1
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Taghvaee S, Shen J, Banach C, La C, Campbell SJ, Paulson SE. Robust quantification of the burst of OH radicals generated by ambient particles in nascent cloud droplets using a direct-to-reagent approach. Sci Total Environ 2023; 900:165736. [PMID: 37495143 DOI: 10.1016/j.scitotenv.2023.165736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 07/15/2023] [Accepted: 07/21/2023] [Indexed: 07/28/2023]
Abstract
Reactive oxygen species (ROS) play a central role in chemistry in cloud water, as well as in other aqueous phases such as lung fluid and in wastewater treatment. Recently, work simulating nascent cloud droplets showed that aerosol particles produce a large burst of OH radicals when they first take up water. This activity stops abruptly, within two minutes. The source of the OH radicals is not well understood, but it likely includes the aqueous phase chemistry of ROS and/or organic hydroperoxides and redox active metals such as iron and copper. ROS and their precursors are in general highly reactive and labile, and thus may not survive during traditional sampling methods, which typically involve multi-hour collection on a filter or direct sampling into water or another collection liquid. Further, these species may further decay during storage. Here, we develop a technique to grow aerosol particles into small droplets and capture the droplets directly into a vial containing the terephthalate probe in water, which immediately scavenges OH radicals produced by aerosol particles. The method uses a Liquid Spot Sampler. Extensive characterization of the approach reveals that the collection liquid picks up substantial OH/OH precursors from the gas phase. This issue is effectively addressed by adding an activated carbon denuder. We then compared OH formation measured with the direct-to-reagent approach vs. filter collection. We find that after a modest correction for OH formed in the collection liquid, the samples collected into the reagent produce about six times those collected on filters, for both PM2.5 and total suspended particulate. This highlights the need for direct-to-reagent measurement approaches to accurately quantify OH production from ambient aerosol particles.
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Affiliation(s)
- Sina Taghvaee
- Department of Atmospheric & Oceanic Sciences, University of California, Los Angeles, CA 90095, USA
| | - Jiaqi Shen
- Department of Atmospheric & Oceanic Sciences, University of California, Los Angeles, CA 90095, USA
| | - Catherine Banach
- Department of Atmospheric & Oceanic Sciences, University of California, Los Angeles, CA 90095, USA
| | - Chris La
- Department of Atmospheric & Oceanic Sciences, University of California, Los Angeles, CA 90095, USA
| | - Steven J Campbell
- Department of Atmospheric & Oceanic Sciences, University of California, Los Angeles, CA 90095, USA
| | - Suzanne E Paulson
- Department of Atmospheric & Oceanic Sciences, University of California, Los Angeles, CA 90095, USA.
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2
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Campbell SJ, Utinger B, Barth A, Paulson SE, Kalberer M. Iron and Copper Alter the Oxidative Potential of Secondary Organic Aerosol: Insights from Online Measurements and Model Development. Environ Sci Technol 2023; 57:13546-13558. [PMID: 37624361 PMCID: PMC10501117 DOI: 10.1021/acs.est.3c01975] [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] [Received: 03/14/2023] [Revised: 07/17/2023] [Accepted: 08/14/2023] [Indexed: 08/26/2023]
Abstract
The oxidative potential (OP) of particulate matter has been widely suggested as a key metric for describing atmospheric particle toxicity. Secondary organic aerosol (SOA) and redox-active transition metals, such as iron and copper, are key drivers of particle OP. However, their relative contributions to OP, as well as the influence of metal-organic interactions and particulate chemistry on OP, remains uncertain. In this work, we simultaneously deploy two novel online instruments for the first time, providing robust quantification of particle OP. We utilize online AA (OPAA) and 2,7-dichlorofluoroscein (ROSDCFH) methods to investigate the influence of Fe(II) and Cu(II) on the OP of secondary organic aerosol (SOA). In addition, we quantify the OH production (OPOH) from these particle mixtures. We observe a range of synergistic and antagonistic interactions when Fe(II) and Cu(II) are mixed with representative biogenic (β-pinene) and anthropogenic (naphthalene) SOA. A newly developed kinetic model revealed key reactions among SOA components, transition metals, and ascorbate, influencing OPAA. Model predictions agree well with OPAA measurements, highlighting metal-ascorbate and -naphthoquinone-ascorbate reactions as important drivers of OPAA. The simultaneous application of multiple OP assays and a kinetic model provides new insights into the influence of metal and SOA interactions on particle OP.
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Affiliation(s)
- Steven J. Campbell
- Department
of Environmental Sciences, University of
Basel, Klingelbergstrasse 27, 4057 Basel, Switzerland
- Department
of Atmospheric and Oceanic Sciences, University
of California at Los Angeles, 520 Portola Plaza, Los Angeles, California 90095, United States
| | - Battist Utinger
- Department
of Environmental Sciences, University of
Basel, Klingelbergstrasse 27, 4057 Basel, Switzerland
| | - Alexandre Barth
- Department
of Environmental Sciences, University of
Basel, Klingelbergstrasse 27, 4057 Basel, Switzerland
| | - Suzanne E. Paulson
- Department
of Atmospheric and Oceanic Sciences, University
of California at Los Angeles, 520 Portola Plaza, Los Angeles, California 90095, United States
| | - Markus Kalberer
- Department
of Environmental Sciences, University of
Basel, Klingelbergstrasse 27, 4057 Basel, Switzerland
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3
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Parinandi NL, Liaugminas A, Oliver PJ, Varadharaj S, Yenigalla A, Elliott AC, Arutla S, Campbell SJ, Kotha SR, Sherwani SI, Kutala VK, McDaniel JC, Maddipati KR, Kuppusamy P, Hund TJ. Classic Phytochemical Antioxidant and Lipoxygenase Inhibitor, Nordihydroguaiaretic Acid, Activates Phospholipase D through Oxidant Signaling and Tyrosine Phosphorylation Leading to Cytotoxicity in Lung Vascular Endothelial Cells. Cell Biochem Biophys 2023:10.1007/s12013-023-01128-1. [PMID: 36820994 DOI: 10.1007/s12013-023-01128-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2023] [Indexed: 02/24/2023]
Abstract
Nordihydroguaiaretic acid (NDGA), a dicatechol and phytochemical polyphenolic antioxidant and an established inhibitor of human arachidonic acid (AA) 5-lipoxygenase (LOX) and 15-LOX, is widely used to ascertain the role of LOXs in vascular endothelial cell (EC) function. As the modulatory effect of NDGA on phospholipase D (PLD), an important lipid signaling enzyme in ECs, thus far has not been reported, here we have investigated the modulation of PLD activity and its regulation by NDGA in the bovine pulmonary artery ECs (BPAECs). NDGA induced the activation of PLD (phosphatidic acid formation) in cells in a dose- and time-dependent fashion that was significantly attenuated by iron chelator and antioxidants. NDGA induced the formation of reactive oxygen species (ROS) in cells in a dose- and time-dependent manner as evidenced from fluorescence microscopy and fluorimetry of ROS and electron paramagnetic resonance spectroscopy of oxygen radicals. Also, NDGA caused a dose-dependent loss of intracellular glutathione (GSH) in BPAECs. Protein tyrosine kinase (PTyK)-specific inhibitors significantly attenuated NDGA-induced PLD activation in BPAECs. NDGA also induced a dose- and time-dependent phosphorylation of tyrosine in proteins in cells. NDGA caused in situ translocation and relocalization of both PLD1 and PLD2 isoforms, in a time-dependent fashion. Cyclooxygenase (COX) inhibitors were ineffective in attenuating NDGA-induced PLD activation in BPAECs, thus ruling out the activation of COXs by NDGA. NDGA inhibited the AA-LOX activity and leukotriene C4 (LTC4) formation in cells. On the other hand, the 5-LOX-specific inhibitors, 5, 8, 11, 14-eicosatetraynoic acid and kaempferol, were ineffective in activating PLD in BPAECs. Antioxidants and PTyK-specific inhibitors effectively attenuated NDGA cytotoxicity in BPAECs. The PLD-specific inhibitor, 5-fluoro-2-indolyl deschlorohalopemide (FIPI), significantly attenuated and protected against the NDGA-induced PLD activation and cytotoxicity in BPAECs. For the first time, these results demonstrated that NDGA, the classic phytochemical polyphenolic antioxidant and LOX inhibitor, activated PLD causing cytotoxicity in ECs through upstream oxidant signaling and protein tyrosine phosphorylation.
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Affiliation(s)
- Narasimham L Parinandi
- Lipid Signaling, Lipidomics, and Vasculotoxicity Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA.
| | - Alex Liaugminas
- Lipid Signaling, Lipidomics, and Vasculotoxicity Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Patrick J Oliver
- Lipid Signaling, Lipidomics, and Vasculotoxicity Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Saradhadevi Varadharaj
- Lipid Signaling, Lipidomics, and Vasculotoxicity Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Anita Yenigalla
- Lipid Signaling, Lipidomics, and Vasculotoxicity Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Austin C Elliott
- Lipid Signaling, Lipidomics, and Vasculotoxicity Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Sukruthi Arutla
- Lipid Signaling, Lipidomics, and Vasculotoxicity Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Steven J Campbell
- Lipid Signaling, Lipidomics, and Vasculotoxicity Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Sainath R Kotha
- Lipid Signaling, Lipidomics, and Vasculotoxicity Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Shariq I Sherwani
- Lipid Signaling, Lipidomics, and Vasculotoxicity Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Vijay K Kutala
- Lipid Signaling, Lipidomics, and Vasculotoxicity Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Jodi C McDaniel
- Lipid Signaling, Lipidomics, and Vasculotoxicity Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
| | - Krishna Rao Maddipati
- Department of Pathology and Lipidomics Core Facility, Wayne State University, Detroit, MI, 48202, USA
| | - Periannan Kuppusamy
- Department of Medicine, Geisel School of Medicine, Dartmouth College, Lebanon, NH, 03756, USA
| | - Thomas J Hund
- Lipid Signaling, Lipidomics, and Vasculotoxicity Laboratory, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Department of Medicine and Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, 43210, USA
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4
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Prior SJ, Mather CA, Campbell SJ. Redesigning Rural Acute Stroke Care: A Person-Centered Approach. Int J Environ Res Public Health 2023; 20:1581. [PMID: 36674336 PMCID: PMC9864304 DOI: 10.3390/ijerph20021581] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 01/10/2023] [Accepted: 01/12/2023] [Indexed: 06/17/2023]
Abstract
Stroke service delivery in rural areas in Australia lacks evidence-based, best practice care protocols as a result of limited resources and opportunity. Healthcare redesign is an approach to improving health services by understanding barriers and enablers to service provision and work with users to develop solutions for improvement. This research aimed to qualitatively evaluate stroke care in rural Tasmania using a person-centered approach, as part of a larger healthcare redesign initiative to improve acute stroke care. Semi-structured interviews, aimed at gaining insight into experiences of healthcare staff and users, were conducted. Thematic analysis revealed three global themes (communication, holistic care, and resourcing) that demonstrated some consistency between healthcare staff and user experience, highlighting that some needs and expectations were not being met. Results of this experiential study provide important perspectives for delivering needs-based improvements in service provision for acute stroke care. Overall, this study showed that systems of stroke care in rural areas could be improved by utilizing a redesign approach including healthcare staff and users in the development of solutions for health service improvement.
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Affiliation(s)
- Sarah J. Prior
- Tasmanian School of Medicine, Rural Clinical School, University of Tasmania, Burnie, TS 7320, Australia
| | - Carey A. Mather
- Australian Institute of Health Service Management, University of Tasmania, Launceston, TS 7250, Australia
| | - Steven J. Campbell
- School of Nursing, University of Tasmania, Launceston, TS 7250, Australia
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5
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Wang S, Gallimore PJ, Liu-Kang C, Yeung K, Campbell SJ, Utinger B, Liu T, Peng H, Kalberer M, Chan AWH, Abbatt JPD. Dynamic Wood Smoke Aerosol Toxicity during Oxidative Atmospheric Aging. Environ Sci Technol 2023; 57:1246-1256. [PMID: 36630690 DOI: 10.1021/acs.est.2c05929] [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: 06/17/2023]
Abstract
Wildfires are a major source of biomass burning aerosol to the atmosphere, with their incidence and intensity expected to increase in a warmer future climate. However, the toxicity evolution of biomass burning organic aerosol (BBOA) during atmospheric aging remains poorly understood. In this study, we report a unique set of chemical and toxicological metrics of BBOA from pine wood smoldering during multiphase aging by gas-phase hydroxyl radicals (OH). Both the fresh and OH-aged BBOA show activity relevant to adverse health outcomes. The results from two acellular assays (DTT and DCFH) show significant oxidative potential (OP) and reactive oxygen species (ROS) formation in OH-aged BBOA. Also, radical concentrations in the aerosol assessed by electron paramagnetic resonance (EPR) spectroscopy increased by 50% following heterogeneous aging. This enhancement was accompanied by a transition from predominantly carbon-centered radicals (85%) in the fresh aerosol to predominantly oxygen-centered radicals (76%) following aging. Both the fresh and aged biomass burning aerosols trigger prominent antioxidant defense during the in vitro exposure, indicating the induction of oxidative stress by BBOA in the atmosphere. By connecting chemical composition and toxicity using an integrated approach, we show that short-term aging initiated by OH radicals can produce biomass burning particles with a higher particle-bound ROS generation capacity, which are therefore a more relevant exposure hazard for residents in large population centers close to wildfire regions than previously studied fresh biomass burning emissions.
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Affiliation(s)
- Shunyao Wang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
| | - Peter J Gallimore
- Department of Earth and Environmental Sciences, University of Manchester, Manchester M13 9PL, United Kingdom
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Carolyn Liu-Kang
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Kirsten Yeung
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Steven J Campbell
- Centre for Atmospheric Science, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
- Department of Environmental Sciences, University of Basel, 4056 Basel, Switzerland
| | - Battist Utinger
- Department of Environmental Sciences, University of Basel, 4056 Basel, Switzerland
| | - Tengyu Liu
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
- Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University, Nanjing 210023, China
| | - Hui Peng
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
- School of the Environment, University of Toronto, Toronto, Ontario M5S 3E8, Canada
| | - Markus Kalberer
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
- Centre for Atmospheric Science, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Arthur W H Chan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada
- School of the Environment, University of Toronto, Toronto, Ontario M5S 3E8, Canada
| | - Jonathan P D Abbatt
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
- School of the Environment, University of Toronto, Toronto, Ontario M5S 3E8, Canada
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6
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Campbell SJ, Wolfer K, Gallimore PJ, Giorio C, Häussinger D, Boillat MA, Kalberer M. Characterization and Quantification of Particle-Bound Criegee Intermediates in Secondary Organic Aerosol. Environ Sci Technol 2022; 56:12945-12954. [PMID: 36054832 PMCID: PMC9494744 DOI: 10.1021/acs.est.2c04101] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 08/18/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
The ozonolysis of alkenes contributes substantially to the formation of secondary organic aerosol (SOA), which are important modulators of air quality and the Earth's climate. Criegee intermediates (CIs) are abundantly formed through this reaction. However, their contributions to aerosol particle chemistry remain highly uncertain. In this work, we present the first application of a novel methodology, using spin traps, which simultaneously quantifies CIs produced from the ozonolysis of volatile organic compounds in the gas and particle phases. Only the smallest CI with one carbon atom was detected in the gas phase of a β-caryophyllene ozonolysis reaction system. However, multiple particle-bound CIs were observed in β-caryophyllene SOA. The concentration of the most abundant CI isomer in the particle phase was estimated to constitute ∼0.013% of the SOA mass under atmospherically relevant conditions. We also demonstrate that the lifetime of CIs in highly viscous SOA particles is at least on the order of minutes, substantially greater than their gas-phase lifetime. The confirmation of substantial concentrations of large CIs with elongated lifetimes in SOA raises new questions regarding their influence on the chemical evolution of viscous SOA particles, where CIs may be a previously underestimated source of reactive species.
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Affiliation(s)
- Steven J. Campbell
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
- Department
of Environmental Sciences, University of
Basel, Basel, Klingelbergstrasse 27, Basel 4056, Switzerland
| | - Kate Wolfer
- Department
of Environmental Sciences, University of
Basel, Basel, Klingelbergstrasse 27, Basel 4056, Switzerland
| | - Peter J. Gallimore
- Department
of Earth and Environmental Sciences, University
of Manchester, Manchester M13 9PS, United Kingdom
| | - Chiara Giorio
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
| | - Daniel Häussinger
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, Basel 4056, Switzerland
| | - Marc-Aurèle Boillat
- Department
of Chemistry, University of Basel, St. Johanns-Ring 19, Basel 4056, Switzerland
| | - Markus Kalberer
- Department
of Environmental Sciences, University of
Basel, Basel, Klingelbergstrasse 27, Basel 4056, Switzerland
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7
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Prior SJ, Heath A, Reeves NS, Campbell SJ, Maxwell H, Bramble M, Marlow A, Doherty D. Determining readiness for a reablement approach to care in Australia: Development of a pre-employment questionnaire. Health Soc Care Community 2022; 30:498-508. [PMID: 32877000 DOI: 10.1111/hsc.13150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 06/25/2020] [Accepted: 08/06/2020] [Indexed: 06/11/2023]
Abstract
Reablement is described as a goal directed intervention with a view to maintain or improve the independence of clients through "doing with, rather than doing for". As a relatively new concept in care, lack of specific skills in reablement is not uncommon, however, intrinsic values aligned with reablement are beneficial to organisations providing care and support to clients. The aim of this study is to develop a pre-employment questionnaire to assess readiness for a reablement approach to care as a step towards developing a reablement culture across organisations. A questionnaire based on activities of daily living (ADL), developed by the research team in consultation with a local community-based care organisation, was completed by 166 staff members at a community-based care organisation in Tasmania across several timepoints during and following reablement education sessions in 2018. The scores from these questionnaires were utilised to develop a questionnaire appropriate for determining readiness for reablement prior to employment within the organisation. Over a period of twelve months, a total of 407 Reablement Readiness Questionnaires were submitted by staff, indicating high levels of willingness to engage in reablement prior to and following the education sessions. Exploratory factor analyses were performed, and the construct validity and internal consistency of the emerging factors were assessed. An exploratory factor analysis indicated that ADL, in relation to reablement, consist of three dimensions-Lifestyle, My body and Connecting. The corresponding questions were subsequently built into an online questionnaire for pre-employment use. This questionnaire also has potential benefit in recruitment of staff to other community service organisations, to ascertain their readiness for reablement prior to beginning a variety of different roles within client care and support.
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Affiliation(s)
- Sarah J Prior
- Tasmanian School of Medicine, University of Tasmania, Burnie, Tasmania, Australia
| | - Anne Heath
- University College, University of Tasmania, Burnie, Tasmania, Australia
| | - Nicole S Reeves
- Tasmanian School of Medicine, University of Tasmania, Burnie, Tasmania, Australia
| | - Steven J Campbell
- School of Nursing, University of Tasmania, Newnham, Tasmania, Australia
| | - Hazel Maxwell
- School of Health Sciences, University of Tasmania, Sydney, New South Wales, Australia
| | - Marguerite Bramble
- School of Nursing, Midwifery and Indigenous Health, Charles Sturt University, Bathurst, New South Wales, Australia
| | - Annette Marlow
- School of Nursing, University of Tasmania, Newnham, Tasmania, Australia
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8
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Young S, Swarts K, Prior SJ, Doherty D, Campbell SJ. Vertical integration in the Australian community care setting: Can it work? A theoretical review of current literature. Int J Health Plann Manage 2022; 37:1299-1310. [PMID: 35001434 DOI: 10.1002/hpm.3412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 12/15/2021] [Accepted: 12/20/2021] [Indexed: 11/06/2022] Open
Abstract
Vertical integration (VI) is considered a strategic management plan whereby an organisation has ownership of its supply chain. It is utilised as a method for managing the economic needs and approaches of an organisation and ensuring that a product is readily available for use. From a healthcare perspective, this pertains to the coordination of services or levels of care and allows for adaptation to changing circumstances. This study reviews existing literature on VI in a healthcare setting to assess feasibility and effectiveness of this proposed solution. A theoretical literature review was performed utilising conceptual categorisation to understand how VI may benefit community care organisations, using the needs of a local organisation as an example. Seventeen articles were included from a range of databases and grey literature with findings categorised according to two research questions. The findings suggest that for VI to be effective and efficient it is important to consider the following themes: market failure, barriers to entry, productive capabilities and specific healthcare issues. In conclusion, from a management and economic perspective, when markets are not functioning efficiently and are in disequilibrium, VI may provide an appropriate avenue to address these problems, in particular for community care organisations.
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Affiliation(s)
- Sarah Young
- Tasmanian School of Medicine, University of Tasmania, College of Health and Medicine, Launceston, Tasmania, Australia
| | - Kevin Swarts
- Tasmanian School of Business and Economics, University of Tasmania Centenary Building, Sandy Bay, Tasmania, Australia
| | - Sarah J Prior
- Tasmanian School of Medicine, University of Tasmania, College of Health and Medicine, Burnie, Tasmania, Australia
| | | | - Steven J Campbell
- School of Nursing, University of Tasmania, College of Health and Medicine, Launceston, Tasmania, Australia
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9
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Campbell SJ, Wolfer K, Utinger B, Westwood J, Zhang ZH, Bukowiecki N, Steimer SS, Vu TV, Xu J, Straw N, Thomson S, Elzein A, Sun Y, Liu D, Li L, Fu P, Lewis AC, Harrison RM, Bloss WJ, Loh M, Miller MR, Shi Z, Kalberer M. Atmospheric conditions and composition that influence PM 2.5 oxidative potential in Beijing, China. Atmos Chem Phys 2021; 21:5549-5573. [PMID: 34462630 PMCID: PMC7611584 DOI: 10.5194/acp-21-5549-2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Epidemiological studies have consistently linked exposure to PM2.5 with adverse health effects. The oxidative potential (OP) of aerosol particles has been widely suggested as a measure of their potential toxicity. Several acellular chemical assays are now readily employed to measure OP; however, uncertainty remains regarding the atmospheric conditions and specific chemical components of PM2.5 that drive OP. A limited number of studies have simultaneously utilised multiple OP assays with a wide range of concurrent measurements and investigated the seasonality of PM2.5 OP. In this work, filter samples were collected in winter 2016 and summer 2017 during the atmospheric pollution and human health in a Chinese megacity campaign (APHH-Beijing), and PM2.5 OP was analysed using four acellular methods: ascorbic acid (AA), dithiothreitol (DTT), 2,7-dichlorofluorescin/hydrogen peroxidase (DCFH) and electron paramagnetic resonance spectroscopy (EPR). Each assay reflects different oxidising properties of PM2.5, including particle-bound reactive oxygen species (DCFH), superoxide radical production (EPR) and catalytic redox chemistry (DTT/AA), and a combination of these four assays provided a detailed overall picture of the oxidising properties of PM2.5 at a central site in Beijing. Positive correlations of OP (normalised per volume of air) of all four assays with overall PM2.5 mass were observed, with stronger correlations in winter compared to summer. In contrast, when OP assay values were normalised for particle mass, days with higher PM2.5 mass concentrations (μgm-3) were found to have lower mass-normalised OP values as measured by AA and DTT. This finding supports that total PM2.5 mass concentrations alone may not always be the best indicator for particle toxicity. Univariate analysis of OP values and an extensive range of additional measurements, 107 in total, including PM2.5 composition, gas-phase composition and meteorological data, provided detailed insight into the chemical components and atmospheric processes that determine PM2.5 OP variability. Multivariate statistical analyses highlighted associations of OP assay responses with varying chemical components in PM2.5 for both mass- and volume-normalised data. AA and DTT assays were well predicted by a small set of measurements in multiple linear regression (MLR) models and indicated fossil fuel combustion, vehicle emissions and biogenic secondary organic aerosol (SOA) as influential particle sources in the assay response. Mass MLR models of OP associated with compositional source profiles predicted OP almost as well as volume MLR models, illustrating the influence of mass composition on both particle-level OP and total volume OP. Univariate and multivariate analysis showed that different assays cover different chemical spaces, and through comparison of mass- and volume-normalised data we demonstrate that mass-normalised OP provides a more nuanced picture of compositional drivers and sources of OP compared to volume-normalised analysis. This study constitutes one of the most extensive and comprehensive composition datasets currently available and provides a unique opportunity to explore chemical variations in PM2.5 and how they affect both PM2.5 OP and the concentrations of particle-bound reactive oxygen species.
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Affiliation(s)
- Steven J. Campbell
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Kate Wolfer
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Battist Utinger
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Joe Westwood
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Zhi-Hui Zhang
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
- Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Nicolas Bukowiecki
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | | | - Tuan V. Vu
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Jingsha Xu
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Nicholas Straw
- Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Steven Thomson
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Atallah Elzein
- Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York, UK
| | - Yele Sun
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
| | - Di Liu
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
| | - Linjie Li
- State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
| | - Pingqing Fu
- Institute of Surface Earth System Science, Tianjin University, Tianjin, China
| | - Alastair C. Lewis
- Wolfson Atmospheric Chemistry Laboratories, Department of Chemistry, University of York, York, UK
- National Centre for Atmospheric Science, University of York, York, UK
| | - Roy M. Harrison
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - William J. Bloss
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Miranda Loh
- Institute of Occupational Medicine, Edinburgh, UK
| | - Mark R. Miller
- Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Zongbo Shi
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Markus Kalberer
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
- Department of Chemistry, University of Cambridge, Cambridge, UK
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10
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Shen J, Griffiths PT, Campbell SJ, Utinger B, Kalberer M, Paulson SE. Ascorbate oxidation by iron, copper and reactive oxygen species: review, model development, and derivation of key rate constants. Sci Rep 2021; 11:7417. [PMID: 33795736 PMCID: PMC8016884 DOI: 10.1038/s41598-021-86477-8] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 03/02/2021] [Indexed: 02/01/2023] Open
Abstract
Ascorbic acid is among the most abundant antioxidants in the lung, where it likely plays a key role in the mechanism by which particulate air pollution initiates a biological response. Because ascorbic acid is a highly redox active species, it engages in a far more complex web of reactions than a typical organic molecule, reacting with oxidants such as the hydroxyl radical as well as redox-active transition metals such as iron and copper. The literature provides a solid outline for this chemistry, but there are large disagreements about mechanisms, stoichiometries and reaction rates, particularly for the transition metal reactions. Here we synthesize the literature, develop a chemical kinetics model, and use seven sets of laboratory measurements to constrain mechanisms for the iron and copper reactions and derive key rate constants. We find that micromolar concentrations of iron(III) and copper(II) are more important sinks for ascorbic acid (both AH2 and AH-) than reactive oxygen species. The iron and copper reactions are catalytic rather than redox reactions, and have unit stoichiometries: Fe(III)/Cu(II) + AH2/AH- + O2 → Fe(III)/Cu(II) + H2O2 + products. Rate constants are 5.7 × 104 and 4.7 × 104 M-2 s-1 for Fe(III) + AH2/AH- and 7.7 × 104 and 2.8 × 106 M-2 s-1 for Cu(II) + AH2/AH-, respectively.
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Affiliation(s)
- Jiaqi Shen
- Department of Atmospheric and Oceanic Sciences, University of California At Los Angeles, Los Angeles, CA, 90095-1565, USA
| | - Paul T Griffiths
- Department of Chemistry, Cambridge University, Lensfield Rd, Cambridge, CB2 1EW, UK
| | - Steven J Campbell
- Department of Environmental Sciences, University of Basel, Klingelbergstrasse 27, 4056, Basel, Switzerland
| | - Battist Utinger
- Department of Environmental Sciences, University of Basel, Klingelbergstrasse 27, 4056, Basel, Switzerland
| | - Markus Kalberer
- Department of Chemistry, Cambridge University, Lensfield Rd, Cambridge, CB2 1EW, UK
- Department of Environmental Sciences, University of Basel, Klingelbergstrasse 27, 4056, Basel, Switzerland
| | - Suzanne E Paulson
- Department of Atmospheric and Oceanic Sciences, University of California At Los Angeles, Los Angeles, CA, 90095-1565, USA.
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11
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Prior SJ, Reeves NS, Campbell SJ. Challenges of delivering evidence‐based stroke services for rural areas in Australia. Aust J Rural Health 2020; 28:15-21. [DOI: 10.1111/ajr.12579] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 09/01/2019] [Accepted: 09/10/2019] [Indexed: 11/30/2022] Open
Affiliation(s)
- Sarah Jane Prior
- College of Health and Medicine School of Medicine University of Tasmania Burnie TAS Australia
| | - Nicole S. Reeves
- College of Health and Medicine School of Medicine University of Tasmania Burnie TAS Australia
| | - Steven J. Campbell
- College of Health and Medicine School of Health Sciences University of Tasmania Newnham TAS Australia
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12
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Campbell SJ, Utinger B, Lienhard DM, Paulson SE, Shen J, Griffiths PT, Stell AC, Kalberer M. Development of a Physiologically Relevant Online Chemical Assay To Quantify Aerosol Oxidative Potential. Anal Chem 2019; 91:13088-13095. [DOI: 10.1021/acs.analchem.9b03282] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Steven J. Campbell
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Department of Environmental Sciences, University of Basel, Klingelbergstrasse 27, 4056 Basel, Switzerland
| | - Battist Utinger
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Department of Environmental Sciences, University of Basel, Klingelbergstrasse 27, 4056 Basel, Switzerland
| | - Daniel M. Lienhard
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Suzanne E. Paulson
- Department of Atmospheric and Oceanic Sciences, University of California at Los Angeles, Los Angeles, California 90095-1565, United States
| | - Jiaqi Shen
- Department of Atmospheric and Oceanic Sciences, University of California at Los Angeles, Los Angeles, California 90095-1565, United States
| | - Paul T. Griffiths
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Angharad C. Stell
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - Markus Kalberer
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
- Department of Environmental Sciences, University of Basel, Klingelbergstrasse 27, 4056 Basel, Switzerland
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13
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Campbell SJ, Stevanovic S, Miljevic B, Bottle SE, Ristovski Z, Kalberer M. Quantification of Particle-Bound Organic Radicals in Secondary Organic Aerosol. Environ Sci Technol 2019; 53:6729-6737. [PMID: 31075990 DOI: 10.1021/acs.est.9b00825] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The chemical composition and evolution of secondary organic aerosol (SOA) in the atmosphere represents one of the largest uncertainties in our current understanding of air quality. Despite vast research, the toxicological mechanisms relating to adverse human health effects upon exposure to particulate matter are still poorly understood. Particle-bound reactive oxygen species (ROS) may substantially contribute to observed health effects by influencing aerosol oxidative potential (OP). The role of radicals in both the formation and aging of aerosol, as well as their contribution to aerosol OP, remains highly uncertain. The profluorescent spin trap BPEAnit (9,10-bis(phenylethynyl)anthracenenitroxide), previously utilized to study combustion-generated aerosol, has been applied to provide the first estimate of particle-bound radical concentrations in SOA. We demonstrate that SOA from different atmospherically important VOC precursors have different particle-bound radical concentrations, estimated for the ozonolysis of α-pinene (0.020 ± 0.0050 nmol/μg), limonene (0.0059 ± 0.0010 nmol/μg), and β-caryophyllene (0.0025 ± 0.00080 nmol/μg), highlighting the potential importance of OH-initiated formation of particle-bound organic radicals. Additionally, the lifetime of particle-bound radical species in α-pinene SOA was estimated, and a pseudo-first-order rate constant of k = 7.3 ± 1.7 × 10-3 s-1 was derived, implying a radical lifetime on the order of minutes.
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Affiliation(s)
- Steven J Campbell
- Centre for Atmospheric Science, Department of Chemistry , University of Cambridge , Cambridge CB2 1EW , United Kingdom
- Department of Environmental Sciences , University of Basel , Klingelbergstrasse 27 , 4056 Basel , Switzerland
| | - Svetlana Stevanovic
- International Laboratory for Air Quality and Health , Queensland University of Technology , Brisbane QLD 4001 , Australia
- School of Engineering , Deakin University , Waurn Ponds , 3126 Australia
| | - Branka Miljevic
- International Laboratory for Air Quality and Health , Queensland University of Technology , Brisbane QLD 4001 , Australia
| | - Steven E Bottle
- ARC Centre for Excellence for Free Radical Chemistry and Biotechnology , Queensland University of Technology , Brisbane , QLD 4001 , Australia
| | - Zoran Ristovski
- International Laboratory for Air Quality and Health , Queensland University of Technology , Brisbane QLD 4001 , Australia
| | - Markus Kalberer
- Centre for Atmospheric Science, Department of Chemistry , University of Cambridge , Cambridge CB2 1EW , United Kingdom
- Department of Environmental Sciences , University of Basel , Klingelbergstrasse 27 , 4056 Basel , Switzerland
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14
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Abstract
Spreading beyond the realm of tertiary academic medical centers, point-of-care ultrasound in the intensive care unit is an important diagnostic tool. The real-time feedback garnered can lead to critical and clinically relevant changes in management and decrease potential complications. Bedside ultrasound evaluation in the intensive care setting with a small, portable equipment is well-suited for placement of central lines, lumbar puncture, thoracentesis or other bedside ICU procedures and in the evaluation of cardiac activity, pleural and abdominal cavity and the overall fluid volume. Formalized curriculums centering on point-of-care ultrasound are emerging that will enhance its applicability and relevance.
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Affiliation(s)
- Steven J Campbell
- Section of Interventional Pulmonology, Division of Pulmonary, Critical Care and Sleep Medicine, Ohio State University Wexner Medical Center, 201 DHLRI, 473 West 12th Avenue, Columbus, OH 43210, USA
| | - Rabih Bechara
- Cancer Treatment Centers of America, Southeastern Regional Medical Center, 600 Celebrate Life Parkway, Newnan, GA 30265, USA
| | - Shaheen Islam
- Section of Interventional Pulmonology, Division of Pulmonary, Critical Care and Sleep Medicine, Ohio State University Wexner Medical Center, 201 DHLRI, 473 West 12th Avenue, Columbus, OH 43210, USA.
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15
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Giorio C, Campbell SJ, Bruschi M, Archibald AT, Kalberer M. Detection and identification of Criegee intermediates from the ozonolysis of biogenic and anthropogenic VOCs: comparison between experimental measurements and theoretical calculations. Faraday Discuss 2018; 200:559-578. [PMID: 28580994 PMCID: PMC5708353 DOI: 10.1039/c7fd00025a] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ozonolysis of alkenes is a key reaction in the atmosphere, playing an important role in determining the oxidising capacity of the atmosphere and acting as a source of compounds that can contribute to local photochemical “smog”. The reaction products of the initial step of alkene-ozonolysis are Criegee intermediates (CIs), which have for many decades eluded direct experimental detection because of their very short lifetime. We use an innovative experimental technique, stabilisation of CIs with spin traps and analysis with proton transfer reaction mass spectrometry, to measure the gas phase concentration of a series of CIs formed from the ozonolysis of a range of both biogenic and anthropogenic alkenes in flow tube experiments. Density functional theory (DFT) calculations were used to assess the stability of the CI-spin trap adducts and show that the reaction of the investigated CIs with the spin trap occurs very rapidly except for the large β-pinene CI. Our measurement method was used successfully to measure all the expected CIs, emphasising that this new technique is applicable to a wide range of CIs with different molecular structures that were previously unidentified experimentally. In addition, for the first time it was possible to study CIs simultaneously in an even more complex reaction system consisting of more than one olefinic precursor. Comparison between our new experimental measurements, calculations of stability of the CI-spin trap adducts and results from numerical modelling, using the master chemical mechanism (MCM), shows that our new method can be used for the quantification of CIs produced in situ in laboratory experiments.
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Affiliation(s)
- Chiara Giorio
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
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16
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Ghafari M, Louzguine-Luzgin DV, Hutchison WD, Feng T, Campbell SJ. Wave nature of conduction electrons in amorphous Co 90Sc 10 and Fe 90Sc 10 alloys. J Phys Condens Matter 2018; 30:455701. [PMID: 30265249 DOI: 10.1088/1361-648x/aae505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The resistivity of amorphous Fe90Sc10 and Co90Sc10 alloys can be described well in terms of a simple model based on the wave character of electrons and their associated tunnelling over the temperature ranges ~1.9 K to 135 K and ~1.9 K to 12 K respectively. The extended range of agreement between experiment and theory for amorphous Fe90Sc10 is linked with its relatively small mean free path of [Formula: see text] = 0.32 nm, thus allowing electron waves to tunnel between clusters. On the other hand the restricted region of tunnelling of electron waves for amorphous Co90Sc10 alloys is linked with its relatively large mean free path of [Formula: see text] = 0.48 nm which restricts the ability for tunnelling between clusters while enabling electron waves to tunnel between different regions with a cluster.
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Affiliation(s)
- M Ghafari
- Nanjing University of Science and Technology, Herbert Gleiter Institute of Nanoscience, Nanjing, Jiangsu, People's Republic of China
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17
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Ghafari M, Hutchison WD, Campbell SJ, Gleiter H, Hahn H, Feng T. Electrical resistivity and wave character of free electrons in amorphous and nanoglass Sc 75Fe 25. J Phys Condens Matter 2018; 30:025702. [PMID: 29236681 DOI: 10.1088/1361-648x/aa9adf] [Citation(s) in RCA: 1] [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] [Indexed: 06/07/2023]
Abstract
The residual electrical resistivity of metallic amorphous alloys, ρ 0, is typically in the range 50 µΩ cm < ρ 0 < 310 µΩ cm corresponding to a mean free path of conduction electrons of order a few interatomic distances. In crystalline metals with low defect levels such as Cu however, the residual electrical resistivity is about ρ 0 ≈ 1.54 × 10-2 µΩ cm, leading to extensive progression of free electrons through the crystalline material, of typically up to 4 × 106 nm. The relatively 'high' values for the electrical resistivity of distorted Sc75Fe25 alloys are discussed here within the framework of the wave character of electrons. The present investigation of amorphous and nanoglass Sc75Fe25 over the temperature range 1.9-320 K, focuses on clarification of the temperature dependence of the resistivity, ρ(T). These alloys systems, which show a range of behaviours for temperature dependent resistivity-including temperature independent residual resistivity, as well as positive and negative polarities for the slope dρ(T)/dT-are examined in detail.
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Affiliation(s)
- M Ghafari
- Nanjing University of Science and Technology, Herbert Gleiter Institute of Nanoscience, Nanjing, Jiangsu, People's Republic of China
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18
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Susilo RA, Cadogan JM, Hutchison WD, Stewart GA, Avdeev M, Campbell SJ. Magnetic structure and spin reorientation of quaternary Dy 2Fe 2Si 2C. J Phys Condens Matter 2017; 29:115806. [PMID: 28170354 DOI: 10.1088/1361-648x/aa52f9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We have investigated the low temperature magnetic properties of Dy2Fe2Si2C by using magnetisation, specific heat, x-ray diffraction, neutron powder diffraction and 57Fe Mössbauer spectroscopy measurements over the temperature range 1.5 K-300 K. Dy2Fe2Si2C exhibits two magnetic transitions at low temperatures: an antiferromagnetic transition at [Formula: see text] K and a spin-reorientation transition at [Formula: see text] K. The magnetic structure above T t can be described with a propagation vector [Formula: see text] with the ordering of the Dy magnetic moments along the monoclinic b-axis whereas on cooling below T t the Dy moment tips away from the b-axis towards the ac-plane. We find that the spin-reorientation in Dy2Fe2Si2C is mainly driven by the competition between the second-order crystal field term B 20 and the higher-order terms, in particular B 40 and B 64.
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Affiliation(s)
- R A Susilo
- School of Physical, Environmental and Mathematical Sciences, UNSW Canberra at the Australian Defence Force Academy, Canberra BC 2610, Australia
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19
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Giorio C, Campbell SJ, Bruschi M, Tampieri F, Barbon A, Toffoletti A, Tapparo A, Paijens C, Wedlake AJ, Grice P, Howe DJ, Kalberer M. Online Quantification of Criegee Intermediates of α-Pinene Ozonolysis by Stabilization with Spin Traps and Proton-Transfer Reaction Mass Spectrometry Detection. J Am Chem Soc 2017; 139:3999-4008. [PMID: 28201872 DOI: 10.1021/jacs.6b10981] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Biogenic alkenes, which are among the most abundant volatile organic compounds in the atmosphere, are readily oxidized by ozone. Characterizing the reactivity and kinetics of the first-generation products of these reactions, carbonyl oxides (often named Criegee intermediates), is essential in defining the oxidation pathways of organic compounds in the atmosphere but is highly challenging due to the short lifetime of these zwitterions. Here, we report the development of a novel online method to quantify atmospherically relevant Criegee intermediates (CIs) in the gas phase by stabilization with spin traps and analysis with proton-transfer reaction mass spectrometry. Ozonolysis of α-pinene has been chosen as a proof-of-principle model system. To determine unambiguously the structure of the spin trap adducts with α-pinene CIs, the reaction was tested in solution, and reaction products were characterized with high-resolution mass spectrometry, electron paramagnetic resonance, and nuclear magnetic resonance spectroscopy. DFT calculations show that addition of the Criegee intermediate to the DMPO spin trap, leading to the formation of a six-membered ring adduct, occurs through a very favorable pathway and that the product is significantly more stable than the reactants, supporting the experimental characterization. A flow tube set up has been used to generate spin trap adducts with α-pinene CIs in the gas phase. We demonstrate that spin trap adducts with α-pinene CIs also form in the gas phase and that they are stable enough to be detected with online mass spectrometry. This new technique offers for the first time a method to characterize highly reactive and atmospherically relevant radical intermediates in situ.
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Affiliation(s)
- Chiara Giorio
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Steven J Campbell
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Maurizio Bruschi
- Dipartimento di Scienze dell'Ambiente e del Territorio e di Scienze della Terra, Università degli Studi di Milano Bicocca , Piazza della Scienza 1, Milano 20126, Italy
| | - Francesco Tampieri
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova , via Marzolo 1, Padova 35131, Italy
| | - Antonio Barbon
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova , via Marzolo 1, Padova 35131, Italy
| | - Antonio Toffoletti
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova , via Marzolo 1, Padova 35131, Italy
| | - Andrea Tapparo
- Dipartimento di Scienze Chimiche, Università degli Studi di Padova , via Marzolo 1, Padova 35131, Italy
| | - Claudia Paijens
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Andrew J Wedlake
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Peter Grice
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Duncan J Howe
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Markus Kalberer
- Department of Chemistry, University of Cambridge , Lensfield Road, Cambridge, CB2 1EW, United Kingdom
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20
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Abstract
A previously healthy young man with a rare genetic condition presented with severe acute respiratory distress syndrome secondary to pneumonia with septic shock. He did not improve with conventional therapy for his known causal organism thus prompting further workup. He was found to be profoundly immunosuppressed raising our suspicion for atypical organisms. A bronchoalveolar lavage sample was positive via PCR for adenovirus which we suspect exacerbated a pre-existing bacterial pneumonia and led to a severe and non-responsive respiratory failure. His serum adenovirus load was markedly elevated. Treatment was started once the diagnosis of disseminated adenovirus infection was made; however, at that time patient was suffering from refractory hypoxaemia, respiratory acidosis, right heart failure and septic shock. Despite maximal supportive measures our patient ultimately expired over the course of 6 days.
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Affiliation(s)
- Steven J Campbell
- Department of Pulmonary, Critical Care, and Sleep, Ohio State University College of Medicine, Columbus, Ohio, USA
| | - Jessica A Kynyk
- Department of Pulmonary, Critical Care, and Sleep, Ohio State University College of Medicine, Columbus, Ohio, USA
| | - John A Davis
- Department of Infectious Diseases, Ohio State University College of Medicine, Columbus, Ohio, USA
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Wang JL, Campbell SJ, Hofmann M, Kennedy SJ, Zeng R, Md Din MF, Dou SX, Arulraj A, Stusser N. Magnetism and magnetic structures of PrMn2Ge2-xSix. J Phys Condens Matter 2013; 25:386003. [PMID: 23988490 DOI: 10.1088/0953-8984/25/38/386003] [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] [Indexed: 06/02/2023]
Abstract
The structural and magnetic properties of seven PrMn2Ge2-xSix compounds with Si concentrations in the range x = 0.0-2.0 have been investigated by x-ray diffraction, magnetic (5-350 K), differential scanning calorimetry (300-500 K) and neutron diffraction (3-480 K) measurements. Replacement of Ge by Si leads to a contraction of the unit cell and significant modifications to the magnetic states--a crossover from ferromagnetism at room temperature for Ge-rich compounds to antiferromagnetism for Si-rich compounds. The compositional dependence of the room temperature lattice parameters exhibits non-linear behaviour around x = 1.2, reflecting the presence of magnetovolume effects. Re-entrant ferromagnetism has been observed in both PrMn2Ge1.0Si1.0 and PrMn2Ge0.8Si1.2 compounds with co-existence of canted ferromagnetism and canted antiferromagnetism detected, with both compounds exhibiting a larger unit cell volume in the canted Fmc state than in the canted AFmc. Combined with earlier studies of this system, the magnetic phase diagram has been constructed over the full range of PrMn2Ge2-xSix compositions (x = 0.0-2.0) and over the temperature range of interest (T = 3-480 K). In common with other systems in the RMn2X2 series, the overall magnetic behaviour of PrMn2Ge2-xSix compounds is governed by the strong dependence of the magnetic couplings on the Mn-Mn spacing within the ab-plane. Both total manganese moment µ(Mn)(tot) and in-plane manganese moment µ(Mn)(ab) at 5 K are found to decrease with increasing Si content, which can be ascribed to the reduction of Mn-Mn separation distance and stronger Si-Mn hybridization compared with Ge-Mn hybridization. Pr site ferromagnetic ordering occurs for x < 1.6 below T(Pr)(C).
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Affiliation(s)
- J L Wang
- Bragg Institute, ANSTO, Lucas Heights, NSW 2234, Australia
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Wang JL, Caron L, Campbell SJ, Kennedy SJ, Hofmann M, Cheng ZX, Din MFM, Studer AJ, Brück E, Dou SX. Driving magnetostructural transitions in layered intermetallic compounds. Phys Rev Lett 2013; 110:217211. [PMID: 23745927 DOI: 10.1103/physrevlett.110.217211] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Indexed: 06/02/2023]
Abstract
We report the dramatic effect of applied pressure and magnetic field on the layered intermetallic compound Pr(0.5)Y(0.5)Mn(2)Ge(2). In the absence of pressure or magnetic field this compound displays interplanar ferromagnetism at room temperature and undergoes an isostructural first order magnetic transition (FOMT) to an antiferromagnetic state below 158 K, followed by another FOMT at 50 K due to the reemergence of ferromagnetism as praseodymium orders (T(C)(Pr)). The application of a magnetic field drives these two transitions towards each other, whereas the application of pressure drives them apart. Pressure also produces a giant magnetocaloric effect such that a threefold increase of the entropy change associated with the lower FOMT (at T(C)(Pr)) is seen under a pressure of 7.5 kbar. First principles calculations, using density functional theory, show that this remarkable magnetic behavior derives from the strong magnetoelastic coupling of the manganese layers in this compound.
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Affiliation(s)
- J L Wang
- Institute for Superconductivity and Electronic Materials, University of Wollongong, Wollongong, New South Wales 2522, Australia.
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23
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Kumar RS, Svane A, Vaitheeswaran G, Zhang Y, Kanchana V, Hofmann M, Campbell SJ, Xiao Y, Chow P, Chen C, Zhao Y, Cornelius AL. Pressure-induced valence and structural changes in YbMn2Ge2-inelastic X-ray spectroscopy and theoretical investigations. Inorg Chem 2013; 52:832-9. [PMID: 23298404 DOI: 10.1021/ic3019698] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The pressure-induced valence change of Yb in YbMn(2)Ge(2) has been studied by high pressure inelastic X-ray emission and absorption spectroscopy in the partial fluorescence yield mode up to 30 GPa. The crystal structure of YbMn(2)Ge(2) has been investigated by high pressure powder X-ray diffraction experiments up to 40 GPa. The experimental investigations have been complemented by first principles density functional theoretical calculations using the generalized gradient approximation with an evolutionary algorithm for structural determination. The Yb valence and magnetic structures have been calculated using the self-interaction corrected local spin density approximation. The X-ray emission results indicate a sharp increase of Yb valence from v = 2.42(2) to v = 2.75(3) around 1.35 GPa, and Yb reaches a near trivalent state (v = 2.95(3)) around 30 GPa. Further, a new monoclinic P1 type high pressure phase is found above 35 GPa; this structure is characterized by the Mn layer of the ambient (I4/mmm) structure transforming into a double layer. The theoretical calculations yield an effective valence of v = 2.48 at ambient pressure in agreement with experiment, although the pure trivalent state is attained theoretically at significantly higher pressures (above 40 GPa).
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Affiliation(s)
- Ravhi S Kumar
- Department of Physics and Astronomy and HiPSEC, University of Nevada Las Vegas, Las Vegas, Nevada 89154, United States.
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Wang JL, Campbell SJ, Kennedy SJ, Zeng R, Dou SX, Wu GH. Critical magnetic transition in TbNi2Mn--magnetization and Mössbauer spectroscopy. J Phys Condens Matter 2011; 23:216002. [PMID: 21555840 DOI: 10.1088/0953-8984/23/21/216002] [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] [Indexed: 05/30/2023]
Abstract
The structural and magnetic properties of the TbNi(2)Mn(x) series (0.9 ≤ x ≤ 1.10) have been investigated using x-ray diffraction, field- and temperature-dependent AC magnetic susceptibility, DC magnetization (5-340 K; 0-5 T) and (57)Fe Mössbauer spectroscopy (5-300 K). TbNi(2)Mn(x) crystallizes in the MgCu(2)-type structure (space group Fd3m). The additional contributions to the magnetic energy terms from transition-metal-transition-metal interactions (T-T) and rare-earth-transition-metal interactions (R-T) in RNi(2)Mn compounds contribute to their increased magnetic ordering temperatures compared with RNi(2) and RMn(2). Both the lattice constant a and the Curie temperature T(C) exhibit maximal values at the x = 1 composition indicating strong magnetostructural coupling. Analyses of the AC magnetic susceptibility and DC magnetization data of TbNi(2)Mn around the Curie temperature T(C) = 147 K confirm that the magnetic transition is second order with critical exponents β = 0.77 ± 0.12, γ = 1.09 ± 0.07 and δ = 2.51 ± 0.06. These exponents establish that the magnetic interactions in TbNi(2)Mn are long range despite mixed occupancies of Tb and Mn atoms at the 8a site and vacancies. The magnetic entropy - ΔS(M) around T(C) is proportional to (μ(0)H/T(C))(2/3) in agreement with the critical magnetic analyses. The Mössbauer spectra above T(C) are fitted by two sub-spectra in agreement with refinement of the x-ray data while below T(C) three sub-spectra are required to represent the three inequivalent local magnetic environments.
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Affiliation(s)
- J L Wang
- School of Physical, Environmental and Mathematical Sciences, The University of New South Wales, The Australian Defence Force Academy, Canberra ACT, Australia
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Wang JL, Campbell SJ, Studer AJ, Avdeev M, Zeng R, Dou SX. Magnetic phase transitions in Pr(1-x)Lu(x)Mn(2)Ge(2) compounds. J Phys Condens Matter 2009; 21:124217. [PMID: 21817459 DOI: 10.1088/0953-8984/21/12/124217] [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] [Indexed: 05/31/2023]
Abstract
The effects of replacing Pr by Lu on the magnetic behaviour and structures of Pr(1-x)Lu(x)Mn(2)Ge(2) (x = 0.2,x = 0.4) have been investigated using x-ray diffraction, Mössbauer spectroscopy, magnetization and neutron diffraction measurements. The substitution of Lu for Pr leads to a decrease in the lattice constants a, c and the unit cell volume V at room temperature with this contraction of the unit cell resulting in modifications of the Pr(1-x)Lu(x)Mn(2)Ge(2) magnetic structures. Four and five magnetic phase transitions-linked primarily with temperature driven changes in the intralayer Mn-Mn separation distances-have been detected within the temperature range 4.5-550 K for Pr(0.8)Lu(0.2)Mn(2)Ge(2) and Pr(0.6)Lu(0.4)Mn(2)Ge(2), respectively, with re-entrant ferromagnetism being detected around T(C)(Pr)∼31 K for Pr(0.6)Lu(0.4)Mn(2)Ge(2). It was found that T(C)(inter) and T(C)(Pr) increase with increasing applied field while T(N)(inter) decreases for Pr(0.6)Lu(0.4)Mn(2)Ge(2), indicating that the canted antiferromagnetic AFmc region contracts with increasing field. The Debye temperatures for Pr(1-x)Lu(x)Mn(2)Ge(2) with x = 0.2 and 0.4 were evaluated as θ(D) = 320 ± 40 K and θ(D) = 400 ± 20 K respectively from the temperature dependence of the average isomer shift. The magnetic structures of both compounds have been determined by means of neutron diffraction measurements over the temperature range 3-300 K with formation of the Fmi magnetic state below T(c/c) = 192 K for Pr(0.8)Lu(0.2)Mn(2)Ge(2) and the occurrence of re-entrant ferromagnetism below T(C)(Pr) = 31 K for Pr(0.6)Lu(0.4)Mn(2)Ge(2) being confirmed.
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Affiliation(s)
- J L Wang
- School of Physical, Environmental and Mathematical Sciences, The University of New South Wales, The Australian Defence Force Academy, Canberra ACT 2600, Australia. Bragg Institute, ANSTO, Lucas Heights, NSW 2234, Australia. Institute for Superconductivity and Electronic Materials, University of Wollongong, Wollongong, NSW 2522, Australia
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Abstract
Epidemiological evidence indicates that the severity of many human neuropathologies is often age-related, and this also appears true in rodent models of human disease. In this study, we examined the inflammatory response within the brain to the archetypal pro-inflammatory cytokines interleukin-1beta (IL-1beta) or tumour necrosis factor-alpha (TNF-alpha). We assessed how the cerebral vasculature changes with age and whether any structural alterations are associated with altered cytokine sensitivities. Six hours after equivalent microinjections of IL-1beta or TNF-alpha, 3-week-old juvenile and 18-month-old aged rats displayed increased leucocyte recruitment, blood-brain barrier (BBB) breakdown, and a loss of specificity in the populations of leucocytes recruited when compared with the restricted profile observed in 2-month-old young adult rat brain. The expression of the tight junction protein claudin-1 was absent in those vessels where neutrophils were being actively recruited. To determine whether changes in the structure of the BBB might be responsible for the increased susceptibility observed at either end of the age spectrum, we compared the number of claudin-1 positive vessels in the unchallenged brain to the total number of vessels. Virtually all vessels in the young adult brain express claudin-1, but a significant proportion of vessels are claudin-1 negative in the juvenile rat brain. In the aged rat brain, the overall number of vessels is markedly reduced, but the majority of these still appear to be claudin-1 positive. The pattern of claudin-1 expression together with the change in vessel density indicates that the properties of the BBB change with age, and, despite similarities, the underlying cause of the heightened inflammatory response in the juvenile and in the aged brain is likely to differ. Indeed, the spatial characteristics of the cytokine-induced BBB breakdown are different at either end of the age spectrum. These studies identify two periods within the lifespan of a rat where susceptibility to pro-inflammatory mediators is dramatically increased.
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Affiliation(s)
- S J Campbell
- Experimental Neuropathology, Department of Pharmacology, University of Oxford, Mansfield Road, Oxfordshire, UK.
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Allen DW, Brooks JS, Campbell SJ. The fate of triorganotin biocides on incorporation into hypalon paint-based marine antifouling systems:119mSn Mössbauer and119Sn NMR studies. Appl Organomet Chem 2004. [DOI: 10.1002/aoc.590070713] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abstract
Src homology 2 (SH2) domains are approximately 100 residue phosphotyrosyl peptide binding modules found in signalling proteins and are important targets for therapeutic intervention. The peptide binding site is evolutionarily well conserved, particularly at the two major binding pockets, pTyr and pTyr + 3. We present a computational analysis of diversity within the peptide binding region and discuss molecular recognition beyond the conventional binding motif, drawing attention to novel conserved ligand interaction sites which may be exploitable in ligand binding studies. The peptide binding site is defined by selecting crystal contacts and domains are clustered according to binding site residue similarity. Comparison with a classification based on experimental peptide screening reveals a high level of qualitative agreement, indicating that the method is able independently to generate functional information. A conservation scoring method reveals extensive patches of conservation in some groups not present across the whole family, challenging the notion that the domains recognise only a linear phosphopeptide sequence. Conservation difference maps determine group-dependent clusters of conserved residues that are not seen when considering a larger experimentally determined group. Many of these residues contact the peptide outside the pTyr to pTyr + 3 motif, challenging the conventional view that this motif is largely responsible for ligand recognition and discrimination.
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Affiliation(s)
- S J Campbell
- School of Biochemistry and Molecular Biology, Garstang Building, University of Leeds, Leeds LS2 9JT, UK
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Li CM, Campbell SJ, Kumararatne DS, Hill AVS, Lammas DA. Response heterogeneity of human macrophages to ATP is associated with P2X7 receptor expression but not to polymorphisms in the P2RX7 promoter. FEBS Lett 2002; 531:127-31. [PMID: 12417299 DOI: 10.1016/s0014-5793(02)03424-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A region 2 kb upstream of exon 1 of the P2X7 gene was sequenced using DNA from nine healthy individuals who exhibited three different ATP response phenotypes (i.e. high, low and interferon gamma-inducible). Five single nucleotide polymorphisms were identified within the nine donor promoter sequences but none were associated with a specific ATP response phenotype. A P2X7 loss of function polymorphism (1513 in exon 13) was also screened for within donor DNA but no response associations were identified. ATP response phenotype was positively associated with P2X(7) receptor expression, as assessed by flow cytometry, but not with any identified receptor or promoter gene polymorphisms.
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Affiliation(s)
- C M Li
- Division of Immunity and Infection, The Medical School, MRC Centre for Immune Regulation, University of Birmingham, Birmingham, UK
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Hall PA, Woodman AC, Campbell SJ, Shepherd NA. Expression of the p53 homologue p63alpha and DeltaNp63alpha in the neoplastic sequence of Barrett's oesophagus: correlation with morphology and p53 protein. Gut 2001; 49:618-23. [PMID: 11600462 PMCID: PMC1728522 DOI: 10.1136/gut.49.5.618] [Citation(s) in RCA: 23] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
BACKGROUND While loss of p53 function is a key oncogenic step in human tumorigenesis, mutations of p53 are generally viewed as late events in the metaplasia-dysplasia-adenocarcinoma sequence of Barrett's oesophagus. Recent reports of a series of genes (p63, p73, and others) exhibiting close homology to p53 raise the possibility that abnormalities of these p53 family members may exert their influence earlier in the sequence. AIM Following recent characterisation of expression of p63 and a major isoform DeltaNp63 by generation of an antiserum that recognises p63 isoforms, but not p53, our aim was a comparative study of expression of p63 protein and p53 protein in a morphologically well defined biopsy series representative of all stages of the metaplasia-dysplasia-carcinoma sequence in Barrett's oesophagus. METHODS A series of 60 biopsy cases representing normal oesophagus through to invasive adenocarcinoma were stained, using immunohistochemistry, with antibodies to p63 and p53. All biopsies derived from patients with endoscopic and histopathological substantiation of a diagnosis of traditional/classical Barrett's oesophagus. RESULTS There was exact concordance in p53 and p63 expression in more advanced forms of neoplasia, high grade dysplasia, and invasive adenocarcinoma, while p63, but not p53, was detected in the proliferative compartment of some non-neoplastic oesophageal tissue, in both squamous mucosa and in the non-neoplastic metaplastic glandular epithelium. CONCLUSIONS In neoplastic Barrett's oesophagus there is upregulation of both p63 and p53 while p63 isoforms may well have an important role in epithelial biology in both non-metaplastic and metaplastic mucosa of the oesophagus. While abnormalities of p53 function represent an indisputable and critical element of neoplastic transformation, other closely linked genes and their proteins have a role in both the physiology and pathophysiology of the oesophageal mucosa.
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Affiliation(s)
- P A Hall
- Department of Histopathology, Gloucestershire Royal Hospital, Great Western Road, Gloucester GL1 3NN, UK
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Campbell SJ, Herbert IR, Warwick CB, Woodgate JM. A continuous flow cooling unit for ESR experiments over the temperature range 3.7-300K. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3735/9/6/008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Wantenaar GHJ, Campbell SJ, Chaplin DH, McKenna TJ, Wilson GVH. AC susceptibility and temperature modulation studies of gadolinium. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0305-4608/9/5/016] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Dempsey CE, Sessions RB, Lamble NV, Campbell SJ. The asparagine-stabilized beta-turn of apamin: contribution to structural stability from dynamics simulation and amide hydrogen exchange analysis. Biochemistry 2000; 39:15944-52. [PMID: 11123921 DOI: 10.1021/bi002044q] [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: 11/29/2022]
Abstract
Molecular dynamics simulations of bee venom apamin, and an analogue having an Asn to Ala substitution at residue 2 (apamin-N2A), were analyzed to explore the contribution of hydrogen bonds involving Asn2 to local (beta-turn residues N2, C3, K4, A5) and global stability. The wild-type peptide retained a stable conformation during 2.4 ns of simulation at 67 degrees C, with high beta-turn stability characterized by backbone-side chain hydrogen bonds involving beta-turn residues K4 and A5, with the N2 side chain amide carbonyl. The loss of stabilizing interactions involving the N2 side chain resulted in the loss of the beta-turn conformation in the apamin N2A simulations (27 or 67 degrees C). This loss of beta-turn stability propagates throughout the peptide structure, with destabilization of the C-terminal helix connected to the N-terminal region by two disulfide bonds. Backbone stability in a synthetic peptide analogue (apamin-N2A) was characterized by NMR and amide hydrogen exchange measurements. Consistent with the simulations, loss of hydrogen bonds involving the N2 side chain resulted in destabilization of both the N-terminal beta-turn and the C-terminal helix. Amide exchange protection factors in the C-terminal helix were reduced by 9-11-fold in apamin N2A as compared with apamin, corresponding to free energy (deltaDeltaG(uf)) of around 1.5 kcal M(-1) at 20 degrees C. This is equivalent to the contribution of hydrogen bond interactions involving the N2 side chain to the stability of the beta-turn. Together with additional measures of exchange protection factors, the three main contributions to backbone stability in apamin that account for virtually the full thermodynamic stability of the peptide have been quantitated.
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Affiliation(s)
- C E Dempsey
- Biochemistry Department and Centre for Molecular Recognition, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, United Kingdom.
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Wantanaar GHJ, Campbell SJ, Chaplin DH, McKenna TJ, Wilson GVH. Thermal modulation studies of the critical magnetic susceptibility of Gd. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/13/30/008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Hall PA, Campbell SJ, O'neill M, Royston DJ, Nylander K, Carey FA, Kernohan NM. Expression of the p53 homologue p63alpha and deltaNp63alpha in normal and neoplastic cells. Carcinogenesis 2000; 21:153-60. [PMID: 10657951 DOI: 10.1093/carcin/21.2.153] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [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: 11/14/2022] Open
Abstract
A burgeoning family of p53-related genes have been described recently, including p73 and p63. Both these genes encode proteins with many similarities to p53 but also with the potential for forming a range of related species by alternative promoter usage and alternative splicing. In order to begin the characterization of p63, we generated a polyclonal serum (designated SC1) that recognizes the C-terminus of p63alpha. We have shown that this reagent recognizes p63alpha but not p53 nor p73. By western blot analysis both p63alpha and the N-terminal truncated form of p63alpha (DeltaNp63alpha) were found in a range of cell lines. Similar immunoblot analysis of tissues reveals considerable complexity with at least four SC1-immunoreactive isoforms being identified. In immunohistological studies SC1 immunoreactivity is widely detectable, being predominantly associated with proliferative compartments in epithelia. However, non-proliferative populations can also show SC1 immunostaining. No simple relationship between the isoforms identified by immunoblotting of tissue lysates and the tissue immunostaining characteristics was identified. A previously unrecognized species intermediate in mobility between p63alpha and DeltaNp63alpha was found in several tissues, including nerve and peripheral blood lymphocytes. Interestingly, there is suppression of p63alpha expression in HaCat cells in a time- and concentration-dependent manner after UV and MMS treatment. Our data provide further information about the complexity of p63 and the SC1 serum will prove to be a useful tool in further studies of this p53 homologue.
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Affiliation(s)
- P A Hall
- Department of Molecular and Cellular Pathology, University of Dundee, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
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Abstract
This paper describes experiments in which the combustion of animal tissue (pork) was measured under a variety of conditions that may be encountered in fire scenes. Combustion depends on substantial preheating of the tissue by an external heat source and the availability of a porous wick (such as charred cellulosic material). Combustion of moderate-size samples can proceed at a moderate rate of 1-3 g/s (3.6-10.8 kg/hr) if provided with an adequate wick and results in only a small fire of 30-50 kW. In the final test, combustion of 26 kg of fat and skin created a fire of 120-130 kW. Such a fire is more likely to cause fire spread to other combustibles nearby. The presence of other, less efficient fuels (like skin and muscle) and the absence of large fuel masses (such as in the very lean pig carcasses used here) results in significantly smaller fires of 40-50 kW. Such fires are more typical of burning human remains when there are minimal contributions from other fuels.
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Affiliation(s)
- J D DeHaan
- California Criminalistics Institute, Sacramento 95820, USA
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O'Neill M, Campbell SJ, Save V, Thompson AM, Hall PA. An immunochemical analysis of mdm2 expression in human breast cancer and the identification of a growth-regulated cross-reacting species p170. J Pathol 1998; 186:254-61. [PMID: 10211113 DOI: 10.1002/(sici)1096-9896(1998110)186:3<254::aid-path185>3.0.co;2-u] [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: 01/01/2023]
Abstract
mdm2 is a 491 amino acid nuclear protein which is involved in complex interactions with important cell-cycle and stress-response regulators including p53, Rb and E2F. Recent data implicate mdm2 in the regulation of both p53 activity and level, and burgeoning data suggest that mdm2 may be involved in human epithelial tumourigenesis, including breast cancer. In this study the expression of mdm2 protein has been investigated in a series of 54 human breast carcinomas using immunoblotting methods. Overexpression of the predominant p90 mdm2 isoform is common in breast cancer (54 per cent) and this is not frequently a consequence of gene amplification. There is no relationship between p90 expression and either p53 protein expression or p53 mutational status. Additional mdm2 immunoreactive species of differing mobilities are identifiable, greatly complicating the analysis. For example, a p170 form is seen in many breast cancer samples (44 per cent) using 2A10 but is not identified by 3G5. This 2A10 immunoreactive species, which is almost certainly not an mdm2 isoform, is a growth-regulated protein, being undetectable in resting peripheral blood lymphocytes and rising to high levels after PHA stimulation. In contrast to mdm2 (p90), p170 is not induced by DNA damage caused by UV light. p170 is identifiable in mdm2 null cells by immunoblotting and is detected as a nuclear protein. While mdm2 immunostaining studies are increasing, this report highlights the complexity of mdm2 analysis in vivo and emphasizes the need to correlate immunohistological and biochemical assays since, in some mdm2 (p90) negative tumours, nuclear immunoreactivity may be identified as a consequence of cross-reacting species such as p170.
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Affiliation(s)
- M O'Neill
- Department of Cellular & Molecular Pathology, University of Dundee, Ninewells Hospital and Medical School, Scotland, U.K
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Wolf CR, Campbell SJ, Clark AJ, Smith A, Bishop JO, Henderson CJ. The use of transgenic animals to assess the role of metabolism in target organ toxicity. Arch Toxicol Suppl 1998; 20:443-53. [PMID: 9442315 DOI: 10.1007/978-3-642-46856-8_39] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- C R Wolf
- Imperial Cancer Research Fund Molecular Pharmacology Unit, Biomedical Research Centre, Ninewells Hospital and Medical School, Dundee, UK
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