have remained limited to date. Motivated by experimental results obtained in humans, we propose in this paper a neural mass model designed to study the interaction between power-line magnetic fields (MFs) (60 Hz in North America) and brain activity. The model includes pyramidal cells; dendrite-projecting, slow GABAergic neurons; soma-projecting, fast GABAergic neurons; and glutamatergic interneurons. A simple phenomenological model of interaction between the induced electric field and neuron membranes is also considered, along with a model of post-synaptic calcium concentration and associated changes in synaptic weights Simulated EEG signals are produced in a simple protocol, both in the absence and presence of a 60 Hz MF. These results are discussed based on results obtained previously in humans. Notably, results highlight that (1) EEG alpha (8-12 Hz) power can be modulated by weak membrane depolarizations induced by the exposure; (2) the level of input noise has a significant impact on EEG power modulation; and (3) the threshold value in MF flux density resulting in a significant effect on the EEG depends on the type of neuronal populations modulated by the MF exposure. Results obtained from the model shed new light on the effects of power-line MFs on brain activity, and will provide guidance in future human experiments. This may represent a valuable contribution to international regulation agencies setting guidelines on MF values to which the general public and workers can be exposed.
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Affiliation(s)
- J Modolo
- Human Threshold Research Group, Lawson Health Research Institute London, ON, Canada ; Department of Medical Biophysics, Western University London, ON, Canada ; Department of Medical Imaging, Western University London, ON, Canada
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Blunden PG, Melnitchouk W, Thomas AW. γZ box corrections to weak charges of heavy nuclei in atomic parity violation. Phys Rev Lett 2012; 109:262301. [PMID: 23368551 DOI: 10.1103/physrevlett.109.262301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Indexed: 06/01/2023]
Abstract
We present a new dispersive formulation of the γZ box radiative corrections to weak charges of bound protons and neutrons in atomic parity violation measurements on heavy nuclei such as 133Cs and 213Ra. We evaluate for the first time a small but important additional correction arising from Pauli blocking of nucleons in a heavy nucleus. Overall, we find a significant shift in the γZ correction to the weak charge of 133Cs, approximately 4 times larger than the current uncertainty on the value of sin2 θ(W), but with a reduced error compared to earlier estimates.
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Affiliation(s)
- P G Blunden
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2
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Cloët IC, Bentz W, Thomas AW. Parity-violating deep inelastic scattering and the flavor dependence of the EMC effect. Phys Rev Lett 2012; 109:182301. [PMID: 23215273 DOI: 10.1103/physrevlett.109.182301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Indexed: 06/01/2023]
Abstract
Isospin-dependent nuclear forces play a fundamental role in nuclear structure. In relativistic models of nuclear structure constructed at the quark level these isovector nuclear forces affect the u and d quarks differently, leading to nontrivial flavor-dependent modifications of the nuclear parton distributions. We explore the effect of isospin dependent forces for parity-violating deep inelastic scattering on nuclear targets and demonstrate that the cross sections for nuclei with N ≠ Z are sensitive to the flavor dependence of the EMC effect. Indeed, for nuclei like lead and gold we find that these flavor-dependent effects are large.
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Affiliation(s)
- I C Cloët
- CSSM and ARC Centre of Excellence for Particle Physics at the Terascale, School of Chemistry and Physics, University of Adelaide, Adelaide, South Australia 5005, Australia
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Thomas AW, Davies NA, Moir H, Watkeys L, Ruffino JS, Isa SA, Butcher LR, Hughes MG, Morris K, Webb R. Exercise-associated generation of PPARγ ligands activates PPARγ signaling events and upregulates genes related to lipid metabolism. J Appl Physiol (1985) 2012; 112:806-15. [DOI: 10.1152/japplphysiol.00864.2011] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of the present study was to test the hypotheses that exercise is associated with generation of peroxisome proliferator-activated receptor-γ (PPARγ) ligands in the plasma and that this may activate PPARγ signaling within circulating monocytes, thus providing a mechanism to underpin the exercise-induced antiatherogenic benefits observed in previous studies. A cohort of healthy individuals undertook an 8-wk exercise-training program; samples were obtained before (Pre) and after (Post) standardized submaximal exercise bouts (45 min of cycling at 70% of maximal O2 uptake, determined at baseline) at weeks 0, 4, and 8. Addition of plasma samples to PPARγ response element (PPRE)-luciferase reporter gene assays showed increased PPARγ activity following standardized exercise bouts (Post/Pre = 1.23 ± 0.10 at week 0, P < 0.05), suggesting that PPARγ ligands were generated during exercise. However, increases in PPARγ/PPRE-luciferase activity in response to the same standardized exercise bout were blunted during the training program (Post/Pre = 1.18 ± 0.14 and 1.10 ± 0.10 at weeks 4 and 8, respectively, P > 0.05 for both), suggesting that the relative intensity of the exercise may affect PPARγ ligand generation. In untrained individuals, specific transient increases in monocyte expression of PPARγ-regulated genes were observed within 1.5–3 h of exercise (1.7 ± 0.4, 2.6 ± 0.4, and 1.4 ± 0.1 fold for CD36, liver X receptor-α, and ATP-binding cassette subfamily A member 1, respectively, P < 0.05), with expression returning to basal levels within 24 h. In contrast, by the end of the exercise program, expression at the protein level of PPARγ target genes had undergone sustained increases that were not associated with an individual exercise bout (e.g., week 8 Pre/ week 0 Pre = 2.79 ± 0.61 for CD36, P < 0.05). Exercise is known to upregulate PPARγ-controlled genes to induce beneficial effects in skeletal muscle (e.g., mitochondrial biogenesis and aerobic respiration). We suggest that parallel exercise-induced benefits may occur in monocytes, as monocyte PPARγ activation has been linked to beneficial antidiabetic effects (e.g., exercise-induced upregulation of monocytic PPARγ-controlled genes is associated with reverse cholesterol transport and anti-inflammatory effects). Thus, exercise-triggered monocyte PPARγ activation may constitute an additional rationale for prescribing exercise to type 2 diabetes patients.
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Affiliation(s)
| | | | - H. Moir
- Cardiff School of Health Sciences and
| | | | | | - S. A. Isa
- Cardiff School of Health Sciences and
| | | | - M. G. Hughes
- Cardiff School of Sport, University of Wales Institute Cardiff, Cardiff, United Kingdom
| | - K. Morris
- Cardiff School of Health Sciences and
| | - R. Webb
- Cardiff School of Health Sciences and
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Legros A, Corbacio M, Beuter A, Modolo J, Goulet D, Prato FS, Thomas AW. Neurophysiological and behavioral effects of a 60 Hz, 1,800 μT magnetic field in humans. Eur J Appl Physiol 2011; 112:1751-62. [PMID: 21894451 DOI: 10.1007/s00421-011-2130-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Accepted: 08/12/2011] [Indexed: 11/29/2022]
Abstract
The effects of time-varying magnetic fields (MF) on humans have been actively investigated for the past three decades. One important unanswered question is the potential for MF exposure to have acute effects on human biology. Different strategies have been used to tackle this question using various physiological, neurophysiological and behavioral indicators. For example, researchers investigating electroencephalography (EEG) have reported that extremely low frequency (ELF, <300 Hz) MF can increase resting occipital alpha rhythm (8-12 Hz). Interestingly, other studies have demonstrated that human motricity can be modulated by ELF MF: a reduction of anteroposterior standing balance or a decrease of physiological tremor intensity have been reported as consequences of exposure. However, the main limitation in this domain lies in the lack of results replication, possibly originating from the large variety of experimental approaches employed. Therefore, the present study aimed to investigate the effects of a 60 Hz, 1,800 μT MF exposure on neurophysiological (EEG) and neuromotor (standing balance, voluntary motor function, and physiological tremor) aspects in humans using a single experimental procedure. Though results from this study suggest a reduction of human standing balance with MF exposure, as well as an increase of physiological tremor amplitude within the frequency range associated with central nervous system contribution, no exposure effect appeared on other investigated parameters (e.g., EEG or voluntary motor control). These results suggest that 1 h of 60 Hz, 1,800 μT MF exposure may modulate human involuntary motor control without being detected in the cortical electrical activity.
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Affiliation(s)
- A Legros
- Imaging Division, Lawson Health Research Institute, St Joseph's Health Care, 268 Grosvenor St, London, ON N6A 4V2, Canada.
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Abstract
Recent lattice QCD calculations have reported evidence for the existence of a bound state with strangeness -2 and baryon number 2 at quark masses somewhat higher than the physical values. By developing a description of the dependence of this binding energy on the up, down and strange quark masses that allows a controlled chiral extrapolation, we explore the hypothesis that this state is to be identified with the H dibaryon. Taking as input the recent results of the HAL and NPLQCD Collaborations, we show that the H dibaryon is likely to be unbound by 13±14 MeV at the physical point.
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Affiliation(s)
- P E Shanahan
- CSSM and CoEPP, School of Chemistry and Physics, University of Adelaide, Adelaide SA 5005, Australia
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Blunden PG, Melnitchouk W, Thomas AW. New formulation of γZ box corrections to the weak charge of the proton. Phys Rev Lett 2011; 107:081801. [PMID: 21929159 DOI: 10.1103/physrevlett.107.081801] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 06/17/2011] [Indexed: 05/31/2023]
Abstract
We present a new formulation of one of the major radiative corrections to the weak charge of the proton-that arising from the axial-vector hadron part of the γZ box diagram, ℜe□(γZ)(A). This formulation, based on dispersion relations, relates the γZ contributions to moments of the F(3)(γZ) interference structure function. It has a clear connection to the pioneering work of Marciano and Sirlin, and enables a systematic approach to improved numerical precision. Using currently available data, the total correction from all intermediate states is ℜe□(γZ)(A)=0.004 4(4) at zero energy, which shifts the theoretical estimate of the proton weak charge from 0.071 3(8) to 0.070 5(8). The energy dependence of this result, which is vital for interpreting the Q(weak) experiment, is also determined.
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Affiliation(s)
- P G Blunden
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB, Canada R3T 2N2
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Abstract
Since its discovery in the 17th century, the red blood cell, recognized in time as the critical cell component for survival, has been the focus of much attention. Its unique role in gas exchange (oxygen/CO(2) transport) and its distinct characteristics (absence of nucleus; biconcave cell shape) together with an - in essence - unlimited supply lead to extensive targeted biochemical, molecular and structural studies. A quick PubMed query with the word "erythrocyte" results in 198 013 scientific articles of which 162 are red blood cell proteomics studies, indicating that this new technique has been only recently applied to the red blood cell and related fields. Standard and comparative proteomics have been widely used to study different blood components. A growing body of proteomics literature has since developed, which deals with the characterization of red blood cells in health and disease. The possibility offered by proteomics to obtain a global snapshot of the whole red blood cell protein make-up, has provided unique insights to many fields including transfusion medicine, anaemia studies, intra-red blood cell parasite biology and translational research. While the contribution of proteomics is beyond doubt, a full red blood cell understanding will ultimately require, in addition to proteomics, lipidomics, glycomics, interactomics and study of post-translational modifications. In this review we will briefly discuss the methodology and limitations of proteomics, the contribution it made to the understanding of the erythrocyte and the advances in red blood cell-related fields brought about by comparative proteomics.
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Affiliation(s)
- E M Pasini
- Biomedical Primate Research Centre, Lange Kleiweg 139, 2288 GJ Rijswijk, The Netherlands
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Yakeu G, Butcher L, Isa S, Webb R, Roberts AW, Thomas AW, Backx K, James PE, Morris K. Low-intensity exercise enhances expression of markers of alternative activation in circulating leukocytes: roles of PPARγ and Th2 cytokines. Atherosclerosis 2010; 212:668-73. [PMID: 20723894 DOI: 10.1016/j.atherosclerosis.2010.07.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 07/02/2010] [Accepted: 07/07/2010] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Pharmacological activation of the nuclear receptor PPARγ is linked to numerous beneficial effects in the contexts of inflammation, lipid homeostasis, Type-2 Diabetes (T2D) and atherosclerosis. These beneficial effects include priming of circulating monocytes for differentiation towards an 'alternative' anti-inflammatory M2 macrophage phenotype. As we have recently shown that participation in low-intensity exercise increases PPARγ expression and activity in leukocytes from previously sedentary individuals, we aimed to elucidate whether low-intensity exercise elicited a pattern of gene expression similar to that reported for M2 monocyte-macrophage differentiation. METHODS 17 sedentary individuals undertook an 8-week low-intensity exercise programme (walking 10,000steps/day, three times/week). Changes in expression of PPARs and the PPARγ co-activators PGC-1α and PGC-1β; Th2 (IL-4; IL-10) and Th1 (IL-6) cytokines; and markers for the M2 (AMAC1, CD14, MR, IL-4) and the 'classical' pro-inflammatory M1 (MCP-1, TNFα, IL-6) phenotypes, were determined using RT-PCR (to assess leukocyte mRNA expression) and ELISA (to assess plasma cytokine levels). RESULTS Exercise was associated with upregulation of M2 markers, PGC-1α and PGC-1β, and with downregulation of M1 markers. Moreover, plasma levels of Th2 cytokines increased after exercise, while those of Th1 cytokines decreased. However, other PPARs (PPARα; PPARβ/δ) did not undergo marked exercise-induced activation or upregulation. Thus, participation in low-intensity exercise may prime monocytes for differentiation towards an M2 macrophage phenotype via PPARγ/PGC-1α/β. CONCLUSION Given the similarities between these effects and pharmacologically induced M2 polarisation, we propose that exercise-induced PPARγ/PGC-1α/β-mediated M2 polarisation may constitute a novel anti-inflammatory benefit of low-intensity exercise.
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Affiliation(s)
- G Yakeu
- Centre for Biomedical Sciences, Cardiff School of Health Sciences, University of Wales Institute Cardiff, Cardiff CF5 2YB, UK
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Thomas AW, Persinger MA. Daily Posttraining Exposure to Pulsed Magnetic Fields that Evoke Morphine-Like Analgesia Affects Consequent Motivation But Not Proficiency in Maze Learning in Rats. ACTA ACUST UNITED AC 2009. [DOI: 10.3109/15368379709016171] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Abstract
A neutron or proton excess in nuclei leads to an isovector-vector mean field which, through its coupling to the quarks in a bound nucleon, implies a shift in the quark distributions with respect to the Bjorken scaling variable. We show that this result leads to an additional correction to the NuTeV measurement of sin2thetaW. The sign of this correction is largely model independent and acts to reduce their result. Explicit calculation in nuclear matter within a covariant and confining Nambu-Jona-Lasinio model predicts that this vector field correction may account for a substantial fraction of the NuTeV anomaly. We are therefore led to offer a new interpretation of the NuTeV measurement, namely, that it provides further evidence for the medium modification of the bound nucleon wave function.
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Affiliation(s)
- I C Cloët
- Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA
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Pain A, Böhme U, Berry AE, Mungall K, Finn RD, Jackson AP, Mourier T, Mistry J, Pasini EM, Aslett MA, Balasubrammaniam S, Borgwardt K, Brooks K, Carret C, Carver TJ, Cherevach I, Chillingworth T, Clark TG, Galinski MR, Hall N, Harper D, Harris D, Hauser H, Ivens A, Janssen CS, Keane T, Larke N, Lapp S, Marti M, Moule S, Meyer IM, Ormond D, Peters N, Sanders M, Sanders S, Sargeant TJ, Simmonds M, Smith F, Squares R, Thurston S, Tivey AR, Walker D, White B, Zuiderwijk E, Churcher C, Quail MA, Cowman AF, Turner CMR, Rajandream MA, Kocken CHM, Thomas AW, Newbold CI, Barrell BG, Berriman M. The genome of the simian and human malaria parasite Plasmodium knowlesi. Nature 2008; 455:799-803. [PMID: 18843368 PMCID: PMC2656934 DOI: 10.1038/nature07306] [Citation(s) in RCA: 309] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Accepted: 07/30/2008] [Indexed: 11/08/2022]
Abstract
Plasmodium knowlesi is an intracellular malaria parasite whose natural vertebrate host is Macaca fascicularis (the 'kra' monkey); however, it is now increasingly recognized as a significant cause of human malaria, particularly in southeast Asia. Plasmodium knowlesi was the first malaria parasite species in which antigenic variation was demonstrated, and it has a close phylogenetic relationship to Plasmodium vivax, the second most important species of human malaria parasite (reviewed in ref. 4). Despite their relatedness, there are important phenotypic differences between them, such as host blood cell preference, absence of a dormant liver stage or 'hypnozoite' in P. knowlesi, and length of the asexual cycle (reviewed in ref. 4). Here we present an analysis of the P. knowlesi (H strain, Pk1(A+) clone) nuclear genome sequence. This is the first monkey malaria parasite genome to be described, and it provides an opportunity for comparison with the recently completed P. vivax genome and other sequenced Plasmodium genomes. In contrast to other Plasmodium genomes, putative variant antigen families are dispersed throughout the genome and are associated with intrachromosomal telomere repeats. One of these families, the KIRs, contains sequences that collectively match over one-half of the host CD99 extracellular domain, which may represent an unusual form of molecular mimicry.
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Affiliation(s)
- A Pain
- Wellcome Trust Sanger Institute, Genome Campus, Hinxton, Cambridgeshire CB10 1SA, UK.
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Owen DG, Bureau Y, Thomas AW, Prato FS, St Lawrence KS. Quantification of pain-induced changes in cerebral blood flow by perfusion MRI. Pain 2008; 136:85-96. [PMID: 17716820 DOI: 10.1016/j.pain.2007.06.021] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 06/15/2007] [Accepted: 06/15/2007] [Indexed: 11/20/2022]
Abstract
The purpose of this study was to assess if the functional activation caused by painful stimuli could be detected with arterial spin labeling (ASL), which is a non-invasive magnetic resonance imaging (MRI) technique for measuring cerebral blood flow (CBF). Because ASL directly measures blood flow, it is well suited to pain conditions that are difficult to assess with current functional MRI, such as chronic pain. However, the use of ASL in neuroimaging has been hampered by its low sensitivity. Recent improvements in MRI technology, namely increased magnetic field strengths and phased array receiver coils, should enable ASL to measure the small changes in CBF associated with pain. In this study, healthy volunteers underwent two ASL imaging sessions, during which a painful thermal stimulus was applied to the left hand. The results demonstrated that the ASL technique measured changes in regional CBF in brain regions that have been previously identified with pain perception. These included bilateral CBF changes in the insula, secondary somatosensory, and cingulate cortices, as well as the supplementary motor area (SMA). Also observed were contralateral primary somatosensory and ipsilateral thalamic CBF changes. The average change in CBF for all regions of interest was 3.68ml/100g/min, ranging from 2.97ml/100g/min in ipsilateral thalamus to 4.91ml/100g/min in contralateral insula. The average resting global CBF was 54+/-9.7ml/100g/min, and there was no change in global CBF due to the noxious thermal stimulus.
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Affiliation(s)
- D G Owen
- Lawson Health Research Institute, St. Joseph's Health Care London, 268 Grosvenor Street, London, Ont., Canada N6A 4V2.
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Malherbe P, Masciadri R, Norcross RD, Knoflach F, Kratzeisen C, Zenner MT, Kolb Y, Marcuz A, Huwyler J, Nakagawa T, Porter RHP, Thomas AW, Wettstein JG, Sleight AJ, Spooren W, Prinssen EP. Characterization of (R,S)-5,7-di-tert-butyl-3-hydroxy-3-trifluoromethyl-3H-benzofuran-2-one as a positive allosteric modulator of GABAB receptors. Br J Pharmacol 2008; 154:797-811. [PMID: 18536733 DOI: 10.1038/bjp.2008.135] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE As baclofen is active in patients with anxiety disorders, GABAB receptors have been implicated in the modulation of anxiety. To avoid the side effects of baclofen, allosteric enhancers of GABAB receptors have been studied to provide an alternative therapeutic avenue for modulation of GABAB receptors. The aim of this study was to characterize derivatives of (R,S)-5,7-di-tert-butyl-3-hydroxy-3-trifluoromethyl-3H-benzofuran-2-one (rac-BHFF) as enhancers of GABAB receptors. EXPERIMENTAL APPROACH Enhancing properties of rac-BHFF were assessed in the Chinese hamster ovary (CHO)-Galpha16-hGABA(B1a,2a) cells by Fluorometric Imaging Plate Reader and GTPgamma[35S]-binding assays, and in rat hippocampal slices by population spike (PS) recordings. In vivo activities of rac-BHFF were assessed using the loss of righting reflex (LRR) and stress-induced hyperthermia (SIH) models. KEY RESULTS In GTPgamma[35S]-binding assays, 0.3 microM rac-BHFF or its pure enantiomer (+)-BHFF shifted the GABA concentration-response curve to the left, an effect that resulted in a large increase in both GABA potency (by 15.3- and 87.3-fold) and efficacy (149% and 181%), respectively. In hippocampal slices, rac-BHFF enhanced baclofen-induced inhibition of PS of CA1 pyramidal cells. In an in vivo mechanism-based model in mice, rac-BHFF increased dose-dependently the LRR induced by baclofen with a minimum effective dose of 3 mg kg(-1) p.o. rac-BHFF (100 mg kg(-1) p.o.) tested alone had no effect on LRR nor on spontaneous locomotor activity, but exhibited anxiolytic-like activity in the SIH model in mice. CONCLUSIONS AND IMPLICATIONS rac-BHFF derivatives may serve as valuable pharmacological tools to elucidate the pathophysiological roles played by GABAB receptors in the central and peripheral nervous systems.
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Affiliation(s)
- P Malherbe
- Discovery Research CNS, F Hoffmann-La Roche Ltd, Basel, Switzerland.
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Morris RHK, Tonks AJ, Jones KP, Ahluwalia MK, Thomas AW, Tonks A, Jackson SK. DPPC regulates COX-2 expression in monocytes via phosphorylation of CREB. Biochem Biophys Res Commun 2008; 370:174-8. [PMID: 18355441 DOI: 10.1016/j.bbrc.2008.03.052] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Accepted: 03/12/2008] [Indexed: 01/08/2023]
Abstract
The major phospholipid in pulmonary surfactant dipalmitoyl phosphatidylcholine (DPPC) has been shown to modulate inflammatory responses. Using human monocytes, this study demonstrates that DPPC significantly increased PGE(2) (P<0.05) production by 2.5-fold when compared to untreated monocyte controls. Mechanistically, this effect was concomitant with an increase in COX-2 expression which was abrogated in the presence of a COX-2 inhibitor. The regulation of COX-2 expression was independent of NF-kappaB activity. Further, DPPC increased the phosphorylation of the cyclic AMP response element binding protein (CREB; an important nuclear transcription factor important in regulating COX-2 expression). In addition, we also show that changing the fatty acid groups of PC (e.g. using l-alpha-phosphatidylcholine beta-arachidonoyl-gamma-palmitoyl (PAPC)) has a profound effect on the regulation of COX-2 expression and CREB activation. This study provides new evidence for the anti-inflammatory activity of DPPC and that this activity is at least in part mediated via CREB activation of COX-2.
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Affiliation(s)
- R H K Morris
- Cardiff School of Health Sciences, University of Wales Institute Cardiff, Western Avenue, Llandaff, Cardiff, Wales CF5 2YB, UK.
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Caddy J, Singh N, Atkin L, Ahluwalia M, Roberts A, Lang D, Thomas AW, Webb R. Rosiglitazone transiently disturbs calcium homeostasis in monocytic cells. Biochem Biophys Res Commun 2007; 366:149-55. [PMID: 18053798 DOI: 10.1016/j.bbrc.2007.11.095] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2007] [Accepted: 11/19/2007] [Indexed: 11/25/2022]
Abstract
The PPARgamma agonist Rosiglitazone exerts anti-hyperglycaemic effects by regulating the long-term expression of genes involved in metabolism, differentiation and inflammation. In the present study, Rosiglitazone treatment rapidly inhibited (5-30 min) the ER Ca(2+) ATPase SERCA2b in monocytic cells (IC(50)=1.88 microM; p<0.05), thereby disrupting short-term Ca(2+) homeostasis (resting [Ca(2+)](cyto)=121.2+/-2.9% basal within 1h; p<0.05). However, extended Rosiglitazone treatment (72 h) induced dose-dependent SERCA2b up-regulation, and restored calcium homeostasis, in monocytic cells (SERCA2b mRNA: 138.7+/-5.7% basal (1 microM)/215.0+/-30.9% basal (10 microM); resting [Ca(2+)](cyto)=97.3+/-8.3% basal (10 microM)). As unfavourable cardiovascular outcomes, possibly related to disrupted cellular Ca(2+) homeostasis, have been linked to Rosiglitazone, this effect may be of clinical interest. In contrast, in PPRE-luciferase reporter-gene assays, Rosiglitazone induced non-dose-dependent PPARgamma-dependent effects (1 microM: 152.5+/-4.9% basal; 10 microM: 136.1+/-5.1% basal (p<0.05 for 1 microM vs. 10 microM)). Thus, we conclude that Rosiglitazone can exert PPARgamma-independent non-genomic effects, such as the SERCA2b inhibition seen here, but that long-term Rosiglitazone treatment did not perturb resting [Ca](cyto) in this study.
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Affiliation(s)
- J Caddy
- Centre for Biomedical Sciences, Cardiff School of Health Sciences, University of Wales Institute Cardiff, Cardiff CF5 2YB, UK
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Saul A, Hensmann M, Sattabongkot J, Collins WE, Barnwell JW, Langermans JAM, Wu Y, Long CA, Dubovsky F, Thomas AW. Immunogenicity in rhesus of the Plasmodium vivax mosquito stage antigen Pvs25H with Alhydrogel and Montanide ISA 720. Parasite Immunol 2007; 29:525-33. [PMID: 17883455 DOI: 10.1111/j.1365-3024.2007.00971.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Pvs25 is an ookinete surface protein from Plasmodium vivax that is the target of transmission-blocking antibodies. Two immunogenicity trials in rhesus monkeys with a recombinant form of the protein, Pvs25H, were undertaken. Monkeys were vaccinated with Pvs25H adsorbed to Alhydrogel or emulsified in Montanide ISA 720 at 0, 4 and 27 weeks (study 1) or in Montanide ISA 720 at 0 and 18 weeks (study 2) with 1.5 or 15 microg Pvs25H in 0.1 or 0.5 mL of emulsion (four combinations). Immunogenicity was assessed by ELISA and by membrane-feeding experiments using P. vivax-infected blood from human volunteers (studies 1 and 2) or from chimpanzees (study 1). Both vaccine trials generated antibodies that blocked transmission of P. vivax to mosquitoes. Antibody titres and transmission blocking were higher with Montanide ISA 720 than with Alhydrogel in the first trial and with the 15 microg Pvs25H/0.5 mL ISA 720 combination in the second trial.
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MESH Headings
- Adjuvants, Immunologic
- Aluminum Hydroxide/immunology
- Animals
- Anopheles/parasitology
- Antibodies, Protozoan/blood
- Antibodies, Protozoan/immunology
- Antigens, Protozoan/administration & dosage
- Antigens, Protozoan/immunology
- Antigens, Surface/administration & dosage
- Antigens, Surface/immunology
- Female
- Humans
- Macaca mulatta
- Malaria Vaccines/administration & dosage
- Malaria Vaccines/immunology
- Malaria, Vivax/immunology
- Malaria, Vivax/parasitology
- Malaria, Vivax/transmission
- Male
- Mannitol/analogs & derivatives
- Mannitol/immunology
- Oleic Acids/immunology
- Plasmodium vivax/growth & development
- Plasmodium vivax/immunology
- Random Allocation
- Recombinant Proteins/immunology
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Affiliation(s)
- A Saul
- Malaria Vaccine Development Branch, National Institutes of Health, Rockville, MD 20852, USA.
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Young RD, Carlini RD, Thomas AW, Roche J. Testing the standard model by precision measurement of the weak charges of quarks. Phys Rev Lett 2007; 99:122003. [PMID: 17930499 DOI: 10.1103/physrevlett.99.122003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Indexed: 05/25/2023]
Abstract
In a global analysis of the latest parity-violating electron scattering measurements on nuclear targets, we demonstrate a significant improvement in the experimental knowledge of the weak neutral-current lepton-quark interactions at low energy. The precision of this new result, combined with earlier atomic parity-violation measurements, places tight constraints on the size of possible contributions from physics beyond the standard model. Consequently, this result improves the lower-bound on the scale of relevant new physics to approximately 1 TeV.
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Affiliation(s)
- R D Young
- Jefferson Lab, 12000 Jefferson Ave., Newport News, Virginia 23606, USA
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Khanolkar MP, Morris RHK, Thomas AW, Bolusani H, Roberts AW, Geen J, Jackson SK, Evans LM. Rosiglitazone produces a greater reduction in circulating platelet activity compared with gliclazide in patients with type 2 diabetes mellitus--an effect probably mediated by direct platelet PPARgamma activation. Atherosclerosis 2007; 197:718-24. [PMID: 17765245 DOI: 10.1016/j.atherosclerosis.2007.07.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Revised: 06/26/2007] [Accepted: 07/11/2007] [Indexed: 11/24/2022]
Abstract
AIMS Type 2 diabetes mellitus (T2DM) is associated with enhanced platelet activation. We conducted a randomised double-blind study to compare the effects of combination metformin and rosiglitazone or metformin and gliclazide therapy on platelet function in persons with T2DM. METHODS Fifty subjects on metformin monotherapy received either rosiglitazone 4 mg or gliclazide 80 mg. HbA1c, HOMA-R, markers of platelet activation, inflammation, endothelial activation and oxidative stress were measured at baseline and after 24 weeks of treatment. Separate in vitro platelet function studies were conducted on platelets pre-incubated with rosiglitazone and gliclazide. RESULTS A significantly greater reduction in platelet aggregation was observed in the rosiglitazone treated group compared to gliclazide. HbA1c and markers of endothelial activation were reduced to a similar extent in both groups. A significant reduction in HOMA-R, markers of inflammation and oxidative stress was only observed with rosiglitazone. Reduction in platelet aggregation with rosiglitazone correlated with reduction in oxidative stress. In the in vitro study, rosiglitazone produced significantly greater reduction in platelet aggregation compared with gliclazide. CONCLUSION Greater reduction in platelet activity observed with rosiglitazone may be related to reduced oxidative stress and a possible direct PPARgamma mediated effect on platelet function.
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Affiliation(s)
- M P Khanolkar
- Llandough Hospital Diabetes Center, Department of Diabetes, Penarth, Cardiff, UK.
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Cook CM, Saucier DM, Thomas AW, Prato FS. Exposure to ELF magnetic and ELF-modulated radiofrequency fields: the time course of physiological and cognitive effects observed in recent studies (2001-2005). Bioelectromagnetics 2006; 27:613-27. [PMID: 16724317 DOI: 10.1002/bem.20247] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In 2002, we published a review of the cognitive and physiological effects of extremely low frequency magnetic fields (ELF MFs) and ELF-modulated radiofrequency fields associated with mobile phones. Since the original preparation of that review, a significant number of studies have been published using techniques such as electroencephalography, event-related potentials and positron emission tomography to investigate electromagnetic field effects upon human physiology and various measures of performance (cognitive, perceptual, behavioral). We review these recent studies, and when effects were observed, we reference the time course of observed effects (immediate or delayed). In our concluding remarks, we discuss a number of variables that are not often considered in human bioelectromagnetics studies, such as personality, individual differences and the specific laterality of ELF MF and mobile phone exposure over the brain. We also consider the sensitivity of various physiological assays and performance measures in the study of biological effects of electromagnetic fields.
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Affiliation(s)
- C M Cook
- Department of Psychology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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Verra F, Polley SD, Thomas AW, Conway DJ. Comparative analysis of molecular variation in Plasmodium falciparum and P. reichenowi maebl gene. Parassitologia 2006; 48:567-72. [PMID: 17688178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
MESH Headings
- Animals
- DNA, Protozoan/genetics
- Evolution, Molecular
- Genes, Protozoan
- Malaria, Falciparum/epidemiology
- Molecular Sequence Data
- Mutation, Missense
- Nigeria/epidemiology
- Phylogeny
- Plasmodium/genetics
- Plasmodium falciparum/genetics
- Protein Structure, Tertiary
- Protozoan Proteins/chemistry
- Protozoan Proteins/genetics
- Receptors, Cell Surface/chemistry
- Receptors, Cell Surface/genetics
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
- Species Specificity
- Zambia/epidemiology
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Okosieme OE, Parkes AB, Premawardhana LDKE, Thomas AW, Evans LM, Lazarus JH. Peripheral cytokine expression in autoimmune thyroiditis: effects of in vitro modulation by rosiglitazone and dexamethasone. Thyroid 2006; 16:953-60. [PMID: 17042679 DOI: 10.1089/thy.2006.16.953] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND In Hashimoto's thyroiditis (HT), there is evidence for activation of peripheral T-lymphocytes that predominantly express a T helper 1 (T(H)1) cytokine bias. However, the immunomodulatory factors involved in regulating this response have so far received scant attention. In this study, we examine the effects of the glucocorticoid, dexamethasone, and the peroxisome proliferator-activated receptor-gamma (PPAR-gamma) ligand, rosiglitazone on the expression of interferon (IFN)-gamma (T(H)1) and interleukin (IL)-4 (T(H)2) by activated peripheral CD4(+) and CD8(+) lymphocytes in patients with HT (n = 10) and healthy control subjects (n = 12). METHODS Peripheral blood mononuclear cells (PBMC) were stimulated in vitro with phorbolmyristate acetate (PMA) and ionomycin in the presence or absence of varying doses of dexamethasone and rosiglitazone (0.01 microM, 1.0 microM, and 100 microM). Cytokine expression was determined by flow cytometry. RESULTS CD4(+) and CD8(+) IFN-gamma expression was greater in HT than controls (14.87 versus 9.25; p < 0.05 and 21.34 versus 10.16; p < 0.01, respectively). A dose-dependent inhibition of IFN-gamma expression was seen with dexamethasone and rosiglitazone. Inhibition of CD4(+) and CD8(+) IFN-gamma expression with both dexamethasone and rosiglitazone was greater in control subjects than in patients (p < 0.05). There was no significant difference in IL-4 expression between patients and control groups and its expression remained unaffected by either compound. CONCLUSIONS We show that CD4(+) and CD8(+) T lymphocytes from HT patients express a type 1 cytokine bias that is significantly more resistant to in vitro modulation by rosiglitazone and dexamethasone. Further studies are needed to clarify if this resistance plays a role in the pathogenesis of autoimmune thyroid disease (AITD).
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Affiliation(s)
- O E Okosieme
- Centre for Endocrine and Diabetes Science, School of Medicine, Cardiff University, Cardiff, United Kingdom.
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Young RD, Roche J, Carlini RD, Thomas AW. Extracting nucleon strange and anapole form factors from world data. Phys Rev Lett 2006; 97:102002. [PMID: 17025805 DOI: 10.1103/physrevlett.97.102002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2006] [Indexed: 05/12/2023]
Abstract
The complete world set of parity-violating electron scattering data up to Q2 approximately 0.3 GeV2 is analyzed. We extract the current experimental determination of the strange electric and magnetic form factors of the proton, as well as the weak axial form factors of the proton and neutron, at Q2=0.1 GeV2. Within experimental uncertainties, we find that the strange form factors are consistent with zero, as are the anapole contributions to the axial form factors. Nevertheless, the correlation between the strange and anapole contributions suggest that there is only a small probability that these form factors all vanish simultaneously.
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Affiliation(s)
- R D Young
- Jefferson Lab, 12000 Jefferson Avenue, Newport News, Virginia 23606, USA
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Leinweber DB, Boinepalli S, Thomas AW, Wang P, Williams AG, Young RD, Zanotti JM, Zhang JB. Strange electric form factor of the proton. Phys Rev Lett 2006; 97:022001. [PMID: 16907436 DOI: 10.1103/physrevlett.97.022001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Indexed: 05/11/2023]
Abstract
By combining the constraints of charge symmetry with new chiral extrapolation techniques and recent low-mass quenched lattice QCD simulations of the individual quark contributions to the electric charge radii of the baryon octet, we obtain an accurate determination of the strange electric charge radius of the proton. While this analysis provides a value for G(E)(s)(Q(2) = 0.1 GeV(2)) in agreement with the best current data, the theoretical error is comparable with that expected from future HAPPEX results from JLab. Together with the earlier determination of G(M)(s), this result considerably constrains the role of hidden flavor in the structure of the nucleon.
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Affiliation(s)
- D B Leinweber
- Special Research Centre for the Subatomic Structure of Matter, and Department of Physics, University of Adelaide, Adelaide SA 5005, Australia
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Bartolozzi M, Leinweber DB, Thomas AW. Stochastic opinion formation in scale-free networks. Phys Rev E Stat Nonlin Soft Matter Phys 2005; 72:046113. [PMID: 16383474 DOI: 10.1103/physreve.72.046113] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2005] [Revised: 08/17/2005] [Indexed: 05/05/2023]
Abstract
The dynamics of opinion formation in large groups of people is a complex nonlinear phenomenon whose investigation is just beginning. Both collective behavior and personal views play an important role in this mechanism. In the present work we mimic the dynamics of opinion formation of a group of agents, represented by two states +/-1, as a stochastic response of each agent to the opinion of his/her neighbors in the social network and to feedback from the average opinion of the whole. In the light of recent studies, a scale-free Barabási-Albert network has been selected to simulate the topology of the interactions. A turbulent-like dynamics, characterized by an intermittent behavior, is observed for a certain range of the model parameters. The problem of uncertainty in decision taking is also addressed both from a topological point of view, using random and targeted removal of agents from the network, and by implementing a three-state model, where the third state, zero, is related to the information available to each agent. Finally, the results of the model are tested against the best known network of social interactions: the stock market. A time series of daily closures of the Dow-Jones index has been used as an indicator of the possible applicability of our model in the financial context. Good qualitative agreement is found.
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Affiliation(s)
- M Bartolozzi
- Special Research Centre for the Subatomic Structure of Matter (CSSM), University of Adelaide, Adelaide, South Australia 5005, Australia
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Cloët IC, Bentz W, Thomas AW. Spin-dependent structure functions in nuclear matter and the polarized EMC effect. Phys Rev Lett 2005; 95:052302. [PMID: 16090869 DOI: 10.1103/physrevlett.95.052302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2005] [Indexed: 05/03/2023]
Abstract
An excellent description of both spin-independent and spin-dependent quark distributions and structure functions has been obtained with a modified Nambu--Jona-Lasinio model, which is free of unphysical thresholds for nucleon decay into quarks--hence incorporating an important aspect of confinement. We utilize this model to investigate nuclear medium modifications to structure functions and find that we are readily able to reproduce both nuclear matter saturation and the experimental F2N(A)/F2N ratio, that is, the European Muon Collaboration (EMC) effect. Applying this framework to determine g1p(A), we find that the ratio g1p(A)/g1p differs significantly from unity, with the quenching caused by the nuclear medium being about twice that of the spin-independent case. This represents an exciting result, which, if confirmed experimentally, will reveal much about the quark structure of nuclear matter.
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Affiliation(s)
- I C Cloët
- Special Research Centre for the Subatomic Structure of Matter and Department of Physics and Mathematical Physics, University of Adelaide, South Australia 5005, Australia.
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Leinweber DB, Boinepalli S, Cloet IC, Thomas AW, Williams AG, Young RD, Zanotti JM, Zhang JB. Precise determination of the strangeness magnetic moment of the nucleon. Phys Rev Lett 2005; 94:212001. [PMID: 16090310 DOI: 10.1103/physrevlett.94.212001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2004] [Indexed: 05/03/2023]
Abstract
By combining the constraints of charge symmetry with new chiral extrapolation techniques and recent low mass quenched lattice-QCD simulations of the individual quark contributions to the magnetic moments of the nucleon octet, we obtain a precise determination of the strange magnetic moment of the proton. The result, namely, G(s)(M)=(-0.046 +/- 0.019)mu(N) is consistent with the latest experimental measurements but an order of magnitude more precise. This poses a tremendous challenge for future experiments.
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Affiliation(s)
- D B Leinweber
- Special Research Centre for the Subatomic Structure of Matter and Department of Physics, University of Adelaide, Adelaide SA 5005, Australia
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