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Wilson CM, Ganesh R, Crandles DA. Localisation of vibrational modes in high-entropy oxides. J Phys Condens Matter 2024; 36:295701. [PMID: 38437726 DOI: 10.1088/1361-648x/ad2ff1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 03/04/2024] [Indexed: 03/06/2024]
Abstract
The recently-discovered high-entropy oxides (HEO's) offer a paradoxical combination of crystalline arrangement and high disorder. They differ qualitatively from established paradigms for disordered solids such as glasses and alloys. In these latter systems, it is well known that disorder induces localised vibrational excitations. In this article, we explore the possibility of disorder-induced localisation in Mg0.2Co0.2Ni0.2Cu0.2Zn0.2O, the prototypical HEO with rock-salt structure. To describe phononic excitations, we model the interatomic potentials for the cation-oxygen interactions by fitting to the physical properties of the parent binary oxides. We validate our model against the experimentally determined crystal structure and optical conductivity. The resulting phonon spectrum shows wave-like propagating modes at low energies and localised modes at high energies. Localisation is reflected in signatures such as participation ratio and correlation amplitude. Finally, we argue that mass disorder can be increased to enhance localisation. We consider a hypothetical material, high-entropy telluride-oxide, where tellurium atoms are admixed into the anion sublattice. This shows a larger localised fraction, with additional localised modes appearing in the middle of the spectrum. Our results demonstrate that HEO's are a promising platform to study Anderson localisation of phonons.
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Affiliation(s)
- C M Wilson
- Department of Physics, Brock University, St. Catharines, Ontario L2S 3A1, Canada
| | - R Ganesh
- Department of Physics, Brock University, St. Catharines, Ontario L2S 3A1, Canada
| | - D A Crandles
- Department of Physics, Brock University, St. Catharines, Ontario L2S 3A1, Canada
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2
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Hsiung CC, Wilson CM, Sambold NA, Dai R, Chen Q, Misiukiewicz S, Arab A, Teyssier N, O'Loughlin T, Cofsky JC, Shi J, Gilbert LA. Higher-order combinatorial chromatin perturbations by engineered CRISPR-Cas12a for functional genomics. bioRxiv 2024:2023.09.18.558350. [PMID: 37781594 PMCID: PMC10541102 DOI: 10.1101/2023.09.18.558350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Multiplexed genetic perturbations are critical for testing functional interactions among coding or non-coding genetic elements. Compared to double-stranded DNA cutting, repressive chromatin formation using CRISPR interference (CRISPRi) avoids genotoxicity and is more effective for perturbing non-coding regulatory elements in pooled assays. However, current CRISPRi pooled screening approaches are limited to targeting 1-3 genomic sites per cell. To develop a tool for higher-order ( > 3) combinatorial targeting of genomic sites with CRISPRi in functional genomics screens, we engineered an Acidaminococcus Cas12a variant -- referred to as mul tiplexed transcriptional interference AsCas12a (multiAsCas12a). multiAsCas12a incorporates a key mutation, R1226A, motivated by the hypothesis of nicking-induced stabilization of the ribonucleoprotein:DNA complex for improving CRISPRi activity. multiAsCas12a significantly outperforms prior state-of-the-art Cas12a variants in combinatorial CRISPRi targeting using high-order multiplexed arrays of lentivirally transduced CRISPR RNAs (crRNA), including in high-throughput pooled screens using 6-plex crRNA array libraries. Using multiAsCas12a CRISPRi, we discover new enhancer elements and dissect the combinatorial function of cis-regulatory elements. These results instantiate a group testing framework for efficiently surveying potentially numerous combinations of chromatin perturbations for biological discovery and engineering.
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3
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Sun S, Wilson CM, Alter S, Ge Y, Hazlett EA, Goodman M, Yehuda R, Galfalvy H, Haghighi F. Association of interleukin-6 with suicidal ideation in veterans: a longitudinal perspective. Front Psychiatry 2023; 14:1231031. [PMID: 37779624 PMCID: PMC10540304 DOI: 10.3389/fpsyt.2023.1231031] [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] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 09/01/2023] [Indexed: 10/03/2023] Open
Abstract
Introduction Studies showing associations between inflammation in suicide are typically cross-sectional. Present study investigated how cytokine levels track with suicidal ideation and severity longitudinally. Methods Veterans with a diagnosis of major depressive disorder (MDD) with or without suicide attempt history (MDD/SA n = 38, MDD/NS n = 41) and non-psychiatric non-attempter controls (HC n = 33) were recruited, MDD/SA and HC groups were followed longitudinally at 3 months and 6 months. Blood plasma was collected and processed using Luminex Immunology Multiplex technology. Results Significant differences in depression severity (BDI) and suicidal ideation severity (SSI) were observed across all groups at study entry, wherein MDD/SA group had the highest scores followed by MDD/NS and HC, respectively. Cytokines IL-1β, IL-4, TNF-α, IFN-γ, and IL-6 were examined at study entry and longitudinally, with IL6 levels differing significantly across the groups (p = 0.0123) at study entry. Significant differences in changes in cytokine levels between depressed attempters and the control group were detected for IL-6 (interaction F1,91.77 = 5.58, p = 0.0203) and TNF-α (F1,101.73 = 4.69, p = 0.0327). However, only depressed attempters showed a significant change, in IL-6 and TNF-α levels, decreasing over time [IL-6: b = -0.04, 95% CI = (-0.08, -0.01), p = 0.0245 and TNF-α: b = -0.02, 95% CI = (-0.04, -0.01), p = 0.0196]. Although IL-6 levels were not predictive of suicidal ideation presence [OR = 1.34, 95% CI = (0.77, 2.33), p = 0.3067], IL-6 levels were significantly associated with suicidal ideation severity (b = 0.19, p = 0.0422). Discussion IL-6 was not associated with presence of suicidal ideation. IL-6 however, was associated with severity of ideation, suggesting that IL-6 may be useful in clinical practice, as an objective marker of heightened suicide risk.
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Affiliation(s)
- Shengnan Sun
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- James J. Peters VAMC, Bronx, NY, United States
| | - Caroline M. Wilson
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- James J. Peters VAMC, Bronx, NY, United States
| | | | - Yongchao Ge
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Erin A. Hazlett
- James J. Peters VAMC, Bronx, NY, United States
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Marianne Goodman
- James J. Peters VAMC, Bronx, NY, United States
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Rachel Yehuda
- James J. Peters VAMC, Bronx, NY, United States
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Hanga Galfalvy
- James J. Peters VAMC, Bronx, NY, United States
- Department of Psychiatry and Department of Biostatistics, Columbia University, New York, NY, United States
| | - Fatemeh Haghighi
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- James J. Peters VAMC, Bronx, NY, United States
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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Hung JSC, Busnaina JH, Chang CWS, Vadiraj AM, Nsanzineza I, Solano E, Alaeian H, Rico E, Wilson CM. Quantum Simulation of the Bosonic Creutz Ladder with a Parametric Cavity. Phys Rev Lett 2021; 127:100503. [PMID: 34533347 DOI: 10.1103/physrevlett.127.100503] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 07/22/2021] [Indexed: 06/13/2023]
Abstract
There has been a growing interest in realizing quantum simulators for physical systems where perturbative methods are ineffective. The scalability and flexibility of circuit quantum electrodynamics make it a promising platform for implementing various types of simulators, including lattice models of strongly coupled field theories. Here, we use a multimode superconducting parametric cavity as a hardware-efficient analog quantum simulator, realizing a lattice in synthetic dimensions with complex hopping interactions. The coupling graph, i.e., the realized model, can be programmed in situ. The complex-valued hopping interaction further allows us to simulate, for instance, gauge potentials and topological models. As a demonstration, we simulate a plaquette of the bosonic Creutz ladder. We characterize the lattice with scattering measurements, reconstructing the experimental Hamiltonian and observing important precursors of topological features including nonreciprocal transport and Aharonov-Bohm caging. This platform can be easily extended to larger lattices and different models involving other interactions.
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Affiliation(s)
- Jimmy S C Hung
- Institute for Quantum Computing and Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - J H Busnaina
- Institute for Quantum Computing and Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - C W Sandbo Chang
- Institute for Quantum Computing and Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - A M Vadiraj
- Institute for Quantum Computing and Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - I Nsanzineza
- Institute for Quantum Computing and Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - E Solano
- Kipu Quantum, Kurwenalstrasse 1, 80804 Munich, Germany
- International Center of Quantum Artificial Intelligence for Science and Technology (QuArtist) and Department of Physics, Shanghai University, 200444 Shanghai, China
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain
- IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, 48009 Bilbao, Spain
| | - H Alaeian
- School of Electrical and Computer Engineering, Department of Physics and Astronomy, Quantum Science and Engineering Institute, Purdue University, West Lafayette, Indiana 47907, USA
| | - E Rico
- Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain
- IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, 48009 Bilbao, Spain
| | - C M Wilson
- Institute for Quantum Computing and Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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Wang Z, Wilson CM, Ge Y, Nemes J, LaValle C, Boutté A, Carr W, Kamimori G, Haghighi F. DNA Methylation Patterns of Chronic Explosive Breaching in U.S. Military Warfighters. Front Neurol 2020; 11:1010. [PMID: 33192958 PMCID: PMC7645105 DOI: 10.3389/fneur.2020.01010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 07/31/2020] [Indexed: 02/01/2023] Open
Abstract
Background: Injuries from exposure to explosions rose dramatically during the Iraq and Afghanistan wars, which motivated investigation of blast-related neurotrauma. We have undertaken human studies involving military "breachers" -exposed to controlled, low-level blast during a 3-days explosive breaching course. Methods: We screened epigenetic profiles in peripheral blood samples from 59 subjects (in two separate U.S. Military training sessions) using Infinium MethylationEPIC BeadChips. Participants had varying numbers of exposures to blast over their military careers (empirically defined as high ≥ 40, and conversely, low < 39 breaching exposures). Daily self-reported physiological symptoms were recorded. Tinnitus, memory problems, headaches, and sleep disturbances are most frequently reported. Results: We identified 14 significantly differentially methylated regions (DMRs) within genes associated with cumulative blast exposure in participants with high relative to low cumulative blast exposure. Notably, NTSR1 and SPON1 were significantly differentially methylated in high relative to low blast exposed groups, suggesting that sleep dysregulation may be altered in response to chronic cumulative blast exposure. In comparing lifetime blast exposure at baseline (prior to exposure in current training), and top associated symptoms, we identified significant DMRs associated with tinnitus, sleep difficulties, and headache. Notably, we identified KCNN3, SOD3, MUC4, GALR1, and WDR45B, which are implicated in auditory function, as differentially methylated associated with self-reported tinnitus. These findings suggest neurobiological mechanisms behind auditory injuries in our military warfighters and are particularly relevant given tinnitus is not only a primary disability among veterans, but has also been demonstrated in active duty medical records for populations exposed to blast in training. Additionally, we found that differentially methylated regions associated with the genes CCDC68 and COMT track with sleep difficulties, and those within FMOD and TNXB track with pain and headache. Conclusion: Sleep disturbances, as well as tinnitus and chronic pain, are widely reported in U.S. military service members and veterans. As we have previously demonstrated, DNA methylation encapsulates lifetime exposure to blast. The current data support previous findings and recapitulate transcriptional regulatory alterations in genes involved in sleep, auditory function, and pain. These data uncovered novel epigenetic and transcriptional regulatory mechanism underlying the etiological basis of these symptoms.
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Affiliation(s)
- Zhaoyu Wang
- James J. Peters VA Medical Center, Medical Epigenetics, Bronx, NY, United States
| | - Caroline M. Wilson
- James J. Peters VA Medical Center, Medical Epigenetics, Bronx, NY, United States
- Icahn School of Medicine at Mount Sinai, Nash Family Department of Neuroscience, New York, NY, United States
| | - Yongchao Ge
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Jeffrey Nemes
- Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Christina LaValle
- Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Angela Boutté
- Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Walter Carr
- Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, United States
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States
| | - Gary Kamimori
- Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, United States
| | - Fatemeh Haghighi
- James J. Peters VA Medical Center, Medical Epigenetics, Bronx, NY, United States
- Icahn School of Medicine at Mount Sinai, Nash Family Department of Neuroscience, New York, NY, United States
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Agustí A, Chang CWS, Quijandría F, Johansson G, Wilson CM, Sabín C. Tripartite Genuine Non-Gaussian Entanglement in Three-Mode Spontaneous Parametric Down-Conversion. Phys Rev Lett 2020; 125:020502. [PMID: 32701323 DOI: 10.1103/physrevlett.125.020502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 06/19/2020] [Indexed: 06/11/2023]
Abstract
We show that the states generated by a three-mode spontaneous parametric down-conversion (SPDC) interaction Hamiltonian possess tripartite entanglement of a different nature to other paradigmatic three-mode entangled states generated by the combination of two-mode SPDC interactions. While two-mode SPDC generates Gaussian states whose entanglement can be characterized by standard criteria based on two-mode quantum correlations, these criteria fail to capture the entanglement generated by three-mode SPDC. We use criteria built from three-mode correlation functions to show that the class of states recently generated in a superconducting-circuit implementation of three-mode SPDC ideally have tripartite entanglement, contrary to recent claims in the literature. These criteria are suitable for triple SPDC but we show that they fail to detect tripartite entanglement in other states which are known to possess it, which illustrates the existence of two fundamentally different notions of tripartite entanglement in three-mode continuous-variable systems.
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Affiliation(s)
- A Agustí
- Instituto de Física Fundamental, CSIC, Serrano, 113-bis, 28006 Madrid, Spain
| | - C W Sandbo Chang
- Institute for Quantum Computing and Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - F Quijandría
- Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - G Johansson
- Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
| | - C M Wilson
- Institute for Quantum Computing and Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - C Sabín
- Instituto de Física Fundamental, CSIC, Serrano, 113-bis, 28006 Madrid, Spain
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7
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Wang Z, Wilson CM, Mendelev N, Ge Y, Galfalvy H, Elder G, Ahlers S, Yarnell AM, LoPresti ML, Kamimori GH, Carr W, Haghighi F. Acute and Chronic Molecular Signatures and Associated Symptoms of Blast Exposure in Military Breachers. J Neurotrauma 2019; 37:1221-1232. [PMID: 31621494 PMCID: PMC7232647 DOI: 10.1089/neu.2019.6742] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Injuries from exposure to explosions rose dramatically during the Iraq and Afghanistan wars, which motivated investigations of blast-related neurotrauma and operational breaching. In this study, military “breachers” were exposed to controlled, low-level blast during a 10-day explosive breaching course. Using an omics approach, we assessed epigenetic, transcriptional, and inflammatory profile changes in blood from operational breaching trainees, with varying levels of lifetime blast exposure, along with daily self-reported symptoms (with tinnitus, headaches, and sleep disturbances as the most frequently reported). Although acute exposure to blast did not confer epigenetic changes, specifically in DNA methylation, differentially methylated regions (DMRs) with coordinated gene expression changes associated with lifetime cumulative blast exposures were identified. The accumulative effect of blast showed increased methylation of PAX8 antisense transcript with coordinated repression of gene expression, which has been associated with sleep disturbance. DNA methylation analyses conducted in conjunction with reported symptoms of tinnitus in the low versus high blast incidents groups identified DMRS in KCNE1 and CYP2E1 genes. KCNE1 and CYP2E1 showed the expected inverse correlation between DNA methylation and gene expression, which have been previously implicated in noise-related hearing loss. Although no significant transcriptional changes were observed in samples obtained at the onset of the training course relative to chronic cumulative blast, we identified a large number of transcriptional perturbations acutely pre- versus post-blast exposure. Acutely, 67 robustly differentially expressed genes (fold change ≥1.5), including UFC1 and YOD1 ubiquitin-related proteins, were identified. Inflammatory analyses of cytokines and chemokines revealed dysregulation of MCP-1, GCSF, HGF, MCSF, and RANTES acutely after blast exposure. These data show the importance of an omics approach, revealing that transcriptional and inflammatory biomarkers capture acute low-level blast overpressure exposure, whereas DNA methylation marks encapsulate chronic long-term symptoms.
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Affiliation(s)
- Zhaoyu Wang
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Caroline M Wilson
- Medical Epigenetics, James J. Peters VA Medical Center, Bronx, New York, USA.,Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Natalia Mendelev
- Medical Epigenetics, James J. Peters VA Medical Center, Bronx, New York, USA.,Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Yongchao Ge
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Hanga Galfalvy
- Medical Epigenetics, James J. Peters VA Medical Center, Bronx, New York, USA.,Department of Biostatistics in Psychiatry, Columbia University, New York, New York, USA
| | - Gregory Elder
- Neurology Service, James J. Peters VA Medical Center, Bronx, New York, USA.,Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.,Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Stephen Ahlers
- Naval Medical Research Center, Silver Spring, Maryland, USA
| | - Angela M Yarnell
- Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | | | - Gary H Kamimori
- Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Walter Carr
- Walter Reed Army Institute of Research, Silver Spring, Maryland, USA.,Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee, USA
| | - Fatemeh Haghighi
- Medical Epigenetics, James J. Peters VA Medical Center, Bronx, New York, USA.,Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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8
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Magazzù L, Forn-Díaz P, Belyansky R, Orgiazzi JL, Yurtalan MA, Otto MR, Lupascu A, Wilson CM, Grifoni M. Probing the strongly driven spin-boson model in a superconducting quantum circuit. Nat Commun 2018; 9:1403. [PMID: 29643365 PMCID: PMC5895759 DOI: 10.1038/s41467-018-03626-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [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: 12/07/2017] [Accepted: 02/28/2018] [Indexed: 11/09/2022] Open
Abstract
Quantum two-level systems interacting with the surroundings are ubiquitous in nature. The interaction suppresses quantum coherence and forces the system towards a steady state. Such dissipative processes are captured by the paradigmatic spin-boson model, describing a two-state particle, the “spin”, interacting with an environment formed by harmonic oscillators. A fundamental question to date is to what extent intense coherent driving impacts a strongly dissipative system. Here we investigate experimentally and theoretically a superconducting qubit strongly coupled to an electromagnetic environment and subjected to a coherent drive. This setup realizes the driven Ohmic spin-boson model. We show that the drive reinforces environmental suppression of quantum coherence, and that a coherent-to-incoherent transition can be achieved by tuning the drive amplitude. An out-of-equilibrium detailed balance relation is demonstrated. These results advance fundamental understanding of open quantum systems and bear potential for the design of entangled light-matter states. Two-level systems interacting with a bosonic environment appear everywhere in physics. Here, the authors use a superconducting device to study this spin-boson model in the presence of coherent driving, showing that the drive enhances dissipation into the environment and can localize or delocalize the system.
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Affiliation(s)
- L Magazzù
- Institute of Physics, University of Augsburg, Universitätsstraße 1, D-86135, Augsburg, Germany
| | - P Forn-Díaz
- Institute for Quantum Computing, University of Waterloo, Waterloo, N2L 3G1, Canada.,Department of Physics and Astronomy, University of Waterloo, Waterloo, N2L 3G1, Canada.,Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, N2L 3G1, Canada.,Barcelona Supercomputing Center (BSC), C/Jordi Girona 29, 08034, Barcelona, Spain
| | - R Belyansky
- Institute for Quantum Computing, University of Waterloo, Waterloo, N2L 3G1, Canada.,Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, N2L 3G1, Canada
| | - J-L Orgiazzi
- Institute for Quantum Computing, University of Waterloo, Waterloo, N2L 3G1, Canada.,Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, N2L 3G1, Canada.,Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, N2L 3G1, Canada
| | - M A Yurtalan
- Institute for Quantum Computing, University of Waterloo, Waterloo, N2L 3G1, Canada.,Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, N2L 3G1, Canada.,Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, N2L 3G1, Canada
| | - M R Otto
- Institute for Quantum Computing, University of Waterloo, Waterloo, N2L 3G1, Canada.,Department of Physics and Astronomy, University of Waterloo, Waterloo, N2L 3G1, Canada.,Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, N2L 3G1, Canada
| | - A Lupascu
- Institute for Quantum Computing, University of Waterloo, Waterloo, N2L 3G1, Canada. .,Department of Physics and Astronomy, University of Waterloo, Waterloo, N2L 3G1, Canada. .,Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, N2L 3G1, Canada.
| | - C M Wilson
- Institute for Quantum Computing, University of Waterloo, Waterloo, N2L 3G1, Canada. .,Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, N2L 3G1, Canada.
| | - M Grifoni
- Institute for Theoretical Physics, University of Regensburg, 93040, Regensburg, Germany.
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9
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Kennedy J, Devlin P, Wilson CM, McGlinchey PG. Sinoatrial Node Disease in Adults with Down's Syndrome. Ulster Med J 2018; 87:37-38. [PMID: 29588556 PMCID: PMC5849953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Download PDF] [Subscribe] [Scholar Register] [Accepted: 07/16/2017] [Indexed: 11/18/2022]
Affiliation(s)
- J Kennedy
- Department of Cardiology, Altnagelvin Area Hospital, Glenshane Road, Derry, Northern Ireland, UK BT47 6SB
| | - P Devlin
- Department of Cardiology, Altnagelvin Area Hospital, Glenshane Road, Derry, Northern Ireland, UK BT47 6SB
| | - CM Wilson
- Department of Cardiology, Altnagelvin Area Hospital, Glenshane Road, Derry, Northern Ireland, UK BT47 6SB
| | - PG McGlinchey
- Department of Cardiology, Altnagelvin Area Hospital, Glenshane Road, Derry, Northern Ireland, UK BT47 6SB, Correspondence to Dr Paul McGlinchey
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Abstract
We propose a quantum heat engine composed of two superconducting transmission line resonators interacting with each other via an optomechanical-like coupling. One resonator is periodically excited by a thermal pump. The incoherently driven resonator induces coherent oscillations in the other one due to the coupling. A limit cycle, indicating finite power output, emerges in the thermodynamical phase space. The system implements an all-electrical analog of a photonic piston. Instead of mechanical motion, the power output is obtained as a coherent electrical charging in our case. We explore the differences between the quantum and classical descriptions of our system by solving the quantum master equation and classical Langevin equations. Specifically, we calculate the mean number of excitations, second-order coherence, as well as the entropy, temperature, power, and mean energy to reveal the signatures of quantum behavior in the statistical and thermodynamic properties of the system. We find evidence of a quantum enhancement in the power output of the engine at low temperatures.
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Affiliation(s)
- Ali Ü C Hardal
- Department of Physics, Koç University, Sarıyer, İstanbul, 34450, Turkey.,Department of Photonics Engineering, Technical University of Denmark, Ørsteds Plads 343, DK-2800 Kgs. Lyngby, Denmark
| | - Nur Aslan
- Department of Physics, Koç University, Sarıyer, İstanbul, 34450, Turkey
| | - C M Wilson
- Institute of Quantum Computing and Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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Vesk PA, Robinson D, van der Ree R, Wilson CM, Saywell S, McCarthy MA. Demographic Effects of Habitat Restoration for the Grey-Crowned Babbler Pomatostomus temporalis, in Victoria, Australia. PLoS One 2015; 10:e0130153. [PMID: 26177497 PMCID: PMC4503698 DOI: 10.1371/journal.pone.0130153] [Citation(s) in RCA: 7] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 05/17/2015] [Indexed: 11/18/2022] Open
Abstract
Background Considerable resources are spent on habitat restoration across the globe to counter the impacts of habitat loss and degradation on wildlife populations. But, because of time and resourcing constraints on many conservation programs, the effectiveness of these habitat restoration programs in achieving their long-term goals of improving the population viability of particular wildlife species is rarely assessed and many restoration programs cannot demonstrate their effectiveness. Without such demonstration, and in particular demonstrating the causal relationships between habitat restoration actions and demographic responses of the target species, investments in restoration to achieve population outcomes are of uncertain value. Approach Here, we describe an approach that builds on population data collected for a threatened Australian bird – the Grey-crowned Babbler Pomatostomus temporalis - to evaluate how effectively targeted habitat restoration work improves its viability. We built upon an extensive historical survey by conducting surveys 13 years later at 117 sites stratified by presence/absence of restoration works and by detection or not of birds in the first survey. Our performance metric was the number of individuals in a social group, which is both a measure of local abundance and directly related to breeding success. We employed an occupancy model to estimate the response of Grey-crowned Babbler social group size to the effects of time, restoration works, local habitat as measured by the density of large trees, and distance to the nearest other known group of babblers. Results and implications Babbler group size decreased over the survey period at sites without restoration works, but restoration works were effective in stemming declines where they were done. Restoration was responsible for a difference of about one bird per group of 3-5 individuals; this is an important effect on the reproductive success of the social group. Effectiveness of restoration works targeted at the Grey-crowned Babbler was only demonstrable by sampling through time and including control sites without restoration works. This work demonstrates that while calls for better monitoring of restoration are valid, scope exists to recover a signal of effectiveness from opportunistic retrospective analyses.
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Affiliation(s)
- Peter A. Vesk
- Australian Research Council Centre of Excellence for Environmental Decisions, School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
| | | | - Rodney van der Ree
- Australian Research Centre for Urban Ecology, c/, School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Caroline M. Wilson
- Australian Research Centre for Urban Ecology, c/, School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Shirley Saywell
- Friends of the Grey-crowned Babbler, Euroa, Victoria, Australia
| | - Michael A. McCarthy
- Australian Research Council Centre of Excellence for Environmental Decisions, School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
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12
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Kennedy BC, McDowell MM, Yang PH, Wilson CM, Li S, Hankinson TC, Feldstein NA, Anderson RCE. Pial synangiosis for moyamoya syndrome in children with sickle cell anemia: a comprehensive review of reported cases. Neurosurg Focus 2014; 36:E12. [PMID: 24380478 DOI: 10.3171/2013.10.focus13405] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Pediatric patients with sickle cell anemia (SCA) carry a significant risk of developing moyamoya syndrome (MMS) and brain ischemia. The authors sought to review the safety and efficacy of pial synangiosis in the treatment of MMS in children with SCA by performing a comprehensive review of all previously reported cases in the literature. METHODS The authors retrospectively reviewed the clinical and radiographic records in 17 pediatric patients with SCA treated at the Morgan Stanley Children's Hospital of New York (MSCHONY) who developed radiological evidence of MMS and underwent pial synangiosis between 1996 and 2012. The authors then added any additional reported cases of pial synangiosis for this population in the literature for a combined analysis of clinical and radiographic outcomes. RESULTS The combined data consisted of 48 pial synangiosis procedures performed in 30 patients. Of these, 27 patients (90%) presented with seizure, stroke, or transient ischemic attack, whereas 3 (10%) were referred after transcranial Doppler screening. At the time of surgery, the median age was 12 years. Thirteen patients (43%) suffered an ischemic stroke while on chronic transfusion therapy. Long-term follow-up imaging (MR angiography or catheter angiography) at a mean of 25 months postoperatively was available in 39 (81%) treated hemispheres. In 34 (87%) of those hemispheres there were demonstrable collateral vessels on imaging. There were 4 neurological events in 1590 cumulative months of follow-up, or 1 event per 33 patient-years. In the patients in whom complete data were available (MSCHONY series, n = 17), the postoperative stroke rate was reduced more than 6-fold from the preoperative rate (p = 0.0003). CONCLUSIONS Pial synangiosis in patients with SCA, MMS, and brain ischemia appears to be a safe and effective treatment option. Transcranial Doppler and/or MRI screening in asymptomatic patients with SCA is recommended for the diagnosis of MMS.
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Affiliation(s)
- Benjamin C Kennedy
- Department of Neurological Surgery, Columbia University Medical Center, New York, New York; and
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13
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Sathyamoorthy SR, Tornberg L, Kockum AF, Baragiola BQ, Combes J, Wilson CM, Stace TM, Johansson G. Quantum nondemolition detection of a propagating microwave photon. Phys Rev Lett 2014; 112:093601. [PMID: 24655250 DOI: 10.1103/physrevlett.112.093601] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Indexed: 05/27/2023]
Abstract
The ability to nondestructively detect the presence of a single, traveling photon has been a long-standing goal in optics, with applications in quantum information and measurement. Realizing such a detector is complicated by the fact that photon-photon interactions are typically very weak. At microwave frequencies, very strong effective photon-photon interactions in a waveguide have recently been demonstrated. Here we show how this type of interaction can be used to realize a quantum nondemolition measurement of a single propagating microwave photon. The scheme we propose uses a chain of solid-state three-level systems (transmons) cascaded through circulators which suppress photon backscattering. Our theoretical analysis shows that microwave-photon detection with fidelity around 90% can be realized with existing technologies.
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Affiliation(s)
- Sankar R Sathyamoorthy
- Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Gothenburg, Sweden
| | - L Tornberg
- Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Gothenburg, Sweden
| | - Anton F Kockum
- Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Gothenburg, Sweden
| | - Ben Q Baragiola
- Center for Quantum Information and Control, University of New Mexico, Albuquerque, New Mexico 87131-0001, USA
| | - Joshua Combes
- Center for Quantum Information and Control, University of New Mexico, Albuquerque, New Mexico 87131-0001, USA
| | - C M Wilson
- Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Gothenburg, Sweden and Institute for Quantum Computing and Electrical and Computer Engineering Department, University of Waterloo, Waterloo N2 L 3G1, Canada
| | - Thomas M Stace
- Centre for Engineered Quantum Systems, School of Physical Sciences, University of Queensland, Saint Lucia, Queensland 4072, Australia
| | - G Johansson
- Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, S-41296 Gothenburg, Sweden
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14
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Hoi IC, Kockum AF, Palomaki T, Stace TM, Fan B, Tornberg L, Sathyamoorthy SR, Johansson G, Delsing P, Wilson CM. Giant cross-Kerr effect for propagating microwaves induced by an artificial atom. Phys Rev Lett 2013; 111:053601. [PMID: 23952397 DOI: 10.1103/physrevlett.111.053601] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 03/21/2013] [Indexed: 06/02/2023]
Abstract
We investigate the effective interaction between two microwave fields, mediated by a transmon-type superconducting artificial atom which is strongly coupled to a coplanar transmission line. The interaction between the fields and atom produces an effective cross-Kerr coupling. We demonstrate average cross-Kerr phase shifts of up to 20 degrees per photon with both coherent microwave fields at the single-photon level. Our results provide an important step toward quantum applications with propagating microwave photons.
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Affiliation(s)
- Io-Chun Hoi
- Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
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15
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Ells AL, Gole GA, Lloyd Hildebrand P, Ingram A, Wilson CM, Geoff Williams R. Response to Dr Uparkar and Dr Kaul. Eye (Lond) 2013; 27:994-5. [PMID: 23680715 DOI: 10.1038/eye.2013.72] [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: 11/09/2022] Open
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16
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Mullins TLK, Rudy BJ, Wilson CM, Sucharew H, Kahn JA. Incidence of sexually transmitted infections in HIV-infected and HIV-uninfected adolescents in the USA. Int J STD AIDS 2013; 24:123-7. [PMID: 23467290 DOI: 10.1177/0956462412472425] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Little is known about the incidence of bacterial sexually transmitted infections (STIs) among HIV-infected versus HIV-uninfected adolescents. This secondary analysis of a national, multisite study included adolescents aged 12-18 years who were behaviourally HIV-infected (n = 346) or HIV-uninfected but at-risk (n = 182). Incidence rates of bacterial STIs (gonorrhoea, chlamydia [CT] and trichomonas [TV; women]) were calculated using Poisson modelling. Factors associated with incident STIs were explored using Cox proportional hazards modelling. HIV-infected versus HIV-uninfected women had higher TV incidence (1.3 versus 0.6/100 person-months; P = 0.002). HIV-uninfected versus HIV-infected women had higher CT incidence (1.6 versus 1.1/100 person-months; P = 0.04). Among women, demographic, behavioural and HIV-related factors were associated with incident STIs. Among men, there were no differences in incident STIs. In this first analysis comparing STI incidence between HIV-infected and HIV-uninfected adolescents, bacterial STI incidence among women significantly differed by HIV status, and factors associated with incident STIs varied by STI and HIV status.
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Affiliation(s)
- T L K Mullins
- Division of Adolescent Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center
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17
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Fan B, Kockum AF, Combes J, Johansson G, Hoi IC, Wilson CM, Delsing P, Milburn GJ, Stace TM. Breakdown of the cross-Kerr scheme for photon counting. Phys Rev Lett 2013; 110:053601. [PMID: 23414018 DOI: 10.1103/physrevlett.110.053601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Indexed: 06/01/2023]
Abstract
We show, in the context of single-photon detection, that an atomic three-level model for a transmon in a transmission line does not support the predictions of the nonlinear polarizability model known as the cross-Kerr effect. We show that the induced displacement of a probe in the presence or absence of a single photon in the signal field, cannot be resolved above the quantum noise in the probe. This strongly suggests that cross-Kerr media are not suitable for photon counting or related single-photon applications. Our results are presented in the context of a transmon in a one-dimensional microwave waveguide, but the conclusions also apply to optical systems.
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Affiliation(s)
- Bixuan Fan
- Center for Engineered Quantum Systems, School of Mathematics and Physics, The University of Queensland, St Lucia, Queensland 4072, Australia
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18
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Abay S, Nilsson H, Wu F, Xu HQ, Wilson CM, Delsing P. High critical-current superconductor-InAs nanowire-superconductor junctions. Nano Lett 2012; 12:5622-5625. [PMID: 23030250 DOI: 10.1021/nl302740f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report on the fabrication of InAs nanowires coupled to superconducting leads with high critical current and widely tunable conductance. We implemented a double lift-off nanofabrication method to get very short nanowire devices with Ohmic contacts. We observe very high critical currents of up to 800 nA in a wire with a diameter of 80 nm. The current-voltage characteristics of longer and suspended nanowires display either Coulomb blockade or supercurrent depending on a local gate voltage, combining different regimes of transport in a single device.
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Affiliation(s)
- Simon Abay
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96 Göteborg, Sweden
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19
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Williams JE, Wilson CM, Biassoni L, Suri R, Fewtrell MS. Dual energy x-ray absorptiometry and quantitative ultrasound are not interchangeable in diagnosing abnormal bones. Arch Dis Child 2012; 97:822-4. [PMID: 22550320 DOI: 10.1136/archdischild-2011-301326] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [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: 11/04/2022]
Abstract
OBJECTIVE To evaluate whether dual energy x-ray absorptiometry (DXA) and quantitative ultrasound (QUS) classify the same children as 'abnormal' (SD (z) score (SDS) ≤-2). METHODS Speed of sound (SOS) was measured at the radius and tibia using QUS and lumbar spine bone mineral density (BMD) using DXA in 621 subjects aged 5-20 years; healthy 412, cystic fibrosis 117 and obese 92. RESULTS BMD SDS positively (p<0.001) and tibia SOS SDS negatively correlated with size (p<0.05). Disagreement between DXA and QUS for 'abnormal' scans occurred in 6-31%. Those with abnormal BMD and normal SOS SDS had lower mean BMI SDS than those with normal BMD and abnormal SOS SDS. SOS measurements were unobtainable in some children, especially in the obese group. CONCLUSIONS DXA and QUS identify different individuals as 'abnormal'. Agreement between BMD and tibia SOS is lower in obese subjects. Without a gold-standard, it is difficult to determine which technique is more 'correct'.
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Affiliation(s)
- J E Williams
- Childhood Nutrition Research Centre, UCL Institute of Child Health, University College London, 30 Guilford St., London, UK.
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20
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Hoi IC, Palomaki T, Lindkvist J, Johansson G, Delsing P, Wilson CM. Generation of nonclassical microwave states using an artificial atom in 1D open space. Phys Rev Lett 2012; 108:263601. [PMID: 23004976 DOI: 10.1103/physrevlett.108.263601] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Indexed: 06/01/2023]
Abstract
We have embedded an artificial atom, a superconducting transmon qubit, in a 1D open space and investigated the scattering properties of an incident microwave coherent state. By studying the statistics of the reflected and transmitted fields, we demonstrate that the scattered states can be nonclassical. In particular, by measuring the second-order correlation function, g((2)), we show photon antibunching in the reflected field and superbunching in the transmitted field. We also compare the elastically and inelastically scattered fields using both phase-sensitive and phase-insensitive measurements.
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Affiliation(s)
- Io-Chun Hoi
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-41296, Göteborg, Sweden
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21
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Hoi IC, Wilson CM, Johansson G, Palomaki T, Peropadre B, Delsing P. Demonstration of a single-photon router in the microwave regime. Phys Rev Lett 2011; 107:073601. [PMID: 21902392 DOI: 10.1103/physrevlett.107.073601] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 06/04/2011] [Indexed: 05/31/2023]
Abstract
We have embedded an artificial atom, a superconducting transmon qubit, in an open transmission line and investigated the strong scattering of incident microwave photons (∼6 GHz). When an input coherent state, with an average photon number N≪1 is on resonance with the artificial atom, we observe extinction of up to 99.6% in the forward propagating field. We use two-tone spectroscopy to study scattering from excited states and we observe electromagnetically induced transparency (EIT). We then use EIT to make a single-photon router, where we can control to what output port an incoming signal is delivered. The maximum on-off ratio is around 99% with a rise and fall time on the order of nanoseconds, consistent with theoretical expectations. The router can easily be extended to have multiple output ports and it can be viewed as a rudimentary quantum node, an important step towards building quantum information networks.
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Affiliation(s)
- Io-Chun Hoi
- MC2, Chalmers University of Technology, Göteborg, Sweden
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22
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McKeag NA, McCann CJ, Daly MJ, Wilson CM. Contaminant, or no contaminant, that is the question. QJM 2011; 104:613-4. [PMID: 20847016 DOI: 10.1093/qjmed/hcq164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- N A McKeag
- The Heart Centre, Royal Victoria Hospital, Belfast, UK.
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24
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Greibe T, Stenberg MPV, Wilson CM, Bauch T, Shumeiko VS, Delsing P. Are "pinholes" the cause of excess current in superconducting tunnel junctions? A study of Andreev current in highly resistive junctions. Phys Rev Lett 2011; 106:097001. [PMID: 21405645 DOI: 10.1103/physrevlett.106.097001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Indexed: 05/30/2023]
Abstract
In highly resistive superconducting tunnel junctions, excess subgap current is usually observed and is often attributed to microscopic pinholes in the tunnel barrier. We have studied the subgap current in superconductor-insulator-superconductor (SIS) and superconductor-insulator-normal-metal (SIN) junctions. In Al/AlO(x)/Al junctions, we observed a decrease of 2 orders of magnitude in the current upon the transition from the SIS to the SIN regime, where it then matched theory. In Al/AlO(x)/Cu junctions, we also observed generic features of coherent diffusive Andreev transport in a junction with a homogenous barrier. We use the quasiclassical Keldysh-Green function theory to quantify single- and two-particle tunneling and find good agreement with experiment over 2 orders of magnitude in transparency. We argue that our observations rule out pinholes as the origin of the excess current.
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Affiliation(s)
- Tine Greibe
- Department of Microelectronics and Nanoscience, Chalmers University of Technology, Göteborg, Sweden
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25
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Wilson CM, Duty T, Sandberg M, Persson F, Shumeiko V, Delsing P. Photon generation in an electromagnetic cavity with a time-dependent boundary. Phys Rev Lett 2010; 105:233907. [PMID: 21231466 DOI: 10.1103/physrevlett.105.233907] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2010] [Revised: 11/03/2010] [Indexed: 05/30/2023]
Abstract
We report the observation of photon generation in a microwave cavity with a time-dependent boundary condition. Our system is a microfabricated quarter-wave coplanar waveguide cavity. The electrical length of the cavity is varied by using the tunable inductance of a superconducting quantum interference device. It is measured at a temperature significantly less than the resonance frequency. When the length is modulated at approximately twice the static resonance frequency, spontaneous parametric oscillations of the cavity field are observed. Time-resolved measurements of the dynamical state of the cavity show multiple stable states. The behavior is well described by theory. Our results may be considered a preliminary step towards demonstrating the dynamical Casimir effect.
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Affiliation(s)
- C M Wilson
- Microtechnology and Nanoscience, Chalmers University of Technology, S-41296 Göteborg, Sweden
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Persson F, Wilson CM, Sandberg M, Johansson G, Delsing P. Excess dissipation in a single-electron box: the Sisyphus resistance. Nano Lett 2010; 10:953-957. [PMID: 20155965 DOI: 10.1021/nl903887x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We present measurements of the ac response of a single-electron box (SEB). We apply a radio frequency signal with a frequency larger than the tunneling rate and drive the system out of equilibrium. We observe much more dissipation in the SEB then one would expect from a simple circuit model. We can explain this in terms of a mechanism that we call the Sisyphus resistance. The Sisyphus resistance has a strong gate dependence which can be used for electrometery applications.
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Affiliation(s)
- F Persson
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96 Goteborg, Sweden.
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Johansson JR, Johansson G, Wilson CM, Nori F. Dynamical Casimir effect in a superconducting coplanar waveguide. Phys Rev Lett 2009; 103:147003. [PMID: 19905595 DOI: 10.1103/physrevlett.103.147003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Indexed: 05/28/2023]
Abstract
We investigate the dynamical Casimir effect in a coplanar waveguide (CPW) terminated by a superconducting quantum interference device (SQUID). Changing the magnetic flux through the SQUID parametrically modulates the boundary condition of the CPW, and thereby, its effective length. Effective boundary velocities comparable to the speed of light in the CPW result in broadband photon generation which is identical to the one calculated in the dynamical Casimir effect for a single oscillating mirror. We estimate the power of the radiation for realistic parameters and show that it is experimentally feasible to directly detect this nonclassical broadband radiation.
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Affiliation(s)
- J R Johansson
- Advanced Science Institute, The Institute of Physical and Chemical Research (RIKEN), Wako-shi, Saitama 351-0198, Japan
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Abstract
The following case of a young mother presenting with post-partum pulmonary oedema, highlights a singular and life-threatening complication of a common condition (thyrotoxicosis). While thyrotoxic heart disease is well described, thyrotoxic storm in the post-partum period associated with dilated cardiomyopathy, congestive cardiac failure and ventricular fibrillation is exceptional.
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Affiliation(s)
- M J Daly
- Regional Centre for Endocrinology and Diabetes, Royal Victoria Hospital, Grosvenor Road, Belfast, Northern Ireland, UK
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Abstract
As survival of preterm infants improves, the long-term care of consequent ophthalmic problems is an expanding field. Preterm birth can inflict a host of challenges on the developing ocular system, resulting in the visual manifestations of varied significance and pathological scope. The ophthalmic condition most commonly associated with preterm birth is retinopathy of prematurity, which has the potential to result in devastating vision loss. However, the visual compromise from increased incidence of refractive errors, strabismus, and cerebral vision impairment has significant impact on visual function, which also has influence on other developmental aspects including psychological and educational. In this review, the normal ocular development is discussed, aiming to exemplify the impact of early exteriorisation on one of the more naive organs of prematurity. This is then related to the incidence and visual consequences of many types of deficit, including refractive error, strabismus, and loss of visual function in preterm populations, with comparisons to term infant studies. Often these conditions are linked with causal and resultant factors being impossible to segregate, but the common factor of increased rates of all types of ophthalmic deficits demonstrates that children born prematurely are indeed premature for life.
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Affiliation(s)
- A R O'Connor
- Division of Orthoptics, University of Liverpool, Liverpool, UK
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Terrar DA, Wilson CM, Graham SG, Bryant SM, Heath BM. Comparison of guinea-pig ventricular myocytes and dog Purkinje fibres for in vitro assessment of drug-induced delayed repolarization. J Pharmacol Toxicol Methods 2007; 56:171-85. [PMID: 17596973 DOI: 10.1016/j.vascn.2007.04.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Accepted: 04/16/2007] [Indexed: 11/26/2022]
Abstract
INTRODUCTION QT interval prolongation and Torsade de Pointes (TdP) arrhythmias are recognised as a potential risk with many drugs, most of which delay cardiac repolarization by inhibiting the rapidly activating K(+) current (I(Kr)). The objective of this study was to compare the effects of compounds on cardiac action potentials recorded from guinea-pig ventricular myocytes and dog Purkinje fibres. METHODS AND RESULTS Effects of dofetilide, sotalol, cisapride, terfenadine, haloperidol and sparfloxacin, compounds known to cause QT prolongation (positive controls), and nifedipine and verapamil, not associated with QT prolongation (negative controls) were studied on intracellular action potentials recorded from guinea-pig isolated ventricular myocytes (VM) and dog isolated Purkinje fibres (PF). Prolongation of action potential duration (APD) by sotalol, dofetilide and sparfloxacin was concentration-dependent and of greater magnitude in dog PF compared to guinea-pig VM. The maximum prolongation of APD in guinea-pig VM at 0.5 and 1 Hz was approximately 25% and this was associated with complete inhibition of I(Kr) by dofetilide. Effects on APD of cisapride and haloperidol in both preparations, and terfenadine in guinea-pig VM, were biphasic, consistent with inhibition of multiple ion channels. There was no effect of terfenadine on APD in dog PF. Haloperidol increased APD by more than 25% in guinea-pig VM, consistent with effects on additional repolarizing currents. The negative controls shortened APD to a greater extent in guinea-pig VM compared to dog PF. In general, the positive control drugs increased action potential triangulation (APD(40-90)) to a greater extent than APD(90). CONCLUSION Guinea-pig isolated VM may be more sensitive for detecting APD prolongation with compounds inhibiting multiple ion channels and action potential triangulation (APD(40-90)). Effects on repolarizing currents other than I(Kr) were also distinguished in guinea-pig VM.
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Affiliation(s)
- Derek A Terrar
- University Department of Pharmacology, Mansfield Road, Oxford, OX1 3QT, United Kingdom.
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Wilson CM, Duty T, Persson F, Sandberg M, Johansson G, Delsing P. Coherence times of dressed states of a superconducting qubit under extreme driving. Phys Rev Lett 2007; 98:257003. [PMID: 17678048 DOI: 10.1103/physrevlett.98.257003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Indexed: 05/16/2023]
Abstract
We measure longitudinal dressed states of a superconducting qubit, the single Cooper-pair box, and an intense microwave field. The dressed states represent the hybridization of the qubit and photon degrees of freedom and appear as avoided level crossings in the combined energy diagram. By embedding the circuit in an rf oscillator, we directly probe the dressed states. We measure their dressed gap as a function of photon number and microwave amplitude, finding good agreement with theory. In addition, we extract the relaxation and dephasing rates of these states.
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Affiliation(s)
- C M Wilson
- Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
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Abstract
A 63-year-old female developed respiratory failure and was admitted to the Intensive Care Unit for non-invasive ventilation, inotropic support and antibiotic therapy. The patient was initially stable but then suddenly deteriorated with acute pulmonary oedema requiring mechanical ventilation. An electrocardiogram showed an acute ST elevation myocardial infarction and the patient subsequently had an urgent coronary angiogram which revealed normal coronary arteries but apical ballooning characteristic of Takotsubo cardiomyopathy. A short review is provided of this relatively newly described heart syndrome which has the potential to present in numbers of intensive care patients. This case emphasises the importance of being aware of uncommon causes of acute ECG changes in the critically ill.
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Affiliation(s)
- J R Bennett
- Regional Intensive Care Unit, Royal Victoria hospital, Grosvenor Road, Belfast BT12 6BA, Northern Ireland, UK.
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Shao W, Tang J, Song W, Wang C, Li Y, Wilson CM, Kaslow RA. CCL3L1 and CCL4L1: variable gene copy number in adolescents with and without human immunodeficiency virus type 1 (HIV-1) infection. Genes Immun 2007; 8:224-31. [PMID: 17330138 DOI: 10.1038/sj.gene.6364378] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
As members of the chemokine family, macrophage inflammatory protein 1 alpha (MIP-1alpha) and MIP-1beta are unique in that they both consist of non-allelic isoforms encoded by different genes, namely chemokine (C-C motif) ligand 3 (CCL3), CCL4, CCL3-like 1 (CCL3L1) and CCL4L1. The products of these genes and of CCL5 (encoding RANTES, i.e., regulated on activation, normal T expressed and secreted) can block or interfere with human immunodeficiency virus type 1 (HIV-1) infection through competitive binding to chemokine (C-C motif) receptor 5 (CCR5). Our analyses of 411 adolescents confirmed that CCL3 and CCL4 genes occurred invariably as single copies (two per diploid genome), whereas the copy numbers of CCL3L1 and CCL4L1 varied extensively (0-11 and 1-6 copies, respectively). Neither CCL3L1 nor CCL4L1 gene copy number variation showed appreciable impact on susceptibility to or control of HIV-1 infection. Within individuals, linear correlation between CCL3L1 and CCL4L1 copy numbers was moderate regardless of ethnicity (Pearson correlation coefficients=0.63-0.65, P<0.0001), suggesting that the two loci are not always within the same segmental duplication unit. Persistently low serum MIP-1alpha and MIP-1beta (in the pg/ml range) compared with high CCL5 concentration (ng/ml range) implied that multi-copy genes CCL3L1 and CCL4L1 conferred little advantage in the intensity of expression among uninfected or infected adolescents.
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Affiliation(s)
- W Shao
- Department of Epidemiology, University of Alabama at Birmingham, Birmingham, AL, USA
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Wang C, Shrestha S, Wilson CM, Tang J, Kaslow RA. Host Factors Associated with Persistent Cervical Human Papillomavirus Infection in Adolescents. Am J Epidemiol 2006. [DOI: 10.1093/aje/163.suppl_11.s196-b] [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: 11/13/2022] Open
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Affiliation(s)
- C M Wilson
- The Biological Laboratories, Harvard University
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Song W, Wilson CM, Allen S, Wang C, Li Y, Kaslow RA, Tang J. Interleukin 18 and human immunodeficiency virus type I infection in adolescents and adults. Clin Exp Immunol 2006; 144:117-24. [PMID: 16542373 PMCID: PMC1809636 DOI: 10.1111/j.1365-2249.2006.03050.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2006] [Indexed: 12/21/2022] Open
Abstract
Interleukin (IL)-18, a proinflammatory cytokine, has been recognized recently as an important factor in both treated and untreated patients with human immunodeficiency virus type 1 (HIV-1) infection. Consistent with all earlier reports, our quantification of serum IL-18 concentrations in 88 HIV-1 seropositive, North American adolescents (14-18 years old) revealed a positive correlation with cell-free HIV-1 viral load at two separate visits (Spearman's r = 0.31 and 0.50, respectively, P < 0.01 for both), along with a negative correlation with CD4+ T cell counts (r = -0.31 and -0.35, P < 0.01 for both). In additional analyses of 66 adults (21-58 years old) from Zambia, HIV-1 seroconversion was associated uniformly with elevated IL-18 production (P < 0.0001). These epidemiological relationships were independent of other population-related characteristics, including age, gender and ethnicity. In neither study population could serum IL-18 concentrations be associated with the IL-18 gene (IL18) promoter genotypes defined by five major single nucleotide polymorphisms. Collectively, these findings suggest that circulating IL-18 rather than the IL18 genotype may provide a useful biomarker for HIV-1-related events or outcomes.
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Affiliation(s)
- W Song
- Department of Epidemiology, University of Alabama at Birmingham, Birmingham, AL 35294-0022, USA
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Wang C, Tang J, Crowley-Nowick PA, Wilson CM, Kaslow RA, Geisler WM. Interleukin (IL)-2 and IL-12 responses to Chlamydia trachomatis infection in adolescents. Clin Exp Immunol 2006; 142:548-54. [PMID: 16297168 PMCID: PMC1809528 DOI: 10.1111/j.1365-2249.2005.02946.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Chlamydia trachomatis infects epithelial cells at the mucosal surface. While in vitro and animal studies have shown changes in mucosal T(H)1-associated cytokines in the presence of C. trachomatis infection and with its progression to the upper genital tract or clearance, in vivo cytokine responses to chlamydial infection in humans are not well understood. Using a quantitative enzyme-linked immunosorbent assay (ELISA), we examined the endocervical production of two T(H)1-associated cytokines, i.e. interleukin (IL)-2 and IL-12, in relation to C. trachomatis infection in adolescents. At a randomly selected visit for 396 females, median endocervical IL-2 levels were significantly lower (190 versus 283 pg/ml, P = 0.02) and median IL-12 levels significantly higher (307 versus 132 pg/ml, P < 0.001) in subjects testing positive versus negative for C. trachomatis. These divergent T(H)1-associated cytokine responses were: (1) confirmed in paired analyses of 96 individuals before and after infection within 6-month intervals, (2) reversible in 97 patients who cleared infection during consecutive visits, (3) not attributable to sociodemographic factors or other genital infections and (4) independent of common genetic variants at the IL2 and IL12B loci associated previously with differential gene expression. From these findings we infer that increased IL-12 and decreased IL-2, observed commonly during mucosal inflammation, are important features of mucosal immune defence against C. trachomatis infection.
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Affiliation(s)
- C Wang
- Department of Epidemiology, University of Alabama at Birmingham, 35294-0007, USA
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Siddiqi I, Vijay R, Pierre F, Wilson CM, Frunzio L, Metcalfe M, Rigetti C, Schoelkopf RJ, Devoret MH, Vion D, Esteve D. Direct observation of dynamical bifurcation between two driven oscillation states of a Josephson junction. Phys Rev Lett 2005; 94:027005. [PMID: 15698220 DOI: 10.1103/physrevlett.94.027005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2003] [Indexed: 05/24/2023]
Abstract
We performed a novel phase-sensitive microwave reflection experiment which directly probes the dynamics of the Josephson plasma resonance in both the linear and the nonlinear regime. When the junction was driven below the plasma frequency into the nonlinear regime, we observed for the first time the transition between two different dynamical states predicted for nonlinear systems. In our experiment, this transition appears as an abrupt change in the reflected signal phase at a critical excitation power. This controlled dynamical switching can form the basis of a sensitive amplifier, in particular, for the readout of superconducting qubits.
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Affiliation(s)
- I Siddiqi
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520-8284, USA
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Siddiqi I, Vijay R, Pierre F, Wilson CM, Metcalfe M, Rigetti C, Frunzio L, Devoret MH. RF-driven Josephson bifurcation amplifier for quantum measurement. Phys Rev Lett 2004; 93:207002. [PMID: 15600958 DOI: 10.1103/physrevlett.93.207002] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2004] [Indexed: 05/24/2023]
Abstract
We have constructed a new type of amplifier whose primary purpose is the readout of superconducting quantum bits. It is based on the transition of a rf-driven Josephson junction between two distinct oscillation states near a dynamical bifurcation point. The main advantages of this new amplifier are speed, high sensitivity, low backaction, and the absence of on-chip dissipation. Pulsed microwave reflection measurements on nanofabricated Al junctions show that actual devices attain the performance predicted by theory.
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Affiliation(s)
- I Siddiqi
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520-8284, USA
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Abstract
Although age-adjusted cancer death rates have started to decline in the United States and other developed nations - thanks in large part to widespread screening programs that detect cancers at early, treatable stages - cancer in developing countries is on the rise. Ironically, rising life expectancy in those nations along with the adoption of 'Western' lifestyles will leave many more people vulnerable to cancer. Unfortunately, the early detection tools and treatment technology that have helped control cancer in wealthier lands are often not readily available in many other countries. Much of this increased cancer burden will take the form of cancers that affect women - not only breast, cervical, and other gynecologic cancers but colorectal cancer, lung cancer, and other malignancies related to tobacco. Physicians specializing in cancer care for women need to be alert to every opportunity to improve cancer screening and prevention among the growing, aging populations of less-developed countries. Less precise but less costly and more widely available screening techniques may save thousands more lives than the most sophisticated technology because low-cost programs can be applied widely instead of being reserved for a fortunate few. In addition, education and prevention efforts directed toward tobacco use need to be put in place to help stem an epidemic of tobacco-related cancers that has largely peaked in developed countries but looms ominously in the future of developing nations.
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Affiliation(s)
- C M Wilson
- Fox Chase Cancer Center, Philadelphia, PA 19111, USA
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Abstract
Tracheal intubating conditions were assessed in 112 children after induction of anaesthesia with propofol and remifentanil 1.0, 2.0 or 3.0 micro g.kg-1. Subjects in a control group were given propofol and mivacurium 0.2 mg.kg-1. Haemodynamic and respiratory parameters were recorded. Plasma catecholamine levels were measured in a subgroup of 40 children. Intubating conditions were acceptable in 14/28 (50%), 18/26 (69%) and 22/27 (82%) in those subjects given remifentanil 1.0, 2.0 or 3.0 micro g.kg-1, respectively, and in 27/28 (96%) of the control group. Intubating conditions in subjects given remifentanil 3.0 micro g.kg-1 were better than in those given remifentanil 1.0 micro g.kg-1 (p < 0.05). There were no significant differences in intubating conditions between those given remifentanil 3.0 micro g.kg-1 and the control group. Systolic blood pressure and heart rate increased in response to tracheal intubation in subjects given remifentanil 1.0 micro g.kg-1 and in the control group (p < 0.05). Time to resumption of spontaneous respiration was prolonged in subjects given remifentanil 3.0 micro g.kg-1 (p < 0.001). In conclusion, remifentanil 2 micro g.kg-1 provides acceptable intubating conditions and haemodynamic stability without prolonging the return of spontaneous respiration.
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Affiliation(s)
- J M Blair
- Department of Anaesthesia, St Helier Hospital, Epsom and St Helier NHS Trust, Wrythe Lane, Carshalton, Surrey UK.
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Wilson CM, Bakewell SE, Miller MR, Hart ND, McMorrow RCN, Barry PW, Collier DJ, Watt SJ, Pollard AJ. Increased resting bronchial tone in normal subjects acclimatised to altitude. Thorax 2002; 57:400-4. [PMID: 11978915 PMCID: PMC1746327 DOI: 10.1136/thorax.57.5.400] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Normal subjects frequently experience troublesome respiratory symptoms when acclimatised to altitude. Bronchial hyperresponsiveness (BHR) and full and partial flow-volume loops were measured before and after ascent to 5000 m altitude to determine if there are changes in resting bronchial tone and BHR that might explain the symptoms. METHODS BHR to histamine was measured using a turbine spirometer to record partial and full flow-volume curves and expressed as log dose slopes. Twenty one subjects were tested at sea level and after acclimatisation at 5000 m altitude. RESULTS No significant change in log dose slope measurements of forced expiratory volume in 1 second occurred after acclimatisation, and the maximal expiratory flow with 30% of forced vital capacity remaining (MEF(30%)) rose on the full loop and fell on the partial loop. Their ratio (full divided by partial) rose on average by 0.28 (95% confidence limits 0.14 to 0.42) from the mean (SD) sea level value of 0.87 (0.20). CONCLUSIONS There is no increase in BHR in normal subjects acclimatised to altitude but an increase in resting bronchial tone occurs that could be released by deep inspiration. This may be the result of increased cholinergic tone.
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Affiliation(s)
- C M Wilson
- Department of Anaesthesia, Sheffield Children's Hospital, Sheffield, UK
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Vermund SH, Sarr M, Murphy DA, Levin L, Abdalian SE, Ma Y, Crowley-Nowick PA, Wilson CM. Douching practices among HIV infected and uninfected adolescents in the United States. J Adolesc Health 2001; 29:80-6. [PMID: 11530307 DOI: 10.1016/s1054-139x(01)00284-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
PURPOSE To characterize sexual behaviors and sociodemographic factors that are associated with douching among geographically diverse adolescent women with and without HIV infection. METHODS HIV infected subjects recruited preferentially and behaviorally comparable high-risk HIV uninfected subjects were enrolled in a prospective HIV study from 15 sites in 13 U.S. cities. Baseline interview data from 1996 to 1999 for females aged 12 to 19 years were analyzed using one-way analysis of variance and multiple logistic regression. RESULTS Among the 342 females/young women, 74.9% were black (non-Hispanic), 11.1% Hispanic/Latina, and 14.0% white or other race/ethnicity; 63.5% were HIV infected. Young women who had dropped out of high school comprised 23.4% of subjects. In the 3 months before the interview, 179 (52.3%) adolescents had douched at least once. In a multivariable logistic regression model, recent douching was more common among sexually active females (OR = 2.2; 95% CI: 1.2-4.2), Blacks (OR = 2.2; 95% CI: 1.2-4.1 vs. Hispanics/Whites/others), females who dropped out of high school (OR = 2.1; 95% CI: 1.2-3.7), and HIV infected females (OR = 1.7; 95% CI: 1.04-2.7). CONCLUSIONS In this nationwide study, adolescents who are sexually active, African-American, dropped out of high school, and HIV infected were most likely to douche. Interventions to discourage douching should pay special attention to these populations.
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Affiliation(s)
- S H Vermund
- University of Alabama at Birmingham, Birmingham, Alabama 35294-2170, USA.
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Abstract
PURPOSE To describe baseline prevalence of oral mucosal diseases among HIV infected adolescents in relationship to biological and behavioral risk factors. METHODS Participants in Reaching for Excellence in Adolescent Care and Health (REACH), a multicenter longitudinal observational study of HIV/AIDS in adolescents, received physical examinations, blood tests, and oral examinations at 3-month intervals. We evaluated participants for oral conditions commonly seen in relationship to HIV, and explored the association of the most common lesion with selected biological and behavioral variables at baseline using contingency tables and Fisher's Exact test. RESULTS Among 294 HIV infected adolescents recruited between March 1996 and March 1999, the majority were female (75%), aged 17 to 18 years (69%), and African-American (73%). More than 90% had a CD4(+) T-lymphocyte count > 200 cells/mm(3) at baseline and 57% had a plasma HIV-1 RNA concentration <or=5000 copies/mL. The most common condition was oral candidiasis (6%), predominantly the pseudomembranous type. The only variable found to be associated with oral candidiasis was elevated plasma HIV-1 RNA concentration (p = .03). Aside from 2 cases of hairy leukoplakia and aphthous ulcers, no other oral mucosal lesions were identified in this subject population with apparently early HIV disease. CONCLUSION Similar types of oral lesions were observed in HIV infected adolescents as have been seen in adults, although the prevalence of these lesions was low. Elevated plasma HIV-1 RNA concentration was found to be associated with the baseline prevalence of oral candidiasis, and appeared to be a better predictor of HIV-related oral disease than CD4(+) T cell count in this cohort at early stage of HIV disease.
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Affiliation(s)
- C H Shiboski
- Department of Stomatology, University of California at San Francisco, San Francisco, California 94143-0422, USA.
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Wilson CM, Ellenberg JH, Sawyer MK, Belzer M, Crowley-Nowick PA, Puga A, Futterman DC, Peralta L. Serologic response to hepatitis B vaccine in HIV infected and high-risk HIV uninfected adolescents in the REACH cohort. Reaching for Excellence in Adolescent Care and Health. J Adolesc Health 2001; 29:123-9. [PMID: 11530313 DOI: 10.1016/s1054-139x(01)00278-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PURPOSE To evaluate hepatitis B (HBV) vaccine response rates in HIV infected and high-risk HIV uninfected youth and examine associations with responsiveness in the HIV infected group. METHODS Cohorts within the Reaching for Excellence in Adolescent Care and Health (REACH) study population were defined based on receipt of HBV vaccine both retrospectively and prospectively. Sero-responsiveness was determined by HBsAb measurements. Testing was done for HBsAg, HBsAb, and HBcAb. For HBsAb, a value of > 10 International Units per liter was considered a positive response, and the data were collected as either positive or negative from each of the reporting laboratories. Covariates of responsiveness were explored in univariate and multivariate models for each cohort. RESULTS Sixty-one subjects had received a three-dose vaccination course at the time of entry into REACH. HIV uninfected subjects had significantly higher rates of response by serology compared with HIV infected subjects (70% vs. 41.1%; chi(2) = .05; RR = .586, 95% CI: .36-.96). By the time of an annual visit 43 subjects had received three vaccinations with at least one occurring in the study period. The rates of response were similar for the HIV infected and uninfected groups (37.1% vs. 37.5%) in this cohort. Univariate and multivariate analysis in the prospective HIV infected group (N = 35) found an association between elevated CD8(+)/CD38(+)/HLA-DR(+) T cells and lack of HBV vaccine responsiveness (6.7% vs. 60%; chi(2) = .03; RR = .12, 95% CI: .02- .55). CONCLUSIONS The poor HBV vaccine response rate in the HIV uninfected high-risk adolescents was unexpected and suggests that HBV vaccination doses have not been optimized for older adolescents. This is the first report of decreased responsiveness in HIV infected subjects being associated with elevated CD8(+)/CD38(+)/HLA(-)DR(+) T cells and suggests that ongoing viral replication and concomitant immune system activation decreases the ability of the immune system in HIV infected subjects to respond to vaccination.
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Affiliation(s)
- C M Wilson
- University of Alabama at Birmingham, Geographic Medicine, Birmingham, Alabama 35294-2170, USA.
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Vermund SH, Wilson CM, Rogers AS, Partlow C, Moscicki AB. Sexually transmitted infections among HIV infected and HIV uninfected high-risk youth in the REACH study. Reaching for Excellence in Adolescent Care and Health. J Adolesc Health 2001; 29:49-56. [PMID: 11530303 DOI: 10.1016/s1054-139x(01)00296-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This review presents the findings of published research in the Reaching for Excellence in Adolescent Care and Health (REACH) Project on sexually transmitted infections (STIs) within the context of the project's scientific agenda. Methods employed in the study for specimen collection, management, and laboratory analysis are presented. This review presents published analyses of cross-sectional data; longitudinal analyses are underway. In addition, baseline prevalence data on selected STIs and sexual risk profiles of the subjects in REACH are presented. High STI rates were evident in both human immunodeficiency virus (HIV) infected and uninfected youth of both genders regardless of sexual orientation. High infection rates at baseline suggest that prevention-oriented programs for risk reduction among adolescents should focus on both HIV infected and at-risk, uninfected youth.
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Affiliation(s)
- S H Vermund
- University of Alabama at Birmingham, Birmingham, Alabama 35294-2170, USA.
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Wilson CM, Houser J, Partlow C, Rudy BJ, Futterman DC, Friedman LB. The REACH (Reaching for Excellence in Adolescent Care and Health) project: study design, methods, and population profile. J Adolesc Health 2001; 29:8-18. [PMID: 11530299 DOI: 10.1016/s1054-139x(01)00291-9] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- C M Wilson
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama 35294-2170, USA.
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Wilson CM, Grace GM, Munoz DG, He BP, Strong MJ. Cognitive impairment in sporadic ALS: a pathologic continuum underlying a multisystem disorder. Neurology 2001; 57:651-7. [PMID: 11524474 DOI: 10.1212/wnl.57.4.651] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.2] [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: 11/15/2022] Open
Abstract
BACKGROUND Traditionally considered a motor neuron-selective disorder, the clinical manifestations of ALS can include a frontotemporal dementia. Although the pathologic substrate of cognitive impairment remains to be defined, the presence of ubiquitin-immunoreactive (Ub+) intraneuronal inclusions in cortical regions has been suggested to constitute a pathologic marker of this process. METHODS The authors compared the neuropathological features of four cognitively impaired patients with ALS, four cognitively intact patients with ALS, and four neurologically normal patients. The extent and load of Ub+ neuronal inclusions, Ub+ dystrophic neurites, and superficial linear spongiosis (SLS) was determined among a number of cortical, hippocampal, and subcortical regions. RESULTS Although Ub+, alpha-synuclein-negative, and tau-negative neuronal inclusions were observed in both cognitively impaired and cognitively intact patients with ALS, their density and extent was greater among the former, with the difference greatest in the cingulate gyrus. Ub+ neurites were observed in a similar distribution. Only the presence of SLS, affecting the first and second cortical layers, reliably distinguished between the cognitively impaired and cognitively intact ALS subpopulations. In three of four cognitively impaired patients with ALS, SLS was associated with transcortical microglial activation, in the absence of detectable differences in astrocytosis, density of calbindin or parvalbumin neurons, or optical density of synaptophysin and SNAP-25. CONCLUSIONS Although intraneuronal Ub+ inclusions and dystrophic neurites are observed in both ALS subpopulations, the presence of cognitive impairment was associated with a greater distribution and load of both neuropathologic features, suggesting a disease continuum. Moreover, cognitive impairment was uniformly associated with superficial linear spongiosis, a pathologic feature common to several forms of frontotemporal dementia.
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Affiliation(s)
- C M Wilson
- Neurodegeneration Research Group, John P. Robarts Research Institute, London, Ontario, Canada
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Wilson CM, Frunzio L, Prober DE. Time-resolved measurements of thermodynamic fluctuations of the particle number in a nondegenerate Fermi gas. Phys Rev Lett 2001; 87:067004. [PMID: 11497846 DOI: 10.1103/physrevlett.87.067004] [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: 02/12/2001] [Indexed: 05/23/2023]
Abstract
We report on time-resolved measurements of thermodynamic fluctuations in the number of particles in a nondegenerate Fermi gas. The gas is comprised of thermal quasiparticles, confined in a superconducting Al box by large-gap Ta leads. The average number of quasiparticles is about 10(5). This number fluctuates due to quasiparticle generation and recombination. The number is measured from the tunneling current through a barrier that bisects the box. The recombination time is independently measured by single-photon excitation and agrees with the frequency dependence of the fluctuations.
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Affiliation(s)
- C M Wilson
- Departments of Applied Physics and Physics, Yale University, New Haven, Connecticut 06520-8284, USA
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