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Danioni F, Coen S, Rosnati R, Barni D. The relationship between direct and indirect measures of values: Is social desirability a significant moderator? European Review of Applied Psychology 2020. [DOI: 10.1016/j.erap.2020.100524] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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2
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Leo F, Hansson T, Ricciardi I, De Rosa M, Coen S, Wabnitz S, Erkintalo M. Walk-Off-Induced Modulation Instability, Temporal Pattern Formation, and Frequency Comb Generation in Cavity-Enhanced Second-Harmonic Generation. Phys Rev Lett 2016; 116:033901. [PMID: 26849598 DOI: 10.1103/physrevlett.116.033901] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Indexed: 06/05/2023]
Abstract
We derive a time-domain mean-field equation to model the full temporal and spectral dynamics of light in singly resonant cavity-enhanced second-harmonic generation systems. We show that the temporal walk-off between the fundamental and the second-harmonic fields plays a decisive role under realistic conditions, giving rise to rich, previously unidentified nonlinear behavior. Through linear stability analysis and numerical simulations, we discover a new kind of quadratic modulation instability which leads to the formation of optical frequency combs and associated time-domain dissipative structures. Our numerical simulations show excellent agreement with recent experimental observations of frequency combs in quadratic nonlinear media [Phys. Rev. A 91, 063839 (2015)]. Thus, in addition to unveiling a new, experimentally accessible regime of nonlinear dynamics, our work enables predictive modeling of frequency comb generation in cavity-enhanced second-harmonic generation systems. We expect our findings to have wide impact on the study of temporal and spectral dynamics in a diverse range of dispersive, quadratically nonlinear resonators.
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Affiliation(s)
- F Leo
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, The University of Auckland, Auckland 1142, New Zealand
| | - T Hansson
- Department of Applied Physics, Chalmers University of Technology, SE-41296 Göteborg, Sweden
- Dipartimento di Ingegneria dell'Informazione, Università di Brescia, via Branze 38, 25123 Brescia, Italy
| | - I Ricciardi
- CNR-INO, Istituto Nazionale di Ottica, Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - M De Rosa
- CNR-INO, Istituto Nazionale di Ottica, Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - S Coen
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, The University of Auckland, Auckland 1142, New Zealand
| | - S Wabnitz
- Dipartimento di Ingegneria dell'Informazione, Università di Brescia, via Branze 38, 25123 Brescia, Italy
- CNR-INO, Istituto Nazionale di Ottica, Via Campi Flegrei 34, 80078 Pozzuoli (NA), Italy
| | - M Erkintalo
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Physics, The University of Auckland, Auckland 1142, New Zealand
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3
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Webb KE, Jang JK, Anthony J, Coen S, Erkintalo M, Murdoch SG. Measurement of microresonator frequency comb coherence by spectral interferometry. Opt Lett 2016; 41:277-280. [PMID: 26766693 DOI: 10.1364/ol.41.000277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We experimentally investigate the spectral coherence of microresonator optical frequency combs. Specifically, we use a spectral interference method, typically used in the context of supercontinuum generation, to explore the variation of the magnitude of the complex degree of first-order coherence across the full comb bandwidth. We measure the coherence of two different frequency combs and observe wholly different coherence characteristics. In particular, we find that the observed dynamical regimes are similar to the stable and unstable modulation instability regimes reported in previous theoretical studies. Results from numerical simulations are found to be in good agreement with experimental observations. In addition to demonstrating a new technique to assess comb stability, our results provide strong experimental support for previous theoretical analyses.
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4
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Nissen TD, Graversen C, Coen S, Hultin L, Aziz Q, Lykkesfeldt J, Drewes AM, Brock C. Translational aspects of rectal evoked potentials: A comparative study in rats and humans. Scand J Pain 2012. [DOI: 10.1016/j.sjpain.2012.05.036] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Abstract
Background
In recent years only few novel drugs targeting visceral pain have been developed. This lack of success may be explained by animal models having poor predictive value. To increase the success of translating results from animals to humans there is a demand for comparable test models. The aim was to establish a comparable and reliable translational model to evoke mechanical rectal pain in rats and humans.
Methods
Mechanical rectal rapid balloon distension was done on two different days in 12 rats (separated by 24.3 ± 7.1 days) and 18 humans (separated by 9.3 ± 1.3 days). Evoked potentials were recorded from permanently implanted skull-electrodes in rats, at stimulation pressure of 80 mmHg and duration of 100 ms. In human surface electrodes and individualized pressure, corresponding to the pain detection threshold, lasting 150 ms, were used. Within- and between days reproducibility were assessed in terms of latencies, amplitudes and frequency content.
Results
In both rats and humans evoked potentials with tri-phasic morphology were recorded. No differences in latencies, amplitudes and power distribution were seen within or between days (all F ≤ 2.0; all P ≥ 0.2). The analyses of the EPs revealed peak-to-peak amplitude as the most reproducible parameter within (ICC ≥ 0.84) and between (ICC ≥ 0.70) days, seen across both species. The spectral analyses showed that the EEG power was distributed mainly in the delta and theta bands. The main power in rats was contained in the theta band (45%), whereas humans had the predominant power in the delta band (46%).
Conclusion
A unique visceral translational platform was established to reliably assess neurophysiologic response to rapid balloon distension in rats and humans. The model provides an approach to study basic and clinical pain as well as pharmacological intervention.
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Affiliation(s)
- Thomas Dahl Nissen
- Mech-Sense , Department of Gastroenterology & Hepatology , Aalborg Hospital , Aarhus University Hospital , Aarhus , Denmark
- Section of Biomedicine , Department of Veterinary Disease Biology , Faculty of Life Sciences , University of Copenhagen , Copenhagen , Denmark
- Bioscience , AstraZeneca R&D , Mölndal , Sweden
| | - Carina Graversen
- Mech-Sense , Department of Gastroenterology & Hepatology , Aalborg Hospital , Aarhus University Hospital , Aarhus , Denmark
| | - Steven Coen
- Wingate Institute of Neurogastroenterology , Barts and the London School of Medicine and Dentistry , Queen Mary University of London , London , England , United Kingdom
| | - Leif Hultin
- Bioscience , AstraZeneca R&D , Mölndal , Sweden
| | - Qasim Aziz
- Wingate Institute of Neurogastroenterology , Barts and the London School of Medicine and Dentistry , Queen Mary University of London , London , England , United Kingdom
| | - Jens Lykkesfeldt
- Section of Biomedicine , Department of Veterinary Disease Biology , Faculty of Life Sciences , University of Copenhagen , Copenhagen , Denmark
| | - Asbjørn Mohr Drewes
- Mech-Sense , Department of Gastroenterology & Hepatology , Aalborg Hospital , Aarhus University Hospital , Aarhus , Denmark
| | - Christina Brock
- Mech-Sense , Department of Gastroenterology & Hepatology , Aalborg Hospital , Aarhus University Hospital , Aarhus , Denmark
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5
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Van Oudenhove L, McKie S, Lassman D, Uddin B, Paine P, Coen S, Gregory L, Tack J, Aziz Q. Fatty acid-induced gut-brain signaling attenuates neural and behavioral effects of sad emotion in humans. J Clin Invest 2011; 121:3094-9. [PMID: 21785220 DOI: 10.1172/jci46380] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2011] [Accepted: 06/01/2011] [Indexed: 12/16/2022] Open
Abstract
Although a relationship between emotional state and feeding behavior is known to exist, the interactions between signaling initiated by stimuli in the gut and exteroceptively generated emotions remain incompletely understood. Here, we investigated the interaction between nutrient-induced gut-brain signaling and sad emotion induced by musical and visual cues at the behavioral and neural level in healthy nonobese subjects undergoing functional magnetic resonance imaging. Subjects received an intragastric infusion of fatty acid solution or saline during neutral or sad emotion induction and rated sensations of hunger, fullness, and mood. We found an interaction between fatty acid infusion and emotion induction both in the behavioral readouts (hunger, mood) and at the level of neural activity in multiple pre-hypothesized regions of interest. Specifically, the behavioral and neural responses to sad emotion induction were attenuated by fatty acid infusion. These findings increase our understanding of the interplay among emotions, hunger, food intake, and meal-induced sensations in health, which may have important implications for a wide range of disorders, including obesity, eating disorders, and depression.
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Affiliation(s)
- Lukas Van Oudenhove
- Translational Research Centre for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium.
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Marquand A, Howard M, Brammer M, Chu C, Coen S, Mourão-Miranda J. Quantitative prediction of subjective pain intensity from whole-brain fMRI data using Gaussian processes. Neuroimage 2009; 49:2178-89. [PMID: 19879364 DOI: 10.1016/j.neuroimage.2009.10.072] [Citation(s) in RCA: 199] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Revised: 10/23/2009] [Accepted: 10/26/2009] [Indexed: 12/11/2022] Open
Abstract
Supervised machine learning (ML) algorithms are increasingly popular tools for fMRI decoding due to their predictive capability and their ability to capture information encoded by spatially correlated voxels. In addition, an important secondary outcome is a multivariate representation of the pattern underlying the prediction. Despite an impressive array of applications, most fMRI applications are framed as classification problems and predictions are limited to categorical class decisions. For many applications, quantitative predictions are desirable that more accurately represent variability within subject groups and that can be correlated with behavioural variables. We evaluate the predictive capability of Gaussian process (GP) models for two types of quantitative prediction (multivariate regression and probabilistic classification) using whole-brain fMRI volumes. As a proof of concept, we apply GP models to an fMRI experiment investigating subjective responses to thermal pain and show GP models predict subjective pain ratings without requiring anatomical hypotheses about functional localisation of relevant brain processes. Even in the case of pain perception, where strong hypotheses do exist, GP predictions were more accurate than any region previously demonstrated to encode pain intensity. We demonstrate two brain mapping methods suitable for GP models and we show that GP regression models outperform state of the art support vector- and relevance vector regression. For classification, GP models perform categorical prediction as accurately as a support vector machine classifier and furnish probabilistic class predictions.
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Affiliation(s)
- Andre Marquand
- Department of Clinical Neuroscience, Centre for Neuroimaging Sciences, Institute of Psychiatry, King's College London, UK.
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7
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Mayer EA, Aziz Q, Coen S, Kern M, Labus J, Lane R, Kuo B, Naliboff B, Tracey I. Brain imaging approaches to the study of functional GI disorders: a Rome working team report. Neurogastroenterol Motil 2009; 21:579-96. [PMID: 19646070 PMCID: PMC3829384 DOI: 10.1111/j.1365-2982.2009.01304.x] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.7] [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] [Indexed: 12/12/2022]
Abstract
Progresses in the understanding of human brain-gut interactions in health and disease have been limited by the lack of non-invasive techniques to study brain activity. The advent of neuroimaging techniques has made it possible not only to study the structure and function of the brain, but also to characterize signaling system underlying brain function. This article gives a brief overview of relevant functional neuroanatomy, and of the most commonly used brain imaging techniques. It summarizes published functional brain imaging studies using acute visceral stimulation of the oesophagus, stomach and colon in healthy control subjects and patients with functional GI disorders, and briefly discusses pertinent findings from these studies. The article concludes with a critical assessment of published studies, and with recommendations for improved study paradigms and analysis strategies.
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Affiliation(s)
- Emeran A Mayer
- Center for Neurobiology of Stress, Departments of Medicine, Physiology and Psychiatry, UCLA, CURE Digestive Diseases Research Center, UCLA Division of Digestive Diseases, Los Angeles, CA
| | - Qasim Aziz
- Wingate Institute for Neurogastroenterology, Neurogastroenterology Group, School of Medicine and Dentistry, Queen Mary University of London, UK
| | - Steven Coen
- Wingate Institute for Neurogastroenterology, Neurogastroenterology Group, School of Medicine and Dentistry, Queen Mary University of London, UK
| | - Mark Kern
- Department of Medicine, Division of Gastroenterology and Hepatology, Medical College of Wisconsin Milwaukee, WI
| | - Jennifer Labus
- Center for Neurobiology of Stress, Departments of Medicine, Physiology and Psychiatry, UCLA, CURE Digestive Diseases Research Center, UCLA Division of Digestive Diseases, Los Angeles, CA
| | - Richard Lane
- Departments of Psychiatry, Psychology and Neuroscience, University of Arizona, AZ
| | - Brad Kuo
- Gastro Intestinal Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Bruce Naliboff
- Center for Neurobiology of Stress, Departments of Medicine, Physiology and Psychiatry, UCLA, CURE Digestive Diseases Research Center, UCLA Division of Digestive Diseases, Los Angeles, CA
| | - Irene Tracey
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain, FMRIB Centre, Oxford University Department of Clinical Neurology, John Radcliffe Hospital Oxford, UK
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8
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Hsieh ASY, Wong GKL, Murdoch SG, Coen S, Vanholsbeeck F, Leonhardt R, Harvey JD. Combined effect of Raman and parametric gain on single-pump parametric amplifiers. Opt Express 2007; 15:8104-14. [PMID: 19547137 DOI: 10.1364/oe.15.008104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We investigate the combined effect of Raman and parametric gain on single-pump parametric amplifiers. The phasematched parametric gain is shown to depend strongly on the real part of the complex Raman susceptibility. In fused silica fibers this results in a significant reduction in the available parametric gain for signal detunings beyond 10 THz. We are able to experimentally measure this effect for signal detunings ranging from 7 to 22 THz. Finally we discuss the implications of these results for the design of broadband optical parametric amplifiers.
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9
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Hsieh ASY, Murdoch SG, Coen S, Leonhardt R, Harvey JD. Influence of Raman susceptibility on optical parametric amplification in optical fibers. Opt Lett 2007; 32:521-3. [PMID: 17392908 DOI: 10.1364/ol.32.000521] [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] [Indexed: 05/14/2023]
Abstract
The real part of the Raman susceptibility is shown to have a strong influence on the peak parametric gain of single-pump parametric amplifiers. This results in a 35% variation in the peak parametric gain over the frequency range 0-30 THz. We are able to experimentally demonstrate this effect in a photonic crystal fiber and obtain good agreement between the experimentally measured and theoretically predicted gains.
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Affiliation(s)
- A S Y Hsieh
- Physics Department, University of Auckland, Private Bag 92019, Auckland, New Zealand
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10
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Yágüez L, Coen S, Gregory LJ, Amaro E, Altman C, Brammer MJ, Bullmore ET, Williams SCR, Aziz Q. Brain response to visceral aversive conditioning: a functional magnetic resonance imaging study. Gastroenterology 2005; 128:1819-29. [PMID: 15940617 DOI: 10.1053/j.gastro.2005.02.068] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [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: 12/02/2022]
Abstract
BACKGROUND & AIMS Brain-imaging studies to date have confounded visceral pain perception with anticipation. We used functional magnetic resonance imaging of the human brain to study the neuroanatomic network involved in aversive conditioning of visceral pain and, thus, anticipation. METHODS Eight healthy volunteers (5 male) participated in the study. We used a classic conditioning paradigm in which 3 neutral stimuli (differently colored circles) that acted as conditioned stimuli were paired with painful esophageal distention, air puff to the wrist, or nothing, which acted as unconditioned stimuli. Neural activity was measured during learning, anticipation (pairing only 50% of conditioned stimuli with their unconditioned stimuli), and extinction (unpaired conditioned stimuli) phases. For magnetic resonance imaging, axial slices depicting blood oxygen level-dependent contrast were acquired with a 1.5-T system. RESULTS Neural responses during the learning phase included areas commonly associated with visceral pain (anterior cingulate cortex, insula, and primary and secondary somatosensory cortices) and innocuous somatosensory perception (primary and secondary somatosensory cortices and insula). During the anticipation and extinction phases of aversive stimulation, brain activity resembled that seen during actual painful esophageal stimulation. In contrast, anticipation and extinction of the innocuous somatic stimulus failed to show that effect. CONCLUSIONS We have shown that actual and anticipated visceral pain elicit similar cortical responses. These results have implications for the design and interpretation of brain-imaging studies of visceral pain. They not only contribute to our understanding of the processing of visceral pain, but also have clinical implications for the management of chronic pain states.
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Affiliation(s)
- Lidia Yágüez
- Department of Psychology, Institute of Psychiatry, King's College, London, United Kingdom.
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11
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Van Simaeys G, Coen S, Haelterman M, Trillo S. Observation of resonance soliton trapping due to a photoinduced gap in wave number. Phys Rev Lett 2004; 92:223902. [PMID: 15245226 DOI: 10.1103/physrevlett.92.223902] [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: 07/16/2003] [Indexed: 05/24/2023]
Abstract
We investigate the nonlinear propagation of two forward propagating modes coupled by a resonant traveling-wave grating, which is photoinduced by illuminating an optical fiber with a beat signal. This interaction, representative of systems whose dispersion relation K=K(Omega) exhibits a gap in momentum K, shows evidence of localization mediated by resonance solitons. The signature of a still (in the grating frame) soliton is grating-induced cancellation of modal group-velocity mismatch.
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Affiliation(s)
- G Van Simaeys
- Service d'optique et d'acoustique, Université Libre de Bruxelles, 50 Avenue F. D. Roosevelt, CP 194/5, 1050 Brussels, Belgium
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12
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Corwin KL, Newbury NR, Dudley JM, Coen S, Diddams SA, Weber K, Windeler RS. Fundamental noise limitations to supercontinuum generation in microstructure fiber. Phys Rev Lett 2003; 90:113904. [PMID: 12688929 DOI: 10.1103/physrevlett.90.113904] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2002] [Indexed: 05/21/2023]
Abstract
Broadband noise on supercontinuum spectra generated in microstructure fiber is shown to lead to amplitude fluctuations as large as 50% for certain input laser pulse parameters. We study this noise using both experimental measurements and numerical simulations with a generalized stochastic nonlinear Schrödinger equation, finding good quantitative agreement over a range of input-pulse energies and chirp values. This noise is shown to arise from nonlinear amplification of two quantum noise inputs: the input-pulse shot noise and the spontaneous Raman scattering down the fiber.
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Affiliation(s)
- K L Corwin
- National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA
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13
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Phillips ML, Gregory LJ, Cullen S, Coen S, Ng V, Andrew C, Giampietro V, Bullmore E, Zelaya F, Amaro E, Thompson DG, Hobson AR, Williams SCR, Brammer M, Aziz Q, Cohen S. The effect of negative emotional context on neural and behavioural responses to oesophageal stimulation. Brain 2003; 126:669-84. [PMID: 12566287 DOI: 10.1093/brain/awg065] [Citation(s) in RCA: 160] [Impact Index Per Article: 7.6] [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: 01/13/2023] Open
Abstract
Sensory experience is influenced by emotional context. Although perception of emotion and unpleasant visceral sensation are associated with activation within the insula and dorsal and ventral anterior cingulate gyri (ACG), regions important for attention to and perception of sensory and emotional information, the neural mechanisms underlying the effect of emotional context upon visceral sensation remain unexplored. Using functional MRI, we examined neural responses to phasic, non-painful oesophageal sensation (OS) in eight healthy subjects (seven male; age range 27-36 years) either during neutral or negative emotional contexts produced, respectively, by presentation of neutral or fearful facial expressions. Activation within right insular and bilateral dorsal ACG was significantly greater (P < 0.01) during OS with fearful than with neutral faces. In a second experiment, we measured anxiety, discomfort and neural responses in eight healthy male subjects (age range 22-41 years) to phasic, non-painful OS during presentation of faces depicting either low, moderate or high intensities of fear. Significantly greater (P < 0.01) discomfort, anxiety and activation predominantly within the left dorsal ACG and bilateral anterior insulae occurred with high-intensity compared with low-intensity expressions. Clusters of voxels were also detected in this region, which exhibited a positive correlation between subjective behaviour and blood oxygenation level-dependent effect (P < 0.05). We report the first evidence for a modulation of neural responses, and perceived discomfort during, non-painful visceral stimulation by the intensity of the negative emotional context in which the stimulation occurs, and suggest a mechanism for the effect of negative context on symptoms in functional pain disorders.
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Affiliation(s)
- Mary L Phillips
- Division of Psychological Medicine, Guy's, St Thomas' and King's College School of Clinical Medicine and Institute of Psychiatry, London, UK
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14
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Coen S, Haelterman M. Domain wall solitons in binary mixtures of Bose-Einstein condensates. Phys Rev Lett 2001; 87:140401. [PMID: 11580632 DOI: 10.1103/physrevlett.87.140401] [Citation(s) in RCA: 3] [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: 11/27/2000] [Revised: 04/23/2001] [Indexed: 05/23/2023]
Abstract
The structure and dynamics of the domain walls separating segregated condensates in trapped mixtures of repulsive Bose-Einstein condensates are studied. Our work reveals that, under fairly general conditions, these domain walls behave as independent dynamical entities, which allows us to identify them as constituting a novel class of multicomponent solitons in Bose-Einstein condensates.
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Affiliation(s)
- S Coen
- Physics Department, The University of Auckland, Private Bag 92019, Auckland, New Zealand
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15
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Sionov RV, Coen S, Goldberg Z, Berger M, Bercovich B, Ben-Neriah Y, Ciechanover A, Haupt Y. c-Abl regulates p53 levels under normal and stress conditions by preventing its nuclear export and ubiquitination. Mol Cell Biol 2001; 21:5869-78. [PMID: 11486026 PMCID: PMC87306 DOI: 10.1128/mcb.21.17.5869-5878.2001] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [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: 02/07/2023] Open
Abstract
The p53 protein is subject to Mdm2-mediated degradation by the ubiquitin-proteasome pathway. This degradation requires interaction between p53 and Mdm2 and the subsequent ubiquitination and nuclear export of p53. Exposure of cells to DNA damage results in the stabilization of the p53 protein in the nucleus. However, the underlying mechanism of this effect is poorly defined. Here we demonstrate a key role for c-Abl in the nuclear accumulation of endogenous p53 in cells exposed to DNA damage. This effect of c-Abl is achieved by preventing the ubiquitination and nuclear export of p53 by Mdm2, or by human papillomavirus E6. c-Abl null cells fail to accumulate p53 efficiently following DNA damage. Reconstitution of these cells with physiological levels of c-Abl is sufficient to promote the normal response of p53 to DNA damage via nuclear retention. Our results help to explain how p53 is accumulated in the nucleus in response to DNA damage.
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Affiliation(s)
- R V Sionov
- Lautenberg Center for General and Tumor Immunology, The Hebrew University Hadassah Medical School, Jerusalem 91120, Israel
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16
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Coen S, Chau AH, Leonhardt R, Harvey JD, Knight JC, Wadsworth WJ, Russell PS. White-light supercontinuum generation with 60-ps pump pulses in a photonic crystal fiber. Opt Lett 2001; 26:1356-8. [PMID: 18049607 DOI: 10.1364/ol.26.001356] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The generation of a spatially single-mode white-light supercontinuum has been observed in a photonic crystal fiber pumped with 60-ps pulses of subkilowatt peak power. The spectral broadening is identified as being due to the combined action of stimulated Raman scattering and parametric four-wave-mixing generation, with a negligible contribution from the self-phase modulation of the pump pulses. The experimental results are in good agreement with detailed numerical simulations. These findings demonstrate that ultrafast femtosecond pulses are not needed for efficient supercontinuum generation in photonic crystal fibers.
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17
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Coen S, Haelterman M. Continuous-wave ultrahigh-repetition-rate pulse-train generation through modulational instability in a passive fiber cavity. Opt Lett 2001; 26:39-41. [PMID: 18033500 DOI: 10.1364/ol.26.000039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Thanks to a passive cavity configuration, modulational instability in fibers is successfully observed, for the first time to our knowledge, in the continuous-wave regime. Our technique provides a new means of generating all-optically ultrahigh-repetition-rate pulse trains and opens up new possibilities for the fundamental study of modulational instability and related phenomena.
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18
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Coen S. Three dimensional diffusion delay time tomography. Phys Rev Lett 2000; 85:683-687. [PMID: 10991373 DOI: 10.1103/physrevlett.85.683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/1999] [Indexed: 05/23/2023]
Abstract
Stable numerical convolution of the diffusion impulse time response with a Gaussian wave packet produces a wave packet whose delay time is governed by an eikonal equation where the diffusivity distribution plays the role of the square of the velocity distribution. Diffusion delay time tomography data can approximately image the diffusivity distribution by solving an inverse problem for the eikonal equation with multiple rays that traverse low diffusivity regions not traversed by earlier related methods, and consequently the resolution in such regions is improved. This is important for medical imaging.
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Affiliation(s)
- S Coen
- BWPOMR, 22 Miller Avenue, Suite C, Mill Valley, California 94941, USA.
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19
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D'Orazi G, Marchetti A, Crescenzi M, Coen S, Sacchi A, Soddu S. Exogenous wt-p53 protein is active in transformed cells but not in their non-transformed counterparts: implications for cancer gene therapy without tumor targeting. J Gene Med 2000; 2:11-21. [PMID: 10765501 DOI: 10.1002/(sici)1521-2254(200001/02)2:1<11::aid-jgm81>3.0.co;2-k] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [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: 11/10/2022] Open
Abstract
BACKGROUND Expression of exogenous wild-type p53 (wt-p53) protein in tumor cells can suppress the transformed phenotype whereas it does not apparently induce detrimental effects in non-transformed cells. This observation may provide a molecular basis for p53-mediated gene therapy of p53-sensitive cancers without the need for tumor targeting. METHODS To understand the molecular mechanisms responsible for this different behavior in tumor versus normal cells, biochemical and functional analyses of exogenous wt-p53 protein were performed on non-transformed C2C12 myoblasts and their transformed counterparts, the C2-ras cells. RESULTS The exogenous wt-p53 protein, which induced persistent growth arrest only in transformed C2-ras cells, was shown to be significantly more stable in transformed than in non-transformed cells. This different stability was due to different p53 proteolytic degradation. Moreover, constitutively, exogenous wt-p53 protein was found to be transcriptionally active only in C2-ras cells but it could also be activated in C2C12 cells by genotoxic damage. CONCLUSIONS Non-transformed C2C12 cells present regulatory system(s) which control the expression and the activity of exogenously expressed wt-p53 protein probably through degradation and maintenance in a latent form. This regulatory system is lost/inactivated upon transformation.
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Affiliation(s)
- G D'Orazi
- Molecular Oncogenesis Laboratory, C.R.S., Regina Elena Cancer Institute, Rome, Italy
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Abstract
Experiments previously performed on 32D and C2C12 cell lines indicated that wild type p53 (wtp53) protein has a role in granulocyte and myotube differentiation. Since these are immortal cells, we asked whether the inhibition of differentiation induced by the expression of dominant-negative p53 (dnp53) proteins was dependent on the immortalization-determined microenvironment. Thus, we evaluated the effects produced by interfering with the endogenous p53 gene in murine primary hemopoietic and muscle cells. Expression of dnp53 protein reduced the differentiation of bone marrow cells into granulocytes and macrophages. Moreover, p53 activation was measurable during the differentiation process of primary myoblasts, while interference with this activation led to a consistent slow down of terminal differentiation. Since the impairment of the differentiation was not accompanied by alterations in the cell cycle withdrawal and in the rate of apoptosis which are coupled with these types of differentiation, the data here reported support a specific role for p53 in the differentiation process. However, the difference in the intensity of inhibition between immortal and primary cells, i. e., complete versus slow down, respectively, suggests that the immortalization process might render the cells more sensitive to the loss of wtp53 activity for the differentiation process.
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Affiliation(s)
- G Mazzaro
- Molecular Oncogenesis Laboratory, Regina Elena Cancer Institute, C.R. S., Via delle Messi d'Oro 156, 00158 Rome, Italy
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Abstract
We study theoretically and experimentally the switching dynamics of a nonlinear optical bistable system that exhibits modulational instability in the vicinity of its lower limit point. We show that modulational instability induces premature upswitching and, in this way, truncates the bistable cycle. The role of the modulation instability is identified experimentally through the observation of the transient pattern formation that precedes upswitching. Our experiment illustrates the importance of cooperative behavior in practical distributed bistable systems.
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Paine-Andrews A, Harris KJ, Fawcett SB, Richter KP, Lewis RK, Francisco VT, Johnston J, Coen S. Evaluating a statewide partnership for reducing risks for chronic diseases. J Community Health 1997; 22:343-59. [PMID: 9353682 DOI: 10.1023/a:1025175504044] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [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: 02/05/2023]
Abstract
We describe a case study evaluation of Kansas LEAN, a statewide partnership with the mission of reducing risks for chronic diseases through dietary and exercise modification. We used a case study design to examine five primary questions related to process and outcome: (a) were the goals of the partnership important to constituents? (process), (b) were constituents satisfied with the partnership (process), (c) were community or systems changes (new or modified programs, policies, or practices) facilitated by partnership efforts (outcome)?, (d) were these changes important to the partnership's mission (outcome)?, and (e) what critical events helped facilitate community changes (outcome)? several measurement instruments--a monitoring and feedback system, constituent surveys, and semistructured interviews--were used to address key evaluation questions. Kansas LEAN is a strong statewide partnership with involvement from key representatives throughout Kansas. It is an ongoing, comprehensive health promotion program that plans and implements multiple components, in a variety of settings, to create awareness, behavior change, and a supportive environment. Kansas LEAN has facilitated several important community or systems changes related to its mission. We conclude with a discussion of the challenges of evaluating partnerships that seek to reduce risks for chronic diseases.
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Affiliation(s)
- A Paine-Andrews
- Work Group on Health Promotion and Community Development, University of Kansas, Lawrence 66045, USA
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Soddu S, Blandino G, Scardigli R, Coen S, Marchetti A, Rizzo MG, Bossi G, Cimino L, Crescenzi M, Sacchi A. Interference with p53 protein inhibits hematopoietic and muscle differentiation. J Biophys Biochem Cytol 1996; 134:193-204. [PMID: 8698814 PMCID: PMC2120910 DOI: 10.1083/jcb.134.1.193] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The involvement of p53 protein in cell differentiation has been recently suggested by some observations made with tumor cells and the correlation found between differentiation and increased levels of p53. However, the effect of p53 on differentiation is in apparent contrast with the normal development of p53-null mice. To test directly whether p53 has a function in cell differentiation, we interfered with the endogenous wt-p53 protein of nontransformed cells of two different murine histotypes: 32D myeloid progenitors, and C2C12 myoblasts. A drastic inhibition of terminal differentiation into granulocytes or myotubes, respectively, was observed upon expression of dominant-negative p53 proteins. This inhibition did not alter the cell cycle withdrawal typical of terminal differentiation, nor p21(WAF1/CIP1) upregulation, indicating that interference with endogenous p53 directly affects cell differentiation, independently of the p53 activity on the cell cycle. We also found that the endogenous wt-p53 protein of C2C12 cells becomes transcriptionally active during myogenesis, and this activity is inhibited by p53 dominant-negative expression. Moreover, we found that p53 DNA-binding and transcriptional activities are both required to induce differentiation in p53-negative K562 cells. Taken together, these data strongly indicate that p53 is a regulator of cell differentiation and it exerts this role, at least in part, through its transcriptional activity.
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Affiliation(s)
- S Soddu
- Molecular Oncogenesis Laboratory, Regina Elena Cancer Institute--Centro Ricerca Sperimentale, Rome, Italy
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Pippert K, Jecha L, Coen S, MacDonald P, Francisco J, Pickard S. A cooperative effort to pass tobacco control ordinances in Wichita, Kansas. J Public Health Manag Pract 1996; 1:18-22. [PMID: 10186604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
In October 1993, the Tobacco-Free Wichita Coalition proposed ordinances to the Wichita City Council that would tightly control access of minors to tobacco and prohibit smoking in public places. The subsequent successful change in local health policy required the collaborative efforts of local and state organizations and health agencies. A simple random telephone survey commissioned and financed by the coalition demonstrated that 76 percent (95 percent CI = 72 percent to 80 percent) of adult Wichita-Sedgwick County residents favored enforced penalties for merchants selling tobacco to minors, and 62 percent (95 percent CI = 58 percent to 66 percent) favored a ban on tobacco vending machines. Fifty-four percent (95 percent CI = 50 percent to 58 percent) favored a smoking ban in all public places.
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Affiliation(s)
- K Pippert
- Behavior Risk Factor Surveillance Unit, Kansas Department of Health and Environment, Topeka, USA
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Paine-Andrews A, Francisco VT, Fawcett SB, Johnston J, Coen S. Health marketing in the supermarket: using prompting, product sampling, and price reduction to increase customer purchases of lower-fat items. Health Mark Q 1995; 14:85-99. [PMID: 10164450 DOI: 10.1300/j026v14n02_08] [Citation(s) in RCA: 23] [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] [Indexed: 11/18/2022]
Abstract
Reducing purchase and consumption of higher-fat foods is an important health objective for the nation since these behaviors are associated with cardiovascular disease and some cancers. Public health agents attempt to promote health-related behaviors, such as purchases of lower-fat foods, by changing key features of relevant environments. This study examined the effects of a marketing intervention in a supermarket on customer purchases of lower-fat products. Customers of one store of a major supermarket chain participated in this study. Direct observations of customer purchases of lower-fat milk, salad dressings, and frozen desserts were conducted. The supermarket intervention consisted of prompting, product sampling, and price reduction (store coupons). Using an interrupted time series design with switching replications, we found low to moderate increases for the lower-fat counterparts of milk, frozen desserts, and salad dressing. The greatest increase in purchases was found with frozen desserts. Findings from this study suggest that prompting, product sampling, and price reduction can increase customer purchases of some lower-fat products. Implications of these findings for the development and evaluation of health marketing interventions are discussed.
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Coen S. White holes in the Fresnel zone causing ambiguous first arrival time tomography interpretation. Phys Rev Lett 1994; 73:3219-3222. [PMID: 10057321 DOI: 10.1103/physrevlett.73.3219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Balconi M, Botto-Micca F, Coen S, Grasso G. [Hospital and territory]. Minerva Pediatr 1978; 30:1923-5. [PMID: 755190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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