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Yim W, Retout M, Chen AA, Ling C, Amer L, Jin Z, Chang YC, Chavez S, Barrios K, Lam B, Li Z, Zhou J, Shi L, Pascal TA, Jokerst JV. Correction to "Goldilocks Energy Minimum: Peptide-Based Reversible Aggregation and Biosensing". ACS Appl Mater Interfaces 2023; 15:48838. [PMID: 37787714 DOI: 10.1021/acsami.3c13967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
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2
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Devlin SW, Jamnuch S, Xu Q, Chen AA, Qian J, Pascal TA, Saykally RJ. Agglomeration Drives the Reversed Fractionation of Aqueous Carbonate and Bicarbonate at the Air-Water Interface. J Am Chem Soc 2023; 145:22384-22393. [PMID: 37774115 DOI: 10.1021/jacs.3c05093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/01/2023]
Abstract
In the course of our investigations of the adsorption of ions to the air-water interface, we previously reported the surprising result that doubly charged carbonate anions exhibit a stronger surface affinity than singly charged bicarbonate anions. In contrast to monovalent, weakly hydrated anions, which generally show enhanced concentrations in the interfacial region, multivalent (and strongly hydrated) anions are expected to show a much weaker surface propensity. In the present work, we use resonantly enhanced deep-UV second-harmonic generation spectroscopy to measure the Gibbs free energy of adsorption of both carbonate (CO32-) and bicarbonate (HCO3-) anions to the air-water interface. Contrasting the predictions of classical electrostatic theory and in support of our previous findings from X-ray photoelectron spectroscopy, we find that carbonate anions do indeed exhibit much stronger surface affinity than do the bicarbonate anions. Extensive computer simulations reveal that strong ion pairing of CO32- with the Na+ countercation in the interfacial region results in the formation of near-neutral agglomerate clusters, consistent with a theory of interfacial ion adsorption based on hydration free energy and capillary waves. Simulated X-ray photoelectron spectra predict a 1 eV shift in the carbonate spectra compared to that of bicarbonate, further confirming our experiments. These findings not only advance our fundamental understanding of ion adsorption chemistry but also impact important practical processes such as ocean acidification, sea-spray aerosol chemistry, and mammalian respiration physiology.
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Affiliation(s)
- Shane W Devlin
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, United States
| | - Sasawat Jamnuch
- ATLAS Materials Science Laboratory, Department of Nano Engineering and Chemical Engineering, University of California, San Diego, La Jolla, California 92023, United States
| | - Qiang Xu
- Chemical Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, United States
| | - Amanda A Chen
- ATLAS Materials Science Laboratory, Department of Nano Engineering and Chemical Engineering, University of California, San Diego, La Jolla, California 92023, United States
| | - Jin Qian
- Chemical Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, United States
| | - Tod A Pascal
- ATLAS Materials Science Laboratory, Department of Nano Engineering and Chemical Engineering, University of California, San Diego, La Jolla, California 92023, United States
- Materials Science and Engineering, University of California San Diego, La Jolla, California 92023, United States
- Sustainable Power and Energy Center, University of California San Diego, La Jolla, California 92023, United States
| | - Richard J Saykally
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Lab, Berkeley, California 94720, United States
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3
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Yim W, Retout M, Chen AA, Ling C, Amer L, Jin Z, Chang YC, Chavez S, Barrios K, Lam B, Li Z, Zhou J, Shi L, Pascal TA, Jokerst JV. Goldilocks Energy Minimum: Peptide-Based Reversible Aggregation and Biosensing. ACS Appl Mater Interfaces 2023; 15:42293-42303. [PMID: 37651748 PMCID: PMC10619458 DOI: 10.1021/acsami.3c09627] [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] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
Colorimetric biosensors based on gold nanoparticle (AuNP) aggregation are often challenged by matrix interference in biofluids, poor specificity, and limited utility with clinical samples. Here, we propose a peptide-driven nanoscale disassembly approach, where AuNP aggregates induced by electrostatic attractions are dissociated in response to proteolytic cleavage. Initially, citrate-coated AuNPs were assembled via a short cationic peptide (RRK) and characterized by experiments and simulations. The dissociation peptides were then used to reversibly dissociate the AuNP aggregates as a function of target protease detection, i.e., main protease (Mpro), a biomarker for severe acute respiratory syndrome coronavirus 2. The dissociation propensity depends on peptide length, hydrophilicity, charge, and ligand architecture. Finally, our dissociation strategy provides a rapid and distinct optical signal through Mpro cleavage with a detection limit of 12.3 nM in saliva. Our dissociation peptide effectively dissociates plasmonic assemblies in diverse matrices including 100% human saliva, urine, plasma, and seawater, as well as other types of plasmonic nanoparticles such as silver. Our peptide-enabled dissociation platform provides a simple, matrix-insensitive, and versatile method for protease sensing.
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Affiliation(s)
- Wonjun Yim
- Materials Science and Engineering Program, University of California San Diego, La Jolla, California 92093, United States
| | - Maurice Retout
- Department of Nano and Chemical Engineering, University of California San Diego, La Jolla, California 92093, United States
| | - Amanda A Chen
- Department of Nano and Chemical Engineering, University of California San Diego, La Jolla, California 92093, United States
| | - Chuxuan Ling
- Department of Nano and Chemical Engineering, University of California San Diego, La Jolla, California 92093, United States
| | - Lubna Amer
- Materials Science and Engineering Program, University of California San Diego, La Jolla, California 92093, United States
| | - Zhicheng Jin
- Department of Nano and Chemical Engineering, University of California San Diego, La Jolla, California 92093, United States
| | - Yu-Ci Chang
- Materials Science and Engineering Program, University of California San Diego, La Jolla, California 92093, United States
| | - Saul Chavez
- Department of Nano and Chemical Engineering, University of California San Diego, La Jolla, California 92093, United States
| | - Karen Barrios
- Department of Nano and Chemical Engineering, University of California San Diego, La Jolla, California 92093, United States
| | - Benjamin Lam
- Department of Nano and Chemical Engineering, University of California San Diego, La Jolla, California 92093, United States
| | - Zhi Li
- Shu Chien-Gene Lay Department of Bioengineering, University of California San Diego, La Jolla, California 92093, United States
| | - Jiajing Zhou
- Department of Nano and Chemical Engineering, University of California San Diego, La Jolla, California 92093, United States
| | - Lingyan Shi
- Shu Chien-Gene Lay Department of Bioengineering, University of California San Diego, La Jolla, California 92093, United States
| | - Tod A Pascal
- Department of Nano and Chemical Engineering, University of California San Diego, La Jolla, California 92093, United States
| | - Jesse V Jokerst
- Materials Science and Engineering Program, University of California San Diego, La Jolla, California 92093, United States
- Department of Nano and Chemical Engineering, University of California San Diego, La Jolla, California 92093, United States
- Department of Radiology, University of California San Diego, La Jolla, California 92093, United States
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Cai G, Chen AA, Lin S, Lee DJ, Yu K, Holoubek J, Yin Y, Mu AU, Meng YS, Liu P, Cohen SM, Pascal TA, Chen Z. Unravelling Ultrafast Li Ion Transport in Functionalized Metal-Organic Framework-Based Battery Electrolytes. Nano Lett 2023; 23:7062-7069. [PMID: 37522917 DOI: 10.1021/acs.nanolett.3c01825] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/01/2023]
Abstract
Nonaqueous fluidic transport and ion solvation properties under nanoscale confinement are poorly understood, especially in ion conduction for energy storage and conversion systems. Herein, metal-organic frameworks (MOFs) and aprotic electrolytes are studied as a robust platform for molecular-level insights into electrolyte behaviors in confined spaces. By employing computer simulations, along with spectroscopic and electrochemical measurements, we demonstrate several phenomena that deviate from the bulk, including modulated solvent molecular configurations, aggregated solvation structures, and tunable transport mechanisms from quasi-solid to quasi-liquid in functionalized MOFs. Technologically, taking advantage of confinement effects may prove useful for addressing stability concerns associated with volatile organic electrolytes while simultaneously endowing ultrafast transport of solvates, resulting in improved battery performance, even at extreme temperatures. The molecular-level insights presented here further our understanding of structure-property relationships of complex fluids at the nanoscale, information that can be exploited for the predictive design of more efficient electrochemical systems.
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Affiliation(s)
- Guorui Cai
- Department of Nano and Chemical Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Amanda A Chen
- Department of Nano and Chemical Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Sharon Lin
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Dong Ju Lee
- Department of Nano and Chemical Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Kunpeng Yu
- Department of Nano and Chemical Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - John Holoubek
- Department of Nano and Chemical Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Yijie Yin
- Program of Materials Science and Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Anthony U Mu
- Department of Nano and Chemical Engineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Ying Shirley Meng
- Department of Nano and Chemical Engineering, University of California, San Diego, La Jolla, California 92093, United States
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States
| | - Ping Liu
- Department of Nano and Chemical Engineering, University of California, San Diego, La Jolla, California 92093, United States
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
- Program of Materials Science and Engineering, University of California, San Diego, La Jolla, California 92093, United States
- Sustainable Power and Energy Center, University of California, San Diego, La Jolla, California 92093, United States
| | - Seth M Cohen
- Department of Nano and Chemical Engineering, University of California, San Diego, La Jolla, California 92093, United States
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Tod A Pascal
- Department of Nano and Chemical Engineering, University of California, San Diego, La Jolla, California 92093, United States
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
- Program of Materials Science and Engineering, University of California, San Diego, La Jolla, California 92093, United States
- Sustainable Power and Energy Center, University of California, San Diego, La Jolla, California 92093, United States
| | - Zheng Chen
- Department of Nano and Chemical Engineering, University of California, San Diego, La Jolla, California 92093, United States
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
- Program of Materials Science and Engineering, University of California, San Diego, La Jolla, California 92093, United States
- Sustainable Power and Energy Center, University of California, San Diego, La Jolla, California 92093, United States
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5
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Psaltis A, Chen AA, Longland R, Connolly DS, Brune CR, Davids B, Fallis J, Giri R, Greife U, Hutcheon DA, Kroll L, Lennarz A, Liang J, Lovely M, Luo M, Marshall C, Paneru SN, Parikh A, Ruiz C, Shotter AC, Williams M. Direct Measurement of Resonances in ^{7}Be(α,γ)^{11}C Relevant to νp-Process Nucleosynthesis. Phys Rev Lett 2022; 129:162701. [PMID: 36306775 DOI: 10.1103/physrevlett.129.162701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 07/01/2022] [Accepted: 08/24/2022] [Indexed: 06/16/2023]
Abstract
We have performed the first direct measurement of two resonances of the ^{7}Be(α,γ)^{11}C reaction with unknown strengths using an intense radioactive ^{7}Be beam and the DRAGON recoil separator. We report on the first measurement of the 1155 and 1110 keV resonance strengths of 1.73±0.25(stat)±0.40(syst) eV and 125_{-25}^{+27}(stat)±15(syst) meV, respectively. The present results have reduced the uncertainty in the ^{7}Be(α,γ)^{11}C reaction rate to ∼9.4%-10.7% over T=1.5-3 GK, which is relevant for nucleosynthesis in the neutrino-driven outflows of core-collapse supernovae (νp process). We find no effect of the new, constrained reaction rate on νp-process nucleosynthesis.
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Affiliation(s)
- A Psaltis
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
- The NuGrid Collaboration
| | - A A Chen
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
- The NuGrid Collaboration
| | - R Longland
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA
- Triangle Universities Nuclear Laboratory, Duke University, Durham, North Carolina 27710, USA
| | - D S Connolly
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - C R Brune
- Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA
| | - B Davids
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - J Fallis
- North Island College, 2300 Ryan Road, Courtenay, British Columbia V9N 8N6, Canada
| | - R Giri
- Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA
| | - U Greife
- Department of Physics, Colorado School of Mines, Golden, Colorado 80401, USA
| | - D A Hutcheon
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - L Kroll
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
- The NuGrid Collaboration
| | - A Lennarz
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
| | - J Liang
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - M Lovely
- Department of Physics, Colorado School of Mines, Golden, Colorado 80401, USA
| | - M Luo
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - C Marshall
- Department of Physics, North Carolina State University, Raleigh, North Carolina 27695, USA
- Triangle Universities Nuclear Laboratory, Duke University, Durham, North Carolina 27710, USA
| | - S N Paneru
- Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA
| | - A Parikh
- Department de Física, Universitat Politècnica de Catalunya, E-08036 Barcelona, Spain
| | - C Ruiz
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
| | - A C Shotter
- School of Physics, University of Edinburgh EH9 3JZ Edinburgh, United Kingdom
| | - M Williams
- TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics, University of York, Heslington, York YO10 5DD, United Kingdom
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6
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Wang Y, Chen AA, Balto KP, Xie Y, Figueroa JS, Pascal TA, Tao AR. Curvature-Selective Nanocrystal Surface Ligation Using Sterically-Encumbered Metal-Coordinating Ligands. ACS Nano 2022; 16:12747-12754. [PMID: 35943141 DOI: 10.1021/acsnano.2c04595] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Organic ligands are critical in determining the physiochemical properties of inorganic nanocrystals. However, precise nanocrystal surface modification is extremely difficult to achieve. Most research focuses on finding ligands that fully passivate the nanocrystal surface, with an emphasis on the supramolecular structure generated by the ligand shell. Inspired by molecular metal-coordination complexes, we devised an approach based on ligand anchoring groups that are flanked by encumbering organic substituents and are chemoselective for binding to nanocrystal corner, edge, and facet sites. Through experiment and theory, we affirmed that the surface-ligand steric pressures generated by these organic substituents are significant enough to impede binding to regions of low nanocurvature, such as nanocrystal facets, and to promote binding to regions of high curvature such as nanocrystal edges.
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Affiliation(s)
- Yufei Wang
- Department of Nanoengineering and Chemical Engineering, University of California San Diego, La Jolla, California 92023-0448, United States
- Materials Science and Engineering Program, University of California San Diego, La Jolla, California 92023, United States
| | - Amanda A Chen
- Department of Nanoengineering and Chemical Engineering, University of California San Diego, La Jolla, California 92023-0448, United States
| | - Krista P Balto
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92023, United States
| | - Yu Xie
- Department of Nanoengineering and Chemical Engineering, University of California San Diego, La Jolla, California 92023-0448, United States
| | - Joshua S Figueroa
- Materials Science and Engineering Program, University of California San Diego, La Jolla, California 92023, United States
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92023, United States
| | - Tod A Pascal
- Department of Nanoengineering and Chemical Engineering, University of California San Diego, La Jolla, California 92023-0448, United States
- Materials Science and Engineering Program, University of California San Diego, La Jolla, California 92023, United States
| | - Andrea R Tao
- Department of Nanoengineering and Chemical Engineering, University of California San Diego, La Jolla, California 92023-0448, United States
- Materials Science and Engineering Program, University of California San Diego, La Jolla, California 92023, United States
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California 92023, United States
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7
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Budner T, Friedman M, Wrede C, Brown BA, José J, Pérez-Loureiro D, Sun LJ, Surbrook J, Ayyad Y, Bardayan DW, Chae K, Chen AA, Chipps KA, Cortesi M, Glassman B, Hall MR, Janasik M, Liang J, O'Malley P, Pollacco E, Psaltis A, Stomps J, Wheeler T. Constraining the ^{30}P(p, γ)^{31}S Reaction Rate in ONe Novae via the Weak, Low-Energy, β-Delayed Proton Decay of ^{31}Cl. Phys Rev Lett 2022; 128:182701. [PMID: 35594108 DOI: 10.1103/physrevlett.128.182701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 01/14/2022] [Accepted: 04/04/2022] [Indexed: 06/15/2023]
Abstract
The ^{30}P(p,γ)^{31}S reaction plays an important role in understanding the nucleosynthesis of A≥30 nuclides in oxygen-neon novae. The Gaseous Detector with Germanium Tagging was used to measure ^{31}Cl β-delayed proton decay through the key J^{π}=3/2^{+}, 260-keV resonance. The intensity I_{βp}^{260}=8.3_{-0.9}^{+1.2}×10^{-6} represents the weakest β-delayed, charged-particle emission ever measured below 400 keV, resulting in a proton branching ratio of Γ_{p}/Γ=2.5_{-0.3}^{+0.4}×10^{-4}. By combining this measurement with shell-model calculations for Γ_{γ} and past work on other resonances, the total ^{30}P(p,γ)^{31}S rate has been determined with reduced uncertainty. The new rate has been used in hydrodynamic simulations to model the composition of nova ejecta, leading to a concrete prediction of ^{30}Si:^{28}Si excesses in presolar nova grains and the calibration of nuclear thermometers.
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Affiliation(s)
- T Budner
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - M Friedman
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- Racah Institute of Physics, Hebrew University, Jerusalem, Israel 91904
| | - C Wrede
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - B A Brown
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - J José
- Departament de Física, Universitat Politècnica de Catalunya, E-08019 Barcelona, Spain
- Institut d'Estudis Espacials de Catalunya, Universitat Politècnica de Catalunya, E-08034 Barcelona, Spain
| | - D Pérez-Loureiro
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - L J Sun
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - J Surbrook
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - Y Ayyad
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- IGFAE, Universidade de Santiago de Compostela, E-15782 Santiago de Compostela, Spain
| | - D W Bardayan
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - K Chae
- Department of Physics, Sungkyunkwan University, Seoul 16419, South Korea
| | - A A Chen
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - K A Chipps
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830-37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - M Cortesi
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
| | - B Glassman
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - M R Hall
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - M Janasik
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - J Liang
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - P O'Malley
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - E Pollacco
- Département de Physique Nucléaire, IRFU, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France
| | - A Psaltis
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - J Stomps
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - T Wheeler
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
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Lotay G, Lennarz A, Ruiz C, Akers C, Chen AA, Christian G, Connolly D, Davids B, Davinson T, Fallis J, Hutcheon DA, Machule P, Martin L, Mountford DJ, Murphy ASJ. Radiative Capture on Nuclear Isomers: Direct Measurement of the ^{26m}Al(p,γ)^{27}Si Reaction. Phys Rev Lett 2022; 128:042701. [PMID: 35148128 DOI: 10.1103/physrevlett.128.042701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/10/2021] [Accepted: 12/24/2021] [Indexed: 06/14/2023]
Abstract
We present the first direct measurement of an astrophysical reaction using a radioactive beam of isomeric nuclei. In particular, we have measured the strength of the key 447-keV resonance in the ^{26m}Al(p,γ)^{27}Si reaction to be 432_{-226}^{+146} meV and find that this resonance dominates the thermally averaged reaction rate for temperatures between 0.3 and 2.5 GK. This work represents a critical development in resolving one of the longest standing issues in nuclear astrophysics research, relating to the measurement of proton capture reactions on excited quantum levels, and offers unique insight into the destruction of isomeric ^{26}Al in astrophysical plasmas.
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Affiliation(s)
- G Lotay
- Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - A Lennarz
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - C Ruiz
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics and Astronomy, University of Victoria, Victoria, BC V8W 2Y2, Canada
| | - C Akers
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics, University of York, Heslington, York YO10 5DD, United Kingdom
| | - A A Chen
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - G Christian
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - D Connolly
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - B Davids
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - T Davinson
- School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - J Fallis
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - D A Hutcheon
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - P Machule
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - L Martin
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - D J Mountford
- School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - A St J Murphy
- School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
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9
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Chen AA, Do A, Pascal TA. The phase diagram of carbon dioxide from correlation functions and a many-body potential. J Chem Phys 2021; 155:024503. [PMID: 34266271 DOI: 10.1063/5.0054314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The phase stability and equilibria of carbon dioxide are investigated from 125-325 K and 1-10 000 atm using extensive molecular dynamics (MD) simulations and the Two-Phase Thermodynamics (2PT) method. We devise a direct approach for calculating phase diagrams, in general, by considering the separate chemical potentials of the isolated phase at specific points on the P-T diagram. The unique ability of 2PT to accurately and efficiently approximate the entropy and Gibbs energy of liquids allows for assignment of phase boundaries from relatively short (∼100 ps) MD simulations. We validate our approach by calculating the critical properties of the flexible elementary physical model 2, showing good agreement with previous results. We show, however, that the incorrect description of the short-range Pauli force and the lack of molecular charge polarization lead to deviations from experiments at high pressures. We, thus, develop a many-body, fluctuating charge model for CO2, termed CO2-Fq, from high level quantum mechanics (QM) calculations that accurately capture the condensed phase vibrational properties of the solid (including the Fermi resonance at 1378 cm-1) as well as the diffusional properties of the liquid, leading to overall excellent agreement with experiments over the entire phase diagram. This work provides an efficient computational approach for determining phase diagrams of arbitrary systems and underscores the critical role of QM charge reorganization physics in molecular phase stability.
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Affiliation(s)
- Amanda A Chen
- Department of NanoEngineering and Chemical Engineering, University of California San Diego, La Jolla, San Diego, California 92023, USA
| | - Alexandria Do
- Department of NanoEngineering and Chemical Engineering, University of California San Diego, La Jolla, San Diego, California 92023, USA
| | - Tod A Pascal
- Department of NanoEngineering and Chemical Engineering, University of California San Diego, La Jolla, San Diego, California 92023, USA
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10
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Cai G, Yin Y, Xia D, Chen AA, Holoubek J, Scharf J, Yang Y, Koh KH, Li M, Davies DM, Mayer M, Han TH, Meng YS, Pascal TA, Chen Z. Sub-nanometer confinement enables facile condensation of gas electrolyte for low-temperature batteries. Nat Commun 2021; 12:3395. [PMID: 34099643 PMCID: PMC8184934 DOI: 10.1038/s41467-021-23603-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 05/05/2021] [Indexed: 12/19/2022] Open
Abstract
Confining molecules in the nanoscale environment can lead to dramatic changes of their physical and chemical properties, which opens possibilities for new applications. There is a growing interest in liquefied gas electrolytes for electrochemical devices operating at low temperatures due to their low melting point. However, their high vapor pressure still poses potential safety concerns for practical usages. Herein, we report facile capillary condensation of gas electrolyte by strong confinement in sub-nanometer pores of metal-organic framework (MOF). By designing MOF-polymer membranes (MPMs) that present dense and continuous micropore (~0.8 nm) networks, we show significant uptake of hydrofluorocarbon molecules in MOF pores at pressure lower than the bulk counterpart. This unique property enables lithium/fluorinated graphite batteries with MPM-based electrolytes to deliver a significantly higher capacity than those with commercial separator membranes (~500 mAh g-1 vs. <0.03 mAh g-1) at -40 °C under reduced pressure of the electrolyte.
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Affiliation(s)
- Guorui Cai
- Department of NanoEngineering, University of California, San Diego, CA, USA
| | - Yijie Yin
- Program of Materials Science and Engineering, University of California, San Diego, CA, USA
| | - Dawei Xia
- Program of Chemical Engineering, University of California, San Diego, CA, USA
| | - Amanda A Chen
- Department of NanoEngineering, University of California, San Diego, CA, USA
- Program of Chemical Engineering, University of California, San Diego, CA, USA
| | - John Holoubek
- Department of NanoEngineering, University of California, San Diego, CA, USA
| | - Jonathan Scharf
- Department of NanoEngineering, University of California, San Diego, CA, USA
| | - Yangyuchen Yang
- Program of Materials Science and Engineering, University of California, San Diego, CA, USA
| | - Ki Hwan Koh
- Department of NanoEngineering, University of California, San Diego, CA, USA
| | - Mingqian Li
- Program of Chemical Engineering, University of California, San Diego, CA, USA
| | - Daniel M Davies
- Department of NanoEngineering, University of California, San Diego, CA, USA
| | - Matthew Mayer
- Department of NanoEngineering, University of California, San Diego, CA, USA
| | - Tae Hee Han
- Department of Organic and Nano Engineering, Hanyang University, Seoul, Republic of Korea
| | - Ying Shirley Meng
- Department of NanoEngineering, University of California, San Diego, CA, USA
- Program of Materials Science and Engineering, University of California, San Diego, CA, USA
- Sustainable Power and Energy Center, University of California, San Diego, CA, USA
| | - Tod A Pascal
- Department of NanoEngineering, University of California, San Diego, CA, USA
- Program of Materials Science and Engineering, University of California, San Diego, CA, USA
- Program of Chemical Engineering, University of California, San Diego, CA, USA
- Sustainable Power and Energy Center, University of California, San Diego, CA, USA
| | - Zheng Chen
- Department of NanoEngineering, University of California, San Diego, CA, USA.
- Program of Materials Science and Engineering, University of California, San Diego, CA, USA.
- Program of Chemical Engineering, University of California, San Diego, CA, USA.
- Sustainable Power and Energy Center, University of California, San Diego, CA, USA.
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11
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Wilkinson R, Lotay G, Lennarz A, Ruiz C, Christian G, Akers C, Catford WN, Chen AA, Connolly D, Davids B, Hutcheon DA, Jedrejcic D, Laird AM, Martin L, McNeice E, Riley J, Williams M. Direct Measurement of the Key E_{c.m.}=456 keV Resonance in the Astrophysical ^{19}Ne(p,γ)^{20}Na Reaction and Its Relevance for Explosive Binary Systems. Phys Rev Lett 2017; 119:242701. [PMID: 29286739 DOI: 10.1103/physrevlett.119.242701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Indexed: 06/07/2023]
Abstract
We have performed a direct measurement of the ^{19}Ne(p,γ)^{20}Na reaction in inverse kinematics using a beam of radioactive ^{19}Ne. The key astrophysical resonance in the ^{19}Ne+p system has been definitely measured for the first time at E_{c.m.}=456_{-2}^{+5} keV with an associated strength of 17_{-5}^{+7} meV. The present results are in agreement with resonance strength upper limits set by previous direct measurements, as well as resonance energies inferred from precision (^{3}He, t) charge exchange reactions. However, both the energy and strength of the 456 keV resonance disagree with a recent indirect study of the ^{19}Ne(d, n)^{20}Na reaction. In particular, the new ^{19}Ne(p,γ)^{20}Na reaction rate is found to be factors of ∼8 and ∼5 lower than the most recent evaluation over the temperature range of oxygen-neon novae and astrophysical x-ray bursts, respectively. Nevertheless, we find that the ^{19}Ne(p,γ)^{20}Na reaction is likely to proceed fast enough to significantly reduce the flux of ^{19}F in nova ejecta and does not create a bottleneck in the breakout from the hot CNO cycles into the rp process.
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Affiliation(s)
- R Wilkinson
- Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - G Lotay
- Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
- National Physical Laboratory, Teddington, Middlesex TW11 0LW, United Kingdom
| | - A Lennarz
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - C Ruiz
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - G Christian
- Cyclotron Institute, Texas A&M University, College Station, Texas 77843-3366, USA
- Department of Physics and Astronomy, Texas A&M University, College Station, Texas 77843-3366, USA
- Nuclear Solutions Institute, Texas A&M University, College Station, Texas 77843-3366, USA
| | - C Akers
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - W N Catford
- Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - A A Chen
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - D Connolly
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - B Davids
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - D A Hutcheon
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - D Jedrejcic
- Colorado School of Mines, Golden, Colorado 80401, USA
| | - A M Laird
- Department of Physics, The University of York, York YO10 5DD, United Kingdom
| | - L Martin
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - E McNeice
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - J Riley
- Department of Physics, The University of York, York YO10 5DD, United Kingdom
| | - M Williams
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics, The University of York, York YO10 5DD, United Kingdom
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12
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Almaraz-Calderon S, Rehm KE, Gerken N, Avila ML, Kay BP, Talwar R, Ayangeakaa AD, Bottoni S, Chen AA, Deibel CM, Dickerson C, Hanselman K, Hoffman CR, Jiang CL, Kuvin SA, Nusair O, Pardo RC, Santiago-Gonzalez D, Sethi J, Ugalde C. Study of the ^{26}Al^{m}(d,p)^{27}Al Reaction and the Influence of the ^{26}Al 0^{+} Isomer on the Destruction of ^{26}Al in the Galaxy. Phys Rev Lett 2017; 119:072701. [PMID: 28949677 DOI: 10.1103/physrevlett.119.072701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Indexed: 06/07/2023]
Abstract
The existence of ^{26}Al (t_{1/2}=7.17×10^{5} yr) in the interstellar medium provides a direct confirmation of ongoing nucleosynthesis in the Galaxy. The presence of a low-lying 0^{+} isomer (^{26}Al^{m}), however, severely complicates the astrophysical calculations. We present for the first time a study of the ^{26}Al^{m}(d,p)^{27}Al reaction using an isomeric ^{26}Al beam. The selectivity of this reaction allowed the study of ℓ=0 transfers to T=1/2, and T=3/2 states in ^{27}Al. Mirror symmetry arguments were then used to constrain the ^{26}Al^{m}(p,γ)^{27}Si reaction rate and provide an experimentally determined upper limit of the rate for the destruction of isomeric ^{26}Al via radiative proton capture reactions, which is expected to dominate the destruction path of ^{26}Al^{m} in asymptotic giant branch stars, classical novae, and core collapse supernovae.
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Affiliation(s)
- S Almaraz-Calderon
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - K E Rehm
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - N Gerken
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - M L Avila
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - B P Kay
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - R Talwar
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A D Ayangeakaa
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - S Bottoni
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - A A Chen
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - C M Deibel
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - C Dickerson
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - K Hanselman
- Department of Physics, Florida State University, Tallahassee, Florida 32306, USA
| | - C R Hoffman
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - C L Jiang
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - S A Kuvin
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, USA
| | - O Nusair
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - R C Pardo
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - D Santiago-Gonzalez
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - J Sethi
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - C Ugalde
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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13
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Lotay G, Christian G, Ruiz C, Akers C, Burke DS, Catford WN, Chen AA, Connolly D, Davids B, Fallis J, Hager U, Hutcheon DA, Mahl A, Rojas A, Sun X. Direct Measurement of the Astrophysical ^{38}K(p,γ)^{39}Ca Reaction and Its Influence on the Production of Nuclides toward the End Point of Nova Nucleosynthesis. Phys Rev Lett 2016; 116:132701. [PMID: 27081974 DOI: 10.1103/physrevlett.116.132701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Indexed: 06/05/2023]
Abstract
We have performed the first direct measurement of the ^{38}K(p,γ)^{39}Ca reaction using a beam of radioactive ^{38}K. A proposed ℓ=0 resonance in the ^{38}K+p system has been identified at 679(2) keV with an associated strength of 120_{-30}^{+50} meV. Upper limits of 1.16 (3.5) and 8.6 (26) meV at the 68% (95%) confidence level were also established for two further expected ℓ=0 resonances at 386 and 515 keV, respectively. The present results have reduced uncertainties in the ^{38}K(p,γ)^{39}Ca reaction rate at temperatures of 0.4 GK by more than 2 orders of magnitude and indicate that Ar and Ca may be ejected in observable quantities by oxygen-neon novae. However, based on the newly evaluated rate, the ^{38}K(p,γ)^{39}Ca path is unlikely to be responsible for the production of Ar and Ca in significantly enhanced quantities relative to solar abundances.
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Affiliation(s)
- G Lotay
- Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
- National Physical Laboratory, Teddington, Middlesex TW11 0LW, United Kingdom
| | - G Christian
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - C Ruiz
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - C Akers
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
- Department of Physics, The University of York, York YO10 5DD, United Kingdom
| | - D S Burke
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - W N Catford
- Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - A A Chen
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - D Connolly
- Colorado School of Mines, Golden, Colorado 80401, USA
| | - B Davids
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - J Fallis
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - U Hager
- Colorado School of Mines, Golden, Colorado 80401, USA
| | - D A Hutcheon
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - A Mahl
- Colorado School of Mines, Golden, Colorado 80401, USA
| | - A Rojas
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
| | - X Sun
- TRIUMF, Vancouver, British Columbia V6T 2A3, Canada
- McGill University, Montreal, Quebec H3A 0G4, Canada
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14
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Bennett MB, Wrede C, Brown BA, Liddick SN, Pérez-Loureiro D, Bardayan DW, Chen AA, Chipps KA, Fry C, Glassman BE, Langer C, Larson NR, McNeice EI, Meisel Z, Ong W, O'Malley PD, Pain SD, Prokop CJ, Schatz H, Schwartz SB, Suchyta S, Thompson P, Walters M, Xu X. Isospin Mixing Reveals ^{30}P(p,γ)^{31}S Resonance Influencing Nova Nucleosynthesis. Phys Rev Lett 2016; 116:102502. [PMID: 27015475 DOI: 10.1103/physrevlett.116.102502] [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: 12/16/2015] [Indexed: 06/05/2023]
Abstract
The thermonuclear ^{30}P(p,γ)^{31}S reaction rate is critical for modeling the final elemental and isotopic abundances of ONe nova nucleosynthesis, which affect the calibration of proposed nova thermometers and the identification of presolar nova grains, respectively. Unfortunately, the rate of this reaction is essentially unconstrained experimentally, because the strengths of key ^{31}S proton capture resonance states are not known, largely due to uncertainties in their spins and parities. Using the β decay of ^{31}Cl, we have observed the β-delayed γ decay of a ^{31}S state at E_{x}=6390.2(7) keV, with a ^{30}P(p,γ)^{31}S resonance energy of E_{r}=259.3(8) keV, in the middle of the ^{30}P(p,γ)^{31}S Gamow window for peak nova temperatures. This state exhibits isospin mixing with the nearby isobaric analog state at E_{x}=6279.0(6) keV, giving it an unambiguous spin and parity of 3/2^{+} and making it an important l=0 resonance for proton capture on ^{30}P.
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Affiliation(s)
- M B Bennett
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - C Wrede
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - B A Brown
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - S N Liddick
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - D Pérez-Loureiro
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - D W Bardayan
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - A A Chen
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - K A Chipps
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - C Fry
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - B E Glassman
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - C Langer
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - N R Larson
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - E I McNeice
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - Z Meisel
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - W Ong
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - P D O'Malley
- Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - S D Pain
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - C J Prokop
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - H Schatz
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - S B Schwartz
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Geology and Physics, University of Southern Indiana, Evansville, Indiana 47712, USA
| | - S Suchyta
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - P Thompson
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - M Walters
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - X Xu
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
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15
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Kanungo R, Sanetullaev A, Tanaka J, Ishimoto S, Hagen G, Myo T, Suzuki T, Andreoiu C, Bender P, Chen AA, Davids B, Fallis J, Fortin JP, Galinski N, Gallant AT, Garrett PE, Hackman G, Hadinia B, Jansen G, Keefe M, Krücken R, Lighthall J, McNeice E, Miller D, Otsuka T, Purcell J, Randhawa JS, Roger T, Rojas A, Savajols H, Shotter A, Tanihata I, Thompson IJ, Unsworth C, Voss P, Wang Z. Evidence of soft dipole resonance in ^{11}li with isoscalar character. Phys Rev Lett 2015; 114:192502. [PMID: 26024166 DOI: 10.1103/physrevlett.114.192502] [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: 12/24/2014] [Indexed: 06/04/2023]
Abstract
The first conclusive evidence of a dipole resonance in ^{11}Li having isoscalar character observed from inelastic scattering with a novel solid deuteron target is reported. The experiment was performed at the newly commissioned IRIS facility at TRIUMF. The results show a resonance peak at an excitation energy of 1.03±0.03 MeV with a width of 0.51±0.11 MeV (FWHM). The angular distribution is consistent with a dipole excitation in the distorted-wave Born approximation framework. The observed resonance energy together with shell model calculations show the first signature that the monopole tensor interaction is important in ^{11}Li. The first ab initio calculations in the coupled cluster framework are also presented.
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Affiliation(s)
- R Kanungo
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
| | - A Sanetullaev
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
- TRIUMF, Vancouver, British Columbia V6T2A3, Canada
| | - J Tanaka
- RCNP, Osaka University, Mihogaoka, Ibaraki, Osaka 567 0047, Japan
| | - S Ishimoto
- High Energy Accelerator Research Organization (KEK), Ibaraki 305-0801, Japan
| | - G Hagen
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - T Myo
- General Education, Faculty of Engineering, Osaka Institute of Technology, Osaka, Osaka 535-8585, Japan
| | - T Suzuki
- Department of Physics, Nihon University, Setagaya-ku, Tokyo 156-8550, Japan
| | - C Andreoiu
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - P Bender
- TRIUMF, Vancouver, British Columbia V6T2A3, Canada
| | - A A Chen
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - B Davids
- TRIUMF, Vancouver, British Columbia V6T2A3, Canada
| | - J Fallis
- TRIUMF, Vancouver, British Columbia V6T2A3, Canada
| | - J P Fortin
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
- Department of Physics, University of Laval, Quebec City, Quebec G1V 0A8, Canada
| | - N Galinski
- TRIUMF, Vancouver, British Columbia V6T2A3, Canada
| | - A T Gallant
- TRIUMF, Vancouver, British Columbia V6T2A3, Canada
| | - P E Garrett
- Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - G Hackman
- TRIUMF, Vancouver, British Columbia V6T2A3, Canada
| | - B Hadinia
- Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - G Jansen
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - M Keefe
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
| | - R Krücken
- TRIUMF, Vancouver, British Columbia V6T2A3, Canada
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - J Lighthall
- TRIUMF, Vancouver, British Columbia V6T2A3, Canada
| | - E McNeice
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - D Miller
- TRIUMF, Vancouver, British Columbia V6T2A3, Canada
| | - T Otsuka
- Department of Physics and Center of Nuclear Studies, University of Tokyo, Bunky-ku, Tokyo 113-0033, Japan
| | - J Purcell
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
| | - J S Randhawa
- Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia B3H 3C3, Canada
| | - T Roger
- Grand Accélérateur National dIons Lourds, CEA/DSM-CNRS/IN2P3, B.P. 55027, F-14076 Caen Cedex 5, France
| | - A Rojas
- TRIUMF, Vancouver, British Columbia V6T2A3, Canada
| | - H Savajols
- Grand Accélérateur National dIons Lourds, CEA/DSM-CNRS/IN2P3, B.P. 55027, F-14076 Caen Cedex 5, France
| | - A Shotter
- School of Physics and Astronomy, University of Edinburgh, EH9 3JZ, Edinburgh, United Kingdom
| | - I Tanihata
- RCNP, Osaka University, Mihogaoka, Ibaraki, Osaka 567 0047, Japan
- School of Physics and Nuclear Energy Engineering and IRCNPC, Beihang University, Beijing 100191, China
| | - I J Thompson
- Lawrence Livermore National Laboratory, L-414, Livermore, California 94551, USA
| | - C Unsworth
- TRIUMF, Vancouver, British Columbia V6T2A3, Canada
| | - P Voss
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Z Wang
- TRIUMF, Vancouver, British Columbia V6T2A3, Canada
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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16
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Bennett MB, Wrede C, Chipps KA, José J, Liddick SN, Santia M, Bowe A, Chen AA, Cooper N, Irvine D, McNeice E, Montes F, Naqvi F, Ortez R, Pain SD, Pereira J, Prokop C, Quaglia J, Quinn SJ, Schwartz SB, Shanab S, Simon A, Spyrou A, Thiagalingam E. Classical-NOVA CONTRIBUTION to the Milky Way's ²⁶Al abundance: exit channel of the key ²⁵Al(p,γ) ²⁶Si resonance. Phys Rev Lett 2013; 111:232503. [PMID: 24476263 DOI: 10.1103/physrevlett.111.232503] [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: 08/20/2013] [Revised: 10/07/2013] [Indexed: 06/03/2023]
Abstract
Classical novae are expected to contribute to the 1809-keV Galactic γ-ray emission by producing its precursor 26Al, but the yield depends on the thermonuclear rate of the unmeasured 25Al(p,γ)26Si reaction. Using the β decay of 26P to populate the key J(π)=3(+) resonance in this reaction, we report the first evidence for the observation of its exit channel via a 1741.6±0.6(stat)±0.3(syst) keV primary γ ray, where the uncertainties are statistical and systematic, respectively. By combining the measured γ-ray energy and intensity with other experimental data on 26Si, we find the center-of-mass energy and strength of the resonance to be E(r)=414.9±0.6(stat)±0.3(syst)±0.6(lit.) keV and ωγ=23±6(stat)(-10)(+11)(lit.) meV, respectively, where the last uncertainties are from adopted literature data. We use hydrodynamic nova simulations to model 26Al production showing that these measurements effectively eliminate the dominant experimental nuclear-physics uncertainty and we estimate that novae may contribute up to 30% of the Galactic 26Al.
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Affiliation(s)
- M B Bennett
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - C Wrede
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - K A Chipps
- Department of Physics, Colorado School of Mines, Golden, Colorado 08401, USA
| | - J José
- Departament Física i Enginyeria Nuclear (UPC) and Institut d'Estudis Espacials de Catalunya (IEEC), E-08034 Barcelona, Spain
| | - S N Liddick
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - M Santia
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - A Bowe
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Physics Department, Kalamazoo College, Kalamazoo, Michigan 49006, USA
| | - A A Chen
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - N Cooper
- Department of Physics and Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520, USA
| | - D Irvine
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - E McNeice
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - F Montes
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - F Naqvi
- Department of Physics and Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520, USA
| | - R Ortez
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Department of Physics, University of Washington, Seattle, Washington 98195, USA
| | - S D Pain
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - J Pereira
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - C Prokop
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - J Quaglia
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA and Department of Electrical Engineering, Michigan State University, East Lansing, Michigan 48824, USA
| | - S J Quinn
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - S B Schwartz
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Geology and Physics Department, University of Southern Indiana, Evansville, Indiana 47712, USA
| | - S Shanab
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
| | - A Simon
- National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - A Spyrou
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824, USA and Joint Institute for Nuclear Astrophysics, Michigan State University, East Lansing, Michigan 48824, USA
| | - E Thiagalingam
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada
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17
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Laird AM, Parikh A, Murphy ASJ, Wimmer K, Chen AA, Deibel CM, Faestermann T, Fox SP, Fulton BR, Hertenberger R, Irvine D, José J, Longland R, Mountford DJ, Sambrook B, Seiler D, Wirth HF. Is γ-ray emission from novae affected by interference effects in the 18F(p,α)15O reaction? Phys Rev Lett 2013; 110:032502. [PMID: 23373915 DOI: 10.1103/physrevlett.110.032502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Indexed: 06/01/2023]
Abstract
The (18)F(p,α)(15)O reaction rate is crucial for constraining model predictions of the γ-ray observable radioisotope (18)F produced in novae. The determination of this rate is challenging due to particular features of the level scheme of the compound nucleus, (19)Ne, which result in interference effects potentially playing a significant role. The dominant uncertainty in this rate arises from interference between J(π)=3/2(+) states near the proton threshold (S(p)=6.411 MeV) and a broad J(π)=3/2(+) state at 665 keV above threshold. This unknown interference term results in up to a factor of 40 uncertainty in the astrophysical S-factor at nova temperatures. Here we report a new measurement of states in this energy region using the (19)F((3)He,t)(19)Ne reaction. In stark contrast to previous assumptions we find at least 3 resonances between the proton threshold and E(cm)=50 keV, all with different angular distributions. None of these are consistent with J(π)=3/2(+) angular distributions. We find that the main uncertainty now arises from the unknown proton width of the 48 keV resonance, not from possible interference effects. Hydrodynamic nova model calculations performed indicate that this unknown width affects (18)F production by at least a factor of two in the model considered.
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Affiliation(s)
- A M Laird
- Department of Physics, University of York, York, United Kingdom.
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18
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Chadee DD, Huntley S, Focks DA, Chen AA. Aedes aegypti in Jamaica, West Indies: container productivity profiles to inform control strategies. Trop Med Int Health 2009; 14:220-7. [PMID: 19236668 DOI: 10.1111/j.1365-3156.2008.02216.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To describe the Aedes aegypti container profile in the three parishes of Portland, St. Anns and St. Catherine, Jamaica. METHOD Traditional stegomyia and pupae per person indices. RESULTS A total of 8855 containers were inspected. A. aegypti were breeding in 19.2% of the 4728 containers in Portland, in 6.7% of the 2639 containers in St. Ann, and in 27.2% of the 1488 containers in Tryhall Heights, St. Catherine. Container types differed between Portland (P > 0.02) on one hand and St. Ann and Tryhall Heights, St. Catherine on the other hand: there were with no vases or potted plants with water saucers in St. Ann and St. Catherine. A. aegypti were breeding in more containers in St. Catherine (38%) (38% in wet season and 21% in the dry season) than in Portland (19%) or St. Ann (6%), both of which had more containers but A. aegypti breeding in fewer: 17.7% and 11.2% in the wet and 20.4% and 3.5% in the dry seasons respectively. The daily production of adult mosquitoes in the three study sites was 1.51, 1.29 and 0.66 adult female mosquitoes per person in Portland, St. Ann and St. Catherine during the dry season and 1.12, 0.23 and 1.04 female mosquitoes per person in the wet season respectively. CONCLUSION All three communities are at risk for dengue outbreaks and vector control should concentrate on reducing the mosquito populations from the most productive containers before a new dengue virus serotype is introduced into Jamaica.
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Affiliation(s)
- D D Chadee
- Department of Life Sciences, University of the West Indies, St. Augustine, Trinidad, West Indies.
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19
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Baggish AL, Lloyd-Jones DM, Blatt J, Richards AM, Lainchbury J, O'Donoghue M, Sakhuja R, Chen AA, Januzzi JL. A clinical and biochemical score for mortality prediction in patients with acute dyspnoea: derivation, validation and incorporation into a bedside programme. Heart 2008; 94:1032-7. [DOI: 10.1136/hrt.2007.128132] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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20
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Chadee DD, Shivnauth B, Rawlins SC, Chen AA. Climate, mosquito indices and the epidemiology of dengue fever in Trinidad (2002-2004). Ann Trop Med Parasitol 2007; 101:69-77. [PMID: 17244411 DOI: 10.1179/136485907x157059] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Between January 2002 and December 2004, a population-based study on the effects of climate and mosquito indices on the incidences of dengue fever (DF) and dengue haemorrhagic fever (DHF) was conducted in Trinidad, West Indies. The incidence of DF was 5.05 cases/1000 population in 2002, largely as the result of a major outbreak, but declined to 0.49 case/1000 in 2004. The monthly Aedes aegypti (L.) Breteau indices (BI) did not decline over the 3-year study period, however, but increased from a mean of 29 in 2002 to one of 36 in 2004, with seasonal variations (BI of 30-46 and 20-34 were recorded in the wet and dry seasons, respectively). No significant correlations were observed between temperature and DF or DHF incidence but rainfall was found to be significantly correlated with DF incidence, with a clearly defined 'dengue season', between June and November, in two of the study years. The apparent decline in dengue transmission since 2002 appears to be largely attributable to the development of 'herd immunity' in the general population and not to the attempts at vector control. Since the introduction of new serotypes or the fading of the herd immunity could lead to an explosive epidemic of dengue in Trinidad, there is clearly a need for continued surveillance.
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Affiliation(s)
- D D Chadee
- Department of Life Sciences, University of the West Indies, St Augustine, Trinidad
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21
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Matei C, Buchmann L, Hannes WR, Hutcheon DA, Ruiz C, Brune CR, Caggiano J, Chen AA, D'Auria J, Laird A, Lamey M, Li ZH, Liu WP, Olin A, Ottewell D, Pearson J, Ruprecht G, Trinczek M, Vockenhuber C, Wrede C. Measurement of the cascade transition via the first excited state of 16O in the 12C(alpha,gamma)16O reaction, and its S factor in stellar helium burning. Phys Rev Lett 2006; 97:242503. [PMID: 17280274 DOI: 10.1103/physrevlett.97.242503] [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: 06/19/2006] [Indexed: 05/13/2023]
Abstract
Radiative alpha-particle capture into the first excited, J(pi)=0+ state of 16O at 6.049 MeV excitation energy has rarely been discussed as contributing to the 12C(alpha,gamma)16O reaction cross section due to experimental difficulties in observing this transition. We report here measurements of this radiative capture in 12C(alpha,gamma)16O for center-of-mass energies of E=2.22 MeV to 5.42 MeV at the DRAGON recoil separator. To determine cross sections, the acceptance of the recoil separator has been simulated in GEANT as well as measured directly. The transition strength between resonances has been identified in R-matrix fits as resulting both from E2 contributions as well as E1 radiative capture. Details of the extrapolation of the total cross section to low energies are then discussed [S6.0(300)=25(-15)(+16) keV b] showing that this transition is likely the most important cascade contribution for 12C(alpha,gamma)16O.
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Affiliation(s)
- C Matei
- Ohio University, Athens, Ohio, USA
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22
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Ruiz C, Parikh A, José J, Buchmann L, Caggiano JA, Chen AA, Clark JA, Crawford H, Davids B, D'Auria JM, Davis C, Deibel C, Erikson L, Fogarty L, Frekers D, Greife U, Hussein A, Hutcheon DA, Huyse M, Jewett C, Laird AM, Lewis R, Mumby-Croft P, Olin A, Ottewell DF, Ouellet CV, Parker P, Pearson J, Ruprecht G, Trinczek M, Vockenhuber C, Wrede C. Measurement of the Ec.m. = 184 keV resonance strength in the 26gAl (p, gamma)27 Si reaction. Phys Rev Lett 2006; 96:252501. [PMID: 16907298 DOI: 10.1103/physrevlett.96.252501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Indexed: 05/11/2023]
Abstract
The strength of the Ec.m. = 184 keV resonance in the 26gAl(p, gamma)27 reaction has been measured in inverse kinematics using the DRAGON recoil separator at TRIUMF's ISAC facility. We measure a value of omega gamma = 35 +/- 7 microeV and a resonance energy of Ec.m. = 184 +/- 1 keV, consistent with p-wave proton capture into the 7652(3) keV state in 27Si, and discuss the implications of these values for 26GAl nucleosynthesis in typical oxygen-neon white-dwarf novae.
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Affiliation(s)
- C Ruiz
- TRIUMF, Vancouver, BC V6T 2A3, Canada.
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23
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Chen AA, Sabatine MS. The management of unstable angina and non-ST-segment elevation myocardial infartion. Minerva Cardioangiol 2003; 51:433-45. [PMID: 14551514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Patients presenting with unstable angina and non-ST elevation myocardial infarction (UA/NSTEM) have a highly variable course. Optimal management is critical because of the high risk of death or myocardial infarction (MI) in the ensuing 30 days. In this article, we review the therapeutic options available to clinicians. Anti-ischemic therapy with beta-blockers and nitrates should be considered in all patients without contraindications. Aspirin remains a cornerstone of antiplatelet therapy and has been shown to substantially reduce the risk of death or MI. Although the data are less robust, unfractionated heparin (UFH) also appears to be efficacious, and the low-molecular-weight heparin (LMWH) enoxaparin appears to be superior to UFH. The GP IIb/IIIa inhibitors, highly beneficial in the setting of percutaneous coronary intervention (PCI), should be considered in patients with continuing ischemia or other high-risk features. The ADP receptor blocker clopidogrel has been shown to be beneficial in patients who are managed conservatively and in those who undergo PCI. Lastly, a strategy of early angiography should be considered in patients with recurrent ischemia or in those who present with high-risk features such as elevated troponins or ST deviation. Thus, early risk stratification using clinical features, electrocardiographic data, and biomarkers allows identification of subgroups of patients who are not only at high risk but also enjoy the greatest benefits from these aggressive therapies and thereby enables clinicians to target these interventions most effectively.
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Affiliation(s)
- A A Chen
- Cardiology Division, Massachusetts General Hospital, Boston, MA 02115, USA.
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24
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Bishop S, Azuma RE, Buchmann L, Chen AA, Chatterjee ML, D'Auria JM, Engel S, Gigliotti D, Greife U, Hernanz M, Hunter D, Hussein A, Hutcheon D, Jewett C, José J, King J, Kubono S, Laird AM, Lamey M, Lewis R, Liu W, Michimasa S, Olin A, Ottewell D, Parker PD, Rogers JG, Strieder F, Wrede C. 21Na(p,gamma)22Mg reaction and oxygen-neon novae. Phys Rev Lett 2003; 90:162501. [PMID: 12731972 DOI: 10.1103/physrevlett.90.162501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2002] [Indexed: 05/24/2023]
Abstract
The 21Na(p,gamma)22Mg reaction is expected to play an important role in the nucleosynthesis of 22Na in oxygen-neon novae. The decay of 22Na leads to the emission of a characteristic 1.275 MeV gamma-ray line. This report provides the first direct measurement of the rate of this reaction using a radioactive 21Na beam, and discusses its astrophysical implications. The energy of the important state was measured to be E(c.m.)=205.7+/-0.5 keV with a resonance strength omegagamma=1.03+/-0.16(stat)+/-0.14(sys) meV.
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Affiliation(s)
- S Bishop
- Simon Fraser University, Burnaby, British Columbia, Canada
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25
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Dunbar DA, Chen AA, Wormsley S, Baserga SJ. The genes for small nucleolar RNAs in Trypanosoma brucei are organized in clusters and are transcribed as a polycistronic RNA. Nucleic Acids Res 2000; 28:2855-61. [PMID: 10908346 PMCID: PMC102681 DOI: 10.1093/nar/28.15.2855] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2000] [Accepted: 06/13/2000] [Indexed: 11/14/2022] Open
Abstract
Because the organization of snoRNA genes in vertebrates, plants and yeast is diverse, we investigated the organization of snoRNA genes in a distantly related organism, Trypanosoma brucei. We have characterized the second example of a snoRNA gene cluster that is tandemly repeated in the T.BRUCEI: genome. The genes encoding the box C/D snoRNAs TBR12, TBR6, TBR4 and TBR2 make up the cluster. In a genomic organization unique to trypanosomes, there are at least four clusters of these four snoRNA genes tandemly repeated in the T. BRUCEI: genome. We show for the first time that the genes encoding snoRNAs in both this cluster and the SLA cluster are transcribed in an unusual way as a polycistronic RNA.
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Affiliation(s)
- D A Dunbar
- Department of Therapeutic Radiology and Department of Genetics, Yale School of Medicine, 333 Cedar Street, PO Box 208040, New Haven, CT 06520-8040, USA
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26
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Abstract
Oxidative damage of the lens causes disulfide bonds between cysteinyl residues of lens proteins and thiols such as glutathione and cysteine, which may lead to cataract. The effect of H2O2 oxidation was determined by comparing bovine lenses incubated with and without 30 mM H2O2. The H2O2 treatment decreased the glutathione and increased the protein-glutathione and protein-cysteine disulfides in the lens. The molecular mass of the gammaB-crystallin isolated from lenses, not treated with H2O2, agreed with the published sequence (Mr 20,966). Some lenses also had a less abundant gammaB-crystallin component 305 Da higher (Mr 21,270), suggesting the presence of a glutathione adduct. The gammaB-crystallins from H2O2 treated lenses had three components, the major one with one GSH adduct, another one with the mass of unmodified gammaB-crystallin, and a third with a mass consistent with addition of two GSH adducts. Mass spectrometric analysis of tryptic peptides of gammaB-crystallins from different lenses indicated that the +305 Da modifications were not at a specific cysteine. For the lenses incubated without H2O2, there was evidence of adducts at Cys-41 and in peptide 10-31, which includes 3 cysteines. Analysis of modified peptide 10-31 by tandem mass spectrometry showed GSH adducts at Cys-15, Cys-18, and Cys-22. In addition, gammaB-crystallins from H2O2-treated lenses had an adduct at Cys-109, partial oxidation at all 7 Met residues, and evidence for two disulfide bonds.
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Affiliation(s)
- S R Hanson
- Department of Chemistry, Department of Veterinary and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska 68583-0905, USA
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27
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Kenny GP, Chen AA, Nurbakhsh BA, Denis PM, Proulx CE, Giesbrecht GG. Moderate exercise increases postexercise thresholds for vasoconstriction and shivering. J Appl Physiol (1985) 1998; 85:1357-61. [PMID: 9760328 DOI: 10.1152/jappl.1998.85.4.1357] [Citation(s) in RCA: 8] [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] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of this study was to evaluate the effect of exercise on the subsequent postexercise thresholds for vasoconstriction and shivering. On two separate days, with six subjects (3 women), a whole body water-perfused suit slowly decreased mean skin temperature (approximately 7.0 degreesC/h) until thresholds for vasoconstriction and shivering were clearly established. Subjects were then rewarmed by increasing water temperature until both esophageal and mean skin temperatures returned to near-baseline values. Subjects either performed 15 min of cycle ergometry (65% maximal O2 consumption) followed by 30 min of recovery (Exercise) or remained seated with no exercise for 45 min (Control). Subjects were then cooled again. We mathematically compensated for changes in skin temperatures by using the established linear cutaneous contribution of skin to the control of vasoconstriction and shivering (20%). The calculated core temperature threshold (at a designated skin temperature of 30.0 degreesC) for vasoconstriction increased significantly from 36.64 +/- 0.20 to 36.89 +/- 0.22 degreesC postexercise (P < 0.01). Similarly, the shivering threshold increased from 35.73 +/- 0.13 to 36.13 +/- 0.12 degreesC postexercise (P < 0.01). In contrast, sequential measurements, without exercise, demonstrate a time-dependent decrease in both the vasoconstriction (0.10 degreesC) and shivering (0.12 degreesC) thresholds. These data indicate that exercise has a prolonged effect by increasing the postexercise thresholds for both cold thermoregulatory responses.
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Affiliation(s)
- G P Kenny
- Faculty of Health Sciences, School of Human Kinetics, University of Ottawa, Ottawa, Ontario K1N 6N5. gkenny.uottawa.ca
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28
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Smith AD, Geisler SC, Chen AA, Resnick DA, Roy BM, Lewi PJ, Arnold E, Arnold GF. Human rhinovirus type 14:human immunodeficiency virus type 1 (HIV-1) V3 loop chimeras from a combinatorial library induce potent neutralizing antibody responses against HIV-1. J Virol 1998; 72:651-9. [PMID: 9420270 PMCID: PMC109419 DOI: 10.1128/jvi.72.1.651-659.1998] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
In an effort to develop a useful AIDS vaccine or vaccine component, we have generated a combinatorial library of chimeric viruses in which the sequence IGPGRAFYTTKN from the V3 loop of the MN strain of human immunodeficiency virus type 1 (HIV-1) is displayed in many conformations on the surface of human rhinovirus 14 (HRV14). The V3 loop sequence was inserted into a naturally immunogenic site of the cold-causing HRV14, bridged by linkers consisting of zero to three randomized amino acids on each side. The library of chimeric viruses obtained was subjected to a variety of immunoselection schemes to isolate viruses that provided the most useful presentations of the V3 loop sequence for potential use in a vaccine against HIV. The utility of the presentations was assessed by measures of antigenicity and immunogenicity. Most of the immunoselected chimeras examined were potently neutralized by each of the four different monoclonal anti-V3 loop antibodies tested. Seven of eight chimeric viruses were able to elicit neutralizing antibody responses in guinea pigs against the MN and ALA-1 strains of HIV-1. Three of the chimeras elicited HIV neutralization titers that exceeded those of all but a small number of previously described HIV immunogens. These results indicate that HRV14:HIV-1 chimeras may serve as useful immunogens for stimulating immunity against HIV-1. This method can be used to flexibly reconstruct varied immunogens on the surface of a safe and immunogenic vaccine vehicle.
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Affiliation(s)
- A D Smith
- Center for Advanced Biotechnology and Medicine and Department of Chemistry, Rutgers University, Piscataway, New Jersey 08854, USA
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29
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Nicolaou G, Chen AA, Johnston CE, Kenny GP, Bristow GK, Giesbrecht GG. Clonidine decreases vasoconstriction and shivering thresholds, without affecting the sweating threshold. Can J Anaesth 1997; 44:636-42. [PMID: 9187784 DOI: 10.1007/bf03015448] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
PURPOSE This study was conducted to test the hypothesis that clonidine produces a dose-dependent increase in the sweating threshold and dose-dependent decreases in vasoconstriction and shivering thresholds. METHODS Six healthy subjects (two female) were studied on four days after taking clonidine in oral doses of either 0 (control), 3, 6 or 9 micrograms.kg-1. The order followed a balanced design in a double-blind fashion. Oesophageal temperature and mean skin temperature (from 12 sites) were measured. Subjects were seated in 37 degrees C water which was gradually warmed until sweating occurred (sweat rate increased above 50 g.m-2.h-1). The water was then cooled gradually until thresholds for vasoconstriction (onset of sustained decrease in fingertip blood flow) and shivering (sustained elevation in metabolism) were determined. Thresholds were then referred to as the core temperature, adjusted to a designated mean skin temperature of 33 degrees C. RESULTS High dose clonidine similarly decreased the adjusted core temperature thresholds for vasoconstriction by 1.16 +/- 0.30 degrees C and for shivering by 1.63 +/- 0.23 degrees C (P < 0.01). The dose response effects were linear for both cold responses with vasoconstriction and shivering thresholds decreasing by 0.13 +/- 0.05 and 0.19 +/- 0.09 degree C.microgram-1 respectively (P < 0.0001). The sweating threshold was unaffected by clonidine, however the interthreshold range between sweating and vasoconstriction thresholds increased from control (0.19 +/- 0.48 degree C) to high dose clonidine (1.31 +/- 0.54 degrees C). CONCLUSION The decreases in core temperature thresholds for cold responses and increased interthreshold range are consistent with the effects of several anaesthetic agents and opioids and is indicative of central thermoregulatory inhibition.
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Affiliation(s)
- G Nicolaou
- Laboratory for Exercise and Environmental Medicine, Health, Leisure and Human Performance Research Institute, Winnipeg, Manitoba, Canada
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Kenny GP, Chen AA, Johnston CE, Thoden JS, Giesbrecht GG. Intense exercise increases the post-exercise threshold for sweating. Eur J Appl Physiol Occup Physiol 1997; 76:116-21. [PMID: 9272768 DOI: 10.1007/s004210050222] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We demonstrated previously that esophageal temperature (T(es)) remains elevated by approximately 0.5 degrees C for at least 65 min after intense exercise. Following exercise, average skin temperature (T(avg)) and skin blood flow returned rapidly to pre-exercise values even though T(es) remained elevated, indicating that the T(es) threshold for vasodilation is elevated during this period. The present study evaluates the hypothesis that the threshold for sweating is also increased following intense exercise. Four males and three females were immersed in water (water temperature, T(w) = 42 degrees C) until onset of sweating (Immersion 1), followed by recovery in air (air temperature, T(a) = 24 degrees C). At a T(a) of 24 degrees C, 15 min of cycle ergometry (70% VO2max) (Exercise) was then followed by 30 min of recovery. Subjects were then immersed again (T(w) = 42 degrees C) until onset of sweating (Immersion 2). Baseline T(es) and T(skavg) were 37.0 (0.1) degrees C and 32.3 (0.3) degrees C, respectively. Because the T(skavg) at the onset of sweating was different during Exercise [30.9 (0.3) degrees C] than during Immersion 1 and Immersion 2 [36.8 (0.2) degrees C and 36.4 (0.2) degrees C, respectively] a corrected core temperature, T((es) (calculated)), was calculated at a single designated skin temperature, T((sk)(designated)), as follows: T((es)(calculated)) = T(es) + [beta/(1-beta)][T(skavg)-T((sk)(designated))]. The T((sk)(designated)) was set at 36.5 degrees C (mean of Immersion 1 and Immersion 2 conditions) and beta represents the fractional contribution of T(skavg) to the sweating response (beta for sweating = 0.1). While T((es)(calculated)) at the onset of sweating was significantly lower during exercise [36.7 (0.2) degrees C] than during Immersion 1 [37.1 (0.1) degrees C], the threshold of sweating during Immersion 2 [37.3 (0.1) degrees C] was greater than during both Exercise and Immersion 1 (P < 0.05). We conclude that intense exercise decreases the sweating threshold during exercise itself, but elicits a subsequent short-term increase in the resting sweating threshold.
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Affiliation(s)
- G P Kenny
- University of Manitoba, Health, Leisure and Human Performance Research Institute, Winnipeg, Canada
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Abstract
An underwater cycle ergometer was designed consisting of an aluminum cycle frame in water connected with a 1:1 gear ratio to a mechanically braked standard cycle ergometer supported above the water. Three progressive maximal exercise tests were performed (n = 10): (a) the underwater ergometer in water (UEW), (b) underwater ergometer in air (UEA), and (c) a standard cycle ergometer in air (SEA). At submaximal power outputs, oxygen consumption (VO2) and heart rate (HR) were generally lower in the SEA condition (p < .05), indicating that exercise in the upright position was more efficient. Exercise in water (UEW) resulted in lower total exercise duration, maximal HR, and maximal Tes than in air conditions. The upright position (SEA) resulted in greater total exercise duration and maximal power output than the semirecumbent positions. Because of positional differences between the standard and underwater ergometers, air-water comparisons should be made by using the underwater ergometer in water and on land.
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Affiliation(s)
- A A Chen
- Laboratory for Exercise and Environmental Medicine, Faculty of Physical Education and Recreation Studies, University of Manitoba, Winnipeg
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Abstract
Two methods were used to evaluate bacterial recovery from beef, pork, and lamb adipose tissue. Higher counts were obtained with a tissue removal and fluid agitation technique (shaking) than with surface swabbing, but only when bacterial levels were low. Bacterial recovery by both methods was unaffected by specie origin of adipose tissue and differences in surface texture, sample storage time (12 versus 6 days), and duration fluid agitation (5 versus 10 min).
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