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Brosey CA, Link TM, Shen R, Moiani D, Burnett K, Hura GL, Jones DE, Tainer JA. Chemical screening by time-resolved X-ray scattering to discover allosteric probes. Nat Chem Biol 2024:10.1038/s41589-024-01609-1. [PMID: 38671223 DOI: 10.1038/s41589-024-01609-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 03/20/2024] [Indexed: 04/28/2024]
Abstract
Drug discovery relies on efficient identification of small-molecule leads and their interactions with macromolecular targets. However, understanding how chemotypes impact mechanistically important conformational states often remains secondary among high-throughput discovery methods. Here, we present a conformational discovery pipeline integrating time-resolved, high-throughput small-angle X-ray scattering (TR-HT-SAXS) and classic fragment screening applied to allosteric states of the mitochondrial import oxidoreductase apoptosis-inducing factor (AIF). By monitoring oxidized and X-ray-reduced AIF states, TR-HT-SAXS leverages structure and kinetics to generate a multidimensional screening dataset that identifies fragment chemotypes allosterically stimulating AIF dimerization. Fragment-induced dimerization rates, quantified with time-resolved SAXS similarity analysis (kVR), capture structure-activity relationships (SAR) across the top-ranked 4-aminoquinoline chemotype. Crystallized AIF-aminoquinoline complexes validate TR-SAXS-guided SAR, supporting this conformational chemotype for optimization. AIF-aminoquinoline structures and mutational analysis reveal active site F482 as an underappreciated allosteric stabilizer of AIF dimerization. This conformational discovery pipeline illustrates TR-HT-SAXS as an effective technology for targeting chemical leads to important macromolecular states.
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Affiliation(s)
- Chris A Brosey
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
| | - Todd M Link
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Runze Shen
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Davide Moiani
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Kathryn Burnett
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Greg L Hura
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA, USA
| | - Darin E Jones
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - John A Tainer
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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Tadros MM, Boshra MS, Scott M, Fleming G, Magee F, Hamed MI, Abuelhana A, Courtenay A, Salem HF, Burnett K. Antimicrobial prescribing in a secondary care setting during the COVID-19 pandemic. JAC Antimicrob Resist 2023; 5:dlad117. [PMID: 37965099 PMCID: PMC10642613 DOI: 10.1093/jacamr/dlad117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 10/19/2023] [Indexed: 11/16/2023] Open
Abstract
Background Increased antimicrobial resistance patterns lead to limited options for antimicrobial agents, affecting patient health and increasing hospital costs. Objectives To investigate the antimicrobial prescribing patterns at two district hospitals in Northern Ireland before and during the COVID-19 pandemic. Methods A mixed prospective-retrospective study was designed to compare pre- and during pandemic antimicrobial prescribing data in both hospitals using a Global Point Prevalence Survey. Results Of the 591 patients surveyed in both hospitals, 43.8% were treated with 402 antimicrobials. A total of 82.8% of antimicrobial prescriptions were for empirical treatment. No significant difference existed in numbers of patients treated or antimicrobials used before and during the pandemic. There was a slight decrease of 3.3% in the compliance rate with hospital antimicrobial guidelines during the pandemic when compared with the pre-pandemic year of 2019, when it was 69.5%. Treatment based on patients' biomarker data also slightly decreased from 83.5% pre-pandemic (2019) to 81.5% during the pandemic (2021). Conclusions There was no overall significant impact of the pandemic on the antimicrobial prescribing patterns in either hospital when compared with the pre-pandemic findings. The antimicrobial stewardship programmes would appear to have played an important role in controlling antimicrobial consumption during the pandemic.
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Affiliation(s)
- Michael M Tadros
- School of Pharmacy and Pharmaceutical Sciences, Ulster University, Coleraine, UK
- Clinical Pharmacy Department, Faculty of Pharmacy, Misr University for Science and Technology (MUST University), P.O. Box 12566, Giza, Egypt
| | - Marian S Boshra
- Clinical Pharmacy Department, Faculty of Pharmacy, Beni-Suef University, P.O. Box 62514, Beni-Suef, Egypt
| | - Michael Scott
- Medicines Optimisation and Innovation Centre (MOIC), Antrim Area Hospital, Antrim, UK
| | - Glenda Fleming
- Medicines Optimisation and Innovation Centre (MOIC), Antrim Area Hospital, Antrim, UK
| | - Fidelma Magee
- Pharmacy Department, Northern Health and Social Care Trust (NHSCT), Antrim, UK
| | - Mohammad I Hamed
- Clinical Pharmacy Department, Faculty of Pharmacy, Misr University for Science and Technology (MUST University), P.O. Box 12566, Giza, Egypt
| | - Ahmed Abuelhana
- School of Pharmacy and Pharmaceutical Sciences, Ulster University, Coleraine, UK
| | - Aaron Courtenay
- School of Pharmacy and Pharmaceutical Sciences, Ulster University, Coleraine, UK
| | - Heba F Salem
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Beni-Suef University, P.O. Box 62514, Beni-Suef, Egypt
| | - Kathryn Burnett
- Regional Pharmaceutical Procurement Service, Northern Health and Social Care Trust (NHSCT), Antrim, UK
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Brosey CA, Shen R, Moiani D, Jones DE, Burnett K, Hura GL, Tainer JA. Applying HT-SAXS to chemical ligand screening. Methods Enzymol 2022; 678:331-350. [PMID: 36641213 DOI: 10.1016/bs.mie.2022.09.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chemical probes are invaluable tools for investigating essential biological processes. Understanding how small-molecule probes engage biomolecular conformations is critical to developing their functional selectivity. High-throughput solution X-ray scattering is well-positioned to profile target-ligand complexes during probe development, bringing conformational insight and selection to traditional ligand binding assays. Access to high-quality synchrotron SAXS datasets and high-throughput data analysis now allows routine academic users to incorporate conformational information into small-molecule development pipelines. Here we describe a general approach for benchmarking and preparing HT-SAXS chemical screens from small fragment libraries. Using the allosteric oxidoreductase Apoptosis-Inducing Factor (AIF) as an exemplary system, we illustrate how HT-SAXS efficiently identifies an allosteric candidate among hits of a microscale thermophoresis ligand screen. We discuss considerations for pursuing HT-SAXS chemical screening with other systems of interest and reflect on advances to extend screening throughput and sensitivity.
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Affiliation(s)
- Chris A Brosey
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States.
| | - Runze Shen
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Davide Moiani
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Darin E Jones
- Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR, United States
| | - Kathryn Burnett
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States
| | - Greg L Hura
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States; Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, United States
| | - John A Tainer
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States; Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, United States; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.
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Burnett K, Martin S, Goudy C, Barron J, O’Hare L, Wilson P, Fleming G, Scott M. Ensuring the quality and quantity of personal protective equipment (PPE) by enhancing the procurement process in Northern Ireland during the coronavirus disease 2019 pandemic: Challenges in the procurement process for PPE in NI. Journal of Patient Safety and Risk Management 2021; 27:42-49. [PMID: 35317420 PMCID: PMC8926917 DOI: 10.1177/25160435211057385] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This article outlines the purchasing process for personal protective equipment that was established for Health and Social Care in Northern Ireland in response to the outbreak of coronavirus disease 2019. The Business Services Organisation Procurement and Logistics Service, who are the sole provider of goods and services for Health and Social Care organisations, was faced with an unprecedented demand for personal protective equipment in response to the coronavirus disease 2019 pandemic. The usual procurement process was further complicated by changing messages within guidelines which resulted in confusion and anxiety when determining whether or not a product would meet the required safety guidance and was therefore suitable for purchase. In order to address these issues in a rapidly changing and escalating scenario the Department of Health asked the Business Services Organisation Procurement and Logistics Service to work with the Medicines Optimisation Innovation Centre to maximise the availability of personal protective equipment whilst ensuring that it met all requisite quality and standards. A process was implemented whereby the Medicines Optimisation Innovation Centre validated all pertinent essential documentation relating to products to ensure that all applicable standards were met, with the Business Services Organisation Procurement and Logistics Service completing all procurement due diligence tasks in line with both normal and coronavirus disease 2019 emergency derogations. It is evident from the data presented that whilst there were a significant number of potential options for supply, a large proportion of these were rejected due to failure to meet the quality assurance criteria. Thus, by the process that was put in place, a large number of unsuitable products were not purchased and only those that met extant standards were approved.
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Affiliation(s)
- Kathryn Burnett
- School of Pharmacy and Pharmaceutical Sciences,Faculty of Life and Health Sciences, Ulster University, UK
| | | | - Catherine Goudy
- Regional Pharmaceutical Procurement Service, Northern Health and Social Care Trust, UK
| | - John Barron
- Business Services Organisation Procurement and Logistics Service, Health and Social Care Services in Northern Ireland, UK
| | - Linda O’Hare
- Business Services Organisation Procurement and Logistics Service, Health and Social Care Services in Northern Ireland, UK
| | - Peter Wilson
- Business Services Organisation Procurement and Logistics Service, Health and Social Care Services in Northern Ireland, UK
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Abuelhana A, Ashfield L, Scott MG, Fleming GF, Sabry N, Farid S, Burnett K. Analysis of activities undertaken by ward-based clinical pharmacy technicians during patient hospital journey. Eur J Hosp Pharm 2021; 28:313-319. [PMID: 34697047 DOI: 10.1136/ejhpharm-2019-001972] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 09/16/2019] [Accepted: 09/30/2019] [Indexed: 11/03/2022] Open
Abstract
INTRODUCTION Previous studies recognise insufficient time as an obstacle to pharmacists expanding their clinical-based activities and services. For such a reason, the role of well-trained ward-based clinical pharmacy technicians (CPTs) is to work as an integral part of the pharmacy team to achieve the best patient outcomes and medicines optimisation, releasing pharmacist time to complete more complex clinical-related activities. OBJECTIVE To demonstrate quantitatively the range and extent of daily activities undertaken by CPTs during a patient's hospital journey. METHOD A prospective-based study has been designed. All daily working services and activities undertaken by ward-based CPTs within a 450-bed Acute District General hospital were quantitatively collected and documented. Data were collected from five medical, two surgical and one cardiology wards of 30 beds in each over a period of 2 weeks for each ward representing a total of 70 working days (14 weeks, excluding weekends). RESULTS Results showed the breakdown of seven different ward-based activities throughout a typical working day with the main working load being reviews of the patients' medication charts in order to supply new medicines and refer medicines-related issues to the ward pharmacist, with an average number reviewed of (23.17±0.85) representing 77.23% of the total patients in a 30-bed ward. The CPTs' highest workload was on Mondays and Fridays, mainly during the morning working hours (09:00-12:00). Also, statistically significant differences (p<0.05; Kruskal-Wallis test) existed between the workload of the three different ward specialties (medical, surgical and cardiology) in five clinical activities out of seven undertaken by CPT per day. CONCLUSION CPTs are completing more than seven different ward pharmacy-related activities which enhance medicines optimisation, medicines management and patient care. They are a valuable resource carrying out many roles which were previously completed by junior pharmacists. Their prioritising of patients for review ensures pharmacists focus their efforts on the most vulnerable patients.
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Affiliation(s)
- Ahmed Abuelhana
- School of Pharmacy and Pharmaceutical Sciences, Faculty of Life and Health Sciences, University of Ulster, Coleraine, UK.,Misr University for Science & Technology, Giza, Egypt
| | - Linden Ashfield
- Medicine Optimisation Innovation Center, Northern Health and Social Care Trust, Antrim, UK
| | - Michael G Scott
- Medicine Optimisation Innovation Center, Northern Health and Social Care Trust, Antrim, UK
| | - Glenda F Fleming
- Medicine Optimisation Innovation Center, Northern Health and Social Care Trust, Antrim, UK
| | - Nermin Sabry
- Faculty of Pharmacy, Cairo University, Giza, Egypt
| | - Samar Farid
- Faculty of Pharmacy, Cairo University, Giza, Egypt
| | - Kathryn Burnett
- School of Pharmacy and Pharmaceutical Sciences, Faculty of Life and Health Sciences, University of Ulster, Coleraine, UK
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Gao J, Nesbitt H, Logan K, Burnett K, White B, Jack IG, Taylor MA, Love M, Callan B, McHale AP, Callan JF. An ultrasound responsive microbubble-liposome conjugate for targeted irinotecan-oxaliplatin treatment of pancreatic cancer. Eur J Pharm Biopharm 2020; 157:233-240. [PMID: 33222772 DOI: 10.1016/j.ejpb.2020.10.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/24/2020] [Accepted: 10/20/2020] [Indexed: 12/22/2022]
Abstract
Survival rates in pancreatic cancer have remained largely unchanged over the past four decades with less than 5% of patients surviving five years following initial diagnosis. FOLFIRINOX chemotherapy, a combination of folinic acid, 5-fluoruracil, irinotecan and oxaliplatin, has shown the greatest survival benefit for patients with advanced disease but is only indicated for those with good physical performance status due to its extreme off-target toxicity. Ultrasound targeted microbubble destruction (UTMD) has emerged as an effective strategy for the targeted delivery of drug payloads to solid tumours and involves using low intensity ultrasound to disrupt (burst) MBs in the tumour vasculature, releasing encapsulated or attached drugs in a targeted manner. In this manuscript, we describe the preparation of a microbubble-liposome complex (IRMB-OxLipo) carrying two of the three cytotoxic drugs present in the FOLFIRINOX combination, namely irinotecan and oxaliplatin. Efficacy of the IRMB-OxLipo complex following UTMD was determined in Panc-01 3D spheroid and BxPC-3 human xenograft murine models of pancreatic cancer. The results revealed that tumours treated with the IRMB-OxLipo complex and ultrasound were 136% smaller than tumours treated with the same concentration of irinotecan/oxaliplatin but delivered in a conventional manner, i.e. as a non-complexed mixture. This suggests that UTMD facilitates a more effective delivery of irinotecan/oxaliplatin improving the overall effectiveness of this drug combination and to the best of our knowledge, is the first reported example of a microbubble-liposome complex used to deliver these two chemotherapies.
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Affiliation(s)
- Jinhui Gao
- Biomedical Sciences Research Institute, University of Ulster, Coleraine, Northern Ireland BT52 1SA, UK
| | - Heather Nesbitt
- Biomedical Sciences Research Institute, University of Ulster, Coleraine, Northern Ireland BT52 1SA, UK
| | - Keiran Logan
- Biomedical Sciences Research Institute, University of Ulster, Coleraine, Northern Ireland BT52 1SA, UK
| | - Kathryn Burnett
- Biomedical Sciences Research Institute, University of Ulster, Coleraine, Northern Ireland BT52 1SA, UK
| | - Bronagh White
- Biomedical Sciences Research Institute, University of Ulster, Coleraine, Northern Ireland BT52 1SA, UK
| | - Iain G Jack
- Biomedical Sciences Research Institute, University of Ulster, Coleraine, Northern Ireland BT52 1SA, UK
| | - Mark A Taylor
- Department of HPB Surgery, Mater Hospital, Belfast, Northern Ireland BT14 6AB, UK
| | - Mark Love
- Imaging Centre, The Royal Victoria Hospital, Grosvenor Road, Belfast, Northern Ireland BT12 6BA, UK
| | - Bridgeen Callan
- Biomedical Sciences Research Institute, University of Ulster, Coleraine, Northern Ireland BT52 1SA, UK
| | - Anthony P McHale
- Biomedical Sciences Research Institute, University of Ulster, Coleraine, Northern Ireland BT52 1SA, UK
| | - John F Callan
- Biomedical Sciences Research Institute, University of Ulster, Coleraine, Northern Ireland BT52 1SA, UK.
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Brosey C, Shen R, Burnett K, Hura G, Moiani D, Jones D, Tainer J. Incorporating HT-SAXS into drug-discovery pipelines. Acta Crystallogr A Found Adv 2020. [DOI: 10.1107/s010876732009861x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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8
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McKay J, Begley E, Kerlin P, O’Carolan D, Cleary G, McKenna G, Burnett K. An analysis of the clinical appropriateness of out-of-hours emergency dental prescribing of antibiotics in Northern Ireland. Br Dent J 2020; 228:598-603. [DOI: 10.1038/s41415-020-1435-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Heaton T, Hardern T, Burnett K, Devlin M. Stress, burnout, depression and work satisfaction among
UK
anaesthetic trainees – a response. Anaesthesia 2020; 75:275-276. [DOI: 10.1111/anae.14913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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)
- T. Heaton
- Manchester University NHS Foundation Trust Manchester UK
| | - T. Hardern
- Manchester University NHS Foundation Trust Manchester UK
| | - K. Burnett
- Manchester University NHS Foundation Trust Manchester UK
| | - M. Devlin
- Manchester University NHS Foundation Trust Manchester UK
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Brosey CA, Shen R, Burnett K, Hura G, Tainer JA. Apoptosis-inducing factor: mechanistic insights and therapeutic opportunities from a metabolic allosteric switch. Acta Crystallogr A Found Adv 2019. [DOI: 10.1107/s0108767319098210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Burnett K, Armer N, Mcgregor J, Farrell M, Baines J, Baker P. WORKFORCE: The career aspirations and expectations of -student -physician associates in the UK. Future Healthc J 2019; 6:36-40. [PMID: 31098584 PMCID: PMC6520094 DOI: 10.7861/futurehosp.6-1-36] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The NHS five year forward view 1 supports the development of a flexible workforce. Expanding the traditional medical workforce using physician associates (PAs) is increasing in popularity. This study explores the career aspirations and expectations of student PAs from a large PA school in England. Thematic analysis of qualitative data from an online survey examined the personal motivations and career aspirations of student PAs. Finally, we make nine recommendations to enhancing recruitment, retention and development of PAs post qualification. Lessons learnt from this data set are generalisable.
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Affiliation(s)
- Kathryn Burnett
- Health Education England, Manchester, UK
- University of Manchester, Manchester, UK
| | | | | | | | - Jacqui Baines
- School of Foundation and Physician Associate, Health Education England, Manchester, UK
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Brosey CA, Shen R, Burnett K, Hura GL, Tainer JA. Shape shifting in apoptosis-inducing factor allostery and interactions: switching between oxidative phosphorylation and cell death. Acta Crystallogr A Found Adv 2018. [DOI: 10.1107/s0108767318099853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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13
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Hutchinson L, Sinclair M, Reid B, Burnett K, Callan B. A descriptive systematic review of salivary therapeutic drug monitoring in neonates and infants. Br J Clin Pharmacol 2018; 84:1089-1108. [PMID: 29442362 PMCID: PMC5980545 DOI: 10.1111/bcp.13553] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 01/30/2018] [Accepted: 01/31/2018] [Indexed: 01/24/2023] Open
Abstract
AIMS Saliva, as a matrix, offers many benefits over blood in therapeutic drug monitoring (TDM), in particular for infantile TDM. However, the accuracy of salivary TDM in infants remains an area of debate. This review explored the accuracy, applicability and advantages of using saliva TDM in infants and neonates. METHODS Databases were searched up to and including September 2016. Studies were included based on PICO as follows: P: infants and neonates being treated with any medication, I: salivary TDM vs. C: traditional methods and O: accuracy, advantages/disadvantages and applicability to practice. Compounds were assessed by their physicochemical and pharmacokinetic properties, as well as published quantitative saliva monitoring data. RESULTS Twenty-four studies and their respective 13 compounds were investigated. Four neutral and two acidic compounds, oxcarbazepine, primidone, fluconazole, busulfan, theophylline and phenytoin displayed excellent/very good correlation between blood plasma and saliva. Lamotrigine was the only basic compound to show excellent correlation with morphine exhibiting no correlation between saliva and blood plasma. Any compound with an acid dissociation constant (pKa) within physiological range (pH 6-8) gave a more varied response. CONCLUSION There is significant potential for infantile saliva testing and in particular for neutral and weakly acidic compounds. Of the properties investigated, pKa was the most influential with both logP and protein binding having little effect on this correlation. To conclude, any compound with a pKa within physiological range (pH 6-8) should be considered with extra care, with the extraction and analysis method examined and optimized on a case-by-case basis.
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Affiliation(s)
- Laura Hutchinson
- Institute of Nursing and Health ResearchUlster UniversityNewtownabbeyCo AntrimUK
| | - Marlene Sinclair
- Institute of Nursing and Health ResearchUlster UniversityNewtownabbeyCo AntrimUK
| | - Bernadette Reid
- Institute of Nursing and Health ResearchUlster UniversityNewtownabbeyCo AntrimUK
| | - Kathryn Burnett
- Biomedical Sciences Research InstituteUlster UniversityNewtownabbeyCo AntrimUK
| | - Bridgeen Callan
- Biomedical Sciences Research InstituteUlster UniversityNewtownabbeyCo AntrimUK
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Tainer JA, Shen R, Ho C, Long WZ, Singh S, Burnett K, Hura GL, Nix JC, Bowman GR, Ellenberger T, Brosey CA. Defining allostery and interactions regulating apoptosis-inducing factor. Acta Crystallogr A Found Adv 2017. [DOI: 10.1107/s0108767317096908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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15
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Brosey CA, Ho C, Long WZ, Singh S, Burnett K, Hura GL, Nix JC, Bowman GR, Ellenberger T, Tainer JA. Defining NADH-Driven Allostery Regulating Apoptosis-Inducing Factor. Structure 2016; 24:2067-2079. [PMID: 27818101 DOI: 10.1016/j.str.2016.09.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 09/08/2016] [Accepted: 10/05/2016] [Indexed: 01/07/2023]
Abstract
Apoptosis-inducing factor (AIF) is critical for mitochondrial respiratory complex biogenesis and for mediating necroptotic parthanatos; these functions are seemingly regulated by enigmatic allosteric switching driven by NADH charge-transfer complex (CTC) formation. Here, we define molecular pathways linking AIF's active site to allosteric switching regions by characterizing dimer-permissive mutants using small-angle X-ray scattering (SAXS) and crystallography and by probing AIF-CTC communication networks using molecular dynamics simulations. Collective results identify two pathways propagating allostery from the CTC active site: (1) active-site H454 links to S480 of AIF's central β-strand to modulate a hydrophobic border at the dimerization interface, and (2) an interaction network links AIF's FAD cofactor, central β-strand, and Cβ-clasp whereby R529 reorientation initiates C-loop release during CTC formation. This knowledge of AIF allostery and its flavoswitch mechanism provides a foundation for biologically understanding and biomedically controlling its participation in mitochondrial homeostasis and cell death.
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Affiliation(s)
- Chris A Brosey
- Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA; Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
| | - Chris Ho
- Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Winnie Z Long
- Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Sukrit Singh
- Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Kathryn Burnett
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Greg L Hura
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Jay C Nix
- Molecular Biology Consortium, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Gregory R Bowman
- Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Tom Ellenberger
- Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - John A Tainer
- MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Molecular and Cellular Oncology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
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Burnett K, Puschner B, Ramsey JJ, Lin Y, Wei A, Fascetti AJ. Lack of glucuronidation products of trans-resveratrol in plasma and urine of cats. J Anim Physiol Anim Nutr (Berl) 2016; 101:284-292. [DOI: 10.1111/jpn.12524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 03/31/2016] [Indexed: 12/31/2022]
Affiliation(s)
- K. Burnett
- Department of Molecular Biosciences; School of Veterinary Medicine; University of California; Davis CA USA
| | - B. Puschner
- Department of Molecular Biosciences; School of Veterinary Medicine; University of California; Davis CA USA
| | - J. J. Ramsey
- Department of Molecular Biosciences; School of Veterinary Medicine; University of California; Davis CA USA
| | - Y. Lin
- Department of Molecular Biosciences; School of Veterinary Medicine; University of California; Davis CA USA
| | - A. Wei
- Department of Molecular Biosciences; School of Veterinary Medicine; University of California; Davis CA USA
| | - A. J. Fascetti
- Department of Molecular Biosciences; School of Veterinary Medicine; University of California; Davis CA USA
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Douglas P, McGuffin L, Laur C, Burnett K, Ray S, McCarthy H. Pilot Evaluation of a Nutrition Training Intervention for Pre‐Registration Pharmacists in Northern Ireland. FASEB J 2015. [DOI: 10.1096/fasebj.29.1_supplement.907.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Pauline Douglas
- UK Need for Nutrition Education/Innovation Programme Ulster University & MRC HNR Cambridge UniversityUnited Kingdom
| | - Lynn McGuffin
- UK Need for Nutrition Education/Innovation Programme Ulster University & MRC HNR Cambridge UniversityUnited Kingdom
| | - Celia Laur
- UK Need for Nutrition Education/Innovation Programme Ulster University & MRC HNR Cambridge UniversityUnited Kingdom
| | - Kathryn Burnett
- School of Pharmacy and Pharmaceutical Science Ulster UniversityUnited Kingdom
| | - Sumantra Ray
- UK Need for Nutrition Education/Innovation Programme Ulster University & MRC HNR Cambridge UniversityUnited Kingdom
| | - Helen McCarthy
- UK Need for Nutrition Education/Innovation Programme Ulster University & MRC HNR Cambridge UniversityUnited Kingdom
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18
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Close A, Sapir A, Burnett K, d'Avossa G. Attention to multiple locations is limited by spatial working memory capacity. J Vis 2014; 14:14.9.17. [DOI: 10.1167/14.9.17] [Citation(s) in RCA: 5] [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: 11/24/2022] Open
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19
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Davis RC, Jensen CJ, Burgette L, Burnett K. Working Smarter on Cold Cases: Identifying Factors Associated with Successful Cold Case Investigations. J Forensic Sci 2014; 59:375-82. [DOI: 10.1111/1556-4029.12384] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2011] [Revised: 12/03/2012] [Accepted: 12/23/2012] [Indexed: 11/27/2022]
Affiliation(s)
- Robert C. Davis
- Police Executive Research Forum; 1120 Connecticut Avenue Washington DC 20036
| | - Carl J. Jensen
- Department of Legal Studies; Center for Intelligence and Security Studies; University of Mississippi; 620 All American Drive University MS 38677
| | - Lane Burgette
- Police Executive Research Forum; 1120 Connecticut Avenue Washington DC 20036
| | - Kathryn Burnett
- Dept of Forensic Psychology; Marymount University; 2807 N Glebe St Arlington VA 22207
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20
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Burnett K, d'Avossa G, Sapir A. Exogenous cue size modulates attentional effects. J Vis 2011. [DOI: 10.1167/11.11.115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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21
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Burnett K, Peckham D, Brownlee K, Denton M. 140 Retrospective analysis of isolation of non-tuberculous mycobacteria from cystic fibrosis sputum samples. J Cyst Fibros 2011. [DOI: 10.1016/s1569-1993(11)60156-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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22
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Battershill JM, Burnett K, Bull S. Factors affecting the incidence of genotoxicity biomarkers in peripheral blood lymphocytes: impact on design of biomonitoring studies. Mutagenesis 2008; 23:423-37. [DOI: 10.1093/mutage/gen040] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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23
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Burnett K, Williams H, Macey B, Mancia A, Gross P, Warr G, Chapman R, Burnett L. Resilience and sensitivity to environmental stress in the American oyster, Crassostrea virginica. Comp Biochem Physiol A Mol Integr Physiol 2008. [DOI: 10.1016/j.cbpa.2008.04.408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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24
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25
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Burnett K, Terwilliger N, van den Thillart G. 21.1. Introduction: Genetic and phenotypic responses to hypoxia. Comp Biochem Physiol A Mol Integr Physiol 2007. [DOI: 10.1016/j.cbpa.2007.06.246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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26
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Szymańska MH, Simons BD, Burnett K. Dynamics of the BCS-BEC crossover in a degenerate Fermi gas. Phys Rev Lett 2005; 94:170402. [PMID: 15904271 DOI: 10.1103/physrevlett.94.170402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Indexed: 05/02/2023]
Abstract
We study the short-time dynamics of a degenerate Fermi gas positioned near a Feshbach resonance following an abrupt jump in the atomic interaction resulting from a change of magnetic field. We investigate the dynamics of the condensate order parameter and pair wave function for a range of field strengths. When the jump is sufficient to span the BCS to Bose-Einstein condensation crossover, we show that the rigidity of the momentum distribution precludes any atom-molecule oscillations in the entrance channel dominated resonances observed in 40K and 6Li. Focusing on material parameters tailored to the 40K Feshbach resonance at 202.1 G, we comment on the integrity of the fast sweep projection technique as a vehicle to explore the condensed phase in the crossover region.
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Affiliation(s)
- M H Szymańska
- Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 OHE, United Kingdom
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27
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Falloon IRH, Mizuno M, Murakami M, Roncone R, Unoka Z, Harangozo J, Pullman J, Gedye R, Held T, Hager B, Erickson D, Burnett K. Structured assessment of current mental state in clinical practice: an international study of the reliability and validity of the Current Psychiatric State interview, CPS-50. Acta Psychiatr Scand 2005; 111:44-50. [PMID: 15636593 DOI: 10.1111/j.1600-0447.2004.00405.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To develop a reliable standardized assessment of psychiatric symptoms for use in clinical practice. METHOD A 50-item interview, the Current Psychiatric State 50 (CPS-50), was used to assess 237 patients with a range of psychiatric diagnoses. Ratings were made by interviewers after a 2-day training. Comparisons of inter-rater reliability on each item and on eight clinical subscales were made across four international centres and between psychiatrists and non-psychiatrists. A principal components analysis was used to validate these clinical scales. RESULTS Acceptable inter-rater reliability (intra-class coefficient > 0.80) was found for 46 of the 50 items, and for all eight subscales. There was no difference between centres or between psychiatrists and non-psychiatrists. The principal components analysis factors were similar to the clinical scales. CONCLUSION The CPS-50 is a reliable standardized assessment of current mental status that can be used in clinical practice by all mental health professionals after brief training.
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Affiliation(s)
- I R H Falloon
- OTP European Coordinating Centre, ARIETE, Perugia, Italy.
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28
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Morgan SA, Rusch M, Hutchinson DAW, Burnett K. Quantitative test of thermal field theory for Bose-Einstein condensates. Phys Rev Lett 2003; 91:250403. [PMID: 14754100 DOI: 10.1103/physrevlett.91.250403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2003] [Indexed: 05/24/2023]
Abstract
We present numerical results from a second-order quantum field theory of Bose-Einstein condensates applied to the 1997 JILA experiment [Phys. Rev. Lett. 78, 764 (1997)]]. Good agreement is found for the energies and decay rates for both the lowest-energy m=2 and m=0 modes. The anomalous behavior of the m=0 mode is due to experimental perturbation of the noncondensate. The theory is gapless and includes the coupled dynamics of the condensate and thermal cloud, the anomalous pair average, and all relevant finite size effects.
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Affiliation(s)
- S A Morgan
- Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom
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29
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Köhler T, Gasenzer T, Julienne PS, Burnett K. Long-range nature of feshbach molecules in bose-einstein condensates. Phys Rev Lett 2003; 91:230401. [PMID: 14683163 DOI: 10.1103/physrevlett.91.230401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2003] [Indexed: 05/24/2023]
Abstract
We discuss the long-range nature of the molecules produced in recent experiments on molecular Bose-Einstein condensation. The properties of these molecules depend on the full two-body Hamiltonian and not just on the states of the system in the absence of interchannel couplings. The very long-range nature of the state is crucial to the efficiency of production in the experiments. Our many-body treatment of the gas accounts for the full binary physics and describes properly how these molecular condensates can be directly probed.
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Affiliation(s)
- T Köhler
- Department of Physics, University of Oxford, Oxford, OX1 3PU, United Kingdom
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30
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Abstract
We consider the localization of a pair of particles in relative-position space. We show how a sequence of scattering interactions progressively entangles two particles, giving rise to a robust state of well-defined separation and thus providing a natural description of relative position. We use two thought experiments to describe the localization process. The first is an interferometer with recoiling mirrors. The second, and more general, case considers photons scattering from a pair of particles and the resulting emergence of a Young's interference pattern. The underlying framework of the localization process suggests a prominent role for entanglement and relative observables at the boundary between quantum and classical mechanics.
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Affiliation(s)
- A V Rau
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK.
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31
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Roberts DC, Burnett K. Probing states in the Mott insulator regime in the case of coherent bosons trapped in an optical lattice. Phys Rev Lett 2003; 90:150401. [PMID: 12732021 DOI: 10.1103/physrevlett.90.150401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2002] [Indexed: 05/24/2023]
Abstract
We propose a method to probe states in the Mott insulator regime produced from a condensate in an optical lattice. We consider a system in which we create time-dependent number fluctuations in a given site by turning off the atomic interactions and lowering the potential barriers on a nearly pure Mott state to allow the atoms to tunnel between sites. We calculate the expected interference pattern and number fluctuations from such a system and show that one can potentially observe a deviation from a pure Mott state. We also discuss a method in which to detect these number fluctuations using time-of-flight imaging.
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Affiliation(s)
- D C Roberts
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
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32
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Bond Brill J, Perry AC, Parker L, Robinson A, Burnett K. Dose-response effect of walking exercise on weight loss. How much is enough? Int J Obes (Lond) 2002; 26:1484-93. [PMID: 12439651 DOI: 10.1038/sj.ijo.0802133] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2002] [Revised: 05/06/2002] [Accepted: 05/20/2002] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Exercise is the cornerstone of behavioral weight loss programs. The total volume of exercise needed to both promote weight loss and elicit health benefits has not been sufficiently investigated. The aim of this study was to examine the effects of two different volumes of walking 'metabolic fitness' exercise prescriptions, in combination with a low-fat, ad libitum diet (LFAL) on weight loss and additional modifiable health-related variables (HRV) in an ethnically diverse sample of overweight premenopausal women. DESIGN Clinical 12 week weight loss intervention study with a 5.0-5.8 MJ diet daily with (a). participants walking 30 min, 5 days per week (DEX1), (b). participants walking 60 min, five times per week (DEX2) or (c). a diet only control group (DO). SUBJECTS A mixed racial sample (predominantly Hispanic) of 56 subjects (mean BMI=34.26+/-6.61, mean age= 39.45+/-7.34) completed the 12 week program. MEASUREMENTS Various body weight, body composition and fat distribution variables, dietary intake and additional HRV such as blood lipids, blood pressure and an estimate of cardiorespiratory fitness at baseline and after 3 months. RESULTS All groups showed similar and significant (P<0.001) declines in body weight, percentage body fat, BMI, WHR, fat mass, fat-free mass and diastolic blood pressure following the program. In addition, total cholesterol, triacylglycerol and the TC:HDL ratio displayed a significant time effect (P<0.05). Significant interactions (P<0.05) were found for waist circumference, sagittal diameter, estimated VO(2max) and LDL-C, with both exercise groups showing similar and significantly greater (P<0.05) improvements than DO. Significant interactions (P<0.05) were also observed for several dietary variables. CONCLUSION Our study showed no dose-response effect of walking exercise on weight loss over diet alone. Both lower and higher volume metabolic fitness prescriptions resulted in similar and significant beneficial changes in several HRV. This data suggests that 30 min of walking on most days of the week may be as beneficial as 60 min (in combination with diet) in promoting numerous additional healthful outcomes over diet alone following a 12 week weight loss program.
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Affiliation(s)
- J Bond Brill
- Department of Exercise and Sport Science, School of Education, University of Miami, Florida 33124-2040, USA.
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33
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Dunningham JA, Burnett K, Barnett SM. Interferometry below the standard quantum limit with Bose-Einstein condensates. Phys Rev Lett 2002; 89:150401. [PMID: 12365974 DOI: 10.1103/physrevlett.89.150401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2002] [Indexed: 05/23/2023]
Abstract
We discuss a scheme for using entangled Bose-Einstein condensates to detect phase differences with a resolution better than the standard quantum limit. To date, schemes have shown that the enhancement in phase resolution gained by entangling condensates is lost when dissipation is present. Here we show how this can be overcome by using number correlated condensates, as have been produced recently in the laboratory. We also outline a scheme for measuring this phase that is not destroyed when the effects of finite detector efficiency are considered.
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Affiliation(s)
- J A Dunningham
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, United Kingdom
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34
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d'Arcy MB, Godun RM, Oberthaler MK, Summy GS, Burnett K, Gardiner SA. Approaching classicality in quantum accelerator modes through decoherence. Phys Rev E Stat Nonlin Soft Matter Phys 2001; 64:056233. [PMID: 11736080 DOI: 10.1103/physreve.64.056233] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2000] [Revised: 08/07/2001] [Indexed: 05/23/2023]
Abstract
We describe measurements of the mean energy of an ensemble of laser-cooled atoms in an atom optical system in which the cold atoms, falling freely under gravity, receive approximate delta-kicks from a pulsed standing wave of laser light. We call this system a "delta-kicked accelerator." Additionally, we can counteract the effect of gravity by appropriate shifting of the position of the standing wave, which restores the dynamics of the standard delta-kicked rotor. The presence of gravity (delta-kicked accelerator) yields quantum phenomena, quantum accelerator modes, which are markedly different from those in the case for which gravity is absent (delta-kicked rotor). Quantum accelerator modes result in a much higher rate of increase in the mean energy of the system than is found in its classical analog. When gravity is counteracted, the system exhibits the suppression of the momentum diffusion characteristic of dynamical localization. The effect of noise is examined and a comparison is made with simulations of both quantum-mechanical and classical versions of the system. We find that the introduction of noise results in the restoration of several signatures of classical behavior, although significant quantum features remain.
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Affiliation(s)
- M B d'Arcy
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
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35
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Davis MJ, Morgan SA, Burnett K. Simulations of Bose fields at finite temperature. Phys Rev Lett 2001; 87:160402. [PMID: 11690189 DOI: 10.1103/physrevlett.87.160402] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2000] [Revised: 09/12/2001] [Indexed: 05/23/2023]
Abstract
We introduce a time-dependent projected Gross-Pitaevskii equation to describe a partially condensed homogeneous Bose gas, and find that this equation will evolve randomized initial wave functions to equilibrium. We compare our numerical data to the predictions of a gapless, second order theory of Bose-Einstein condensation [S. A. Morgan, J. Phys. B 33, 3847 (2000)], and find that we can determine a temperature when the theory is valid. As the Gross-Pitaevskii equation is nonperturbative, we expect that it can describe the correct thermal behavior of a Bose gas as long as all relevant modes are highly occupied. Our method could be applied to other boson fields.
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Affiliation(s)
- M J Davis
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
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36
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Rusch M, Morgan SA, Hutchinson DA, Burnett K. Second order theory of excitations in trapped bose condensates at finite temperatures. Phys Rev Lett 2000; 85:4844-4847. [PMID: 11102132 DOI: 10.1103/physrevlett.85.4844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2000] [Indexed: 05/23/2023]
Abstract
We present a finite temperature field theory for collective excitations of trapped Bose condensates which includes the dynamics of the thermal cloud. In spherical traps we show that excitations couple strongly to a small number of modes, giving resonance structure in their frequency spectra. Where possible, we derive energy shifts and lifetimes of excitations. For the l = 0 mode we show that the simple picture of a decay rate fails, which should be observable in suitable experiments. It also suggests a possible explanation for the anomalous behavior of the m = 0 mode observed in anisotropic traps.
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Affiliation(s)
- M Rusch
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
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37
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Ellington JE, Samper J, Jones A, Oliver SA, Burnett K, Wright RW. Effects of bovine serum albumin on function of cryopreserved stallion spermatozoa during medium culture and uterine tube epithelial cell coculture. Am J Vet Res 1999; 60:363-7. [PMID: 10188821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
OBJECTIVE To compare function of cultured cryopreserved stallion spermatozoa in a modified Tyrode's medium (TM), with or without bovine serum albumin (BSA), or in uterine tube (oviduct) epithelial cell (OEC) coculture in TM, with or without BSA. SAMPLE POPULATION Cryopreserved spermatozoa from 6 proven stallions and OEC from bovine reproductive tracts in follicular phase. PROCEDURE Thawed spermatozoa were cultured in TM, with or without BSA, or cocultured with OEC monolayers in TM, with or without BSA. Percentages of capacitated and acrosome-reacted spermatozoa were measured at 5 hours for TM cultures. Spermatozoal survival and motility characteristics were observed over time for all culture methods. Number of spermatozoa attaching to OEC were compared for cocultures. RESULTS Use of TM without BSA altered spermatozoal function in cell-free medium culture and OEC coculture. A higher percentage of spermatozoa were acrosome reacted in TM with BSA, although percentages of capacitated spermatozoa did not differ. Spermatozoa survived longer and maintained superior motion in TM culture without BSA and in OEC cocultures. More spermatozoa were able to attach to OEC in TM without BSA. CONCLUSIONS Incubation of cryopreserved spermatozoa in media with BSA resulted in rapid decrease in percentage of intact, motile spermatozoa and limited their ability to interact with OEC. CLINICAL RELEVANCE Current culture media used for assisted reproduction techniques in horses do not provide functionally capacitated spermatozoa. Removal of BSA from such media improves spermatozoal quality and survival.
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Affiliation(s)
- J E Ellington
- Department of Veterinary Comparative Anatomy, Pharmacology, and Physiology, College of Veterinary Medicine, Washington State University, Pullman 99164, USA
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Dodd R, Clark C, Edwards M, Burnett K. Characterizing the coherence of Bose-Einstein condensates and atom lasers. Opt Express 1997; 1:284-292. [PMID: 19373414 DOI: 10.1364/oe.1.000284] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
For a dilute, interacting Bose gas of magnetically-trapped atoms at temperatures below the critical temperature T0 for Bose-Einstein condensation, we determine the second-order coherence function g (2) (r1 ; r2) within the framework of a finite-temperature quantum field theory. We show that, because of the different spatial distributions of condensate and thermal atoms in the trap, g (2) (r1 ; r2) does not depend on jr1 r2j alone. This means that the experimental determinations of g (2) reported to date give only its spatial average. Such an average may underestimate the degree of coherence attainable in an atom laser by judicious engineering of the output coupler.
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Burnett K, Ironson G, Benight C, Wynings C, Greenwood D, Carver CS, Cruess D, Baum A, Schneiderman N. Measurement of perceived disruption during rebuilding following Hurricane Andrew. J Trauma Stress 1997; 10:673-81. [PMID: 9391950 DOI: 10.1023/a:1024858122311] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The purpose of this study was to develop and evaluate a measure of perceived disruption during rebuilding following a disaster. Two eight-item scales, which measured intensity of disruption during the entire repair phase (Intensity-RP) and intensity of disruption during the past month (Intensity-PM) were developed and administered to 135 survivors of Hurricane Andrew. At 9 to 12 months postdisaster, Intensity-RP and Intensity-PM were both significantly associated with scores on the Global Severity Index of the SCL-90-R, and with scores on the Impact of Event-Intrusion Scale; Intensity-PM alone was significantly associated with PTSD scores. Regression analyses indicated that each scale contributed significant unique variance in predicting mental health symptoms, even after controlling for relevant demographic and initial disaster exposure variables.
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Affiliation(s)
- K Burnett
- Counseling Psychology Program, University of Miami, Coral Gables 33124, USA
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40
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Rubin DL, Falk KL, Sperling MJ, Ross M, Saini S, Rothman B, Shellock F, Zerhouni E, Stark D, Outwater EK, Schmiedl U, Kirby LC, Chezmar J, Coates T, Chang M, Silverman JM, Rofsky N, Burnett K, Engel J, Young SW. A multicenter clinical trial of Gadolite Oral Suspension as a contrast agent for MRI. J Magn Reson Imaging 1997; 7:865-72. [PMID: 9307913 DOI: 10.1002/jmri.1880070515] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The purpose of this study was to assess the effectiveness and safety of Gadolite Oral Suspension as a gastrointestinal (GI) contrast agent for MRI in a phase II and two phase III multicenter clinical trials. Gadolite was administered to 306 patients with known or suspected abdominal and/or pelvic disease. MRI with T1- and T2-weighted sequences was performed before and after ingestion. Efficacy was evaluated by having two masked readers rate the certainty of their MR diagnosis (0 = uncertain, 1 = probable, 2 = definite) on randomly presented pre- and post-Gadolite Oral Suspension enhanced images. Principal investigators also evaluated the images and established the final diagnosis. Vital signs, clinical chemistries, and adverse events were documented. Blood and urine samples were analyzed for gadolinium content to determine whether Gadolite Oral Suspension was absorbed systemically. Certainty in MR diagnosis increased significantly (P < .001) for both blinded readers between pre- and post-Gadolite images (.49-1.18 for reader 1: .46-1.53 for reader 2). Sensitivity, specificity, and accuracy also increased for both masked readers. No gadolinium was detected in blood or urine samples. There were no serious adverse events and no apparent drug-related trends in mean vital signs or laboratory values. Gadolite is a highly effective, safe, and well tolerated contrast agent for clinical use with MRI.
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Affiliation(s)
- D L Rubin
- Good Samaritan Hospital, San Jose, CA, USA
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41
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Ruprecht PA, Edwards M, Burnett K, Clark CW. Probing the linear and nonlinear excitations of Bose-condensed neutral atoms in a trap. Phys Rev A 1996; 54:4178-4187. [PMID: 9913968 DOI: 10.1103/physreva.54.4178] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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43
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44
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Edwards M, Ruprecht PA, Burnett K, Dodd RJ, Clark CW. Collective Excitations of Atomic Bose-Einstein Condensates. Phys Rev Lett 1996; 77:1671-1674. [PMID: 10063142 DOI: 10.1103/physrevlett.77.1671] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Burnett K, Julienne PS, Suominen K. Laser-Driven Collisions between Atoms in a Bose-Einstein Condensed Gas. Phys Rev Lett 1996; 77:1416-1419. [PMID: 10063073 DOI: 10.1103/physrevlett.77.1416] [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] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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46
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Watson JB, Keitel CH, Knight PL, Burnett K. Entropic measure of wave-packet spreading and ionization in laser-driven atoms. Phys Rev A 1996; 54:729-735. [PMID: 9913530 DOI: 10.1103/physreva.54.729] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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47
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Barnett SM, Burnett K, Vaccaro JA. Why a Condensate Can Be Thought of as Having a Definite Phase. J Res Natl Inst Stand Technol 1996; 101:593-600. [PMID: 27805112 PMCID: PMC4907620 DOI: 10.6028/jres.101.059] [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] [Indexed: 05/14/2023]
Abstract
We present an argument for assigning a definite phase to an assembly of Bose-Einstein Condensed atoms. This relies on the demonstration that a coherent state of the condensed system is a robust state in the presence of interactions between the condensate and its environment.
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Affiliation(s)
- S M Barnett
- Department of Physics and Applied Physics, University of Strathclyde, Glasgow, G4 0NG, UK
| | - K Burnett
- Department of Physics, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK
| | - J A Vaccaro
- Physics Department, The Open University, Milton Keynes, MK7 6AA, UK
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Edwards M, Dodd RJ, Clark CW, Burnett K. Zero-Temperature, Mean-Field Theory of Atomic Bose-Einstein Condensates. J Res Natl Inst Stand Technol 1996; 101:553-565. [PMID: 27805108 PMCID: PMC4907624 DOI: 10.6028/jres.101.055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/15/1996] [Indexed: 05/24/2023]
Abstract
We review the application of zero-temperature, mean-field theory to current experimental atomic Bose-Einstein condensates. We assess the validity of the approximations made by comparing the mean-field results with a variety of experimental data.
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Affiliation(s)
- Mark Edwards
- Department of Physics, Georgia Southern University, Statesboro, GA 30460-8031
| | - R J Dodd
- National Institute of Standards and Technology, Gaithersburg, MD 20899-0001
| | - Charles W Clark
- National Institute of Standards and Technology, Gaithersburg, MD 20899-0001
| | - K Burnett
- National Institute of Standards and Technology, Gaithersburg, MD 20899-0001
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Dodd RJ, Edwards M, Williams CJ, Clark CW, Holland MJ, Ruprecht PA, Burnett K. Role of attractive interactions on Bose-Einstein condensation. Phys Rev A 1996; 54:661-664. [PMID: 9913522 DOI: 10.1103/physreva.54.661] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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50
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Proukakis NP, Burnett K. Generalized Mean Fields for Trapped Atomic Bose-Einstein Condensates. J Res Natl Inst Stand Technol 1996; 101:457-469. [PMID: 27805101 PMCID: PMC4907630 DOI: 10.6028/jres.101.048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/15/1996] [Indexed: 05/22/2023]
Abstract
We describe generalized time-dependent mean-field equations for partially condensed samples of trapped and evaporatively cooled atoms. These equations give a way of investigating the various order parameters that may be present as well as the existence of a mean value of the field due to condensed atoms. Our approach provides us with a closed system of self-consistent equations for the order parameters present. The equations we derive are shown to reduce to other treatments in the literature in various limits. We also show how the equation of motion method allows us to construct a formalism that can handle the evolution of these mean fields due to two-loop kinetics.
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Affiliation(s)
- N P Proukakis
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - K Burnett
- Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
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