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Chakrabarti B, Shelley MJ, Fürthauer S. Collective Motion and Pattern Formation in Phase-Synchronizing Active Fluids. Phys Rev Lett 2023; 130:128202. [PMID: 37027863 DOI: 10.1103/physrevlett.130.128202] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 11/21/2022] [Accepted: 02/22/2023] [Indexed: 06/19/2023]
Abstract
Many active particles, such as swimming micro-organisms or motor proteins, do work on their environment by going though a periodic sequence of shapes. Interactions between particles can lead to synchronization of their duty cycles. Here, we study the collective dynamics of a suspension of active particles coupled through hydrodynamics. We find that at high enough density the system transitions to a state of collective motion by a mechanism that is distinct from other instabilities in active matter systems. Second, we demonstrate that the emergent nonequilibrium states feature stationary chimera patterns in which synchronized and phase-isotropic regions coexist. Third, we show that in confinement, oscillatory flows and robust unidirectional pumping states exist, and can be selected by choice of alignment boundary conditions. These results point toward a new route to collective motion and pattern formation and could guide the design of new active materials.
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Affiliation(s)
- Brato Chakrabarti
- Center for Computational Biology, Flatiron Institute, New York, New York 10010, USA
| | - Michael J Shelley
- Center for Computational Biology, Flatiron Institute, New York, New York 10010, USA
- Courant Institute, New York University, New York, New York 10012, USA
| | - Sebastian Fürthauer
- Center for Computational Biology, Flatiron Institute, New York, New York 10010, USA
- Institute of Applied Physics, TU Wien, A-1040 Wien, Austria
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Bonacci F, Chakrabarti B, Saintillan D, du Roure O, Lindner A. Dynamics of flexible filaments in oscillatory shear flows. J Fluid Mech 2023; 955:jfm.2022.1040. [PMID: 36936351 PMCID: PMC7614318 DOI: 10.1017/jfm.2022.1040] [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: 06/18/2023]
Abstract
The fluid-structure interactions between flexible fibers and viscous flows play an essential role in various biological phenomena, medical problems, and industrial processes. Of particular interest is the case of particles freely transported in time-dependent flows. This work elucidates the dynamics and morphologies of actin filaments under oscillatory shear flows by combining microfluidic experiments, numerical simulations, and theoretical modeling. Our work reveals that, in contrast to steady shear flows, in which small orientational fluctuations from a flow-aligned state initiate tumbling and deformations, the periodic flow reversal allows the filament to explore many different configurations at the beginning of each cycle. Investigation of filament motion during half time periods of oscillation highlights the critical role of the initial filament orientation on the emergent dynamics. This strong coupling between orientation and deformation results in new deformation regimes and novel higher-order buckling modes absent in steady shear flows. The primary outcome of our analysis is the possibility of suppression of buckling instabilities for certain combinations of the oscillation frequency and initial filament orientation, even in very strong flows. We explain this unusual behavior through a weakly nonlinear Landau theory of buckling, in which we treat the filaments as inextensible Brownian Euler-Bernoulli rods whose hydrodynamics are described by local slender-body theory.
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Affiliation(s)
- Francesco Bonacci
- PMMH, CNRS, ESPCI Paris, Université PSL, Sorbonne Université, Université Paris Cité, F-75005, Paris, France
| | - Brato Chakrabarti
- Center for Computational Biology, Flatiron Institute, New York, New York 10010, USA
| | - David Saintillan
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093, USA
| | - Olivia du Roure
- PMMH, CNRS, ESPCI Paris, Université PSL, Sorbonne Université, Université Paris Cité, F-75005, Paris, France
| | - Anke Lindner
- PMMH, CNRS, ESPCI Paris, Université PSL, Sorbonne Université, Université Paris Cité, F-75005, Paris, France
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Quillen AC, Peshkov A, Chakrabarti B, Skerrett N, McGaffigan S, Zapiach R. Fluid circulation driven by collectively organized metachronal waves in swimming T. aceti nematodes. Phys Rev E 2022; 106:064401. [PMID: 36671190 DOI: 10.1103/physreve.106.064401] [Citation(s) in RCA: 3] [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: 09/09/2022] [Accepted: 11/17/2022] [Indexed: 06/17/2023]
Abstract
Recent experiments have shown that the nematode T. aceti can assemble into collectively undulating groups at the edge of fluid drops. This coordinated state consists of metachronal waves and drives fluid circulation inside the drop. We find that the circulation velocity is about 2 mm/s and nearly half the speed of the metachronal wave. We develop a quasi-two-dimensional hydrodynamics model using the Stokes flow approximation. The periodic motion of the nematodes constitute our moving boundary condition that drives the flow. Our model suggests that large-amplitude excursions of the nematode tails produce the fluid circulation. We discuss the constraints on containers that would enhance fluid motion, which could be used in the future design of on demand flow generating systems.
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Affiliation(s)
- A C Quillen
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - A Peshkov
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - Brato Chakrabarti
- Center for Computational Biology, Flatiron Institute, New York, New York 10010, USA
| | - Nathan Skerrett
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - Sonia McGaffigan
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - Rebeca Zapiach
- Department of Mechanical Engineering, University of Rochester, Rochester, New York 14627, USA
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Chakrabarti B, Fürthauer S, Shelley MJ. A multiscale biophysical model gives quantized metachronal waves in a lattice of beating cilia. Proc Natl Acad Sci U S A 2022; 119:e2113539119. [PMID: 35046031 PMCID: PMC8795537 DOI: 10.1073/pnas.2113539119] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 12/02/2021] [Indexed: 11/18/2022] Open
Abstract
Motile cilia are slender, hair-like cellular appendages that spontaneously oscillate under the action of internal molecular motors and are typically found in dense arrays. These active filaments coordinate their beating to generate metachronal waves that drive long-range fluid transport and locomotion. Until now, our understanding of their collective behavior largely comes from the study of minimal models that coarse grain the relevant biophysics and the hydrodynamics of slender structures. Here we build on a detailed biophysical model to elucidate the emergence of metachronal waves on millimeter scales from nanometer-scale motor activity inside individual cilia. Our study of a one-dimensional lattice of cilia in the presence of hydrodynamic and steric interactions reveals how metachronal waves are formed and maintained. We find that, in homogeneous beds of cilia, these interactions lead to multiple attracting states, all of which are characterized by an integer charge that is conserved. This even allows us to design initial conditions that lead to predictable emergent states. Finally, and very importantly, we show that, in nonuniform ciliary tissues, boundaries and inhomogeneities provide a robust route to metachronal waves.
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Affiliation(s)
- Brato Chakrabarti
- Center for Computational Biology, Flatiron Institute, New York, NY 10010
| | - Sebastian Fürthauer
- Center for Computational Biology, Flatiron Institute, New York, NY 10010;
- Institute of Applied Physics, TU Wien, Vienna 1040, Austria
| | - Michael J Shelley
- Center for Computational Biology, Flatiron Institute, New York, NY 10010;
- Courant Institute, New York University, New York, NY 10012
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Mason L, Shic F, Falck-Ytter T, Chakrabarti B, Charman T, Loth E, Tillmann J, Banaschewski T, Baron-Cohen S, Bölte S, Buitelaar J, Durston S, Oranje B, Persico AM, Beckmann C, Bougeron T, Dell'Acqua F, Ecker C, Moessnang C, Murphy D, Johnson MH, Jones EJH. Preference for biological motion is reduced in ASD: implications for clinical trials and the search for biomarkers. Mol Autism 2021; 12:74. [PMID: 34911565 PMCID: PMC8672507 DOI: 10.1186/s13229-021-00476-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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: 07/02/2021] [Accepted: 11/03/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The neurocognitive mechanisms underlying autism spectrum disorder (ASD) remain unclear. Progress has been largely hampered by small sample sizes, variable age ranges and resulting inconsistent findings. There is a pressing need for large definitive studies to delineate the nature and extent of key case/control differences to direct research towards fruitful areas for future investigation. Here we focus on perception of biological motion, a promising index of social brain function which may be altered in ASD. In a large sample ranging from childhood to adulthood, we assess whether biological motion preference differs in ASD compared to neurotypical participants (NT), how differences are modulated by age and sex and whether they are associated with dimensional variation in concurrent or later symptomatology. METHODS Eye-tracking data were collected from 486 6-to-30-year-old autistic (N = 282) and non-autistic control (N = 204) participants whilst they viewed 28 trials pairing biological (BM) and control (non-biological, CTRL) motion. Preference for the biological motion stimulus was calculated as (1) proportion looking time difference (BM-CTRL) and (2) peak look duration difference (BM-CTRL). RESULTS The ASD group showed a present but weaker preference for biological motion than the NT group. The nature of the control stimulus modulated preference for biological motion in both groups. Biological motion preference did not vary with age, gender, or concurrent or prospective social communicative skill within the ASD group, although a lack of clear preference for either stimulus was associated with higher social-communicative symptoms at baseline. LIMITATIONS The paired visual preference we used may underestimate preference for a stimulus in younger and lower IQ individuals. Our ASD group had a lower average IQ by approximately seven points. 18% of our sample was not analysed for various technical and behavioural reasons. CONCLUSIONS Biological motion preference elicits small-to-medium-sized case-control effects, but individual differences do not strongly relate to core social autism associated symptomatology. We interpret this as an autistic difference (as opposed to a deficit) likely manifest in social brain regions. The extent to which this is an innate difference present from birth and central to the autistic phenotype, or the consequence of a life lived with ASD, is unclear.
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Affiliation(s)
- L Mason
- Centre for Brain and Cognitive Development, Birkbeck, University of London, Malet St, London, WC1E 7HX, UK.
| | - F Shic
- Center for Child Health, Behavior and Development, Seattle Children's Research Institute, Seattle, WA, USA
- Department of General Pediatrics, University of Washington School of Medicine, Seattle, WA, USA
- Department of Computer Science, University of Washington, Seattle, WA, USA
| | - T Falck-Ytter
- Development and Neurodiversity Lab, Department of Psychology, Uppsala University, Uppsala, Sweden
- Center of Neurodevelopmental Disorders (KIND), Centre for Psychiatry Research; Department of Women's and Children's Health, Karolinska Institutet and Child and Adolescent Psychiatry, Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden
- Swedish Collegium for Advanced Study, Uppsala, Sweden
| | - B Chakrabarti
- Centre for Autism, School of Psychology and Clinical Language Sciences, University of Reading, Reading, RG6 6AL, UK
- Department of Psychology, Ashoka University, Sonipat, India
- India Autism Center, Kolkata, India
| | - T Charman
- Institute of Psychiatry, Psychology and Neuroscience, King's College, London, London, UK
| | - E Loth
- Institute of Psychiatry, Psychology and Neuroscience, King's College, London, London, UK
| | - J Tillmann
- Institute of Psychiatry, Psychology and Neuroscience, King's College, London, London, UK
| | - T Banaschewski
- Central Institute of Mental Health, University of Heidelberg, Mannheim, Germany
| | - S Baron-Cohen
- Department of Psychology, University of Cambridge, Cambridge, UK
| | - S Bölte
- Center of Neurodevelopmental Disorders (KIND), Centre for Psychiatry Research; Department of Women's and Children's Health, Karolinska Institutet and Child and Adolescent Psychiatry, Stockholm Health Care Services, Region Stockholm, Stockholm, Sweden
| | - J Buitelaar
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
| | - S Durston
- NICHE-Lab, Dept. of Psychiatry, UMC Utrecht Brain Center, Utrecht, The Netherlands
| | - B Oranje
- NICHE-Lab, Dept. of Psychiatry, UMC Utrecht Brain Center, Utrecht, The Netherlands
| | - A M Persico
- Interdepartmental Program "Autism 0-90", University of Messina, Messina, Italy
| | - C Beckmann
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
| | - T Bougeron
- Human Genetics and Cognitive Functions, Institut Pasteur, UMR3571 CNRS, Université de Paris, 75015, Paris, France
| | - F Dell'Acqua
- Institute of Psychiatry, Psychology and Neuroscience, King's College, London, London, UK
| | - C Ecker
- Institute of Psychiatry, Psychology and Neuroscience, King's College, London, London, UK
- Department of Child and Adolescent Psychiatry, University Hospital, Goethe University, Frankfurt am Main, Germany
| | - C Moessnang
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, University of Heidelberg, Mannheim, Germany
| | - D Murphy
- Institute of Psychiatry, Psychology and Neuroscience, King's College, London, London, UK
| | - M H Johnson
- Centre for Brain and Cognitive Development, Birkbeck, University of London, Malet St, London, WC1E 7HX, UK
- Department of Psychology, University of Cambridge, Cambridge, UK
| | - E J H Jones
- Centre for Brain and Cognitive Development, Birkbeck, University of London, Malet St, London, WC1E 7HX, UK
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Chakrabarti B, Gaillard C, Saintillan D. Trapping, gliding, vaulting: transport of semiflexible polymers in periodic post arrays. Soft Matter 2020; 16:5534-5544. [PMID: 32507870 DOI: 10.1039/d0sm00390e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The transport of deformable particles through porous media underlies a wealth of applications ranging from filtration to oil recovery to the transport and spreading of biological agents. Using direct numerical simulations, we analyze the dynamics of semiflexible polymers under the influence of an imposed flow in a structured two-dimensional lattice serving as an idealization of a porous medium. This problem has received much attention in the limit of reptation and for long-chain polymer molecules such as DNA that are transported through micropost arrays for electrophoretic chromatographic separation. In contrast to long entropic molecules, the dynamics of elastic polymers results from a combination of scattering with the obstacles and flow-induced buckling instabilities. We identify three dominant modes of transport that involve trapping, gliding and vaulting of the polymers around the obstacles, and we reveal their essential features using tools from dynamical systems theory. The interplay of these scattering dynamics with transport and deformations in the imposed flow results in the long-time asymptotic dispersion of the center of mass, which we quantify in terms of a hydrodynamic dispersion tensor. We then discuss a simple yet efficient chromatographic device that exploits the competition between different modes of transport to sort filaments in a dilute suspension according to their lengths.
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Affiliation(s)
- Brato Chakrabarti
- Department of Mechanical and Aerospace Engineering, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
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Pasquina-Lemonche L, Burns J, Turner RD, Kumar S, Tank R, Mullin N, Wilson JS, Chakrabarti B, Bullough PA, Foster SJ, Hobbs JK. The architecture of the Gram-positive bacterial cell wall. Nature 2020; 582:294-297. [PMID: 32523118 PMCID: PMC7308169 DOI: 10.1038/s41586-020-2236-6] [Citation(s) in RCA: 172] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 02/25/2020] [Indexed: 02/05/2023]
Abstract
The primary structural component of the bacterial cell wall is peptidoglycan, which is essential for viability and the synthesis of which is the target for crucial antibiotics1,2. Peptidoglycan is a single macromolecule made of glycan chains crosslinked by peptide side branches that surrounds the cell, acting as a constraint to internal turgor1,3. In Gram-positive bacteria, peptidoglycan is tens of nanometres thick, generally portrayed as a homogeneous structure that provides mechanical strength4-6. Here we applied atomic force microscopy7-12 to interrogate the morphologically distinct Staphylococcus aureus and Bacillus subtilis species, using live cells and purified peptidoglycan. The mature surface of live cells is characterized by a landscape of large (up to 60 nm in diameter), deep (up to 23 nm) pores constituting a disordered gel of peptidoglycan. The inner peptidoglycan surface, consisting of more nascent material, is much denser, with glycan strand spacing typically less than 7 nm. The inner surface architecture is location dependent; the cylinder of B. subtilis has dense circumferential orientation, while in S. aureus and division septa for both species, peptidoglycan is dense but randomly oriented. Revealing the molecular architecture of the cell envelope frames our understanding of its mechanical properties and role as the environmental interface13,14, providing information complementary to traditional structural biology approaches.
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Affiliation(s)
- L Pasquina-Lemonche
- Krebs Institute, University of Sheffield, Sheffield, UK
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
- The Florey Institute, University of Sheffield, Sheffield, UK
| | - J Burns
- Krebs Institute, University of Sheffield, Sheffield, UK
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
| | - R D Turner
- Krebs Institute, University of Sheffield, Sheffield, UK
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
- Department of Computer Science, University of Sheffield, Sheffield, UK
| | - S Kumar
- Krebs Institute, University of Sheffield, Sheffield, UK
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - R Tank
- Krebs Institute, University of Sheffield, Sheffield, UK
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
| | - N Mullin
- Krebs Institute, University of Sheffield, Sheffield, UK
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
| | - J S Wilson
- Krebs Institute, University of Sheffield, Sheffield, UK
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - B Chakrabarti
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK
| | - P A Bullough
- Krebs Institute, University of Sheffield, Sheffield, UK
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - S J Foster
- Krebs Institute, University of Sheffield, Sheffield, UK.
- The Florey Institute, University of Sheffield, Sheffield, UK.
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK.
| | - J K Hobbs
- Krebs Institute, University of Sheffield, Sheffield, UK.
- Department of Physics and Astronomy, University of Sheffield, Sheffield, UK.
- The Florey Institute, University of Sheffield, Sheffield, UK.
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Bera S, Chakrabarti B, Gammal A, Tsatsos MC, Lekala ML, Chatterjee B, Lévêque C, Lode AUJ. Sorting Fermionization from Crystallization in Many-Boson Wavefunctions. Sci Rep 2019; 9:17873. [PMID: 31784539 PMCID: PMC6884621 DOI: 10.1038/s41598-019-53179-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 10/23/2019] [Indexed: 11/23/2022] Open
Abstract
Fermionization is what happens to the state of strongly interacting repulsive bosons interacting with contact interactions in one spatial dimension. Crystallization is what happens for sufficiently strongly interacting repulsive bosons with dipolar interactions in one spatial dimension. Crystallization and fermionization resemble each other: in both cases - due to their repulsion - the bosons try to minimize their spatial overlap. We trace these two hallmark phases of strongly correlated one-dimensional bosonic systems by exploring their ground state properties using the one- and two-body density matrix. We solve the N-body Schrödinger equation accurately and from first principles using the multiconfigurational time-dependent Hartree for bosons (MCTDHB) and for fermions (MCTDHF) methods. Using the one- and two-body density, fermionization can be distinguished from crystallization in position space. For N interacting bosons, a splitting into an N-fold pattern in the one-body and two-body density is a unique feature of both, fermionization and crystallization. We demonstrate that this splitting is incomplete for fermionized bosons and restricted by the confinement potential. This incomplete splitting is a consequence of the convergence of the energy in the limit of infinite repulsion and is in agreement with complementary results that we obtain for fermions using MCTDHF. For crystalline bosons, in contrast, the splitting is complete: the interaction energy is capable of overcoming the confinement potential. Our results suggest that the spreading of the density as a function of the dipolar interaction strength diverges as a power law. We describe how to distinguish fermionization from crystallization experimentally from measurements of the one- and two-body density.
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Affiliation(s)
- S Bera
- Department of Physics, Presidency University, 86/1 College Street, Kolkata, 700 073, India
| | - B Chakrabarti
- Department of Physics, Presidency University, 86/1 College Street, Kolkata, 700 073, India
- Instituto de Física, Universidade de São Paulo, CEP 05508-090, São Paulo, Brazil
| | - A Gammal
- Instituto de Física, Universidade de São Paulo, CEP 05508-090, São Paulo, Brazil
| | - M C Tsatsos
- Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970, São Carlos, SP, Brazil
| | - M L Lekala
- Department of Physics, University of South Africa P.O. Box-392, Pretoria, 0003, South Africa
| | - B Chatterjee
- Department of Physics, Indian Institute of Technology-Kanpur, Kanpur, 208016, India
| | - C Lévêque
- Wolfgang Pauli Institute c/o Faculty of Mathematics, University of Vienna, Oskar-Morgenstern Platz 1, 1090, Vienna, Austria
- Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, 1020, Vienna, Austria
| | - A U J Lode
- Wolfgang Pauli Institute c/o Faculty of Mathematics, University of Vienna, Oskar-Morgenstern Platz 1, 1090, Vienna, Austria.
- Vienna Center for Quantum Science and Technology, Atominstitut, TU Wien, Stadionallee 2, 1020, Vienna, Austria.
- Institute of Physics, Albert-Ludwig University of Freiburg, Hermann-Herder-Strasse 3, 79104, Freiburg, Germany.
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Chakrabarti B, Saintillan D. Hydrodynamic Synchronization of Spontaneously Beating Filaments. Phys Rev Lett 2019; 123:208101. [PMID: 31809101 DOI: 10.1103/physrevlett.123.208101] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 09/12/2019] [Indexed: 06/10/2023]
Abstract
Using a geometric feedback model of the flagellar axoneme accounting for dynein motor kinetics, we study elastohydrodynamic phase synchronization in a pair of spontaneously beating filaments with waveforms ranging from sperm to cilia and Chlamydomonas. Our computations reveal that both in-phase and antiphase synchrony can emerge for asymmetric beats while symmetric waveforms go in phase, and elucidate the mechanism for phase slips due to biochemical noise. Model predictions agree with recent experiments and illuminate the crucial roles of hydrodynamics and mechanochemical feedback in synchronization.
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Affiliation(s)
- Brato Chakrabarti
- Department of Mechanical and Aerospace Engineering, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
| | - David Saintillan
- Department of Mechanical and Aerospace Engineering, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
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Chakrabarti B, Singh SD, Bhatia A, Kumar V, Harit RC. Yield and Nitrogen Uptake in Wheat and Chickpea Grown Under Elevated Carbon Dioxide Level. Natl Acad Sci Lett 2019. [DOI: 10.1007/s40009-019-00816-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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11
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Dey SK, Chakrabarti B, Purakayastha TJ, Prasanna R, Mittal R, Singh SD, Pathak H. Interplay of phosphorus doses, cyanobacterial inoculation, and elevated carbon dioxide on yield and phosphorus dynamics in cowpea. Environ Monit Assess 2019; 191:223. [PMID: 30879142 DOI: 10.1007/s10661-019-7378-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 03/07/2019] [Indexed: 06/09/2023]
Abstract
Phosphorus (P) demand is likely to increase especially in legumes to harness greater benefits of nitrogen fixation under elevated CO2 condition. In the following study, seed yield and seed P uptake in cowpea increased by 26.8% and 20.9%, respectively, under elevated CO2 level. With an increase in phosphorus dose up to 12 mg kg-1, seed yield enhanced from 2.6 to 5.4 g plant-1. P application and cyanobacterial inoculation increased the microbial activity of soil, leading to increased availability of P. Under elevated CO2 condition, microbial activity, measured as dehydrogenase, acid phosphatase, and alkaline phosphatase activities showed stimulation. Soil available P also increased under elevated CO2 condition and was stimulated by both P application and cyanobacterial inoculation. Higher P uptake in elevated CO2 condition led to lower values of inorganic P in soil. Stepwise regression analysis showed that aboveground P uptake, soil available P, and alkaline phosphatase activity of soil influenced the yield while available P, and organic and inorganic P influenced the aboveground P uptake of the crop. This study revealed that under elevated CO2 condition, P application and cyanobacterial inoculation facilitated P uptake and yield, mediated through enhanced availability of nutrients, in cowpea crop.
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Affiliation(s)
- Sumit Kumar Dey
- ICAR-Indian Agricultural Research Institute, New Delhi, 110 012, India
| | - B Chakrabarti
- ICAR-Indian Agricultural Research Institute, New Delhi, 110 012, India.
| | - T J Purakayastha
- ICAR-Indian Agricultural Research Institute, New Delhi, 110 012, India
| | - Radha Prasanna
- ICAR-Indian Agricultural Research Institute, New Delhi, 110 012, India
| | - R Mittal
- ICAR-Indian Agricultural Research Institute, New Delhi, 110 012, India
| | - S D Singh
- ICAR-Indian Agricultural Research Institute, New Delhi, 110 012, India
| | - H Pathak
- ICAR-Indian Agricultural Research Institute, New Delhi, 110 012, India
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Abstract
The morphological dynamics, instabilities, and transitions of elastic filaments in viscous flows underlie a wealth of biophysical processes from flagellar propulsion to intracellular streaming and are also key to deciphering the rheological behavior of many complex fluids and soft materials. Here, we combine experiments and computational modeling to elucidate the dynamical regimes and morphological transitions of elastic Brownian filaments in a simple shear flow. Actin filaments are used as an experimental model system and their conformations are investigated through fluorescence microscopy in microfluidic channels. Simulations matching the experimental conditions are also performed using inextensible Euler-Bernoulli beam theory and nonlocal slender-body hydrodynamics in the presence of thermal fluctuations and agree quantitatively with observations. We demonstrate that filament dynamics in this system are primarily governed by a dimensionless elasto-viscous number comparing viscous drag forces to elastic bending forces, with thermal fluctuations playing only a secondary role. While short and rigid filaments perform quasi-periodic tumbling motions, a buckling instability arises above a critical flow strength. A second transition to strongly deformed shapes occurs at a yet larger value of the elasto-viscous number and is characterized by the appearance of localized high-curvature bends that propagate along the filaments in apparent "snaking" motions. A theoretical model for the as yet unexplored onset of snaking accurately predicts the transition and explains the observed dynamics. We present a complete characterization of filament morphologies and transitions as a function of elasto-viscous number and scaled persistence length and demonstrate excellent agreement between theory, experiments, and simulations.
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Affiliation(s)
- Yanan Liu
- Physique et Mécanique des Milieux Hétérogènes (PMMH), ESPCI Paris, PSL University, CNRS, Sorbonne Université, Université Paris Diderot, 75005 Paris, France
| | - Brato Chakrabarti
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093
| | - David Saintillan
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093
| | - Anke Lindner
- Physique et Mécanique des Milieux Hétérogènes (PMMH), ESPCI Paris, PSL University, CNRS, Sorbonne Université, Université Paris Diderot, 75005 Paris, France;
| | - Olivia du Roure
- Physique et Mécanique des Milieux Hétérogènes (PMMH), ESPCI Paris, PSL University, CNRS, Sorbonne Université, Université Paris Diderot, 75005 Paris, France
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13
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Bayat FM, Prezioso M, Chakrabarti B, Nili H, Kataeva I, Strukov D. Implementation of multilayer perceptron network with highly uniform passive memristive crossbar circuits. Nat Commun 2018; 9:2331. [PMID: 29899421 PMCID: PMC5998062 DOI: 10.1038/s41467-018-04482-4] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 05/02/2018] [Indexed: 11/09/2022] Open
Abstract
The progress in the field of neural computation hinges on the use of hardware more efficient than the conventional microprocessors. Recent works have shown that mixed-signal integrated memristive circuits, especially their passive (0T1R) variety, may increase the neuromorphic network performance dramatically, leaving far behind their digital counterparts. The major obstacle, however, is immature memristor technology so that only limited functionality has been reported. Here we demonstrate operation of one-hidden layer perceptron classifier entirely in the mixed-signal integrated hardware, comprised of two passive 20 × 20 metal-oxide memristive crossbar arrays, board-integrated with discrete conventional components. The demonstrated network, whose hardware complexity is almost 10× higher as compared to previously reported functional classifier circuits based on passive memristive crossbars, achieves classification fidelity within 3% of that obtained in simulations, when using ex-situ training. The successful demonstration was facilitated by improvements in fabrication technology of memristors, specifically by lowering variations in their I-V characteristics.
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Affiliation(s)
- F Merrikh Bayat
- Electrical and Computer Engineering Department, University of California, Santa Barbara, CA, 93117, USA
| | - M Prezioso
- Electrical and Computer Engineering Department, University of California, Santa Barbara, CA, 93117, USA
| | - B Chakrabarti
- Electrical and Computer Engineering Department, University of California, Santa Barbara, CA, 93117, USA
| | - H Nili
- Electrical and Computer Engineering Department, University of California, Santa Barbara, CA, 93117, USA
| | - I Kataeva
- DENSO CORP, 500-1 Minamiyama, Komenoki-cho, Nisshin, 470-0111, Japan.
| | - D Strukov
- Electrical and Computer Engineering Department, University of California, Santa Barbara, CA, 93117, USA.
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14
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Wordingham-Baker S, O’Reilly J, Duffy N, Plant P, Chakrabarti B, Craig S, Manuel A. P214 Remote monitoring in the early stages of continuous positive airway pressure (cpap) initiation in obstructive sleep apnoea (osa) allows early detection of poor compliance and mask problems. Sleep Breath 2017. [DOI: 10.1136/thoraxjnl-2017-210983.356] [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: 11/03/2022]
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15
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Zeestraten EA, Gudbrandsen MC, Daly E, de Schotten MT, Catani M, Dell'Acqua F, Lai MC, Ruigrok ANV, Lombardo MV, Chakrabarti B, Baron-Cohen S, Ecker C, Murphy DGM, Craig MC. Sex differences in frontal lobe connectivity in adults with autism spectrum conditions. Transl Psychiatry 2017; 7:e1090. [PMID: 28398337 PMCID: PMC5416715 DOI: 10.1038/tp.2017.9] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 11/28/2016] [Accepted: 11/30/2016] [Indexed: 01/04/2023] Open
Abstract
Autism spectrum conditions (ASC) are more prevalent in males than females. The biological basis of this difference remains unclear. It has been postulated that one of the primary causes of ASC is a partial disconnection of the frontal lobe from higher-order association areas during development (that is, a frontal 'disconnection syndrome'). Therefore, in the current study we investigated whether frontal connectivity differs between males and females with ASC. We recruited 98 adults with a confirmed high-functioning ASC diagnosis (61 males: aged 18-41 years; 37 females: aged 18-37 years) and 115 neurotypical controls (61 males: aged 18-45 years; 54 females: aged 18-52 years). Current ASC symptoms were evaluated using the Autism Diagnostic Observation Schedule (ADOS). Diffusion tensor imaging was performed and fractional anisotropy (FA) maps were created. Mean FA values were determined for five frontal fiber bundles and two non-frontal fiber tracts. Between-group differences in mean tract FA, as well as sex-by-diagnosis interactions were assessed. Additional analyses including ADOS scores informed us on the influence of current ASC symptom severity on frontal connectivity. We found that males with ASC had higher scores of current symptom severity than females, and had significantly lower mean FA values for all but one tract compared to controls. No differences were found between females with or without ASC. Significant sex-by-diagnosis effects were limited to the frontal tracts. Taking current ASC symptom severity scores into account did not alter the findings, although the observed power for these analyses varied. We suggest these findings of frontal connectivity abnormalities in males with ASC, but not in females with ASC, have the potential to inform us on some of the sex differences reported in the behavioral phenotype of ASC.
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Affiliation(s)
- E A Zeestraten
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - M C Gudbrandsen
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - E Daly
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - M T de Schotten
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - M Catani
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - F Dell'Acqua
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - M-C Lai
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK
- Child and Youth Mental Health Collaborative at the Centre for Addiction and Mental Health and The Hospital for Sick Children, Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Department of Psychiatry, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan
| | - A N V Ruigrok
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - M V Lombardo
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK
- Department of Psychology and Center for Applied Neuroscience, University of Cyprus, Nicosia, Cyprus
| | - B Chakrabarti
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK
- School of Psychology and Clinical Language Sciences, Centre for Integrative Neuroscience and Neurodynamics, University of Reading, Reading, UK
| | - S Baron-Cohen
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK
- CLASS Clinic, Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK
| | - C Ecker
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - D G M Murphy
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- Sackler Institute for Translational Neurodevelopment, Institute of Psychiatry, King's College London, London, UK
| | - M C Craig
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- National Autism Unit, Bethlem Royal Hospital, SLAM NHS Foundation Trust, London, UK
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16
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Chakrabarti B, Lastras-Montaño MA, Adam G, Prezioso M, Hoskins B, Payvand M, Madhavan A, Ghofrani A, Theogarajan L, Cheng KT, Strukov DB. A multiply-add engine with monolithically integrated 3D memristor crossbar/CMOS hybrid circuit. Sci Rep 2017; 7:42429. [PMID: 28195239 PMCID: PMC5307953 DOI: 10.1038/srep42429] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 01/09/2017] [Indexed: 11/24/2022] Open
Abstract
Silicon (Si) based complementary metal-oxide semiconductor (CMOS) technology has been the driving force of the information-technology revolution. However, scaling of CMOS technology as per Moore’s law has reached a serious bottleneck. Among the emerging technologies memristive devices can be promising for both memory as well as computing applications. Hybrid CMOS/memristor circuits with CMOL (CMOS + “Molecular”) architecture have been proposed to combine the extremely high density of the memristive devices with the robustness of CMOS technology, leading to terabit-scale memory and extremely efficient computing paradigm. In this work, we demonstrate a hybrid 3D CMOL circuit with 2 layers of memristive crossbars monolithically integrated on a pre-fabricated CMOS substrate. The integrated crossbars can be fully operated through the underlying CMOS circuitry. The memristive devices in both layers exhibit analog switching behavior with controlled tunability and stable multi-level operation. We perform dot-product operations with the 2D and 3D memristive crossbars to demonstrate the applicability of such 3D CMOL hybrid circuits as a multiply-add engine. To the best of our knowledge this is the first demonstration of a functional 3D CMOL hybrid circuit.
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Affiliation(s)
- B Chakrabarti
- Electrical and Computer Engineering Department, University of California, Santa Barbara, CA, 93106, USA
| | - M A Lastras-Montaño
- Electrical and Computer Engineering Department, University of California, Santa Barbara, CA, 93106, USA
| | - G Adam
- Electrical and Computer Engineering Department, University of California, Santa Barbara, CA, 93106, USA
| | - M Prezioso
- Electrical and Computer Engineering Department, University of California, Santa Barbara, CA, 93106, USA
| | - B Hoskins
- Materials Department, University of California, Santa Barbara, CA, 93106, USA
| | | | | | | | | | - K-T Cheng
- Electrical and Computer Engineering Department, University of California, Santa Barbara, CA, 93106, USA.,School of Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - D B Strukov
- Electrical and Computer Engineering Department, University of California, Santa Barbara, CA, 93106, USA
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17
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Chakrabarti B, Emegbo S, Craig S, Duffy N, O’Reilly JF. S24 A comparison of pulse transit time between subjects with obstructive sleep apnoea syndrome, nocturnal inspiratory flow limitation and the absence of significant sleep disordered breathing. Thorax 2016. [DOI: 10.1136/thoraxjnl-2016-209333.30] [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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18
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Ashcroft H, Ando H, Halhead R, Chakrabarti B, Young CA, Cousins R, Angus RM. S57 Qualitative assessment of the experience of telemonitoring in ventilated patients with motor neurone disease. Thorax 2016. [DOI: 10.1136/thoraxjnl-2016-209333.63] [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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19
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Affiliation(s)
| | - F. J. Scandrett
- Department of Clinical Chemistry, Royal Infirmary, Edinburgh
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20
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Abstract
We tend to like those who mimic us. In this study we formally test if mimicry changes the reward value of the mimicker, using gaze bias as a proxy for reward. Previous research has demonstrated that people show gaze bias towards more rewarding targets, suggesting that gaze bias can be considered a proxy for relative reward value. Forty adults participated in a conditioning task, where they were mimicked by one face and 'anti-mimicked' by another. Subsequently, they were found to show gaze-bias towards faces that mimicked them compared to those that did not, in a preferential looking task. The strength of this effect correlated positively with individual levels of trait empathy. In a separate, similar task, these participants showed a gaze bias for faces paired with high vs low monetary rewards, thus validating the use of gaze bias as a proxy for learnt reward. Together, these results demonstrate that mimicry changes the reward value of social stimuli, and empathy influences the extent of this change. This can potentially inform conditions marked by deficits in forming social bonds, such as Autism.
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Affiliation(s)
- J Neufeld
- Centre for Integrative Neuroscience and Neurodynamics, School of Psychology and Clinical Language Sciences, University of Reading, Reading, United Kingdom.,Center of Neurodevelopmental Disorders, Karolinska Institutet (KIND), Stockholm, Sweden
| | - B Chakrabarti
- Centre for Integrative Neuroscience and Neurodynamics, School of Psychology and Clinical Language Sciences, University of Reading, Reading, United Kingdom
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21
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Frost F, Al-Hakim B, Wordingham-Baker S, Ford V, Ashcroft H, Ward K, Parker R, Chakrabarti B, Angus R, Duffy N. P194 Inpatient adjustment of sub-optimal home mechanical ventilation (HMV) – an effective use of resources?: Abstract P194 Table 1. Thorax 2015. [DOI: 10.1136/thoraxjnl-2015-207770.331] [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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22
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Ward K, Ford V, Ashcroft H, Wordingham-Baker S, Chakrabarti B, Duffy N, Angus R, Parker R. P195 Demographics and outcomes of NIV in MND: a frontline perspective. Thorax 2015. [DOI: 10.1136/thoraxjnl-2015-207770.332] [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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23
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Chakrabarti B, Emegbo S, Craig S, Heseltine J, Wright T, Duffy N, O’Reilly JF. P111 Respiratory Flow Limitation in the absence of Obstructive Sleep Apnoea responds to CPAP therapy. Thorax 2015. [DOI: 10.1136/thoraxjnl-2015-207770.248] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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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24
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Ashcroft HJ, Ando H, Chakrabarti B, Halhead R, Levene P, Angus RM. P190 Development of a respiratory question set for remote monitoring in motor neurone disease (MND). Thorax 2015. [DOI: 10.1136/thoraxjnl-2015-207770.327] [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: 11/03/2022]
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25
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Chakrabarti B, Roy S, Mallik C, Bhattacharya KS, Mukherjee S. Chronic inflammatory demyelinating polyneuropathy, diagnosed as a paraneoplastic manifestation of small cell neuroendocrine carcinoma of the cervix. Southern African Journal of Gynaecological Oncology 2015. [DOI: 10.1080/20742835.2013.11441205] [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: 10/23/2022] Open
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26
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Baron-Cohen S, Auyeung B, Nørgaard-Pedersen B, Hougaard DM, Abdallah MW, Melgaard L, Cohen AS, Chakrabarti B, Ruta L, Lombardo MV. Elevated fetal steroidogenic activity in autism. Mol Psychiatry 2015; 20:369-76. [PMID: 24888361 PMCID: PMC4184868 DOI: 10.1038/mp.2014.48] [Citation(s) in RCA: 308] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 03/25/2014] [Accepted: 03/27/2014] [Indexed: 12/16/2022]
Abstract
Autism affects males more than females, giving rise to the idea that the influence of steroid hormones on early fetal brain development may be one important early biological risk factor. Utilizing the Danish Historic Birth Cohort and Danish Psychiatric Central Register, we identified all amniotic fluid samples of males born between 1993 and 1999 who later received ICD-10 (International Classification of Diseases, 10th Revision) diagnoses of autism, Asperger syndrome or PDD-NOS (pervasive developmental disorder not otherwise specified) (n=128) compared with matched typically developing controls. Concentration levels of Δ4 sex steroids (progesterone, 17α-hydroxy-progesterone, androstenedione and testosterone) and cortisol were measured with liquid chromatography tandem mass spectrometry. All hormones were positively associated with each other and principal component analysis confirmed that one generalized latent steroidogenic factor was driving much of the variation in the data. The autism group showed elevations across all hormones on this latent generalized steroidogenic factor (Cohen's d=0.37, P=0.0009) and this elevation was uniform across ICD-10 diagnostic label. These results provide the first direct evidence of elevated fetal steroidogenic activity in autism. Such elevations may be important as epigenetic fetal programming mechanisms and may interact with other important pathophysiological factors in autism.
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Affiliation(s)
- S Baron-Cohen
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK,Autism Research Centre, Department of Psychiatry, University of Cambridge, Douglas House, 18B Trumpington Road, Cambridge CB2 8AH, UK. E-mail:
| | - B Auyeung
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK,Department of Psychology, University of Edinburgh, Edinburgh, UK
| | - B Nørgaard-Pedersen
- Department of Clinical Biochemistry and Immunology, Statens Serum Institute Copenhagen, Copenhagen, Denmark
| | - D M Hougaard
- Department of Clinical Biochemistry and Immunology, Statens Serum Institute Copenhagen, Copenhagen, Denmark
| | - M W Abdallah
- Department of Clinical Biochemistry and Immunology, Statens Serum Institute Copenhagen, Copenhagen, Denmark,Department of Child and Adolescent Neuropsychiatry, Rostock University Medical Centre, Rostock, Germany,Section for Epidemiology, Department of Public Health, Aarhus University, Aarhus, Denmark
| | - L Melgaard
- Department of Clinical Biochemistry and Immunology, Statens Serum Institute Copenhagen, Copenhagen, Denmark
| | - A S Cohen
- Department of Clinical Biochemistry and Immunology, Statens Serum Institute Copenhagen, Copenhagen, Denmark
| | - B Chakrabarti
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK,Centre for Integrative Neuroscience and Neurodynamics, School of Psychology and Clinical Language Sciences, University of Reading, Reading, UK
| | - L Ruta
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK,Division of Child Neurology and Psychiatry, Stella Maris Scientific Institute, Pisa, Italy
| | - M V Lombardo
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK,Department of Psychology, University of Cyprus, Nicosia, Cyprus,Centre for Applied Neuroscience, University of Cyprus, Nicosia, Cyprus
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27
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Auyeung B, Lombardo MV, Heinrichs M, Chakrabarti B, Sule A, Deakin JB, Bethlehem RAI, Dickens L, Mooney N, Sipple JAN, Thiemann P, Baron-Cohen S. Oxytocin increases eye contact during a real-time, naturalistic social interaction in males with and without autism. Transl Psychiatry 2015; 5:e507. [PMID: 25668435 PMCID: PMC4445747 DOI: 10.1038/tp.2014.146] [Citation(s) in RCA: 163] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 11/03/2014] [Accepted: 12/01/2014] [Indexed: 12/31/2022] Open
Abstract
Autism spectrum conditions (autism) affect ~1% of the population and are characterized by deficits in social communication. Oxytocin has been widely reported to affect social-communicative function and its neural underpinnings. Here we report the first evidence that intranasal oxytocin administration improves a core problem that individuals with autism have in using eye contact appropriately in real-world social settings. A randomized double-blind, placebo-controlled, within-subjects design is used to examine how intranasal administration of 24 IU of oxytocin affects gaze behavior for 32 adult males with autism and 34 controls in a real-time interaction with a researcher. This interactive paradigm bypasses many of the limitations encountered with conventional static or computer-based stimuli. Eye movements are recorded using eye tracking, providing an objective measurement of looking patterns. The measure is shown to be sensitive to the reduced eye contact commonly reported in autism, with the autism group spending less time looking to the eye region of the face than controls. Oxytocin administration selectively enhanced gaze to the eyes in both the autism and control groups (transformed mean eye-fixation difference per second=0.082; 95% CI:0.025-0.14, P=0.006). Within the autism group, oxytocin has the most effect on fixation duration in individuals with impaired levels of eye contact at baseline (Cohen's d=0.86). These findings demonstrate that the potential benefits of oxytocin in autism extend to a real-time interaction, providing evidence of a therapeutic effect in a key aspect of social communication.
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Affiliation(s)
- B Auyeung
- Department of Psychology, The School of Philosophy, Psychology and Language Sciences, University of Edinburgh, Edinburgh, UK,Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK,Department of Psychology, The School of Philosophy, Psychology and Language Sciences, University of Edinburgh, 7 George Square, Edinburgh EH8 9JZ, UK. E-mail:
| | - M V Lombardo
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK,Department of Psychology, University of Cyprus, Nicosia, Cyprus,Center for Applied Neuroscience, University of Cyprus, Nicosia, Cyprus
| | - M Heinrichs
- Department of Psychology, Laboratory for Biological and Personality Psychology, University of Freiburg, Freiburg, Germany,Freiburg Brain Imaging Center, University Medical Center, University of Freiburg, Freiburg, Germany
| | - B Chakrabarti
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK,School of Psychology and Clinical Language Sciences, University of Reading, Whiteknights, Reading, UK
| | - A Sule
- South Essex Partnership University NHS Foundation Trust, Bedford, UK
| | - J B Deakin
- Department of Psychiatry, University of Cambridge, Cambridge, UK,Cambridgeshire and Peterborough NHS Foundation Trust (CPFT), Cambridge, UK
| | - R A I Bethlehem
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - L Dickens
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - N Mooney
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - J A N Sipple
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - P Thiemann
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - S Baron-Cohen
- Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK,Cambridgeshire and Peterborough NHS Foundation Trust (CPFT), Cambridge, UK
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28
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Yadavilli R, Chakrabarti B, McDougall S, Horne L, Emegbo S, Craig S, Duffy N, Parker R, O'Reilly J. S25 Sleepy Snorers With "flow Limitation Syndrome": A Missed Opportunity For Cpap? Thorax 2014. [DOI: 10.1136/thoraxjnl-2014-206260.31] [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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29
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Grundy S, Kwok A, Guerin M, Beattie V, Chakrabarti B. 63 The impact of a new rapid access pleural out-patients service. Lung Cancer 2014. [DOI: 10.1016/s0169-5002(14)70063-7] [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: 11/29/2022]
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30
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Parker R, Sunderland G, Ford V, Ward K, Ashcroft H, Molyneux V, Cheney J, Chakrabarti B, O'Reilly J, Duffy N, Angus R. S85 Initiation of long-term non-invasive ventilation enables successful weaning from prolonged mechanical ventilation. Thorax 2013. [DOI: 10.1136/thoraxjnl-2013-204457.92] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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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31
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Zaidi S, MacFarlane K, Dodd K, Ford V, Ward K, Ashcroft H, Cheney J, Molyneux V, Chakrabarti B, O'Reilly J, Duffy N, Angus R, Parker R. P172 Acute NIV and mortality - failure of delivery or patient selection? Thorax 2013. [DOI: 10.1136/thoraxjnl-2013-204457.323] [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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32
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Sucksmith E, Allison C, Baron-Cohen S, Chakrabarti B, Hoekstra RA. Empathy and emotion recognition in people with autism, first-degree relatives, and controls. Neuropsychologia 2013; 51:98-105. [PMID: 23174401 PMCID: PMC6345368 DOI: 10.1016/j.neuropsychologia.2012.11.013] [Citation(s) in RCA: 139] [Impact Index Per Article: 12.6] [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: 08/20/2012] [Revised: 10/19/2012] [Accepted: 11/11/2012] [Indexed: 11/21/2022]
Abstract
Empathy is the lens through which we view others' emotion expressions, and respond to them. In this study, empathy and facial emotion recognition were investigated in adults with autism spectrum conditions (ASC; N=314), parents of a child with ASC (N=297) and IQ-matched controls (N=184). Participants completed a self-report measure of empathy (the Empathy Quotient [EQ]) and a modified version of the Karolinska Directed Emotional Faces Task (KDEF) using an online test interface. Results showed that mean scores on the EQ were significantly lower in fathers (p<0.05) but not mothers (p>0.05) of children with ASC compared to controls, whilst both males and females with ASC obtained significantly lower EQ scores (p<0.001) than controls. On the KDEF, statistical analyses revealed poorer overall performance by adults with ASC (p<0.001) compared to the control group. When the 6 distinct basic emotions were analysed separately, the ASC group showed impaired performance across five out of six expressions (happy, sad, angry, afraid and disgusted). Parents of a child with ASC were not significantly worse than controls at recognising any of the basic emotions, after controlling for age and non-verbal IQ (all p>0.05). Finally, results indicated significant differences between males and females with ASC for emotion recognition performance (p<0.05) but not for self-reported empathy (p>0.05). These findings suggest that self-reported empathy deficits in fathers of autistic probands are part of the 'broader autism phenotype'. This study also reports new findings of sex differences amongst people with ASC in emotion recognition, as well as replicating previous work demonstrating empathy difficulties in adults with ASC. The use of empathy measures as quantitative endophenotypes for ASC is discussed.
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Affiliation(s)
- E Sucksmith
- Department of Life, Health and Chemical Sciences, The Open University, Milton Keynes MK7 6AA, UK.
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Singh B, Wootton DG, Brown J, Chakrabarti B, Cooke RPD, Gordon SB. Using the BTS CAP audit to evaluate local data. Thorax 2012; 67:832; author reply 832-3. [DOI: 10.1136/thoraxjnl-2011-200876] [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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Li Y, O’Dell S, Wilson R, Wu X, Schmidt SD, Hogerkorp C, Louder MK, Longo N, Poulsen C, Guenaga J, Chakrabarti B, Doria-Rose N, Roederer M, Connors M, Mascola JR, Wyatt RT. HIV-1 neutralizing antibodies display dual specificity for the primary and coreceptor binding sites and preferential recognition of fully-cleaved Env. Retrovirology 2012. [PMCID: PMC3442062 DOI: 10.1186/1742-4690-9-s2-p99] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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35
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Chakrabarti B, Piette BMAG, Zakrzewski WJ. Biopolymer hairpin loops sustained by polarons. Phys Rev E Stat Nonlin Soft Matter Phys 2012; 86:021910. [PMID: 23005788 DOI: 10.1103/physreve.86.021910] [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: 04/23/2012] [Revised: 07/11/2012] [Indexed: 06/01/2023]
Abstract
We show that polarons can sustain looplike configurations in flexible biopolymers and that the size of the loops depend on both the flexural rigidity of the polymer and the electron-phonon coupling constant. In particular we show that for single stranded DNA (ssDNA) and polyacetylene such loops can have as few as seven monomers. We also show that these configurations are very stable under thermal fluctuations and so could facilitate the formation of hairpin loops of ssDNA.
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Affiliation(s)
- B Chakrabarti
- Department of Mathematical Sciences, University of Durham, Durham DH1 3LE, United Kingdom
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Oliver SE, Hughes E, Lal P, Lees DC, Cooke RP, Chakrabarti B. P224 The impact of implementing a collaborative antimicrobial ward round model within the Respiratory Directorate of a large university teaching hospital. Thorax 2011. [DOI: 10.1136/thoraxjnl-2011-201054c.224] [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: 11/03/2022]
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Valentini E, Hu L, Chakrabarti B, Hu Y, Aglioti SM, Iannetti GD. The primary somatosensory cortex largely contributes to the early part of the cortical response elicited by nociceptive stimuli. Neuroimage 2011; 59:1571-81. [PMID: 21906686 DOI: 10.1016/j.neuroimage.2011.08.069] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 08/18/2011] [Accepted: 08/21/2011] [Indexed: 10/17/2022] Open
Abstract
Research on the cortical sources of nociceptive laser-evoked brain potentials (LEPs) began almost two decades ago (Tarkka and Treede, 1993). Whereas there is a large consensus on the sources of the late part of the LEP waveform (N2 and P2 waves), the relative contribution of the primary somatosensory cortex (S1) to the early part of the LEP waveform (N1 wave) is still debated. To address this issue we recorded LEPs elicited by the stimulation of four limbs in a large population (n=35). Early LEP generators were estimated both at single-subject and group level, using three different approaches: distributed source analysis, dipolar source modeling, and probabilistic independent component analysis (ICA). We show that the scalp distribution of the earliest LEP response to hand stimulation was maximal over the central-parietal electrodes contralateral to the stimulated side, while that of the earliest LEP response to foot stimulation was maximal over the central-parietal midline electrodes. Crucially, all three approaches indicated hand and foot S1 areas as generators of the earliest LEP response. Altogether, these findings indicate that the earliest part of the scalp response elicited by a selective nociceptive stimulus is largely explained by activity in the contralateral S1, with negligible contribution from the secondary somatosensory cortex (S2).
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Affiliation(s)
- E Valentini
- Department of Neuroscience, Physiology and Pharmacology, University College London, UK
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Chakrabarti B, Angus RM, Calverley PMA. Authors' response. Thorax 2011. [DOI: 10.1136/thx.2010.149757] [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: 11/03/2022]
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Chakrabarti B, Ando H, Thornton E, Ford V, Young CA, Angus RM. P156 Does analysis of patient-ventilator interaction offer benefits in addition to overnight pulse oximetry in patients with motor neurone disease being followed on non-invasive ventilation? Thorax 2010. [DOI: 10.1136/thx.2010.151043.7] [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: 11/03/2022]
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Chakrabarti B, Spencer LG, Kwok A, Albert P, Warburton CJ, Earis JE. P88 The Aintree Hospital Pleural Disease Training Programme: achieving competency in intercostal drain insertion and in management of pleural problems on the 'acute take'. Thorax 2010. [DOI: 10.1136/thx.2010.150979.39] [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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Tack G, Osman-Hicks V, Hicks A, Perry Y, Angus RM, Calverley PMA, Chakrabarti B. S166 The role of clinical, metabolic and cardiac biomarkers in predicting outcome from COPD exacerbations requiring hospital admission: A prospective observational study. Thorax 2010. [DOI: 10.1136/thx.2010.150953.17] [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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Mukherjee R, Moore VC, Purkait S, Goon P, Warburton CJ, Chakrabarti B, Calverley PMA. P121 Feasibility of performing valid spirometry in rural India: preliminary results from a population study assessing the prevalence of COPD. Thorax 2010. [DOI: 10.1136/thx.2010.150987.22] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [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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Chakrabarti B, Dudbridge F, Kent L, Wheelwright S, Hill-Cawthorne G, Allison C, Banerjee-Basu S, Baron-Cohen S. Genes related to sex steroids, neural growth, and social-emotional behavior are associated with autistic traits, empathy, and Asperger syndrome. Autism Res 2009; 2:157-77. [PMID: 19598235 DOI: 10.1002/aur.80] [Citation(s) in RCA: 214] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Genetic studies of autism spectrum conditions (ASC) have mostly focused on the "low functioning" severe clinical subgroup, treating it as a rare disorder. However, ASC is now thought to be relatively common ( approximately 1%), and representing one end of a quasi-normal distribution of autistic traits in the general population. Here we report a study of common genetic variation in candidate genes associated with autistic traits and Asperger syndrome (AS). We tested single nucleotide polymorphisms in 68 candidate genes in three functional groups (sex steroid synthesis/transport, neural connectivity, and social-emotional responsivity) in two experiments. These were (a) an association study of relevant behavioral traits (the Empathy Quotient (EQ), the Autism Spectrum Quotient (AQ)) in a population sample (n=349); and (b) a case-control association study on a sample of people with AS, a "high-functioning" subgroup of ASC (n=174). 27 genes showed a nominally significant association with autistic traits and/or ASC diagnosis. Of these, 19 genes showed nominally significant association with AQ/EQ. In the sex steroid group, this included ESR2 and CYP11B1. In the neural connectivity group, this included HOXA1, NTRK1, and NLGN4X. In the socio-responsivity behavior group, this included MAOB, AVPR1B, and WFS1. Fourteen genes showed nominally significant association with AS. In the sex steroid group, this included CYP17A1 and CYP19A1. In the socio-emotional behavior group, this included OXT. Six genes were nominally associated in both experiments, providing a partial replication. Eleven genes survived family wise error rate (FWER) correction using permutations across both experiments, which is greater than would be expected by chance. CYP11B1 and NTRK1 emerged as significantly associated genes in both experiments, after FWER correction (P<0.05). This is the first candidate-gene association study of AS and of autistic traits. The most promising candidate genes require independent replication and fine mapping.
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Affiliation(s)
- B Chakrabarti
- Autism Research Centre, Department of Psychiatry, Cambridge University, UK.
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Chakrabarti B, Mondal N. O160 Adolescent ovarian malignancy. Int J Gynaecol Obstet 2009. [DOI: 10.1016/s0020-7292(09)60532-4] [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: 10/20/2022]
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Sundling C, Soldemo M, Chakrabarti B, Forsell MN, Loré K, Wyatt RT, Douagi I, Hedestam GBK. P05-07. Evaluation of peripheral and bone marrow B cell responses in rhesus macaques after immunization with soluble HIV-1 gp140 trimers. Retrovirology 2009. [PMCID: PMC2767988 DOI: 10.1186/1742-4690-6-s3-p83] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Chakrabarti B, Valentini E, Aglioti S. 106 LASER EVOKED POTENTIALS AND SUBJECTIVE REPORTS DISTINGUISH PLACEBO FROM ANALGESIC TREATMENT. Eur J Pain 2009. [DOI: 10.1016/s1090-3801(09)60109-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- B. Chakrabarti
- Department of Psychology, University of Reading, UK, Reading, United Kingdom
- Autism Research Centre, University of Cambridge, Cambridge, United Kingdom
| | - E. Valentini
- Department of Psychology, University of Rome “La Sapienza”, Rome, Italy
- IRCCS, Fondazione Santa Lucia, Roma, Italy
| | - S. Aglioti
- Department of Psychology, University of Rome “La Sapienza”, Rome, Italy
- IRCCS, Fondazione Santa Lucia, Roma, Italy
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Chakrabarti B, Ghosh SK, Basu B, Gupta P, Ghorai S, Ray SG, Das C. Non-adenomatous non-epithelial carcinoma (hemangiopericytoma) of prostate treated with conservative surgery followed by adjuvant chemoradiation. Curr Oncol 2009; 16:71-3. [PMID: 19672428 PMCID: PMC2722051 DOI: 10.3747/co.v16i4.408] [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] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Hemangiopericytoma is a malignant vascular tumour of soft tissue. Microscopically, the tumour shows tightly packed cellular areas surrounding thin-walled branching blood vessels. Traditionally these tumours are treated using wide surgical excision. Only a very few cases of hemangiopericytoma of the prostate have been described worldwide. The feasibility of managing such a case with a combination of conservative surgery and adjuvant anti-malignancy treatment is unexplored. Here, we report a case of hemangiopericytoma of the prostate treated with local excision, with preservation of prostate, followed by adjuvant radiotherapy (40 Gy in 20 fractions to pelvis followed by 24 Gy in 12 fractions as boost to prostate) and chemotherapy (doxorubicin and iphosphamide). Post-treatment computed tomography scan after 4 weeks showed regression of pelvic lymph nodes and a normal-appearing prostate. Levels of serum prostate-specific and carcinogenic embryonic antigen were normal throughout the period of treatment. To date, followup has been uneventful, except for occasional bouts of diarrhea.We conclude that conservative surgery followed by adjuvant radiation and chemotherapy, with subsequent close follow-up, may adequately control localized disease in selected cases of hemangiopericytoma of the prostate. The role of conservative surgery in tumours located at other sites has yet to be defined.
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Affiliation(s)
- B Chakrabarti
- Department of Radiotherapy, Calcutta Medical College, Kolkata, India.
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Chakrabarti B, Phillips C. Noninvasive positive-pressure ventilation: consensus, controversies and new horizons. Breathe (Sheff) 2009. [DOI: 10.1183/18106838.0504.371] [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: 11/05/2022] Open
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Chakrabarti B, Angus RM, Agarwal S, Lane S, Calverley PMA. Hyperglycaemia as a predictor of outcome during non-invasive ventilation in decompensated COPD. Thorax 2009; 64:857-62. [PMID: 19454410 DOI: 10.1136/thx.2008.106989] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
RATIONALE Hyperglycaemia predicts a poor outcome in Intensive Care Unit (ICU) patients. Whether this is true for respiratory failure necessitating non-invasive ventilation (NIV) is not known. OBJECTIVES To determine whether hyperglycaemia within 24 h of admission independently predicts outcome of NIV during acute decompensated ventilatory failure complicating chronic obstructive pulmonary disease (COPD) exacerbations. METHODS Patients with COPD presenting with acute hypercapnic respiratory failure at University Hospital Aintree between June 2006 and September 2007 and receiving NIV within 24 h of admission were studied prospectively. Random blood glucose levels were measured before NIV administration. RESULTS 88 patients (mean baseline pH 7.25, PaCO(2) 10.20 kPa, and PaO(2) 8.19 kPa) met the inclusion criteria, with NIV normalising arterial pH off therapy in 79 (90%). After multivariate logistic regression, the following predicted outcome: baseline respiratory rate (OR 0.91; 95% CI 0.84 to 0.99), random glucose > or = 7 mmol/l (OR 0.07; 95% CI 0.007 to 0.63) and admission APACHE II (Acute Physiology and Chronic Health Evaluation II) score (OR 0.75; 95% CI 0.62 to 0.90). The combination of baseline respiratory rate (RR) <30 breaths/min and random glucose <7 mmol/l increased prediction of NIV success to 97%, whilst use of all three factors was 100% predictive. CONCLUSIONS In acute decompensated ventilatory failure complicating COPD, hyperglycaemia upon presentation was associated with a poor outcome. Baseline RR and hyperglycaemia are as good at predicting clinical outcomes as the APACHE II score. Combining these variables increases predictive accuracy, providing a simple method of early risk stratification.
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Affiliation(s)
- B Chakrabarti
- Clinical Sciences Centre, University Hospital Aintree, University of Liverpool, Liverpool L9 7AL, UK.
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