1
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Frantzis I, Messina M, Taylor JM, Aschheim K, Hu H, Hairston JC, Lauren CT, Gershon A, Feldstein N, Orange J, Saiman L. Varicella in the Neonatal ICU due to the Varicella Vaccine Oka Strain. J Neonatal Perinatal Med 2023; 16:179-182. [PMID: 36744349 DOI: 10.3233/npm-221031] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Varicella vaccination of non-immune post-partum women is recommended to reduce the risk of chickenpox in mothers and their infants. Though rare, transmission of the varicella vaccine strain vOka can occur from recent vaccinees to non-immune contacts who usually develop mild chickenpox. METHODS/RESULTS Here we describe an infant hospitalized in the neonatal ICU with vaccine-strain varicella due to transmission from their mother who received the varicella vaccine post-partum. We describe the infection prevention and control strategies implemented to prevent further transmission. CONCLUSION Vaccine-strain varicella transmission from mother to infant is a rare event and its occurrence in the neonatal ICU setting can be challenging. Anticipatory guidance for mothers vaccinated in the postpartum period and support of parents of an infected infant are recommended.
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Affiliation(s)
- I Frantzis
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA.,NewYork-Presbyterian Morgan Stanley Children's Hospital, New York, NY, USA
| | - M Messina
- Department of Infection Prevention and Control, New York-Presbyterian Hospital, New York, NY, USA
| | - J M Taylor
- Department of Pediatrics, Northwell Health Physician Partners, Northern Westchester Hospital, Mount Kisco, NY USA
| | - K Aschheim
- NewYork-Presbyterian Morgan Stanley Children's Hospital, New York, NY, USA
| | - H Hu
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA.,NewYork-Presbyterian Morgan Stanley Children's Hospital, New York, NY, USA
| | - J C Hairston
- Department of Obstetrics and Gynecology, Columbia University Irving Medical Center, New York, NY, USA
| | - C T Lauren
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA.,Department of Dermatology, Columbia University Irving Medical Center, New York, NY, USA
| | - A Gershon
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
| | - N Feldstein
- Department of Neurosurgery, Columbia University Irving Medical Center, New York, NY, USA
| | - J Orange
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
| | - L Saiman
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA.,Department of Infection Prevention and Control, New York-Presbyterian Hospital, New York, NY, USA
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2
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Gullans MJ, Diehl S, Rittenhouse ST, Ruzic BP, D'Incao JP, Julienne P, Gorshkov AV, Taylor JM. Efimov States of Strongly Interacting Photons. Phys Rev Lett 2017; 119:233601. [PMID: 29286689 DOI: 10.1103/physrevlett.119.233601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Indexed: 06/07/2023]
Abstract
We demonstrate the emergence of universal Efimov physics for interacting photons in cold gases of Rydberg atoms. We consider the behavior of three photons injected into the gas in their propagating frame, where a paraxial approximation allows us to consider them as massive particles. In contrast to atoms and nuclei, the photons have a large anisotropy between their longitudinal mass, arising from dispersion, and their transverse mass, arising from diffraction. Nevertheless, we show that, in suitably rescaled coordinates, the effective interactions become dominated by s-wave scattering near threshold and, as a result, give rise to an Efimov effect near unitarity. We show that the three-body loss of these Efimov trimers can be strongly suppressed and determine conditions under which these states are observable in current experiments. These effects can be naturally extended to probe few-body universality beyond three bodies, as well as the role of Efimov physics in the nonequilibrium, many-body regime.
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Affiliation(s)
- M J Gullans
- Joint Quantum Institute, NIST and University of Maryland, College Park, Maryland 20742, USA
- Joint Center for Quantum Information and Computer Science, NIST and University of Maryland, College Park, Maryland 20742, USA
| | - S Diehl
- Institut für Theoretische Physik, Universität zu Köln, D-50937 Cologne, Germany
| | - S T Rittenhouse
- Department of Physics, The United States Naval Academy, Annapolis, Maryland 21402, USA
| | - B P Ruzic
- Joint Quantum Institute, NIST and University of Maryland, College Park, Maryland 20742, USA
| | - J P D'Incao
- JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - P Julienne
- Joint Quantum Institute, NIST and University of Maryland, College Park, Maryland 20742, USA
| | - A V Gorshkov
- Joint Quantum Institute, NIST and University of Maryland, College Park, Maryland 20742, USA
- Joint Center for Quantum Information and Computer Science, NIST and University of Maryland, College Park, Maryland 20742, USA
| | - J M Taylor
- Joint Quantum Institute, NIST and University of Maryland, College Park, Maryland 20742, USA
- Joint Center for Quantum Information and Computer Science, NIST and University of Maryland, College Park, Maryland 20742, USA
- Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Meguro-ku, Tokyo, 153-8904, Japan
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3
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Liu YY, Stehlik J, Eichler C, Mi X, Hartke TR, Gullans MJ, Taylor JM, Petta JR. Threshold Dynamics of a Semiconductor Single Atom Maser. Phys Rev Lett 2017; 119:097702. [PMID: 28949587 DOI: 10.1103/physrevlett.119.097702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Indexed: 06/07/2023]
Abstract
We demonstrate a single atom maser consisting of a semiconductor double quantum dot (DQD) that is embedded in a high-quality-factor microwave cavity. A finite bias drives the DQD out of equilibrium, resulting in sequential single electron tunneling and masing. We develop a dynamic tuning protocol that allows us to controllably increase the time-averaged repumping rate of the DQD at a fixed level detuning, and quantitatively study the transition through the masing threshold. We further examine the crossover from incoherent to coherent emission by measuring the photon statistics across the masing transition. The observed threshold behavior is in agreement with an existing single atom maser theory when small corrections from lead emission are taken into account.
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Affiliation(s)
- Y-Y Liu
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - J Stehlik
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - C Eichler
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - X Mi
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - T R Hartke
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - M J Gullans
- Joint Quantum Institute and Joint Center for Quantum Information and Computer Science, NIST and University of Maryland, College Park, Maryland 20742, USA
| | - J M Taylor
- Joint Quantum Institute and Joint Center for Quantum Information and Computer Science, NIST and University of Maryland, College Park, Maryland 20742, USA
| | - J R Petta
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
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4
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Buckley C, Carvalho MT, Young LK, Rider SA, McFadden C, Berlage C, Verdon RF, Taylor JM, Girkin JM, Mullins JJ. Precise spatio-temporal control of rapid optogenetic cell ablation with mem-KillerRed in Zebrafish. Sci Rep 2017; 7:5096. [PMID: 28698677 PMCID: PMC5506062 DOI: 10.1038/s41598-017-05028-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [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: 02/16/2017] [Accepted: 05/23/2017] [Indexed: 11/09/2022] Open
Abstract
The ability to kill individual or groups of cells in vivo is important for studying cellular processes and their physiological function. Cell-specific genetically encoded photosensitizing proteins, such as KillerRed, permit spatiotemporal optogenetic ablation with low-power laser light. We report dramatically improved resolution and speed of cell targeting in the zebrafish kidney through the use of a selective plane illumination microscope (SPIM). Furthermore, through the novel incorporation of a Bessel beam into the SPIM imaging arm, we were able to improve on targeting speed and precision. The low diffraction of the Bessel beam coupled with the ability to tightly focus it through a high NA lens allowed precise, rapid targeting of subsets of cells at anatomical depth in live, developing zebrafish kidneys. We demonstrate that these specific targeting strategies significantly increase the speed of optoablation as well as fish survival.
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Affiliation(s)
- C Buckley
- BHF/University Centre for Cardiovascular Science, University of Edinburgh, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK.
| | - M T Carvalho
- Biophysical Sciences Institute, Department of Physics, Durham University, South Road, Durham, DH1 3LE, UK
| | - L K Young
- Biophysical Sciences Institute, Department of Physics, Durham University, South Road, Durham, DH1 3LE, UK
| | - S A Rider
- BHF/University Centre for Cardiovascular Science, University of Edinburgh, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - C McFadden
- BHF/University Centre for Cardiovascular Science, University of Edinburgh, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - C Berlage
- Biophysical Sciences Institute, Department of Physics, Durham University, South Road, Durham, DH1 3LE, UK
| | - R F Verdon
- Biophysical Sciences Institute, Department of Physics, Durham University, South Road, Durham, DH1 3LE, UK
| | - J M Taylor
- School of Physics and Astronomy, University of Glasgow, Kelvin Building, Glasgow, G12 8QQ, UK
| | - J M Girkin
- Biophysical Sciences Institute, Department of Physics, Durham University, South Road, Durham, DH1 3LE, UK
| | - J J Mullins
- BHF/University Centre for Cardiovascular Science, University of Edinburgh, Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
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5
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Xu H, Kemiktarak U, Fan J, Ragole S, Lawall J, Taylor JM. Observation of optomechanical buckling transitions. Nat Commun 2017; 8:14481. [PMID: 28248293 PMCID: PMC5337942 DOI: 10.1038/ncomms14481] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 01/04/2017] [Indexed: 11/10/2022] Open
Abstract
Correlated phases of matter provide long-term stability for systems as diverse as solids, magnets and potential exotic quantum materials. Mechanical systems, such as buckling transition spring switches, can have engineered, stable configurations whose dependence on a control variable is reminiscent of non-equilibrium phase transitions. In hybrid optomechanical systems, light and matter are strongly coupled, allowing engineering of rapid changes in the force landscape, storing and processing information, and ultimately probing and controlling behaviour at the quantum level. Here we report the observation of first- and second-order buckling transitions between stable mechanical states in an optomechanical system, in which full control of the nature of the transition is obtained by means of the laser power and detuning. The underlying multiwell confining potential we create is highly tunable, with a sub-nanometre distance between potential wells. Our results enable new applications in photonics and information technology, and may enable explorations of quantum phase transitions and macroscopic quantum tunnelling in mechanical systems. Optomechanical systems could form logic gates, but key requirements are two stable static states and the ability to switch between them. Here, the authors observe radiation-pressure induced buckling transitions in an optomechanical system, and control this transition by varying laser power and detuning.
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Affiliation(s)
- H Xu
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
| | - U Kemiktarak
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA.,National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - J Fan
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - S Ragole
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA.,Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, Maryland 20742, USA
| | - J Lawall
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - J M Taylor
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA.,National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.,Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, Maryland 20742, USA
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6
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Hinze LL, Hulse-Kemp AM, Wilson IW, Zhu QH, Llewellyn DJ, Taylor JM, Spriggs A, Fang DD, Ulloa M, Burke JJ, Giband M, Lacape JM, Van Deynze A, Udall JA, Scheffler JA, Hague S, Wendel JF, Pepper AE, Frelichowski J, Lawley CT, Jones DC, Percy RG, Stelly DM. Diversity analysis of cotton (Gossypium hirsutum L.) germplasm using the CottonSNP63K Array. BMC Plant Biol 2017; 17:37. [PMID: 28158969 PMCID: PMC5291959 DOI: 10.1186/s12870-017-0981-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 01/23/2017] [Indexed: 05/20/2023]
Abstract
BACKGROUND Cotton germplasm resources contain beneficial alleles that can be exploited to develop germplasm adapted to emerging environmental and climate conditions. Accessions and lines have traditionally been characterized based on phenotypes, but phenotypic profiles are limited by the cost, time, and space required to make visual observations and measurements. With advances in molecular genetic methods, genotypic profiles are increasingly able to identify differences among accessions due to the larger number of genetic markers that can be measured. A combination of both methods would greatly enhance our ability to characterize germplasm resources. Recent efforts have culminated in the identification of sufficient SNP markers to establish high-throughput genotyping systems, such as the CottonSNP63K array, which enables a researcher to efficiently analyze large numbers of SNP markers and obtain highly repeatable results. In the current investigation, we have utilized the SNP array for analyzing genetic diversity primarily among cotton cultivars, making comparisons to SSR-based phylogenetic analyses, and identifying loci associated with seed nutritional traits. RESULTS The SNP markers distinctly separated G. hirsutum from other Gossypium species and distinguished the wild from cultivated types of G. hirsutum. The markers also efficiently discerned differences among cultivars, which was the primary goal when designing the CottonSNP63K array. Population structure within the genus compared favorably with previous results obtained using SSR markers, and an association study identified loci linked to factors that affect cottonseed protein content. CONCLUSIONS Our results provide a large genome-wide variation data set for primarily cultivated cotton. Thousands of SNPs in representative cotton genotypes provide an opportunity to finely discriminate among cultivated cotton from around the world. The SNPs will be relevant as dense markers of genome variation for association mapping approaches aimed at correlating molecular polymorphisms with variation in phenotypic traits, as well as for molecular breeding approaches in cotton.
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Affiliation(s)
- Lori L. Hinze
- USDA-ARS, Crop Germplasm Research Unit, College Station, TX 77845 USA
| | - Amanda M. Hulse-Kemp
- Department of Plant Sciences and Seed Biotechnology Center, University of California-Davis, Davis, CA 95616 USA
| | - Iain W. Wilson
- CSIRO Agriculture & Food, Black Mountain Laboratories, Canberra, ACT 2601 Australia
| | - Qian-Hao Zhu
- CSIRO Agriculture & Food, Black Mountain Laboratories, Canberra, ACT 2601 Australia
| | - Danny J. Llewellyn
- CSIRO Agriculture & Food, Black Mountain Laboratories, Canberra, ACT 2601 Australia
| | - Jen M. Taylor
- CSIRO Agriculture & Food, Black Mountain Laboratories, Canberra, ACT 2601 Australia
| | - Andrew Spriggs
- CSIRO Agriculture & Food, Black Mountain Laboratories, Canberra, ACT 2601 Australia
| | - David D. Fang
- USDA-ARS, Cotton Fiber Bioscience Research Unit, New Orleans, LA 70124 USA
| | - Mauricio Ulloa
- USDA-ARS, Cropping Systems Research Laboratory, Plant Stress and Germplasm Development Research Unit, Lubbock, TX 79415 USA
| | - John J. Burke
- USDA-ARS, Cropping Systems Research Laboratory, Plant Stress and Germplasm Development Research Unit, Lubbock, TX 79415 USA
| | - Marc Giband
- CIRAD, UMR AGAP, Montpellier, F34398 France
- EMBRAPA, Algodão, Nucleo Cerrado, 75.375-000 Santo Antônio de Goias, GO Brazil
| | | | - Allen Van Deynze
- Department of Plant Sciences and Seed Biotechnology Center, University of California-Davis, Davis, CA 95616 USA
| | - Joshua A. Udall
- Plant and Wildlife Science Department, Brigham Young University, Provo, UT 84602 USA
| | - Jodi A. Scheffler
- USDA-ARS, Jamie Whitten Delta States Research Center, Stoneville, MS 38776 USA
| | - Steve Hague
- Department of Soil & Crop Sciences, Texas A&M University, College Station, TX 77843 USA
| | - Jonathan F. Wendel
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011 USA
| | - Alan E. Pepper
- Department of Biology, Texas A&M University, College Station, TX 77843 USA
- Interdisciplinary Department of Genetics, Texas A&M University, College Station, TX 77843 USA
| | | | - Cindy T. Lawley
- Illumina Inc., 499 Illinois Street, San Francisco, CA 94158 USA
| | - Don C. Jones
- Cotton Incorporated, Agricultural Research, Cary, NC 27513 USA
| | - Richard G. Percy
- USDA-ARS, Crop Germplasm Research Unit, College Station, TX 77845 USA
| | - David M. Stelly
- Department of Soil & Crop Sciences, Texas A&M University, College Station, TX 77843 USA
- Interdisciplinary Department of Genetics, Texas A&M University, College Station, TX 77843 USA
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7
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Gullans MJ, Stehlik J, Liu YY, Eichler C, Petta JR, Taylor JM. Sisyphus Thermalization of Photons in a Cavity-Coupled Double Quantum Dot. Phys Rev Lett 2016; 117:056801. [PMID: 27517784 PMCID: PMC5245799 DOI: 10.1103/physrevlett.117.056801] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Indexed: 06/06/2023]
Abstract
We investigate the nonclassical states of light that emerge in a microwave resonator coupled to a periodically driven electron in a nanowire double quantum dot (DQD). Under certain drive configurations, we find that the resonator approaches a thermal state at the temperature of the surrounding substrate with a chemical potential given by a harmonic of the drive frequency. Away from these thermal regions we find regions of gain and loss, where the system can lase, or regions where the DQD acts as a single-photon source. These effects are observable in current devices and have broad utility for quantum optics with microwave photons.
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Affiliation(s)
- M J Gullans
- Joint Quantum Institute, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
- Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, Maryland 20742, USA
| | - J Stehlik
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Y-Y Liu
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - C Eichler
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - J R Petta
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - J M Taylor
- Joint Quantum Institute, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
- Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, Maryland 20742, USA
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8
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Abstract
We show how to achieve optical, spin-selective transitions from the ground state to excited orbital states of group-V donors (P, As, Sb, Bi) in silicon. We consider two approaches based on either resonant, far-infrared (IR) transitions of the neutral donor or resonant, near-IR excitonic transitions. For far-IR light, we calculate the dipole matrix elements between the valley-orbit and spin-orbit split states for all the goup-V donors using effective mass theory. We then calculate the maximum rate and amount of electron-nuclear spin-polarization achievable through optical pumping with circularly polarized light. We find this approach is most promising for Bi donors due to their large spin-orbit and valley-orbit interactions. Using near-IR light, spin-selective excitation is possible for all the donors by driving a two-photon Λ-transition from the ground state to higher orbitals with even parity. We show that externally applied electric fields or strain allow similar, spin-selective Λ-transition to odd-parity excited states. We anticipate these results will be useful for future spectroscopic investigations of donors, quantum control and state preparation of donor spin qubits, and for developing a coherent interface between donor spin qubits and single photons.
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Affiliation(s)
- M J Gullans
- Joint Quantum Institute, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA; Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, MD 20742, USA
| | - J M Taylor
- Joint Quantum Institute, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA; Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, MD 20742, USA
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9
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Abstract
Emission linewidth is an important figure of merit for masers and lasers. We recently demonstrated a semiconductor double quantum dot (DQD) micromaser where photons are generated through single electron tunneling events. Charge noise directly couples to the DQD energy levels, resulting in a maser linewidth that is more than 100 times larger than the Schawlow-Townes prediction. Here we demonstrate a linewidth narrowing of more than a factor 10 by locking the DQD emission to a coherent tone that is injected to the input port of the cavity. We measure the injection locking range as a function of cavity input power and show that it is in agreement with the Adler equation. The position and amplitude of distortion sidebands that appear outside of the injection locking range are quantitatively examined. Our results show that this unconventional maser, which is impacted by strong charge noise and electron-phonon coupling, is well described by standard laser models.
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Affiliation(s)
- Y-Y Liu
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - J Stehlik
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - M J Gullans
- Joint Quantum Institute, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA; Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, Maryland 20742, USA
| | - J M Taylor
- Joint Quantum Institute, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA; Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, Maryland 20742, USA
| | - J R Petta
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA; Department of Physics, University of California, Santa Barbara, California 93106, USA
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10
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Thomas AE, Guyver PM, Taylor JM, Czipri M, Talbot NJ, Sharpe IT. Tibiotalocalcaneal arthrodesis with a compressive retrograde nail: A retrospective study of 59 nails. Foot Ankle Surg 2015; 21:202-5. [PMID: 26235861 DOI: 10.1016/j.fas.2015.01.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 01/01/2015] [Accepted: 01/02/2015] [Indexed: 02/04/2023]
Abstract
BACKGROUND Tibiotalocalcaneal arthrodesis is an important salvage method for patients with complex hindfoot problems. This study reports the elective results of combined subtalar and ankle arthrodesis using one design of retrograde intramedullary compression nail. METHODS Retrospective review identified 58 patients undergoing 59 tibiotalocalcaneal arthrodesis procedures. Mean follow up was 9.15 (3-36) months with average age 60.7 (22-89) years. A function and subjective patient satisfaction questionnaire was achieved in 89%. RESULTS 53 patients (93%) achieved union at a mean time of 4.17 months. Four patients (8%) subjectively thought the procedure was of no benefit while 42 (84%) had an excellent or good result. The mean visual analogue scale (VAS) score for preoperative functional pain was 7.46 compared to 1.98 post-operatively (p<0.001). CONCLUSIONS This device and technique offers an effective treatment of hindfoot pathology giving reliable compression and subsequent fusion with excellent patient satisfaction and pain relief. LEVEL OF EVIDENCE IV case series.
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Affiliation(s)
- A E Thomas
- Royal Devon and Exeter Hospital, Barrack Road, Exeter EX2 5DW, United Kingdom.
| | - P M Guyver
- Royal Devon and Exeter Hospital, Barrack Road, Exeter EX2 5DW, United Kingdom.
| | - J M Taylor
- Radiology Department, Level 6, Derriford Hospital, Plymouth PL6 8DH, United Kingdom.
| | - M Czipri
- Royal Devon and Exeter Hospital, Barrack Road, Exeter EX2 5DW, United Kingdom.
| | - N J Talbot
- Royal Devon and Exeter Hospital, Barrack Road, Exeter EX2 5DW, United Kingdom.
| | - I T Sharpe
- Royal Devon and Exeter Hospital, Barrack Road, Exeter EX2 5DW, United Kingdom.
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11
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Gullans MJ, Liu YY, Stehlik J, Petta JR, Taylor JM. Phonon-assisted gain in a semiconductor double quantum dot maser. Phys Rev Lett 2015; 114:196802. [PMID: 26024190 DOI: 10.1103/physrevlett.114.196802] [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: 12/18/2014] [Indexed: 06/04/2023]
Abstract
We develop a microscopic model for the recently demonstrated double-quantum-dot maser. In characterizing the gain of this device we find that, in addition to the direct stimulated emission of photons, there is a large contribution from the simultaneous emission of a photon and a phonon, i.e., the phonon sideband. We show that this phonon-assisted gain typically dominates the overall gain, which leads to masing. Recent experimental data are well fit with our model.
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Affiliation(s)
- M J Gullans
- Joint Quantum Institute, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
- Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, Maryland 20742, USA
| | - Y-Y Liu
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - J Stehlik
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - J R Petta
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
- Department of Physics, University of California, Santa Barbara, California 93106, USA
| | - J M Taylor
- Joint Quantum Institute, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
- Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, Maryland 20742, USA
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12
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Hulse-Kemp AM, Lemm J, Plieske J, Ashrafi H, Buyyarapu R, Fang DD, Frelichowski J, Giband M, Hague S, Hinze LL, Kochan KJ, Riggs PK, Scheffler JA, Udall JA, Ulloa M, Wang SS, Zhu QH, Bag SK, Bhardwaj A, Burke JJ, Byers RL, Claverie M, Gore MA, Harker DB, Islam MS, Jenkins JN, Jones DC, Lacape JM, Llewellyn DJ, Percy RG, Pepper AE, Poland JA, Mohan Rai K, Sawant SV, Singh SK, Spriggs A, Taylor JM, Wang F, Yourstone SM, Zheng X, Lawley CT, Ganal MW, Van Deynze A, Wilson IW, Stelly DM. Development of a 63K SNP Array for Cotton and High-Density Mapping of Intraspecific and Interspecific Populations of Gossypium spp. G3 (Bethesda) 2015; 5:1187-209. [PMID: 25908569 PMCID: PMC4478548 DOI: 10.1534/g3.115.018416] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 04/11/2015] [Indexed: 11/18/2022]
Abstract
High-throughput genotyping arrays provide a standardized resource for plant breeding communities that are useful for a breadth of applications including high-density genetic mapping, genome-wide association studies (GWAS), genomic selection (GS), complex trait dissection, and studying patterns of genomic diversity among cultivars and wild accessions. We have developed the CottonSNP63K, an Illumina Infinium array containing assays for 45,104 putative intraspecific single nucleotide polymorphism (SNP) markers for use within the cultivated cotton species Gossypium hirsutum L. and 17,954 putative interspecific SNP markers for use with crosses of other cotton species with G. hirsutum. The SNPs on the array were developed from 13 different discovery sets that represent a diverse range of G. hirsutum germplasm and five other species: G. barbadense L., G. tomentosum Nuttal × Seemann, G. mustelinum Miers × Watt, G. armourianum Kearny, and G. longicalyx J.B. Hutchinson and Lee. The array was validated with 1,156 samples to generate cluster positions to facilitate automated analysis of 38,822 polymorphic markers. Two high-density genetic maps containing a total of 22,829 SNPs were generated for two F2 mapping populations, one intraspecific and one interspecific, and 3,533 SNP markers were co-occurring in both maps. The produced intraspecific genetic map is the first saturated map that associates into 26 linkage groups corresponding to the number of cotton chromosomes for a cross between two G. hirsutum lines. The linkage maps were shown to have high levels of collinearity to the JGI G. raimondii Ulbrich reference genome sequence. The CottonSNP63K array, cluster file and associated marker sequences constitute a major new resource for the global cotton research community.
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Affiliation(s)
- Amanda M Hulse-Kemp
- Department of Soil & Crop Sciences, Texas A&M University, College Station, Texas 77843 Interdisciplinary Degree Program in Genetics, Texas A&M University, College Station, Texas 77843
| | - Jana Lemm
- TraitGenetics GmbH, 06466 Gatersleben, Germany
| | | | - Hamid Ashrafi
- Department of Plant Sciences and Seed Biotechnology Center, University of California-Davis, Davis, California 95616
| | - Ramesh Buyyarapu
- Dow AgroSciences, Trait Genetics and Technologies, Indianapolis, Indiana 46268
| | - David D Fang
- USDA-ARS-SRRC, Cotton Fiber Bioscience Research Unit, New Orleans, Louisiana 70124
| | - James Frelichowski
- USDA-ARS-SPARC, Crop Germplasm Research Unit, College Station, Texas 77845
| | - Marc Giband
- CIRAD, UMR AGAP, Montpellier, F34398, France EMBRAPA, Algodão, Nucleo Cerrado, 75.375-000 Santo Antônio de Goias, GO, Brazil
| | - Steve Hague
- Department of Soil & Crop Sciences, Texas A&M University, College Station, Texas 77843
| | - Lori L Hinze
- USDA-ARS-SPARC, Crop Germplasm Research Unit, College Station, Texas 77845
| | - Kelli J Kochan
- Department of Animal Science, Texas A&M University, College Station, Texas 77843
| | - Penny K Riggs
- Interdisciplinary Degree Program in Genetics, Texas A&M University, College Station, Texas 77843 Department of Animal Science, Texas A&M University, College Station, Texas 77843
| | - Jodi A Scheffler
- USDA-ARS, Jamie Whitten Delta States Research Center, Stoneville, Mississippi 38776
| | - Joshua A Udall
- Brigham Young University, Plant and Wildlife Science Department, Provo, Utah 84602
| | - Mauricio Ulloa
- USDA-ARS, PA, Plant Stress and Germplasm Development Research Unit, Lubbock, Texas 79415
| | - Shirley S Wang
- USDA-ARS-SPARC, Crop Germplasm Research Unit, College Station, Texas 77845
| | - Qian-Hao Zhu
- CSIRO Agriculture Flagship, Black Mountain Laboratories, ACT 2601, Australia
| | - Sumit K Bag
- CSIR-National Botanical Research Institute, Plant Molecular Biology Division, Lucknow-226001, UP, India
| | - Archana Bhardwaj
- CSIR-National Botanical Research Institute, Plant Molecular Biology Division, Lucknow-226001, UP, India
| | - John J Burke
- USDA-ARS, PA, Plant Stress and Germplasm Development Research Unit, Lubbock, Texas 79415
| | - Robert L Byers
- Brigham Young University, Plant and Wildlife Science Department, Provo, Utah 84602
| | | | - Michael A Gore
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853
| | - David B Harker
- Brigham Young University, Plant and Wildlife Science Department, Provo, Utah 84602
| | - Md S Islam
- USDA-ARS-SRRC, Cotton Fiber Bioscience Research Unit, New Orleans, Louisiana 70124
| | - Johnie N Jenkins
- USDA-ARS, Genetics and Precision Agriculture Research, Mississippi State, Mississippi 39762
| | - Don C Jones
- Cotton Incorporated, Agricultural Research, Cary, North Carolina 27513
| | | | - Danny J Llewellyn
- CSIRO Agriculture Flagship, Black Mountain Laboratories, ACT 2601, Australia
| | - Richard G Percy
- USDA-ARS-SPARC, Crop Germplasm Research Unit, College Station, Texas 77845
| | - Alan E Pepper
- Interdisciplinary Degree Program in Genetics, Texas A&M University, College Station, Texas 77843 Department of Biology, Texas A&M University, College Station, Texas 77843
| | - Jesse A Poland
- Wheat Genetics Resource Center, Department of Plant Pathology and Department of Agronomy, Kansas State University, Manhattan, Kansas 66506
| | - Krishan Mohan Rai
- CSIR-National Botanical Research Institute, Plant Molecular Biology Division, Lucknow-226001, UP, India
| | - Samir V Sawant
- CSIR-National Botanical Research Institute, Plant Molecular Biology Division, Lucknow-226001, UP, India
| | - Sunil Kumar Singh
- CSIR-National Botanical Research Institute, Plant Molecular Biology Division, Lucknow-226001, UP, India
| | - Andrew Spriggs
- CSIRO Agriculture Flagship, Black Mountain Laboratories, ACT 2601, Australia
| | - Jen M Taylor
- CSIRO Agriculture Flagship, Black Mountain Laboratories, ACT 2601, Australia
| | - Fei Wang
- Department of Soil & Crop Sciences, Texas A&M University, College Station, Texas 77843
| | - Scott M Yourstone
- Brigham Young University, Plant and Wildlife Science Department, Provo, Utah 84602
| | - Xiuting Zheng
- Department of Soil & Crop Sciences, Texas A&M University, College Station, Texas 77843
| | | | | | - Allen Van Deynze
- Department of Plant Sciences and Seed Biotechnology Center, University of California-Davis, Davis, California 95616
| | - Iain W Wilson
- CSIRO Agriculture Flagship, Black Mountain Laboratories, ACT 2601, Australia
| | - David M Stelly
- Department of Soil & Crop Sciences, Texas A&M University, College Station, Texas 77843 Interdisciplinary Degree Program in Genetics, Texas A&M University, College Station, Texas 77843
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Affiliation(s)
- H R Withers
- Department of Radiation Oncology, UCLA Medical Center
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Bishop JM, Deng CT, Faras AJ, Goodman HM, Guntaka RR, Levinson WE, Cordell-Stewart B, Taylor JM, Varmus HE. Transcription of the Rous sarcoma virus genome in vitro and in vivo. Bibl Haematol 2015:517-23. [PMID: 51635 DOI: 10.1159/000397569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
RNA-directed DNA synthesis by detergent-disrupted virions of Rous sarcoma virus (RSV) initiates by the covalent attachment of pdA to the 3'-terminal rA of a 4S RNA hydrogen-bonded to the 70S RNA template. This 4S "primer" has structural features of tRNA and can be aminoacylated with methionine. Synthesis and integration of provirus DNA can be monitored in both permissive (duck) and nonpermissive (mouse) cells acutely infected with RSV. The results of these studies, as well as data obtained with RSV-infected mammalian cells which have reverted from a transformed to a pheno-typically normal state, indicate that integration of viral genes into the host chromosome is not sufficient cause for transformation. Pertinent features of virus-specific RNA-directed DNA synthesis in vitro and in vivo are reviewed and compared.
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Abstract
High rates of cigarette smoking have been observed among HIV-positive individuals. Smoking has been linked to HIV-related medical complications and non-AIDS defining cancers and negatively impacts on immune function and virologic control. Although internalized heterosexism has been related to smoking behaviors, little is known about associations between partners' reports of smoking, internalized heterosexism, and HIV medication management in male couples with HIV. A sample of 266 male couples completed baseline assessments for a cohort study examining relationship factors and HIV treatment. A computer-based survey assessed self-reported smoking behaviors, alcohol use, internalized heterosexism, and antiretroviral therapy (ART) adherence. HIV-positive men also provided blood samples to assess viral load. Approximately 30% of the sample reported that they are currently smoking cigarettes. After adjusting for demographic characteristics, men in a primary relationship with a partner who reported currently smoking had more than five-fold greater odds of reporting smoking. Higher levels of internalized heterosexism and financial hardship were each independently associated with greater odds of reporting smoking. Among HIV-positive men on ART (n = 371), having a partner who reported smoking was associated with almost three-fold greater odds of having a detectable viral load. Our findings add new support to the evidence of romantic partners influencing each other's health behaviors, and demonstrate an association between smoking and disease management within male couples. Future research should explore the interpersonal and social contexts of smoking in order to develop interventions that meet the unique needs of male couples.
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Affiliation(s)
- K E Gamarel
- a Department of Psychiatry and Human Behavior , Alpert Medical School of Brown University , Providence , RI , USA
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Mittal S, Fan J, Faez S, Migdall A, Taylor JM, Hafezi M. Topologically robust transport of photons in a synthetic gauge field. Phys Rev Lett 2014; 113:087403. [PMID: 25192126 DOI: 10.1103/physrevlett.113.087403] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Indexed: 06/03/2023]
Abstract
Electronic transport is localized in low-dimensional disordered media. The addition of gauge fields to disordered media leads to fundamental changes in the transport properties. We implement a synthetic gauge field for photons using silicon-on-insulator technology. By determining the distribution of transport properties, we confirm that waves are localized in the bulk and localization is suppressed in edge states. Our system provides a new platform for investigating the transport properties of photons in the presence of synthetic gauge fields.
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Affiliation(s)
- S Mittal
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA and Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742, USA
| | - J Fan
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - S Faez
- Huygens-Kamerlingh Onnes Laboratorium, Universiteit Leiden, Postbus 9504, 2300 RA Leiden, The Netherlands
| | - A Migdall
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - J M Taylor
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA
| | - M Hafezi
- Joint Quantum Institute, NIST/University of Maryland, College Park, Maryland 20742, USA and Department of Electrical and Computer Engineering, University of Maryland, College Park, Maryland 20742, USA
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17
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Liu YY, Petersson KD, Stehlik J, Taylor JM, Petta JR. Photon emission from a cavity-coupled double quantum dot. Phys Rev Lett 2014; 113:036801. [PMID: 25083659 DOI: 10.1103/physrevlett.113.036801] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Indexed: 06/03/2023]
Abstract
We study a voltage biased InAs double quantum dot (DQD) that is coupled to a superconducting transmission line resonator. Inelastic tunneling in the DQD is mediated by electron phonon coupling and coupling to the cavity mode. We show that electronic transport through the DQD leads to photon emission from the cavity at a rate of 10 MHz. With a small cavity drive field, we observe a gain of up to 15 in the cavity transmission. Our results are analyzed in the context of existing theoretical models and suggest that it may be necessary to account for inelastic tunneling processes that proceed via simultaneous emission of a phonon and a photon.
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Affiliation(s)
- Y-Y Liu
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - K D Petersson
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - J Stehlik
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - J M Taylor
- Joint Quantum Institute/NIST, College Park, Maryland 20742, USA
| | - J R Petta
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
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18
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Xu H, Hafezi M, Fan J, Taylor JM, Strouse GF, Ahmed Z. Ultra-sensitive chip-based photonic temperature sensor using ring resonator structures. Opt Express 2014; 22:3098-3104. [PMID: 24663600 DOI: 10.1364/oe.22.003098] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Resistance thermometry provides a time-tested method for taking temperature measurements. However, fundamental limits to resistance-based approaches has produced considerable interest in developing photonic temperature sensors to leverage advances in frequency metrology and to achieve greater mechanical and environmental stability. Here we show that silicon-based optical ring resonator devices can resolve temperature differences of 1 mK using the traditional wavelength scanning methodology. An even lower noise floor of 80 μK for measuring temperature difference is achieved in the side-of-fringe, constant power mode measurement.
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Gamarel KE, Starks TJ, Dilworth SE, Neilands TB, Taylor JM, Johnson MO. Personal or relational? Examining sexual health in the context of HIV serodiscordant same-sex male couples. AIDS Behav 2014. [PMID: 23636681 DOI: 10.1007/s10461-013-0490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Couples' ability to adopt a "we" orientation has been associated with optimal health outcomes. This study examined how personal and relational motivations are uniquely associated with unprotected anal intercourse (UAI), protected anal intercourse (PAI), and the absence of sexual activity within HIV-serodiscordant same-sex male couples. HIV-positive men and their HIV-negative partners (N = 116 couples, 232 men) completed questionnaires and HIV-positive men had blood drawn for viral load. Results of a multinomial logistic regression illustrated that sexual satisfaction was positively associated with PAI among HIV-negative partners and negatively associated with PAI among HIV-positive partners. Endorsing a "we" orientation was positively associated with PAI among HIV-positive partners. Findings suggest that HIV-positive partners who espouse a "we" orientation may be willing to forgo their personal interests to protect their HIV-negative partners from HIV transmission. Couples-based interventions are warranted to help strengthen relationship dynamics to enhance the sexual health of serodiscordant couples.
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Affiliation(s)
- Kristi E Gamarel
- Department of Psychology, The Graduate Center of CUNY, New York, NY, USA,
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20
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Gamarel KE, Starks TJ, Dilworth SE, Neilands TB, Taylor JM, Johnson MO. Personal or relational? Examining sexual health in the context of HIV serodiscordant same-sex male couples. AIDS Behav 2014; 18:171-9. [PMID: 23636681 PMCID: PMC3982720 DOI: 10.1007/s10461-013-0490-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [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: 02/07/2023]
Abstract
Couples' ability to adopt a "we" orientation has been associated with optimal health outcomes. This study examined how personal and relational motivations are uniquely associated with unprotected anal intercourse (UAI), protected anal intercourse (PAI), and the absence of sexual activity within HIV-serodiscordant same-sex male couples. HIV-positive men and their HIV-negative partners (N = 116 couples, 232 men) completed questionnaires and HIV-positive men had blood drawn for viral load. Results of a multinomial logistic regression illustrated that sexual satisfaction was positively associated with PAI among HIV-negative partners and negatively associated with PAI among HIV-positive partners. Endorsing a "we" orientation was positively associated with PAI among HIV-positive partners. Findings suggest that HIV-positive partners who espouse a "we" orientation may be willing to forgo their personal interests to protect their HIV-negative partners from HIV transmission. Couples-based interventions are warranted to help strengthen relationship dynamics to enhance the sexual health of serodiscordant couples.
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Affiliation(s)
- Kristi E Gamarel
- Department of Psychology, The Graduate Center of CUNY, New York, NY, USA,
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21
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Taylor JM, Telford RJ, Kinsella DC, Watkinson AF, Thompson JF. Long-term clinical and functional outcome following treatment for Paget–Schroetter syndrome. Br J Surg 2013; 100:1459-64. [DOI: 10.1002/bjs.9279] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2013] [Indexed: 11/10/2022]
Abstract
Abstract
Background
Effort-related thrombosis of the axillosubclavian vein (Paget–Schroetter syndrome, PSS) is uncommon. It tends to affect young, active individuals and yet consensus on management is lacking. The aim here was to analyse late outcomes in a series of patients treated for PSS using a standard protocol.
Methods
The medical records of patients treated for PSS over 16 years were analysed. Patients were divided into four groups according to their management. Clinical and functional outcomes were analysed regarding residual venous defects after treatment, and Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire scores, respectively.
Results
Some 117 patients (52 men and 65 women, mean age 32 years) were included. Catheter-directed thrombolysis was successful in 42 of 56 treated patients. Thoracic outlet decompression surgery was performed in 95 patients. DASH scores improved significantly in patients treated surgically (P < 0.001 to P = 0·009); early surgery had a better outcome than delayed surgery (P = 0·040). Patients who were managed conservatively showed no improvement (P = 0·116). Where venoplasty was necessary, it was successful in 18 of 25 patients. A short duration of lysis (less than 24 h) increased the risk of rethrombosis (P = 0·020). The method of postoperative anticoagulation had no influence on the rate of rethrombosis.
Conclusion
Patients treated surgically for PSS had better functional outcomes than those managed conservatively. Prompt thrombolysis and surgery was superior to delayed management with respect to rethrombosis and functional outcome.
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Affiliation(s)
- J M Taylor
- Exeter Vascular Service and University of Exeter Medical School, Exeter, UK
| | - R J Telford
- Department of Anaesthetics, Royal Devon and Exeter Hospital, Exeter, UK
| | - D C Kinsella
- Department of Interventional Radiology, Royal Devon and Exeter Hospital, Exeter, UK
| | - A F Watkinson
- Department of Interventional Radiology, Royal Devon and Exeter Hospital, Exeter, UK
| | - J F Thompson
- Exeter Vascular Service and University of Exeter Medical School, Exeter, UK
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Medford J, Beil J, Taylor JM, Bartlett SD, Doherty AC, Rashba EI, DiVincenzo DP, Lu H, Gossard AC, Marcus CM. Self-consistent measurement and state tomography of an exchange-only spin qubit. Nat Nanotechnol 2013; 8:654-659. [PMID: 23995458 DOI: 10.1038/nnano.2013.168] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 07/20/2013] [Indexed: 06/02/2023]
Abstract
Quantum-dot spin qubits characteristically use oscillating magnetic or electric fields, or quasi-static Zeeman field gradients, to realize full qubit control. For the case of three confined electrons, exchange interaction between two pairs allows qubit rotation around two axes, hence full control, using only electrostatic gates. Here, we report initialization, full control, and single-shot readout of a three-electron exchange-driven spin qubit. Control via the exchange interaction is fast, yielding a demonstrated 75 qubit rotations in less than 2 ns. Measurement and state tomography are performed using a maximum-likelihood estimator method, allowing decoherence, leakage out of the qubit state space, and measurement fidelity to be quantified. The methods developed here are generally applicable to systems with state leakage, noisy measurements and non-orthogonal control axes.
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Affiliation(s)
- J Medford
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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23
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Taylor JM, Srinivasa V, Medford J. Electrically protected resonant exchange qubits in triple quantum dots. Phys Rev Lett 2013; 111:050502. [PMID: 23952376 DOI: 10.1103/physrevlett.111.050502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Indexed: 06/02/2023]
Abstract
We present a modulated microwave approach for quantum computing with qubits comprising three spins in a triple quantum dot. This approach includes single- and two-qubit gates that are protected against low-frequency electrical noise, due to an operating point with a narrowband response to high frequency electric fields. Furthermore, existing double quantum dot advances, including robust preparation and measurement via spin-to-charge conversion, are immediately applicable to the new qubit. Finally, the electric dipole terms implicit in the high frequency coupling enable strong coupling with superconducting microwave resonators, leading to more robust two-qubit gates.
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Affiliation(s)
- J M Taylor
- Joint Quantum Institute/National Institute of Standards and Technology, College Park, Maryland 20742, USA.
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Medford J, Beil J, Taylor JM, Rashba EI, Lu H, Gossard AC, Marcus CM. Quantum-dot-based resonant exchange qubit. Phys Rev Lett 2013; 111:050501. [PMID: 23952375 DOI: 10.1103/physrevlett.111.050501] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Indexed: 06/02/2023]
Abstract
We introduce a solid-state qubit in which exchange interactions among confined electrons provide both the static longitudinal field and the oscillatory transverse field, allowing rapid and full qubit control via rf gate-voltage pulses. We demonstrate two-axis control at a detuning sweet spot, where leakage due to hyperfine coupling is suppressed by the large exchange gap. A π/2-gate time of 2.5 ns and a coherence time of 19 μs, using multipulse echo, are also demonstrated. Model calculations that include effects of hyperfine noise are in excellent quantitative agreement with experiment.
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Affiliation(s)
- J Medford
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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Hawes EM, Deal AM, Funk-Adcock D, Gosselin R, Jeanneret C, Cook AM, Taylor JM, Whinna HC, Winkler AM, Moll S. Performance of coagulation tests in patients on therapeutic doses of dabigatran: a cross-sectional pharmacodynamic study based on peak and trough plasma levels. J Thromb Haemost 2013; 11:1493-502. [PMID: 23718677 DOI: 10.1111/jth.12308] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Indexed: 12/01/2022]
Abstract
BACKGROUND Knowledge of anticoagulation status during dabigatran therapy may be desirable in certain clinical situations. OBJECTIVE To determine the coagulation tests that are most useful for assessing dabigatran's anticoagulant effect. METHODS Peak and trough blood samples from 35 patients taking dabigatran 150 mg twice daily, and one sample each from 30 non-anticoagulated individuals, were collected. Mass spectrometry and various coagulation assays were performed. 'Therapeutic range' was defined as the range of plasma dabigatran concentrations determined by mass spectrometry between the 2.5th and 97.5th percentiles of all values. RESULTS The therapeutic range was 27-411 ng mL(-1) . The prothrombin time (PT) and activated partial thromboplastin time (APTT), determined with multiple reagents, and activated clotting time (ACT) were insensitive to therapeutic dabigatran: 29%, 18% and 40% of samples had a normal PT, APTT, and ACT, respectively. However, normal PT, ACT and APTT ruled out dabigatran levels above the 75th percentile. The thrombin clotting time (TCT) correlated well and linearly with dabigatran levels below the 50th percentile, but was unmeasurable above it. The dilute thrombin time, ecarin clotting time and ecarin chromogenic assay showed linear correlations with dabigatran levels over a broad range, and identified therapeutic and supratherapeutic levels. CONCLUSIONS The prothrombin time, APTT and ACT are often normal in spite of therapeutic dabigatran plasma levels. The TCT is useful for detecting minimal dabigatran levels. The dilute thrombin time and chromogenic and clotting ecarin assays accurately identify therapeutic and supratherapeutic dabigatran levels. This trial is registered at www.clinicaltrials.gov (#NCT01588327).
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Affiliation(s)
- E M Hawes
- Department of Pharmacy, School of Medicine, Department of Family Medicine, University of North Carolina, Chapel Hill, NC 27599, USA.
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Bonney KM, Gifford KM, Taylor JM, Chen CI, Engman DM. Cardiac damage induced by immunization with heat-killed Trypanosoma cruzi is not antibody mediated. Parasite Immunol 2013; 35:1-10. [PMID: 23009341 DOI: 10.1111/pim.12008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 07/31/2012] [Indexed: 11/28/2022]
Abstract
Cardiac inflammation that develops during infection with Trypanosoma cruzi may result in part from autoimmunity, which may occur after bystander activation, after parasite-induced cardiomyocyte damage, or molecular mimicry. A/J mice infected with T. cruzi or immunized with heat-killed T. cruzi (HKTC) develop strong autoimmunity accompanied by cardiac damage. To determine whether this cardiac damage occurs via an antibody-dependent mechanism, we analysed T. cruzi-infected and HKTC-immunized mice for the presence of autoantibodies, cardiac antibody deposition, and serum cardiac troponin I as a measure of cardiac damage. We also performed a serum transfer experiment in which sera from T. cruzi-infected and T. cruzi-immunized mice (and controls) were transferred into naïve recipients, which were then analysed for the presence of antibodies and serum troponin. Unlike T. cruzi-infected mice, T. cruzi-immunized mice did not show significant antibody deposition in the myocardium. These results indicate that antibody deposition does not precede cardiac damage and inflammation in mice immunized with or infected with T. cruzi. Serum adoptive transfer did not induce cardiac damage in any recipients. Based on these findings, we conclude that the cardiac damage induced by immunization with HKTC is not mediated by antibodies.
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Affiliation(s)
- K M Bonney
- Departments of Pathology and Microbiology-Immunology, Northwestern University, Feinberg Cardiovascular Research Institute, Chicago, IL, USA
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Srinivasa V, Nowack KC, Shafiei M, Vandersypen LMK, Taylor JM. Simultaneous spin-charge relaxation in double quantum dots. Phys Rev Lett 2013; 110:196803. [PMID: 23705734 DOI: 10.1103/physrevlett.110.196803] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Indexed: 06/02/2023]
Abstract
We investigate phonon-induced spin and charge relaxation mediated by spin-orbit and hyperfine interactions for a single electron confined within a double quantum dot. A simple toy model incorporating both direct decay to the ground state of the double dot and indirect decay via an intermediate excited state yields an electron spin relaxation rate that varies nonmonotonically with the detuning between the dots. We confirm this model with experiments performed on a GaAs double dot, demonstrating that the relaxation rate exhibits the expected detuning dependence and can be electrically tuned over several orders of magnitude. Our analysis suggests that spin-orbit mediated relaxation via phonons serves as the dominant mechanism through which the double-dot electron spin-flip rate varies with detuning.
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Affiliation(s)
- V Srinivasa
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA.
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28
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Abstract
One approach to quantum information processing is to use photons as quantum bits and rely on linear optical elements for most operations. However, some optical nonlinearity is necessary to enable universal quantum computing. Here, we suggest a circuit-QED approach to nonlinear optics quantum computing in the microwave regime, including a deterministic two-photon phase gate. Our specific example uses a hybrid quantum system comprising a LC resonator coupled to a superconducting flux qubit to implement a nonlinear coupling. Compared to the self-Kerr nonlinearity, we find that our approach has improved tolerance to noise in the qubit while maintaining fast operation.
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Affiliation(s)
- Prabin Adhikari
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
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Kielpinski D, Kafri D, Woolley MJ, Milburn GJ, Taylor JM. Quantum interface between an electrical circuit and a single atom. Phys Rev Lett 2012; 108:130504. [PMID: 22540687 DOI: 10.1103/physrevlett.108.130504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Indexed: 05/31/2023]
Abstract
We show how to bridge the divide between atomic systems and electronic devices by engineering a coupling between the motion of a single ion and the quantized electric field of a resonant circuit. Our method can be used to couple the internal state of an ion to the quantized circuit with the same speed as the internal-state coupling between two ions. All the well-known quantum information protocols linking ion internal and motional states can be converted to protocols between circuit photons and ion internal states. Our results enable quantum interfaces between solid state qubits, atomic qubits, and light, and lay the groundwork for a direct quantum connection between electrical and atomic metrology standards.
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Affiliation(s)
- D Kielpinski
- Centre for Quantum Dynamics, Griffith University, Nathan, Queensland 4111, Australia
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30
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Taylor JM, Sørensen AS, Marcus CM, Polzik ES. Laser cooling and optical detection of excitations in a LC electrical circuit. Phys Rev Lett 2011; 107:273601. [PMID: 22243310 DOI: 10.1103/physrevlett.107.273601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Indexed: 05/31/2023]
Abstract
We explore a method for laser cooling and optical detection of excitations in a room temperature LC electrical circuit. Our approach uses a nanomechanical oscillator as a transducer between optical and electronic excitations. An experimentally feasible system with the oscillator capacitively coupled to the LC and at the same time interacting with light via an optomechanical force is shown to provide strong electromechanical coupling. Conditions for improved sensitivity and quantum limited readout of electrical signals with such an "optical loud speaker" are outlined.
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Affiliation(s)
- J M Taylor
- Joint Quantum Institute/NIST, College Park, Maryland, USA
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31
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Abstract
We propose and demonstrate an all-optical approach to single-electron sensing using the optical transitions of a semiconductor quantum dot. The measured electric-field sensitivity of 5 (V/m)/√Hz corresponds to detecting a single electron located 5 μm from the quantum dot-nearly 10 times greater than the diffraction limited spot size of the excitation laser-in 1 s. The quantum-dot-based electrometer is more sensitive than other devices operating at a temperature of 4.2 K or higher and further offers suppressed backaction on the measured system.
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Affiliation(s)
- A N Vamivakas
- Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom
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32
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Marcos D, Wubs M, Taylor JM, Aguado R, Lukin MD, Sørensen AS. Coupling nitrogen-vacancy centers in diamond to superconducting flux qubits. Phys Rev Lett 2010; 105:210501. [PMID: 21231275 DOI: 10.1103/physrevlett.105.210501] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2010] [Indexed: 05/30/2023]
Abstract
We propose a method to achieve coherent coupling between nitrogen-vacancy (NV) centers in diamond and superconducting (SC) flux qubits. The resulting coupling can be used to create a coherent interaction between the spin states of distant NV centers mediated by the flux qubit. Furthermore, the magnetic coupling can be used to achieve a coherent transfer of quantum information between the flux qubit and an ensemble of NV centers. This enables a long-term memory for a SC quantum processor and possibly an interface between SC qubits and light.
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Affiliation(s)
- D Marcos
- Theory and Simulation of Materials Department, Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco 28049, Madrid, Spain
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33
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Reilly DJ, Taylor JM, Petta JR, Marcus CM, Hanson MP, Gossard AC. Exchange control of nuclear spin diffusion in a double quantum dot. Phys Rev Lett 2010; 104:236802. [PMID: 20867261 DOI: 10.1103/physrevlett.104.236802] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Indexed: 05/25/2023]
Abstract
The influence of gate-controlled two-electron exchange on the relaxation of nuclear polarization in small ensembles (N∼10(6)) of nuclear spins is examined in a GaAs double quantum dot system. Waiting in the (2,0) charge configuration, which has large exchange splitting, reduces the nuclear diffusion rate compared to that of the (1,1) configuration. Matching exchange to Zeeman splitting significantly increases the nuclear diffusion rate.
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Affiliation(s)
- D J Reilly
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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34
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Gullans M, Krich JJ, Taylor JM, Bluhm H, Halperin BI, Marcus CM, Stopa M, Yacoby A, Lukin MD. Dynamic nuclear polarization in double quantum dots. Phys Rev Lett 2010; 104:226807. [PMID: 20867197 DOI: 10.1103/physrevlett.104.226807] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Indexed: 05/29/2023]
Abstract
We theoretically investigate the controlled dynamic polarization of lattice nuclear spins in GaAs double quantum dots containing two electrons. Three regimes of long-term dynamics are identified, including the buildup of a large difference in the Overhauser fields across the dots, the saturation of the nuclear polarization process associated with formation of so-called "dark states", and the elimination of the difference field. We show that in the case of unequal dots, buildup of difference fields generally accompanies the nuclear polarization process, whereas for nearly identical dots, buildup of difference fields competes with polarization saturation in dark states. The elimination of the difference field does not, in general, correspond to a stable steady state of the polarization process.
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Affiliation(s)
- M Gullans
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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35
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Jiang L, Hodges JS, Maze JR, Maurer P, Taylor JM, Cory DG, Hemmer PR, Walsworth RL, Yacoby A, Zibrov AS, Lukin MD. Repetitive readout of a single electronic spin via quantum logic with nuclear spin ancillae. Science 2009; 326:267-72. [PMID: 19745117 DOI: 10.1126/science.1176496] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Robust measurement of single quantum bits plays a key role in the realization of quantum computation and communication as well as in quantum metrology and sensing. We have implemented a method for the improved readout of single electronic spin qubits in solid-state systems. The method makes use of quantum logic operations on a system consisting of a single electronic spin and several proximal nuclear spin ancillae in order to repetitively readout the state of the electronic spin. Using coherent manipulation of a single nitrogen vacancy center in room-temperature diamond, full quantum control of an electronic-nuclear system consisting of up to three spins was achieved. We took advantage of a single nuclear-spin memory in order to obtain a 10-fold enhancement in the signal amplitude of the electronic spin readout. We also present a two-level, concatenated procedure to improve the readout by use of a pair of nuclear spin ancillae, an important step toward the realization of robust quantum information processors using electronic- and nuclear-spin qubits. Our technique can be used to improve the sensitivity and speed of spin-based nanoscale diamond magnetometers.
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Affiliation(s)
- L Jiang
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
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36
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Abstract
Optical binding interactions between laser-trapped spherical microparticles are familiar in a wide range of trapping configurations. Recently it has been demonstrated that these experiments can be accurately modeled using Mie scattering or coupled dipole models. This can help confirm the physical phenomena underlying the inter-particle interactions, but does not necessarily develop a conceptual understanding of the effects that can lead to future predictions. Here we interpret results from a Mie scattering model to obtain a physical description which predict the behavior and trends for chains of trapped particles in Gaussian beam traps. In particular, it describes the non-uniform particle spacing and how it changes with the number of particles. We go further than simply demonstrating agreement, by showing that the mechanisms "hidden" within a mathematically and computationally demanding Mie scattering description can be explained in easily-understood terms.
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Affiliation(s)
- J M Taylor
- Department of Physics, Durham University, South Road, Durham DH1 3LE, United Kingdom.
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37
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Kurucz Z, Sørensen MW, Taylor JM, Lukin MD, Fleischhauer M. Qubit protection in nuclear-spin quantum dot memories. Phys Rev Lett 2009; 103:010502. [PMID: 19659130 DOI: 10.1103/physrevlett.103.010502] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Indexed: 05/28/2023]
Abstract
We present a mechanism to protect quantum information stored in an ensemble of nuclear spins in a semiconductor quantum dot. When the dot is charged the nuclei interact with the spin of the excess electron through the hyperfine coupling. If this coupling is made off-resonant, it leads to an energy gap between the collective storage states and all other states. We show that the energy gap protects the quantum memory from local spin-flip and spin-dephasing noise. Effects of nonperfect initial spin polarization and inhomogeneous hyperfine coupling are discussed.
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Affiliation(s)
- Z Kurucz
- Fachbereich Physik, University of Kaiserslautern, D-67663 Kaiserslautern, Germany
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38
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Taylor JM, Love GD. Multipole expansion of Bessel and Gaussian beams for Mie scattering calculations. J Opt Soc Am A Opt Image Sci Vis 2009; 26:278-282. [PMID: 19183678 DOI: 10.1364/josaa.26.000278] [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: 05/27/2023]
Abstract
Multipole expansions of Bessel and Gaussian beams, suitable for use in Mie scattering calculations, are derived. These results allow Mie scattering calculations to be carried out considerably faster than existing methods, something that is of particular interest for time evolution simulations where large numbers of scattering calculations must be performed. An analytic result is derived for the Bessel beam that improves on a previously published expression requiring the evaluation of an integral. An analogous expression containing a single integral, similar to existing results quoted, but not derived, in literature, is derived for a Gaussian beam, valid from the paraxial limit all the way to arbitrarily high numerical apertures.
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Affiliation(s)
- J M Taylor
- Department of Physics, Durham University, South Road, Durham DH1 3LE, United Kingdom.
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39
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Daley AJ, Taylor JM, Diehl S, Baranov M, Zoller P. Atomic three-body loss as a dynamical three-body interaction. Phys Rev Lett 2009; 102:040402. [PMID: 19257406 DOI: 10.1103/physrevlett.102.040402] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2008] [Indexed: 05/27/2023]
Abstract
We discuss how large three-body loss of atoms in an optical lattice can give rise to effective hard-core three-body interactions. For bosons, in addition to the usual atomic superfluid, a dimer superfluid can then be observed for attractive two-body interactions. The nonequilibrium dynamics of preparation and stability of these phases are studied in 1D by combining time-dependent density matrix renormalization group techniques with a quantum trajectories method.
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Affiliation(s)
- A J Daley
- Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck, Austria
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40
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Reilly DJ, Taylor JM, Laird EA, Petta JR, Marcus CM, Hanson MP, Gossard AC. Measurement of temporal correlations of the overhauser field in a double quantum dot. Phys Rev Lett 2008; 101:236803. [PMID: 19113577 DOI: 10.1103/physrevlett.101.236803] [Citation(s) in RCA: 10] [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: 12/24/2007] [Indexed: 05/27/2023]
Abstract
In quantum dots made from materials with nonzero nuclear spins, hyperfine coupling creates a fluctuating effective Zeeman field (Overhauser field) felt by electrons, which can be a dominant source of spin qubit decoherence. We characterize the spectral properties of the fluctuating Overhauser field in a GaAs double quantum dot by measuring correlation functions and power spectra of the rate of singlet-triplet mixing of two separated electrons. Away from zero field, spectral weight is concentrated below 10 Hz, with approximately 1/f2 dependence on frequency f. This is consistent with a model of nuclear spin diffusion, and indicates that decoherence can be largely suppressed by echo techniques.
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Affiliation(s)
- D J Reilly
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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41
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Maze JR, Stanwix PL, Hodges JS, Hong S, Taylor JM, Cappellaro P, Jiang L, Dutt MVG, Togan E, Zibrov AS, Yacoby A, Walsworth RL, Lukin MD. Nanoscale magnetic sensing with an individual electronic spin in diamond. Nature 2008; 455:644-7. [PMID: 18833275 DOI: 10.1038/nature07279] [Citation(s) in RCA: 544] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Accepted: 07/18/2008] [Indexed: 11/09/2022]
Abstract
Detection of weak magnetic fields with nanoscale spatial resolution is an outstanding problem in the biological and physical sciences. For example, at a distance of 10 nm, the spin of a single electron produces a magnetic field of about 1 muT, and the corresponding field from a single proton is a few nanoteslas. A sensor able to detect such magnetic fields with nanometre spatial resolution would enable powerful applications, ranging from the detection of magnetic resonance signals from individual electron or nuclear spins in complex biological molecules to readout of classical or quantum bits of information encoded in an electron or nuclear spin memory. Here we experimentally demonstrate an approach to such nanoscale magnetic sensing, using coherent manipulation of an individual electronic spin qubit associated with a nitrogen-vacancy impurity in diamond at room temperature. Using an ultra-pure diamond sample, we achieve detection of 3 nT magnetic fields at kilohertz frequencies after 100 s of averaging. In addition, we demonstrate a sensitivity of 0.5 muT Hz(-1/2) for a diamond nanocrystal with a diameter of 30 nm.
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Affiliation(s)
- J R Maze
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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43
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Abstract
Coherent spin states in semiconductor quantum dots offer promise as electrically controllable quantum bits (qubits) with scalable fabrication. For few-electron quantum dots made from gallium arsenide (GaAs), fluctuating nuclear spins in the host lattice are the dominant source of spin decoherence. We report a method of preparing the nuclear spin environment that suppresses the relevant component of nuclear spin fluctuations below its equilibrium value by a factor of approximately 70, extending the inhomogeneous dephasing time for the two-electron spin state beyond 1 microsecond. The nuclear state can be readily prepared by electrical gate manipulation and persists for more than 10 seconds.
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Affiliation(s)
- D J Reilly
- Department of Physics, Harvard University, Cambridge, MA 02138, USA
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Werb Z, Chin JR, Takemura R, Oropeza RL, Bainton DF, Stenberg P, Taylor JM, Reardon C. The cell and molecular biology of apolipoprotein E synthesis by macrophages. Ciba Found Symp 2008; 118:155-71. [PMID: 3525037 DOI: 10.1002/9780470720998.ch11] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Mononuclear phagocytes secrete over 50 different proteins that are regulated during differentiation and that are under the influence of various materials and factors in their extracellular milieu as part of the inflammatory response. The complex nature of the regulation of the expression of these molecules is displayed by apolipoprotein E (ApoE). ApoE mRNA first appears as monocytes differentiate into macrophages, and this expression is paralleled by the secretion of ApoE by the cells. In mature macrophages ApoE synthesis and secretion are decreased by activation of macrophages with endotoxin and interferon-gamma. Although these macrophages contain abundant translatable ApoE mRNA, little ApoE is synthesized, suggesting that this decrease occurs largely at the translational level. ApoE is also controlled at the level of secretion. ApoE is concentrated in the Golgi complex of macrophages and is also found in endoplasmic reticulum, secretion vesicles and coated vesicles. When macrophages come in contact with immune complexes the intracellular ApoE compartment degranulates rapidly. Therefore, ApoE is regulated at the levels of secretion, translation and transcription.
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Abstract
Sub-micron particles have been observed to spontaneously form regular two-dimensional structures in counterpropagating evanescent laser fields. We show that collective properties of large numbers of optically-trapped particles can be qualitatively different to the properties of small numbers. This is demonstrated both with a computer model and with experimental results. As the number of particles in the structure is increased, optical binding forces can be sufficiently large to overcome the optical landscape imposed by the interference fringes of the laser beams and impose a different, competing structure.
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Affiliation(s)
- J M Taylor
- Department of Physics, Durham University, South Road, Durham DH1 3LE, UK.
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46
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Jiang L, Dutt MVG, Togan E, Childress L, Cappellaro P, Taylor JM, Lukin MD. Coherence of an optically illuminated single nuclear spin qubit. Phys Rev Lett 2008; 100:073001. [PMID: 18352544 DOI: 10.1103/physrevlett.100.073001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Indexed: 05/26/2023]
Abstract
We investigate the coherence properties of individual nuclear spin quantum bits in diamond [Dutt, Science 316, 1312 (2007)10.1126/science.1139831] when a proximal electronic spin associated with a nitrogen-vacancy (N-V) center is being interrogated by optical radiation. The resulting nuclear spin dynamics are governed by time-dependent hyperfine interaction associated with rapid electronic transitions, which can be described by a spin-fluctuator model. We show that due to a process analogous to motional averaging in nuclear magnetic resonance, the nuclear spin coherence can be preserved after a large number of optical excitation cycles. Our theoretical analysis is in good agreement with experimental results. It indicates a novel approach that could potentially isolate the nuclear spin system completely from the electronic environment.
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Affiliation(s)
- L Jiang
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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47
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Petta JR, Taylor JM, Johnson AC, Yacoby A, Lukin MD, Marcus CM, Hanson MP, Gossard AC. Dynamic nuclear polarization with single electron spins. Phys Rev Lett 2008; 100:067601. [PMID: 18352516 DOI: 10.1103/physrevlett.100.067601] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Indexed: 05/26/2023]
Abstract
We polarize nuclear spins in a GaAs double quantum dot by controlling two-electron spin states near the anticrossing of the singlet (S) and m(S)= +1 triplet (T+) using pulsed gates. An initialized S state is cyclically brought into resonance with the T+ state, where hyperfine fields drive rapid rotations between S and T+, "flipping" an electron spin and "flopping" a nuclear spin. The resulting Overhauser field approaches 80 mT, in agreement with a simple rate-equation model. A self-limiting pulse sequence is developed that allows the steady-state nuclear polarization to be set using a gate voltage.
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Affiliation(s)
- J R Petta
- Department of Physics, Harvard University, 17 Oxford St., Cambridge, Massachusetts 02138, USA
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48
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Taylor JM, Lauer S, Elshourbagy N, Reardon C, Taxman E, Walker D, Chang D, Paik YK. Structure and evolution of human apolipoprotein genes: identification of regulatory elements of the human apolipoprotein E gene. Ciba Found Symp 2007; 130:70-86. [PMID: 2894932 DOI: 10.1002/9780470513507.ch6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The structures of the major human apolipoprotein genes have been determined. The genes for apoE, apoC-I, apoC-II, apoC-III, apoA-I, apoA-II and apoA-IV have similar structures, consisting of four exons and three introns, which suggests that they evolved from a common ancestral gene. The third and fourth exons of the ancestral gene appear to have evolved from the duplication of a 66-nucleotide repeat unit that encodes a 22-residue alpha-helical peptide element of amphipathic character. The apoA-I, apoC-III and apoA-IV genes are linked closely within a 20-kilobase (kb) span of chromosome 11. The apoE and apoC-I genes, together with an apoC-I' pseudogene, are linked closely within a 25-kb span of chromosome 19. To characterize potential functional relationships among the apolipoprotein genes, initial studies have been done to identify the molecular elements involved in the regulation of the human apoE gene. Fragments of the 5'-flanking portion of this gene were inserted into appropriate plasmid vectors, which contained the bacterial chloramphenicol acetyl transferase gene, and were examined for promoter activity and potential enhancer activity after transfection into cultured mammalian cells. Deletion mapping of the promoter region has identified multiple functional elements, including an enhancer, two G-C boxes (Sp 1 transcription factor binding sites) and an upstream control element. In addition, there is an enhancer located in the first intron. Interactions among these various control elements are likely to determine the ways in which the expression of the apoE gene is regulated.
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Affiliation(s)
- J M Taylor
- Department of Physiology, University of California, San Francisco 94140
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Orr Y, Taylor JM, Cartland S, Bannon PG, Geczy C, Kritharides L. Conformational activation of CD11b without shedding of L-selectin on circulating human neutrophils. J Leukoc Biol 2007; 82:1115-25. [PMID: 17675559 DOI: 10.1189/jlb.0906545] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [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: 11/24/2022] Open
Abstract
Membrane-activated complex 1 (Mac-1; CD11b/CD18) is a beta(2) integrin implicated in the pathophysiology of neutrophil-mediated tissue injury whose functional capacity is determined by stimulus-induced conformational activation rather than up-regulation. Mac-1 up-regulation and conformational activation, together with shedding of L-selectin, are reported after in vitro neutrophil activation. However, their regulation on circulating human neutrophils during acute inflammation is unclear. Using flow cytometry, we investigated neutrophil expression of Mac-1, its activation-reporter neo-epitope CBRM1/5, and L-selectin during the inflammatory stimulus of cardiac surgery. A subpopulation of circulating neutrophils expressed CBRM1/5 (CBRM1/5+) under basal conditions (6.28+/-2.59%) and was persistently expanded (9.95+/-4.0%-15.2+/-4.2%; P<0.0001) peri-operatively, whereas total CD11b expression increased only transiently, intra-operatively. L-selectin expression was unchanged on CBRM1/5+ neutrophils, and soluble L-selectin levels decreased intra-operatively (P<0.01), indicating that L-selectin was not shed. Increased CBRM1/5 expression without L-selectin loss or CD11b up-regulation was replicated in vitro by neutrophil stimulation with IL-8, C3a, and platelet-activating factor. Heparin, a known CD11b ligand, which is administered during cardiac surgery, markedly reduced neutrophil expression of conformationally active CD11b in vivo and in vitro, identifying a potential mechanism for its anti-inflammatory properties. We conclude that conformational activation of CD11b occurs on circulating neutrophils in vivo and can occur in the absence of CD11b up-regulation and L-selectin shedding.
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Affiliation(s)
- Y Orr
- Centre for Vascular Research, School of Medical Sciences, 4th Floor Wallace Wurth Building, The University of New South Wales, Kensington, NSW, Australia
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50
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Garside JP, Kerrin DP, Brownlee KG, Gooi HC, Taylor JM, Conway SP. Low gammaglobulin subclass 2 levels in paediatric cystic fibrosis patients followed over a 2-year period. Pediatr Pulmonol 2007; 42:125-30. [PMID: 17186508 DOI: 10.1002/ppul.20473] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The aim of this study was to relate serum immunoglobulin G2 subclass levels in a large paediatric population with cystic fibrosis, to clinical status and antibody levels to Haemophilus influenzae type b and Streptococcus pneumoniae and to observe any changes over a 2-year period. IgG subclasses were measured in 131 patients. Results were compared with levels from age-related normal population data. The following clinical data were collected at baseline and 2 years later; genotype: height, weight, and BMI z-scores: FEV1 (as percent predicted): Shwachman-Kulczcyki and Northern chest X-ray scores: Pseudomonas aeruginosa status. Antibody levels to H. influenzae type b and S. pneumoniae measured at baseline were related to IgG2 level. There was a reduction in the prevalence of low levels of IgG2 from 29% to 10% over the 2-year period. Low levels of IgG2 were not associated with any decline in clinical well-being. Low levels of IgG2 alone were associated with low antibody levels to S. pneumoniae. Low levels of IgG2 and low levels of antibody to H. influenzae and S. pneumoniae were not associated with any decline in clinical well-being. Children with high levels of IgG2 had worse lung function, worse Shwachman-Kulczcyki and Northern chest X-ray scores and higher levels of P. aeruginosa infection. Children with low IgG2 levels were not worse clinically compared to those with normal or high IgG2 levels. High IgG2 levels were associated with a worse clinical status.
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Affiliation(s)
- J P Garside
- Department of Paediatrics Huddersfield Royal Infirmary, Huddersfield, United Kingdom
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