1
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Gomes B, Singh A, O'Sullivan JW, Schnurr TM, Goddard PC, Loong S, Amar D, Hughes JW, Kostur M, Haddad F, Salerno M, Foo R, Montgomery SB, Parikh VN, Meder B, Ashley EA. Genetic architecture of cardiac dynamic flow volumes. Nat Genet 2024; 56:245-257. [PMID: 38082205 DOI: 10.1038/s41588-023-01587-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 10/23/2023] [Indexed: 02/04/2024]
Abstract
Cardiac blood flow is a critical determinant of human health. However, the definition of its genetic architecture is limited by the technical challenge of capturing dynamic flow volumes from cardiac imaging at scale. We present DeepFlow, a deep-learning system to extract cardiac flow and volumes from phase-contrast cardiac magnetic resonance imaging. A mixed-linear model applied to 37,653 individuals from the UK Biobank reveals genome-wide significant associations across cardiac dynamic flow volumes spanning from aortic forward velocity to aortic regurgitation fraction. Mendelian randomization reveals a causal role for aortic root size in aortic valve regurgitation. Among the most significant contributing variants, localizing genes (near ELN, PRDM6 and ADAMTS7) are implicated in connective tissue and blood pressure pathways. Here we show that DeepFlow cardiac flow phenotyping at scale, combined with genotyping data, reinforces the contribution of connective tissue genes, blood pressure and root size to aortic valve function.
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Affiliation(s)
- Bruna Gomes
- Departments of Medicine, Genetics, Computer Science and Biomedical Data Science, Stanford University, Stanford, CA, USA
- Department of Cardiology, Pneumology and Angiology, Heidelberg University Hospital, Heidelberg, Germany
- Informatics for Life, Heidelberg, Germany
| | - Aditya Singh
- Departments of Medicine, Genetics, Computer Science and Biomedical Data Science, Stanford University, Stanford, CA, USA
| | - Jack W O'Sullivan
- Departments of Medicine, Genetics, Computer Science and Biomedical Data Science, Stanford University, Stanford, CA, USA
| | - Theresia M Schnurr
- Departments of Medicine, Genetics, Computer Science and Biomedical Data Science, Stanford University, Stanford, CA, USA
| | - Pagé C Goddard
- Departments of Medicine, Genetics, Computer Science and Biomedical Data Science, Stanford University, Stanford, CA, USA
| | - Shaun Loong
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - David Amar
- Departments of Medicine, Genetics, Computer Science and Biomedical Data Science, Stanford University, Stanford, CA, USA
| | - J Weston Hughes
- Departments of Medicine, Genetics, Computer Science and Biomedical Data Science, Stanford University, Stanford, CA, USA
| | - Mykhailo Kostur
- Department of Cardiology, Pneumology and Angiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Francois Haddad
- Departments of Medicine, Genetics, Computer Science and Biomedical Data Science, Stanford University, Stanford, CA, USA
| | - Michael Salerno
- Departments of Medicine, Genetics, Computer Science and Biomedical Data Science, Stanford University, Stanford, CA, USA
| | - Roger Foo
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Stephen B Montgomery
- Departments of Medicine, Genetics, Computer Science and Biomedical Data Science, Stanford University, Stanford, CA, USA
| | - Victoria N Parikh
- Departments of Medicine, Genetics, Computer Science and Biomedical Data Science, Stanford University, Stanford, CA, USA
| | - Benjamin Meder
- Department of Cardiology, Pneumology and Angiology, Heidelberg University Hospital, Heidelberg, Germany
- Informatics for Life, Heidelberg, Germany
| | - Euan A Ashley
- Departments of Medicine, Genetics, Computer Science and Biomedical Data Science, Stanford University, Stanford, CA, USA.
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2
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Ouyang D, Theurer J, Stein NR, Hughes JW, Elias P, He B, Yuan N, Duffy G, Sandhu RK, Ebinger J, Botting P, Jujjavarapu M, Claggett B, Tooley JE, Poterucha T, Chen JH, Nurok M, Perez M, Perotte A, Zou JY, Cook NR, Chugh SS, Cheng S, Albert CM. Electrocardiographic deep learning for predicting post-procedural mortality: a model development and validation study. Lancet Digit Health 2024; 6:e70-e78. [PMID: 38065778 DOI: 10.1016/s2589-7500(23)00220-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/01/2023] [Accepted: 10/18/2023] [Indexed: 12/22/2023]
Abstract
BACKGROUND Preoperative risk assessments used in clinical practice are insufficient in their ability to identify risk for postoperative mortality. Deep-learning analysis of electrocardiography can identify hidden risk markers that can help to prognosticate postoperative mortality. We aimed to develop a prognostic model that accurately predicts postoperative mortality in patients undergoing medical procedures and who had received preoperative electrocardiographic diagnostic testing. METHODS In a derivation cohort of preoperative patients with available electrocardiograms (ECGs) from Cedars-Sinai Medical Center (Los Angeles, CA, USA) between Jan 1, 2015 and Dec 31, 2019, a deep-learning algorithm was developed to leverage waveform signals to discriminate postoperative mortality. We randomly split patients (8:1:1) into subsets for training, internal validation, and final algorithm test analyses. Model performance was assessed using area under the receiver operating characteristic curve (AUC) values in the hold-out test dataset and in two external hospital cohorts and compared with the established Revised Cardiac Risk Index (RCRI) score. The primary outcome was post-procedural mortality across three health-care systems. FINDINGS 45 969 patients had a complete ECG waveform image available for at least one 12-lead ECG performed within the 30 days before the procedure date (59 975 inpatient procedures and 112 794 ECGs): 36 839 patients in the training dataset, 4549 in the internal validation dataset, and 4581 in the internal test dataset. In the held-out internal test cohort, the algorithm discriminates mortality with an AUC value of 0·83 (95% CI 0·79-0·87), surpassing the discrimination of the RCRI score with an AUC of 0·67 (0·61-0·72). The algorithm similarly discriminated risk for mortality in two independent US health-care systems, with AUCs of 0·79 (0·75-0·83) and 0·75 (0·74-0·76), respectively. Patients determined to be high risk by the deep-learning model had an unadjusted odds ratio (OR) of 8·83 (5·57-13·20) for postoperative mortality compared with an unadjusted OR of 2·08 (0·77-3·50) for postoperative mortality for RCRI scores of more than 2. The deep-learning algorithm performed similarly for patients undergoing cardiac surgery (AUC 0·85 [0·77-0·92]), non-cardiac surgery (AUC 0·83 [0·79-0·88]), and catheterisation or endoscopy suite procedures (AUC 0·76 [0·72-0·81]). INTERPRETATION A deep-learning algorithm interpreting preoperative ECGs can improve discrimination of postoperative mortality. The deep-learning algorithm worked equally well for risk stratification of cardiac surgeries, non-cardiac surgeries, and catheterisation laboratory procedures, and was validated in three independent health-care systems. This algorithm can provide additional information to clinicians making the decision to perform medical procedures and stratify the risk of future complications. FUNDING National Heart, Lung, and Blood Institute.
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Affiliation(s)
- David Ouyang
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Division of Artificial Intelligence in Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
| | - John Theurer
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Nathan R Stein
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - J Weston Hughes
- Department of Computer Science, Stanford University, Palo Alto, CA, USA
| | - Pierre Elias
- Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA; Department of Biomedical Informatics, Columbia University Irving Medical Center, New York, NY, USA
| | - Bryan He
- Department of Computer Science, Stanford University, Palo Alto, CA, USA
| | - Neal Yuan
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Grant Duffy
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Roopinder K Sandhu
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Joseph Ebinger
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Patrick Botting
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Melvin Jujjavarapu
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Brian Claggett
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - James E Tooley
- Division of Cardiology, Stanford University, Palo Alto, CA, USA
| | - Tim Poterucha
- Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Jonathan H Chen
- Division of Bioinformatics Research, Stanford University, Palo Alto, CA, USA
| | - Michael Nurok
- Division of Anesthesia, Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Marco Perez
- Division of Cardiology, Stanford University, Palo Alto, CA, USA
| | - Adler Perotte
- Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - James Y Zou
- Department of Computer Science, Stanford University, Palo Alto, CA, USA; Department of Medicine, and Department of Biomedical Data Science, Stanford University, Palo Alto, CA, USA
| | - Nancy R Cook
- Division of Preventive Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA
| | - Sumeet S Chugh
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Division of Artificial Intelligence in Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Susan Cheng
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Christine M Albert
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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3
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Wang Q, Tang TM, Youlton N, Weldy CS, Kenney AM, Ronen O, Hughes JW, Chin ET, Sutton SC, Agarwal A, Li X, Behr M, Kumbier K, Moravec CS, Tang WHW, Margulies KB, Cappola TP, Butte AJ, Arnaout R, Brown JB, Priest JR, Parikh VN, Yu B, Ashley EA. Epistasis regulates genetic control of cardiac hypertrophy. Res Sq 2023:rs.3.rs-3509208. [PMID: 38045390 PMCID: PMC10690313 DOI: 10.21203/rs.3.rs-3509208/v1] [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] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
The combinatorial effect of genetic variants is often assumed to be additive. Although genetic variation can clearly interact non-additively, methods to uncover epistatic relationships remain in their infancy. We develop low-signal signed iterative random forests to elucidate the complex genetic architecture of cardiac hypertrophy. We derive deep learning-based estimates of left ventricular mass from the cardiac MRI scans of 29,661 individuals enrolled in the UK Biobank. We report epistatic genetic variation including variants close to CCDC141, IGF1R, TTN, and TNKS. Several loci not prioritized by univariate genome-wide association analysis are identified. Functional genomic and integrative enrichment analyses reveal a complex gene regulatory network in which genes mapped from these loci share biological processes and myogenic regulatory factors. Through a network analysis of transcriptomic data from 313 explanted human hearts, we show that these interactions are preserved at the level of the cardiac transcriptome. We assess causality of epistatic effects via RNA silencing of gene-gene interactions in human induced pluripotent stem cell-derived cardiomyocytes. Finally, single-cell morphology analysis using a novel high-throughput microfluidic system shows that cardiomyocyte hypertrophy is non-additively modifiable by specific pairwise interactions between CCDC141 and both TTN and IGF1R. Our results expand the scope of genetic regulation of cardiac structure to epistasis.
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Affiliation(s)
- Qianru Wang
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Tiffany M. Tang
- Department of Statistics, University of California, Berkeley, Berkeley, CA, USA
| | - Nathan Youlton
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Chad S. Weldy
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Ana M. Kenney
- Department of Statistics, University of California, Berkeley, Berkeley, CA, USA
| | - Omer Ronen
- Department of Statistics, University of California, Berkeley, Berkeley, CA, USA
| | - J. Weston Hughes
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Elizabeth T. Chin
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Shirley C. Sutton
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Abhineet Agarwal
- Department of Statistics, University of California, Berkeley, Berkeley, CA, USA
| | - Xiao Li
- Department of Statistics, University of California, Berkeley, Berkeley, CA, USA
| | - Merle Behr
- Faculty of Informatics and Data Science, University of Regensburg, Regensburg, Germany
| | - Karl Kumbier
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Christine S. Moravec
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - W. H. Wilson Tang
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
- Department of Cardiovascular Medicine, Heart Vascular and Thoracic Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Kenneth B. Margulies
- Division of Cardiovascular Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Hospital of The University of Pennsylvania, Philadelphia, PA, USA
| | - Thomas P. Cappola
- Division of Cardiovascular Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Hospital of The University of Pennsylvania, Philadelphia, PA, USA
| | - Atul J. Butte
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA, USA
- Chan Zuckerberg Biohub – San Francisco, San Francisco, CA, USA
| | - Rima Arnaout
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA, USA
- Chan Zuckerberg Biohub – San Francisco, San Francisco, CA, USA
| | - James B. Brown
- Department of Statistics, University of California, Berkeley, Berkeley, CA, USA
- Chan Zuckerberg Biohub – San Francisco, San Francisco, CA, USA
- Division of Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - James R. Priest
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
- Chan Zuckerberg Biohub – San Francisco, San Francisco, CA, USA
- Tenaya Therapeutics, San Francisco, CA, USA
| | - Victoria N. Parikh
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Bin Yu
- Department of Statistics, University of California, Berkeley, Berkeley, CA, USA
- Chan Zuckerberg Biohub – San Francisco, San Francisco, CA, USA
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley, CA, USA
- Center for Computational Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Euan A. Ashley
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
- Chan Zuckerberg Biohub – San Francisco, San Francisco, CA, USA
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4
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Wang Q, Tang TM, Youlton N, Weldy CS, Kenney AM, Ronen O, Hughes JW, Chin ET, Sutton SC, Agarwal A, Li X, Behr M, Kumbier K, Moravec CS, Tang WHW, Margulies KB, Cappola TP, Butte AJ, Arnaout R, Brown JB, Priest JR, Parikh VN, Yu B, Ashley EA. Epistasis regulates genetic control of cardiac hypertrophy. medRxiv 2023:2023.11.06.23297858. [PMID: 37987017 PMCID: PMC10659487 DOI: 10.1101/2023.11.06.23297858] [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] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The combinatorial effect of genetic variants is often assumed to be additive. Although genetic variation can clearly interact non-additively, methods to uncover epistatic relationships remain in their infancy. We develop low-signal signed iterative random forests to elucidate the complex genetic architecture of cardiac hypertrophy. We derive deep learning-based estimates of left ventricular mass from the cardiac MRI scans of 29,661 individuals enrolled in the UK Biobank. We report epistatic genetic variation including variants close to CCDC141, IGF1R, TTN, and TNKS. Several loci not prioritized by univariate genome-wide association analysis are identified. Functional genomic and integrative enrichment analyses reveal a complex gene regulatory network in which genes mapped from these loci share biological processes and myogenic regulatory factors. Through a network analysis of transcriptomic data from 313 explanted human hearts, we show that these interactions are preserved at the level of the cardiac transcriptome. We assess causality of epistatic effects via RNA silencing of gene-gene interactions in human induced pluripotent stem cell-derived cardiomyocytes. Finally, single-cell morphology analysis using a novel high-throughput microfluidic system shows that cardiomyocyte hypertrophy is non-additively modifiable by specific pairwise interactions between CCDC141 and both TTN and IGF1R. Our results expand the scope of genetic regulation of cardiac structure to epistasis.
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Affiliation(s)
- Qianru Wang
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Tiffany M. Tang
- Department of Statistics, University of California, Berkeley, Berkeley, CA, USA
| | - Nathan Youlton
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Chad S. Weldy
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Ana M. Kenney
- Department of Statistics, University of California, Berkeley, Berkeley, CA, USA
| | - Omer Ronen
- Department of Statistics, University of California, Berkeley, Berkeley, CA, USA
| | - J. Weston Hughes
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Elizabeth T. Chin
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Shirley C. Sutton
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Abhineet Agarwal
- Department of Statistics, University of California, Berkeley, Berkeley, CA, USA
| | - Xiao Li
- Department of Statistics, University of California, Berkeley, Berkeley, CA, USA
| | - Merle Behr
- Faculty of Informatics and Data Science, University of Regensburg, Regensburg, Germany
| | - Karl Kumbier
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Christine S. Moravec
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - W. H. Wilson Tang
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
- Department of Cardiovascular Medicine, Heart Vascular and Thoracic Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Kenneth B. Margulies
- Division of Cardiovascular Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Hospital of The University of Pennsylvania, Philadelphia, PA, USA
| | - Thomas P. Cappola
- Division of Cardiovascular Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Hospital of The University of Pennsylvania, Philadelphia, PA, USA
| | - Atul J. Butte
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA, USA
- Chan Zuckerberg Biohub – San Francisco, San Francisco, CA, USA
| | - Rima Arnaout
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA, USA
- Chan Zuckerberg Biohub – San Francisco, San Francisco, CA, USA
| | - James B. Brown
- Department of Statistics, University of California, Berkeley, Berkeley, CA, USA
- Chan Zuckerberg Biohub – San Francisco, San Francisco, CA, USA
- Division of Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - James R. Priest
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
- Chan Zuckerberg Biohub – San Francisco, San Francisco, CA, USA
- Tenaya Therapeutics, San Francisco, CA, USA
| | - Victoria N. Parikh
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Bin Yu
- Department of Statistics, University of California, Berkeley, Berkeley, CA, USA
- Chan Zuckerberg Biohub – San Francisco, San Francisco, CA, USA
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley, CA, USA
- Center for Computational Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Euan A. Ashley
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, USA
- Chan Zuckerberg Biohub – San Francisco, San Francisco, CA, USA
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5
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Hughes JW, Tooley J, Torres Soto J, Ostropolets A, Poterucha T, Christensen MK, Yuan N, Ehlert B, Kaur D, Kang G, Rogers A, Narayan S, Elias P, Ouyang D, Ashley E, Zou J, Perez MV. A deep learning-based electrocardiogram risk score for long term cardiovascular death and disease. NPJ Digit Med 2023; 6:169. [PMID: 37700032 PMCID: PMC10497604 DOI: 10.1038/s41746-023-00916-6] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 08/30/2023] [Indexed: 09/14/2023] Open
Abstract
The electrocardiogram (ECG) is the most frequently performed cardiovascular diagnostic test, but it is unclear how much information resting ECGs contain about long term cardiovascular risk. Here we report that a deep convolutional neural network can accurately predict the long-term risk of cardiovascular mortality and disease based on a resting ECG alone. Using a large dataset of resting 12-lead ECGs collected at Stanford University Medical Center, we developed SEER, the Stanford Estimator of Electrocardiogram Risk. SEER predicts 5-year cardiovascular mortality with an area under the receiver operator characteristic curve (AUC) of 0.83 in a held-out test set at Stanford, and with AUCs of 0.78 and 0.83 respectively when independently evaluated at Cedars-Sinai Medical Center and Columbia University Irving Medical Center. SEER predicts 5-year atherosclerotic disease (ASCVD) with an AUC of 0.67, similar to the Pooled Cohort Equations for ASCVD Risk, while being only modestly correlated. When used in conjunction with the Pooled Cohort Equations, SEER accurately reclassified 16% of patients from low to moderate risk, uncovering a group with an actual average 9.9% 10-year ASCVD risk who would not have otherwise been indicated for statin therapy. SEER can also predict several other cardiovascular conditions such as heart failure and atrial fibrillation. Using only lead I of the ECG it predicts 5-year cardiovascular mortality with an AUC of 0.80. SEER, used alongside the Pooled Cohort Equations and other risk tools, can substantially improve cardiovascular risk stratification and aid in medical decision making.
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Affiliation(s)
- J Weston Hughes
- Department of Computer Science, Stanford University, Palo Alto, CA, USA.
| | - James Tooley
- Department of Medicine, Stanford University, Palo Alto, CA, USA
| | - Jessica Torres Soto
- Department of Biomedical Informatics, Stanford University, Palo Alto, CA, USA
| | - Anna Ostropolets
- Department of Biomedical Informatics, Columbia University Irving Medical Center, New York, NY, USA
| | - Tim Poterucha
- Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Matthew Kai Christensen
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Neal Yuan
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Ben Ehlert
- Department of Biomedical Informatics, Stanford University, Palo Alto, CA, USA
| | | | - Guson Kang
- Department of Medicine, Stanford University, Palo Alto, CA, USA
| | - Albert Rogers
- Department of Medicine, Stanford University, Palo Alto, CA, USA
| | - Sanjiv Narayan
- Department of Medicine, Stanford University, Palo Alto, CA, USA
| | - Pierre Elias
- Department of Biomedical Informatics, Columbia University Irving Medical Center, New York, NY, USA
- Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - David Ouyang
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Euan Ashley
- Department of Medicine, Stanford University, Palo Alto, CA, USA
| | - James Zou
- Department of Computer Science, Stanford University, Palo Alto, CA, USA
- Department of Biomedical Data Science, Stanford University, Palo Alto, CA, USA
| | - Marco V Perez
- Department of Medicine, Stanford University, Palo Alto, CA, USA
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6
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Somani S, Hughes JW, Ashley EA, Witteles RM, Perez MV. Development and validation of a rapid visual technique for left ventricular hypertrophy detection from the electrocardiogram. Front Cardiovasc Med 2023; 10:1251511. [PMID: 37711561 PMCID: PMC10499494 DOI: 10.3389/fcvm.2023.1251511] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 08/08/2023] [Indexed: 09/16/2023] Open
Abstract
Introduction Left ventricular hypertrophy (LVH) detection techniques on by electrocardiogram (ECG) are cumbersome to remember with modest performance. This study validated a rapid technique for LVH detection and measured its performance against other techniques. Methods This was a retrospective cohort study of patients at Stanford Health Care who received ECGs and resting transthoracic echocardiograms (TTE) from 2006 through 2018. The novel technique, Witteles-Somani (WS), assesses for S- and R-wave overlap on adjacent precordial leads. The WS, Sokolow-Lyon, Cornell, and Peguero-Lo Presti techniques were algorithmically implemented on ECGs. Classification metrics, receiver-operator curves, and Pearson correlations measured performance. Age- and sex-adjusted Cox proportional hazard models evaluated associations between incident cardiovascular outcomes and each technique. Results A total of 53,333 ECG-TTE pairs from 18,873 patients were identified. Of all ECG-TTE pairs, 21,638 (40.6%) had TTE-diagnosed LVH. The WS technique had a sensitivity of 0.46, specificity of 0.66, and AUROC of 0.56, compared to Sokolow-Lyon (AUROC 0.55), Cornell (AUROC 0.63), and Peguero-Lo Presti (AUROC 0.63). Patients meeting LVH by WS technique had a higher risk of cardiovascular mortality [HR 1.18, 95% CI (1.12, 1.24), P < 0.001] and a higher risk of developing any cardiovascular disease [HR 1.29, 95% CI (1.22, 1.36), P < 0.001], myocardial infarction [HR 1.60, 95% CI (1.44, 1.78), P < 0.005], and heart failure [HR 1.24, 95% CI (1.17, 1.32), P < 0.001]. Conclusions The WS criteria is a rapid visual technique for LVH detection with performance like other LVH detection techniques and is associated with incident cardiovascular outcomes.
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Affiliation(s)
- Sulaiman Somani
- Division of Internal Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
- Stanford Cardiovascular Institute, Stanford, CA, United States
| | - J. Weston Hughes
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
- Department of Computer Science, Stanford University, Stanford, CA, United States
| | - Euan A. Ashley
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
| | - Ronald M. Witteles
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
| | - Marco V. Perez
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA, United States
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7
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Holmstrom L, Christensen M, Yuan N, Weston Hughes J, Theurer J, Jujjavarapu M, Fatehi P, Kwan A, Sandhu RK, Ebinger J, Cheng S, Zou J, Chugh SS, Ouyang D. Deep learning-based electrocardiographic screening for chronic kidney disease. Commun Med (Lond) 2023; 3:73. [PMID: 37237055 DOI: 10.1038/s43856-023-00278-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 03/10/2023] [Indexed: 05/28/2023] Open
Abstract
BACKGROUND Undiagnosed chronic kidney disease (CKD) is a common and usually asymptomatic disorder that causes a high burden of morbidity and early mortality worldwide. We developed a deep learning model for CKD screening from routinely acquired ECGs. METHODS We collected data from a primary cohort with 111,370 patients which had 247,655 ECGs between 2005 and 2019. Using this data, we developed, trained, validated, and tested a deep learning model to predict whether an ECG was taken within one year of the patient receiving a CKD diagnosis. The model was additionally validated using an external cohort from another healthcare system which had 312,145 patients with 896,620 ECGs between 2005 and 2018. RESULTS Using 12-lead ECG waveforms, our deep learning algorithm achieves discrimination for CKD of any stage with an AUC of 0.767 (95% CI 0.760-0.773) in a held-out test set and an AUC of 0.709 (0.708-0.710) in the external cohort. Our 12-lead ECG-based model performance is consistent across the severity of CKD, with an AUC of 0.753 (0.735-0.770) for mild CKD, AUC of 0.759 (0.750-0.767) for moderate-severe CKD, and an AUC of 0.783 (0.773-0.793) for ESRD. In patients under 60 years old, our model achieves high performance in detecting any stage CKD with both 12-lead (AUC 0.843 [0.836-0.852]) and 1-lead ECG waveform (0.824 [0.815-0.832]). CONCLUSIONS Our deep learning algorithm is able to detect CKD using ECG waveforms, with stronger performance in younger patients and more severe CKD stages. This ECG algorithm has the potential to augment screening for CKD.
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Affiliation(s)
- Lauri Holmstrom
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Center for Cardiac Arrest Prevention, Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Research Unit of Internal Medicine, Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
- Division of Artificial Intelligence in Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Matthew Christensen
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Division of Artificial Intelligence in Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Neal Yuan
- Department of Medicine, Division of Cardiology, San Francisco VA, UCSF, San Francisco, CA, USA
| | - J Weston Hughes
- Department of Computer Science, Stanford University, Palo Alto, CA, USA
| | - John Theurer
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Division of Artificial Intelligence in Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Melvin Jujjavarapu
- Enterprise Information Service, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Pedram Fatehi
- Division of Nephrology, Department of Medicine, Stanford University, Palo Alto, CA, USA
| | - Alan Kwan
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Roopinder K Sandhu
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Joseph Ebinger
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Susan Cheng
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - James Zou
- Department of Computer Science, Stanford University, Palo Alto, CA, USA
- Department of Biomedical Data Science, Stanford University, Palo Alto, CA, USA
| | - Sumeet S Chugh
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Center for Cardiac Arrest Prevention, Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Division of Artificial Intelligence in Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - David Ouyang
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
- Division of Artificial Intelligence in Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
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8
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Mathews A, Hughes JW, Terry JL, Baek SG. Deep Electric Field Predictions by Drift-Reduced Braginskii Theory with Plasma-Neutral Interactions Based on Experimental Images of Boundary Turbulence. Phys Rev Lett 2022; 129:235002. [PMID: 36563220 DOI: 10.1103/physrevlett.129.235002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 11/08/2022] [Indexed: 06/17/2023]
Abstract
We present two-dimensional turbulent electric field calculations via physics-informed deep learning consistent with (i) drift-reduced Braginskii theory under the framework of an axisymmetric fusion plasma with purely toroidal field and (ii) experimental estimates of the fluctuating electron density and temperature on open field lines obtained from analysis of gas puff imaging of a discharge on the Alcator C-Mod tokamak. The inclusion of effects from the locally puffed atomic helium on particle and energy sources within the reduced plasma turbulence model is found to strengthen correlations between the electric field and electron pressure. The neutrals are also directly associated with broadening the distribution of turbulent field amplitudes and increasing E×B shearing rates. This demonstrates a novel approach in plasma experiments by solving for nonlinear dynamics consistent with partial differential equations and data without encoding explicit boundary nor initial conditions.
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Affiliation(s)
- A Mathews
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - J W Hughes
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - J L Terry
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - S G Baek
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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9
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Odstrcil T, Laggner FM, Rosenthal AM, Bortolon A, Hughes JW, Spendlove JC, Wilks TM. Robust identification of multiple-input single-output system response for efficient pickup noise removal from tokamak diagnostics. Rev Sci Instrum 2022; 93:103503. [PMID: 36319373 DOI: 10.1063/5.0100988] [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: 05/27/2022] [Accepted: 08/04/2022] [Indexed: 06/16/2023]
Abstract
Electromagnetic pickup noise in the tokamak environment imposes an imminent challenge for measuring weak diagnostic photocurrents in the nA range. The diagnostic signal can be contaminated by an unknown mixture of crosstalk signals from coils powered by currents in the kA range. To address this issue, an algorithm for robust identification of linear multi-input single-output (MISO) systems has been developed. The MISO model describes the dynamic relationship between measured signals from power sources and observed signals in the diagnostic and allows for a precise subtraction of the noise component. The proposed method was tested on experimental diagnostic data from the DIII-D tokamak, and it has reduced noise by up to 20 dB in the 1-20 kHz range.
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Affiliation(s)
- T Odstrcil
- General Atomics, San Diego, California 92186-5608, USA
| | - F M Laggner
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - A M Rosenthal
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - A Bortolon
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - J W Hughes
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | | | - T M Wilks
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
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10
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Elias P, Poterucha TJ, Rajaram V, Moller LM, Rodriguez V, Bhave S, Hahn RT, Tison G, Abreau SA, Barrios J, Torres JN, Hughes JW, Perez MV, Finer J, Kodali S, Khalique O, Hamid N, Schwartz A, Homma S, Kumaraiah D, Cohen DJ, Maurer MS, Einstein AJ, Nazif T, Leon MB, Perotte AJ. Deep Learning Electrocardiographic Analysis for Detection of Left-Sided Valvular Heart Disease. J Am Coll Cardiol 2022; 80:613-626. [PMID: 35926935 DOI: 10.1016/j.jacc.2022.05.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/05/2022] [Accepted: 05/09/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND Valvular heart disease is an important contributor to cardiovascular morbidity and mortality and remains underdiagnosed. Deep learning analysis of electrocardiography (ECG) may be useful in detecting aortic stenosis (AS), aortic regurgitation (AR), and mitral regurgitation (MR). OBJECTIVES This study aimed to develop ECG deep learning algorithms to identify moderate or severe AS, AR, and MR alone and in combination. METHODS A total of 77,163 patients undergoing ECG within 1 year before echocardiography from 2005-2021 were identified and split into train (n = 43,165), validation (n = 12,950), and test sets (n = 21,048; 7.8% with any of AS, AR, or MR). Model performance was assessed using area under the receiver-operating characteristic (AU-ROC) and precision-recall curves. Outside validation was conducted on an independent data set. Test accuracy was modeled using different disease prevalence levels to simulate screening efficacy using the deep learning model. RESULTS The deep learning algorithm model accuracy was as follows: AS (AU-ROC: 0.88), AR (AU-ROC: 0.77), MR (AU-ROC: 0.83), and any of AS, AR, or MR (AU-ROC: 0.84; sensitivity 78%, specificity 73%) with similar accuracy in external validation. In screening program modeling, test characteristics were dependent on underlying prevalence and selected sensitivity levels. At a prevalence of 7.8%, the positive and negative predictive values were 20% and 97.6%, respectively. CONCLUSIONS Deep learning analysis of the ECG can accurately detect AS, AR, and MR in this multicenter cohort and may serve as the basis for the development of a valvular heart disease screening program.
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Affiliation(s)
- Pierre Elias
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center and NewYork-Presbyterian Hospital, New York, New York, USA
| | - Timothy J Poterucha
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center and NewYork-Presbyterian Hospital, New York, New York, USA
| | - Vijay Rajaram
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center and NewYork-Presbyterian Hospital, New York, New York, USA
| | - Luca Matos Moller
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center and NewYork-Presbyterian Hospital, New York, New York, USA
| | - Victor Rodriguez
- Department of Biomedical Informatics, Columbia University, New York, New York, USA
| | - Shreyas Bhave
- Department of Biomedical Informatics, Columbia University, New York, New York, USA
| | - Rebecca T Hahn
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center and NewYork-Presbyterian Hospital, New York, New York, USA
| | - Geoffrey Tison
- Division of Cardiology, University of California-San Francisco, San Francisco, California, USA
| | - Sean A Abreau
- Division of Cardiology, University of California-San Francisco, San Francisco, California, USA
| | - Joshua Barrios
- Division of Cardiology, University of California-San Francisco, San Francisco, California, USA
| | | | - J Weston Hughes
- Division of Cardiology, Stanford University, Palo Alto, California, USA
| | - Marco V Perez
- Division of Cardiology, Stanford University, Palo Alto, California, USA
| | - Joshua Finer
- NewYork-Presbyterian Hospital, New York, New York, USA
| | - Susheel Kodali
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center and NewYork-Presbyterian Hospital, New York, New York, USA
| | - Omar Khalique
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center and NewYork-Presbyterian Hospital, New York, New York, USA
| | - Nadira Hamid
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center and NewYork-Presbyterian Hospital, New York, New York, USA
| | - Allan Schwartz
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center and NewYork-Presbyterian Hospital, New York, New York, USA
| | - Shunichi Homma
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center and NewYork-Presbyterian Hospital, New York, New York, USA
| | - Deepa Kumaraiah
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center and NewYork-Presbyterian Hospital, New York, New York, USA
| | - David J Cohen
- Cardiovascular Research Foundation, New York, New York, USA; Department of Cardiology, St. Francis Hospital, Roslyn, New York, USA
| | - Mathew S Maurer
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center and NewYork-Presbyterian Hospital, New York, New York, USA
| | - Andrew J Einstein
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center and NewYork-Presbyterian Hospital, New York, New York, USA
| | - Tamim Nazif
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center and NewYork-Presbyterian Hospital, New York, New York, USA
| | - Martin B Leon
- Seymour, Paul, and Gloria Milstein Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center and NewYork-Presbyterian Hospital, New York, New York, USA; Cardiovascular Research Foundation, New York, New York, USA
| | - Adler J Perotte
- Department of Biomedical Informatics, Columbia University, New York, New York, USA.
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11
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Mathews A, Terry JL, Baek SG, Hughes JW, Kuang AQ, LaBombard B, Miller MA, Stotler D, Reiter D, Zholobenko W, Goto M. Deep modeling of plasma and neutral fluctuations from gas puff turbulence imaging. Rev Sci Instrum 2022; 93:063504. [PMID: 35778003 DOI: 10.1063/5.0088216] [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: 02/14/2022] [Accepted: 05/17/2022] [Indexed: 06/15/2023]
Abstract
The role of turbulence in setting boundary plasma conditions is presently a key uncertainty in projecting to fusion energy reactors. To robustly diagnose edge turbulence, we develop and demonstrate a technique to translate brightness measurements of HeI line radiation into local plasma fluctuations via a novel integrated deep learning framework that combines neutral transport physics and collisional radiative theory for the 33D - 23P transition in atomic helium with unbounded correlation constraints between the electron density and temperature. The tenets for experimental validity are reviewed, illustrating that this turbulence analysis for ionized gases is transferable to both magnetized and unmagnetized environments with arbitrary geometries. Based on fast camera data on the Alcator C-Mod tokamak, we present the first two-dimensional time-dependent experimental measurements of the turbulent electron density, electron temperature, and neutral density, revealing shadowing effects in a fusion plasma using a single spectral line.
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Affiliation(s)
- A Mathews
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - J L Terry
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - S G Baek
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - J W Hughes
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - A Q Kuang
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - B LaBombard
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - M A Miller
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - D Stotler
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - D Reiter
- Institut für Laser- und Plasmaphysik, Heinrich-Heine-Universität, Düsseldorf, Nordrhein-Westfalen 40225, Germany
| | - W Zholobenko
- Max-Planck-Institut für Plasmaphysik, Garching, Bayern 85748, Germany
| | - M Goto
- National Institute for Fusion Science, Toki-shi, Gifu-ken 509-5292, Japan
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12
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Soto JT, Weston Hughes J, Sanchez PA, Perez M, Ouyang D, Ashley EA. Multimodal deep learning enhances diagnostic precision in left ventricular hypertrophy . Eur Heart J Digit Health 2022; 3:380-389. [PMID: 36712167 PMCID: PMC9707995 DOI: 10.1093/ehjdh/ztac033] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 04/25/2022] [Indexed: 02/01/2023]
Abstract
Aims Determining the aetiology of left ventricular hypertrophy (LVH) can be challenging due to the similarity in clinical presentation and cardiac morphological features of diverse causes of disease. In particular, distinguishing individuals with hypertrophic cardiomyopathy (HCM) from the much larger set of individuals with manifest or occult hypertension (HTN) is of major importance for family screening and the prevention of sudden death. We hypothesized that an artificial intelligence method based joint interpretation of 12-lead electrocardiograms and echocardiogram videos could augment physician interpretation. Methods and results We chose not to train on proximate data labels such as physician over-reads of ECGs or echocardiograms but instead took advantage of electronic health record derived clinical blood pressure measurements and diagnostic consensus (often including molecular testing) among physicians in an HCM centre of excellence. Using more than 18 000 combined instances of electrocardiograms and echocardiograms from 2728 patients, we developed LVH-fusion. On held-out test data, LVH-fusion achieved an F1-score of 0.71 in predicting HCM, and 0.96 in predicting HTN. In head-to-head comparison with human readers LVH-fusion had higher sensitivity and specificity rates than its human counterparts. Finally, we use explainability techniques to investigate local and global features that positively and negatively impact LVH-fusion prediction estimates providing confirmation from unsupervised analysis the diagnostic power of lateral T-wave inversion on the ECG and proximal septal hypertrophy on the echocardiogram for HCM. Conclusion These results show that deep learning can provide effective physician augmentation in the face of a common diagnostic dilemma with far reaching implications for the prevention of sudden cardiac death.
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Affiliation(s)
| | | | - Pablo Amador Sanchez
- Department of Medicine, Division of Cardiology, Stanford University, Stanford, California, USA
| | - Marco Perez
- Department of Medicine, Division of Cardiology, Stanford University, Stanford, California, USA
| | - David Ouyang
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, USA,Division of Artificial Intelligence in Medicine, Department of Medicine, Cedars-Sinai Medical Center, USA
| | - Euan A Ashley
- Corresponding author. Tel: 650 498-4900, Fax: 650 498-7452,
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13
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Hughes JW, Olgin JE, Avram R, Abreau SA, Sittler T, Radia K, Hsia H, Walters T, Lee B, Gonzalez JE, Tison GH. Performance of a Convolutional Neural Network and Explainability Technique for 12-Lead Electrocardiogram Interpretation. JAMA Cardiol 2021; 6:1285-1295. [PMID: 34347007 PMCID: PMC8340011 DOI: 10.1001/jamacardio.2021.2746] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [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] [Received: 12/01/2020] [Accepted: 06/04/2021] [Indexed: 01/12/2023]
Abstract
Importance Millions of clinicians rely daily on automated preliminary electrocardiogram (ECG) interpretation. Critical comparisons of machine learning-based automated analysis against clinically accepted standards of care are lacking. Objective To use readily available 12-lead ECG data to train and apply an explainability technique to a convolutional neural network (CNN) that achieves high performance against clinical standards of care. Design, Setting, and Participants This cross-sectional study was conducted using data from January 1, 2003, to December 31, 2018. Data were obtained in a commonly available 12-lead ECG format from a single-center tertiary care institution. All patients aged 18 years or older who received ECGs at the University of California, San Francisco, were included, yielding a total of 365 009 patients. Data were analyzed from January 1, 2019, to March 2, 2021. Exposures A CNN was trained to predict the presence of 38 diagnostic classes in 5 categories from 12-lead ECG data. A CNN explainability technique called LIME (Linear Interpretable Model-Agnostic Explanations) was used to visualize ECG segments contributing to CNN diagnoses. Main Outcomes and Measures Area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were calculated for the CNN in the holdout test data set against cardiologist clinical diagnoses. For a second validation, 3 electrophysiologists provided consensus committee diagnoses against which the CNN, cardiologist clinical diagnosis, and MUSE (GE Healthcare) automated analysis performance was compared using the F1 score; AUC, sensitivity, and specificity were also calculated for the CNN against the consensus committee. Results A total of 992 748 ECGs from 365 009 adult patients (mean [SD] age, 56.2 [17.6] years; 183 600 women [50.3%]; and 175 277 White patients [48.0%]) were included in the analysis. In 91 440 test data set ECGs, the CNN demonstrated an AUC of at least 0.960 for 32 of 38 classes (84.2%). Against the consensus committee diagnoses, the CNN had higher frequency-weighted mean F1 scores than both cardiologists and MUSE in all 5 categories (CNN frequency-weighted F1 score for rhythm, 0.812; conduction, 0.729; chamber diagnosis, 0.598; infarct, 0.674; and other diagnosis, 0.875). For 32 of 38 classes (84.2%), the CNN had AUCs of at least 0.910 and demonstrated comparable F1 scores and higher sensitivity than cardiologists, except for atrial fibrillation (CNN F1 score, 0.847 vs cardiologist F1 score, 0.881), junctional rhythm (0.526 vs 0.727), premature ventricular complex (0.786 vs 0.800), and Wolff-Parkinson-White (0.800 vs 0.842). Compared with MUSE, the CNN had higher F1 scores for all classes except supraventricular tachycardia (CNN F1 score, 0.696 vs MUSE F1 score, 0.714). The LIME technique highlighted physiologically relevant ECG segments. Conclusions and Relevance The results of this cross-sectional study suggest that readily available ECG data can be used to train a CNN algorithm to achieve comparable performance to clinical cardiologists and exceed the performance of MUSE automated analysis for most diagnoses, with some exceptions. The LIME explainability technique applied to CNNs highlights physiologically relevant ECG segments that contribute to the CNN's diagnoses.
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Affiliation(s)
- J. Weston Hughes
- RISE Lab, Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley
| | - Jeffrey E. Olgin
- Department of Medicine, Division of Cardiology, University of California, San Francisco, San Francisco
- Cardiovascular Research Institute, San Francisco, California
| | - Robert Avram
- Department of Medicine, Division of Cardiology, University of California, San Francisco, San Francisco
- Cardiovascular Research Institute, San Francisco, California
| | - Sean A. Abreau
- Department of Medicine, Division of Cardiology, University of California, San Francisco, San Francisco
- Cardiovascular Research Institute, San Francisco, California
| | - Taylor Sittler
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco
| | - Kaahan Radia
- RISE Lab, Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley
| | - Henry Hsia
- Department of Medicine, Division of Cardiology, University of California, San Francisco, San Francisco
| | - Tomos Walters
- Department of Medicine, Division of Cardiology, University of California, San Francisco, San Francisco
| | - Byron Lee
- Department of Medicine, Division of Cardiology, University of California, San Francisco, San Francisco
| | - Joseph E. Gonzalez
- RISE Lab, Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley
| | - Geoffrey H. Tison
- RISE Lab, Department of Electrical Engineering and Computer Science, University of California, Berkeley, Berkeley
- Department of Medicine, Division of Cardiology, University of California, San Francisco, San Francisco
- Cardiovascular Research Institute, San Francisco, California
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco
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14
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Hughes JW, Yuan N, He B, Ouyang J, Ebinger J, Botting P, Lee J, Theurer J, Tooley JE, Nieman K, Lungren MP, Liang DH, Schnittger I, Chen JH, Ashley EA, Cheng S, Ouyang D, Zou JY. Deep learning evaluation of biomarkers from echocardiogram videos. EBioMedicine 2021; 73:103613. [PMID: 34656880 PMCID: PMC8524103 DOI: 10.1016/j.ebiom.2021.103613] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 09/16/2021] [Accepted: 09/20/2021] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Laboratory testing is routinely used to assay blood biomarkers to provide information on physiologic state beyond what clinicians can evaluate from interpreting medical imaging. We hypothesized that deep learning interpretation of echocardiogram videos can provide additional value in understanding disease states and can evaluate common biomarkers results. METHODS We developed EchoNet-Labs, a video-based deep learning algorithm to detect evidence of anemia, elevated B-type natriuretic peptide (BNP), troponin I, and blood urea nitrogen (BUN), as well as values of ten additional lab tests directly from echocardiograms. We included patients (n = 39,460) aged 18 years or older with one or more apical-4-chamber echocardiogram videos (n = 70,066) from Stanford Healthcare for training and internal testing of EchoNet-Lab's performance in estimating the most proximal biomarker result. Without fine-tuning, the performance of EchoNet-Labs was further evaluated on an additional external test dataset (n = 1,301) from Cedars-Sinai Medical Center. We calculated the area under the curve (AUC) of the receiver operating characteristic curve for the internal and external test datasets. FINDINGS On the held-out test set of Stanford patients not previously seen during model training, EchoNet-Labs achieved an AUC of 0.80 (0.79-0.81) in detecting anemia (low hemoglobin), 0.86 (0.85-0.88) in detecting elevated BNP, 0.75 (0.73-0.78) in detecting elevated troponin I, and 0.74 (0.72-0.76) in detecting elevated BUN. On the external test dataset from Cedars-Sinai, EchoNet-Labs achieved an AUC of 0.80 (0.77-0.82) in detecting anemia, of 0.82 (0.79-0.84) in detecting elevated BNP, of 0.75 (0.72-0.78) in detecting elevated troponin I, and of 0.69 (0.66-0.71) in detecting elevated BUN. We further demonstrate the utility of the model in detecting abnormalities in 10 additional lab tests. We investigate the features necessary for EchoNet-Labs to make successful detection and identify potential mechanisms for each biomarker using well-known and novel explainability techniques. INTERPRETATION These results show that deep learning applied to diagnostic imaging can provide additional clinical value and identify phenotypic information beyond current imaging interpretation methods. FUNDING J.W.H. and B.H. are supported by the NSF Graduate Research Fellowship. D.O. is supported by NIH K99 HL157421-01. J.Y.Z. is supported by NSF CAREER 1942926, NIH R21 MD012867-01, NIH P30AG059307 and by a Chan-Zuckerberg Biohub Fellowship.
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Affiliation(s)
- J Weston Hughes
- Department of Computer Science, Stanford University, Palo Alto, CA 94025
| | - Neal Yuan
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, 90048
| | - Bryan He
- Department of Computer Science, Stanford University, Palo Alto, CA 94025
| | - Jiahong Ouyang
- Department of Electrical Engineering, Stanford University, Palo Alto, CA, 94025
| | - Joseph Ebinger
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, 90048
| | - Patrick Botting
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, 90048
| | - Jasper Lee
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, 90048
| | - John Theurer
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, 90048
| | - James E Tooley
- Department of Medicine, Stanford University, Palo Alto, CA, 94025
| | - Koen Nieman
- Department of Medicine, Stanford University, Palo Alto, CA, 94025; Department of Radiology, Stanford University, Palo Alto, CA, 94025
| | | | - David H Liang
- Department of Medicine, Stanford University, Palo Alto, CA, 94025
| | | | - Jonathan H Chen
- Department of Medicine, Stanford University, Palo Alto, CA, 94025
| | - Euan A Ashley
- Department of Medicine, Stanford University, Palo Alto, CA, 94025
| | - Susan Cheng
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, 90048
| | - David Ouyang
- Department of Cardiology, Smidt Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, 90048.
| | - James Y Zou
- Department of Computer Science, Stanford University, Palo Alto, CA 94025; Department of Electrical Engineering, Stanford University, Palo Alto, CA, 94025; Department of Biomedical Data Science, Stanford University, Palo Alto, CA, 94025.
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15
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Mathews A, Francisquez M, Hughes JW, Hatch DR, Zhu B, Rogers BN. Uncovering turbulent plasma dynamics via deep learning from partial observations. Phys Rev E 2021; 104:025205. [PMID: 34525532 DOI: 10.1103/physreve.104.025205] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 07/26/2021] [Indexed: 06/13/2023]
Abstract
One of the most intensely studied aspects of magnetic confinement fusion is edge plasma turbulence which is critical to reactor performance and operation. Drift-reduced Braginskii two-fluid theory has for decades been widely applied to model boundary plasmas with varying success. Towards better understanding edge turbulence in both theory and experiment, we demonstrate that a physics-informed deep learning framework constrained by partial differential equations can accurately learn turbulent fields consistent with the two-fluid theory from partial observations of electron pressure which is not otherwise possible using conventional equilibrium models. This technique presents a paradigm for the advanced design of plasma diagnostics and validation of magnetized plasma turbulence theories in challenging thermonuclear environments.
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Affiliation(s)
- A Mathews
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - M Francisquez
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - J W Hughes
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - D R Hatch
- Institute for Fusion Studies, University of Texas, Austin, Texas 78704, USA
| | - B Zhu
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - B N Rogers
- Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755, USA
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16
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Chen X, Ruiz JR, Howard NT, Guttenfelder W, Candy J, Hughes JW, Granetz RS, White AE. Feasibility study for a high-k temperature fluctuation diagnostic based on soft x-ray imaging. Rev Sci Instrum 2021; 92:053537. [PMID: 34243288 DOI: 10.1063/5.0043819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 04/09/2021] [Indexed: 06/13/2023]
Abstract
A new pseudolocal tomography algorithm is developed for soft X-ray(SXR) imaging measurements of the turbulent electron temperature fluctuations (δ Te) in tokamaks and stellarators. The algorithm overcomes the constraints of limited viewing ports on the vessel wall (viewing angle) and limited number of lines of sight (LOS). This is accomplished by increasing the number of LOS locally in a region of interest. Numerical modeling demonstrates that the wavenumber spectrum of the turbulence can be reliably reconstructed, with an acceptable number of viewing angles and LOS and suitable low SNR detectors. We conclude that a SXR imaging diagnostic for measurements of turbulent δ Te using a pseudolocal reconstruction algorithm is feasible.
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Affiliation(s)
- X Chen
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA
| | - J Ruiz Ruiz
- Department of Physics, University of Oxford, Oxford OX1 3NP, United Kingdom
| | - N T Howard
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA
| | - W Guttenfelder
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08536, USA
| | - J Candy
- General Atomics, San Diego, California 92127, USA
| | - J W Hughes
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA
| | - R S Granetz
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA
| | - A E White
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA
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17
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Rosenthal AM, Hughes JW, Bortolon A, Laggner FM, Wilks TM, Vieira R, Leccacorvi R, Marmar E, Nagy A, Freeman C, Mauzey D. A 1D Lyman-alpha profile camera for plasma edge neutral studies on the DIII-D tokamak. Rev Sci Instrum 2021; 92:033523. [PMID: 33820041 DOI: 10.1063/5.0024115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 02/11/2021] [Indexed: 06/12/2023]
Abstract
A one dimensional, absolutely calibrated pinhole camera system was installed on the DIII-D tokamak to measure edge Lyman-alpha (Ly-α) emission from hydrogen isotopes, which can be used to infer neutral density and ionization rate profiles. The system is composed of two cameras, each providing a toroidal fan of 20 lines of sight, viewing the plasma edge on the inboard and outboard side of DIII-D. The cameras' views lie in a horizontal plane 77 cm below the midplane. At its tangency radius, each channel provides a radial resolution of ∼2 cm full width at half maximum (FWHM) with a total coverage of 22 cm. Each camera consists of a rectangular pinhole, Ly-α reflective mirror, narrow-band Ly-α transmission filter, and a 20 channel AXUV photodetector. The combined mirror and transmission filter have a FWHM of 5 nm, centered near the Ly-α wavelength of 121.6 nm and is capable of rejecting significant, parasitic carbon-III (C-III) emission from intrinsic plasma impurities. To provide a high spatial resolution measurement in a compact footprint, the camera utilizes advanced engineering and manufacturing techniques including 3D printing, high stability mirror mounts, and a novel alignment procedure. Absolutely calibrated, spatially resolved Ly-α brightness measurements utilize a bright, isolated line with low parasitic surface reflections and enable quantitative comparison to modeling to study divertor neutral leakage, main chamber fueling, and radial particle transport.
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Affiliation(s)
- A M Rosenthal
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - J W Hughes
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - A Bortolon
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - F M Laggner
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - T M Wilks
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - R Vieira
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - R Leccacorvi
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - E Marmar
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - A Nagy
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - C Freeman
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - D Mauzey
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
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18
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Laggner FM, Bortolon A, Rosenthal AM, Wilks TM, Hughes JW, Freeman C, Golfinopoulos T, Nagy A, Mauzey D, Shafer MW. Absolute calibration of the Lyman-α measurement apparatus at DIII-D. Rev Sci Instrum 2021; 92:033522. [PMID: 33820112 DOI: 10.1063/5.0038134] [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] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 01/13/2021] [Indexed: 06/12/2023]
Abstract
The LLAMA (Lyman-Alpha Measurement Apparatus) diagnostic was recently installed on the DIII-D tokamak [Rosenthal et al., Rev. Sci. Instrum. (submitted) (2020)]. LLAMA is a pinhole camera system with a narrow band Bragg mirror, a bandpass interference filter, and an absolute extreme ultraviolet photodiode detector array, which measures the Ly-α brightness in the toroidal direction on the inboard, high field side (HFS) and outboard, low field side (LFS). This contribution presents a setup and a procedure for an absolute calibration near the Ly-α line at 121.6 nm. The LLAMA in-vacuum components are designed as a compact, transferable setup that can be mounted in an ex situ vacuum enclosure that is equipped with an absolutely calibrated Ly-α source. The spectral purity and stability of the Ly-α source are characterized using a vacuum ultraviolet spectrometer, while the Ly-α source brightness is measured by a NIST-calibrated photodiode. The non-uniform nature of the Ly-α source emission was overcome by performing a calibration procedure that scans the Ly-α source position and employs a numerical optimization to determine the emission pattern. Nominal and measured calibration factors are determined and compared, showing agreement within their uncertainties. A first conversion of the measured signal obtained from DIII-D indicates that the Ly-α brightness on the HFS and LFS is on the order of 1020 Ph sr-1 m-2 s-1. The established calibration setup and procedure will be regularly used to re-calibrate the LLAMA during DIII-D vents to monitor possible degradation of optical components and detectors.
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Affiliation(s)
- F M Laggner
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - A Bortolon
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - A M Rosenthal
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - T M Wilks
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - J W Hughes
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - C Freeman
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - T Golfinopoulos
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - A Nagy
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - D Mauzey
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - M W Shafer
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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19
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Avram R, Olgin JE, Kuhar P, Hughes JW, Marcus GM, Pletcher MJ, Aschbacher K, Tison GH. A digital biomarker of diabetes from smartphone-based vascular signals. Nat Med 2020; 26:1576-1582. [PMID: 32807931 DOI: 10.1038/s41591-020-1010-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 07/06/2020] [Indexed: 12/11/2022]
Abstract
The global burden of diabetes is rapidly increasing, from 451 million people in 2019 to 693 million by 20451. The insidious onset of type 2 diabetes delays diagnosis and increases morbidity2. Given the multifactorial vascular effects of diabetes, we hypothesized that smartphone-based photoplethysmography could provide a widely accessible digital biomarker for diabetes. Here we developed a deep neural network (DNN) to detect prevalent diabetes using smartphone-based photoplethysmography from an initial cohort of 53,870 individuals (the 'primary cohort'), which we then validated in a separate cohort of 7,806 individuals (the 'contemporary cohort') and a cohort of 181 prospectively enrolled individuals from three clinics (the 'clinic cohort'). The DNN achieved an area under the curve for prevalent diabetes of 0.766 in the primary cohort (95% confidence interval: 0.750-0.782; sensitivity 75%, specificity 65%) and 0.740 in the contemporary cohort (95% confidence interval: 0.723-0.758; sensitivity 81%, specificity 54%). When the output of the DNN, called the DNN score, was included in a regression analysis alongside age, gender, race/ethnicity and body mass index, the area under the curve was 0.830 and the DNN score remained independently predictive of diabetes. The performance of the DNN in the clinic cohort was similar to that in other validation datasets. There was a significant and positive association between the continuous DNN score and hemoglobin A1c (P ≤ 0.001) among those with hemoglobin A1c data. These findings demonstrate that smartphone-based photoplethysmography provides a readily attainable, non-invasive digital biomarker of prevalent diabetes.
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Affiliation(s)
- Robert Avram
- Division of Cardiology, Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Jeffrey E Olgin
- Division of Cardiology, Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
| | | | - J Weston Hughes
- Department of Computer Science, University of California, Berkeley, Berkeley, CA, USA
| | - Gregory M Marcus
- Division of Cardiology, Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
| | - Mark J Pletcher
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA
| | - Kirstin Aschbacher
- Division of Cardiology, Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA.,Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA, USA.,Department of Psychiatry, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, USA
| | - Geoffrey H Tison
- Division of Cardiology, Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA. .,Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA, USA.
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20
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Saintilan NJ, Selby D, Hughes JW, Schlatter D, Kolb J, Boyce A. Mineral separation protocol for accurate and precise rhenium-osmium (Re-Os) geochronology and sulphur isotope composition of individual sulphide species. MethodsX 2020; 7:100944. [PMID: 32566491 PMCID: PMC7298518 DOI: 10.1016/j.mex.2020.100944] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 05/20/2020] [Indexed: 11/16/2022] Open
Abstract
A temporal framework for mineral deposits is essential when addressing the history of their formation and conceptualizing genetic models of their origin. This knowledge is critical to understand how crust-forming processes are related to metal accumulations at specific time and conditions of Earth evolution. To this end, high-precision absolute geochronology utilising the rhenium-osmium (Re-Os) radiometric system in specific sulphide minerals is becoming a method of choice. Here, we present a procedure to obtain mineral separates of individual sulphide species that may coexist within specific mineralized horizons in ore deposits. This protocol is based on preliminary petrographic and paragenetic investigations of sulphide and gangue minerals using reflected and transmitted light microscopy. Our approach emphasizes the key role of a stepwise use of a Frantz isodynamic separator to produce mineral separates of individual sulphide species that are subsequently processed for Re-Os and sulphur isotope geochemistry.•Detailed method and its graphical illustration modified from an original procedure introduced by [1], [2].•Quality control and validation of monophasic mineral separates made by microscopic investigations and qualitative analysis of aliquots embedded in epoxy mounts.•The present method, which contributed to the successful results presented in the co-publication by Saintilan et al. (2020), demonstrates why other studies reporting Re-Os isotope data for mixtures of sulphide minerals should be considered with caution.
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Affiliation(s)
- N J Saintilan
- Department of Earth Sciences, University of Durham, Durham DH1 3LE, United Kingdom.,Department of Earth Sciences, Institute of Geochemistry and Petrology, ETH Zürich, Clausiusstraße 25, 8092 Zürich, Switzerland
| | - D Selby
- Department of Earth Sciences, University of Durham, Durham DH1 3LE, United Kingdom.,State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Resources, China University of Geosciences, Wuhan, China
| | - J W Hughes
- Department of Earth Sciences, University of Durham, Durham DH1 3LE, United Kingdom.,Bluejay Mining Plc, 2nd Floor, 7-9 Swallow Street, London, W1B 4DE, United Kingdom
| | - D Schlatter
- Helvetica Exploration Services GmbH, Carl-Spitteler-Strasse 100, 8053 Zürich, Switzerland
| | - J Kolb
- Department of Geochemistry and Economic Geology, Institute of Applied Geosciences, Karlsruhe Institute of Technology, Adenauerring 20b, 76131 Karlsruhe, Germany
| | - A Boyce
- Isotope Geoscience Unit, SUERC, Rankine Avenue, East Kilbride, Glasgow G75 0QF, United Kingdom
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21
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Baek SG, Wallace GM, Bonoli PT, Brunner D, Faust IC, Hubbard AE, Hughes JW, LaBombard B, Parker RR, Porkolab M, Shiraiwa S, Wukitch S. Observation of Efficient Lower Hybrid Current Drive at High Density in Diverted Plasmas on the Alcator C-Mod Tokamak. Phys Rev Lett 2018; 121:055001. [PMID: 30118250 DOI: 10.1103/physrevlett.121.055001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 06/22/2018] [Indexed: 06/08/2023]
Abstract
Efficient lower hybrid current drive (LHCD) is demonstrated at densities up to n[over ¯]_{e}≈1.5×10^{20} m^{-3} in diverted plasmas on the Alcator C-Mod tokamak by operating at increased plasma current-and therefore reduced Greenwald density fraction. This density exceeds the nominal "LH density limit" at n[over ¯]_{e}≈1.0×10^{20} m^{-3} reported previously, above which an anomalous loss of current drive efficiency was observed. The recovery of current drive efficiency to a level consistent with engineering scalings is correlated with a reduction in density shoulders and turbulence levels in the far scrape-off layer. Concurrently, rf wave interaction with the edge and/or scrape-off-layer plasma is reduced, as indicated by a minimal broadening of the wave frequency spectrum measured at the plasma edge. These results have important implications for sustaining steady-state tokamak operation and indicate a pathway forward for implementing efficient LHCD in a reactor.
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Affiliation(s)
- S G Baek
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - G M Wallace
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - P T Bonoli
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - D Brunner
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - I C Faust
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
- Max Planck Institute for Plasma Physics, Munich, Bavaria 85748, Germany
| | - A E Hubbard
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - J W Hughes
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - B LaBombard
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - R R Parker
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - M Porkolab
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - S Shiraiwa
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - S Wukitch
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
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22
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Chang CS, Ku S, Tynan GR, Hager R, Churchill RM, Cziegler I, Greenwald M, Hubbard AE, Hughes JW. Fast Low-to-High Confinement Mode Bifurcation Dynamics in a Tokamak Edge Plasma Gyrokinetic Simulation. Phys Rev Lett 2017; 118:175001. [PMID: 28498701 DOI: 10.1103/physrevlett.118.175001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Indexed: 06/07/2023]
Abstract
Transport barrier formation and its relation to sheared flows in fluids and plasmas are of fundamental interest in various natural and laboratory observations and of critical importance in achieving an economical energy production in a magnetic fusion device. Here we report the first observation of an edge transport barrier formation event in an electrostatic gyrokinetic simulation carried out in a realistic diverted tokamak edge geometry under strong forcing by a high rate of heat deposition. The results show that turbulent Reynolds-stress-driven sheared E×B flows act in concert with neoclassical orbit loss to quench turbulent transport and form a transport barrier just inside the last closed magnetic flux surface.
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Affiliation(s)
- C S Chang
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - S Ku
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - G R Tynan
- University of California San Diego, La Jolla, California 92093, USA
| | - R Hager
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - R M Churchill
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - I Cziegler
- University of California San Diego, La Jolla, California 92093, USA
| | - M Greenwald
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - A E Hubbard
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - J W Hughes
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
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23
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Cziegler I, Hubbard AE, Hughes JW, Terry JL, Tynan GR. Turbulence Nonlinearities Shed Light on Geometric Asymmetry in Tokamak Confinement Transitions. Phys Rev Lett 2017; 118:105003. [PMID: 28339277 DOI: 10.1103/physrevlett.118.105003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Indexed: 06/06/2023]
Abstract
A comprehensive study of fully frequency-resolved nonlinear kinetic energy transfer has been performed for the first time in a diverted tokamak, providing new insight into the parametric dependences of edge turbulence transitions. Measurements using gas puff imaging in the turbulent L-mode state illuminate the source of the long known but as yet unexplained "favorable-unfavorable" geometric asymmetry of the power threshold for transition to the turbulence-suppressed H mode. Results from the recently discovered I mode point to a competition between zonal flow (ZF) and geodesic-acoustic modes (GAM) for turbulent energy, while showing new evidence that the I-to-H transition is still dominated by ZFs. The availability of nonlinear drive for the GAM against net heat flux through the edge corresponds very well to empirical scalings found experimentally for accessing the I mode.
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Affiliation(s)
- I Cziegler
- York Plasma Institute, Department of Physics, University of York, Heslington YO10 5DD, United Kingdom
| | - A E Hubbard
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - J W Hughes
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - J L Terry
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - G R Tynan
- University of California San Diego, La Jolla, California 92093, USA
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24
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Houshmandyar S, Yang ZJ, Phillips PE, Rowan WL, Hubbard AE, Rice JE, Hughes JW, Wolfe SM. Temperature gradient scale length measurement: A high accuracy application of electron cyclotron emission without calibration. Rev Sci Instrum 2016; 87:11E101. [PMID: 27910677 DOI: 10.1063/1.4955297] [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
Calibration is a crucial procedure in electron temperature (Te) inference from a typical electron cyclotron emission (ECE) diagnostic on tokamaks. Although the calibration provides an important multiplying factor for an individual ECE channel, the parameter ΔTe/Te is independent of any calibration. Since an ECE channel measures the cyclotron emission for a particular flux surface, a non-perturbing change in toroidal magnetic field changes the view of that channel. Hence the calibration-free parameter is a measure of Te gradient. BT-jog technique is presented here which employs the parameter and the raw ECE signals for direct measurement of electron temperature gradient scale length.
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Affiliation(s)
- S Houshmandyar
- Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Z J Yang
- Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - P E Phillips
- Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712, USA
| | - W L Rowan
- Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712, USA
| | - A E Hubbard
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02129, USA
| | - J E Rice
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02129, USA
| | - J W Hughes
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02129, USA
| | - S M Wolfe
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02129, USA
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25
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Diallo A, Hughes JW, Greenwald M, Labombard B, Davis E, Baek SG, Theiler C, Snyder P, Canik J, Walk J, Golfinopoulos T, Terry J, Churchill M, Hubbard A, Porkolab M, Delgado-Aparicio L, Reinke ML, White A. Observation of edge instability limiting the pedestal growth in tokamak plasmas. Phys Rev Lett 2014; 112:115001. [PMID: 24702380 DOI: 10.1103/physrevlett.112.115001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Indexed: 06/03/2023]
Abstract
With fusion device performance hinging on the edge pedestal pressure, it is imperative to experimentally understand the physical mechanism dictating the pedestal characteristics and to validate and improve pedestal predictive models. This Letter reports direct evidence of density and magnetic fluctuations showing the stiff onset of an edge instability leading to the saturation of the pedestal on the Alcator C-Mod tokamak. Edge stability analyses indicate that the pedestal is unstable to both ballooning mode and kinetic ballooning mode in agreement with observations.
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Affiliation(s)
- A Diallo
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - J W Hughes
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - M Greenwald
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - B Labombard
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - E Davis
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - S-G Baek
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - C Theiler
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - P Snyder
- General Atomics, San Diego, California 92186, USA
| | - J Canik
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - J Walk
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - T Golfinopoulos
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - J Terry
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - M Churchill
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - A Hubbard
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - M Porkolab
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | | | - M L Reinke
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - A White
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Rice JE, Podpaly YA, Reinke ML, Mumgaard R, Scott SD, Shiraiwa S, Wallace GM, Chouli B, Fenzi-Bonizec C, Nave MFF, Diamond PH, Gao C, Granetz RS, Hughes JW, Parker RR, Bonoli PT, Delgado-Aparicio L, Eriksson LG, Giroud C, Greenwald MJ, Hubbard AE, Hutchinson IH, Irby JH, Kirov K, Mailloux J, Marmar ES, Wolfe SM. Effects of magnetic shear on toroidal rotation in tokamak plasmas with lower hybrid current drive. Phys Rev Lett 2013; 111:125003. [PMID: 24093268 DOI: 10.1103/physrevlett.111.125003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Indexed: 06/02/2023]
Abstract
Application of lower hybrid (LH) current drive in tokamak plasmas can induce both co- and countercurrent directed changes in toroidal rotation, depending on the core q profile. For discharges with q(0) <1, rotation increments in the countercurrent direction are observed. If the LH-driven current is sufficient to suppress sawteeth and increase q(0) above unity, the core toroidal rotation change is in the cocurrent direction. This change in sign of the rotation increment is consistent with a change in sign of the residual stress (the divergence of which constitutes an intrinsic torque that drives the flow) through its dependence on magnetic shear.
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Affiliation(s)
- J E Rice
- PSFC MIT, Cambridge, Massachusetts 02139, USA
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Delgado-Aparicio L, Sugiyama L, Granetz R, Gates DA, Rice JE, Reinke ML, Bitter M, Fredrickson E, Gao C, Greenwald M, Hill K, Hubbard A, Hughes JW, Marmar E, Pablant N, Podpaly Y, Scott S, Wilson R, Wolfe S, Wukitch S. Formation and stability of impurity "snakes" in tokamak plasmas. Phys Rev Lett 2013; 110:065006. [PMID: 23432265 DOI: 10.1103/physrevlett.110.065006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Indexed: 06/01/2023]
Abstract
New observations of the formation and dynamics of long-lived impurity-induced helical "snake" modes in tokamak plasmas have recently been carried out on Alcator C-Mod. The snakes form as an asymmetry in the impurity ion density that undergoes a seamless transition from a small helically displaced density to a large crescent-shaped helical structure inside q<1, with a regularly sawtoothing core. The observations show that the conditions for the formation and persistence of a snake cannot be explained by plasma pressure alone. Instead, many features arise naturally from nonlinear interactions in a 3D MHD model that separately evolves the plasma density and temperature.
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Rice JE, Cziegler I, Diamond PH, Duval BP, Podpaly YA, Reinke ML, Ennever PC, Greenwald MJ, Hughes JW, Ma Y, Marmar ES, Porkolab M, Tsujii N, Wolfe SM. Rotation reversal bifurcation and energy confinement saturation in tokamak Ohmic L-mode plasmas. Phys Rev Lett 2011; 107:265001. [PMID: 22243160 DOI: 10.1103/physrevlett.107.265001] [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: 05/10/2011] [Indexed: 05/31/2023]
Abstract
Direction reversals of intrinsic toroidal rotation have been observed in diverted Alcator C-Mod Ohmic L-mode plasmas following electron density ramps. For low density discharges, the core rotation is directed cocurrent, and reverses to countercurrent following an increase in the density above a certain threshold. Such reversals occur together with a decrease in density fluctuations with 2 cm(-1)≤k(θ)≤11 cm(-1) and frequencies above 70 kHz. There is a strong correlation between the reversal density and the density at which the Ohmic L-mode energy confinement changes from the linear to the saturated regime.
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Affiliation(s)
- J E Rice
- Plasma Science & Fusion Center (PSFC), Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Rice JE, Hughes JW, Diamond PH, Kosuga Y, Podpaly YA, Reinke ML, Greenwald MJ, Gürcan ÖD, Hahm TS, Hubbard AE, Marmar ES, McDevitt CJ, Whyte DG. Edge temperature gradient as intrinsic rotation drive in Alcator C-Mod tokamak plasmas. Phys Rev Lett 2011; 106:215001. [PMID: 21699305 DOI: 10.1103/physrevlett.106.215001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Indexed: 05/31/2023]
Abstract
Intrinsic rotation has been observed in I-mode plasmas from the C-Mod tokamak, and is found to be similar to that in H mode, both in its edge origin and in the scaling with global pressure. Since both plasmas have similar edge ∇T, but completely different edge ∇n, it may be concluded that the drive of the intrinsic rotation is the edge ∇T rather than ∇P. Evidence suggests that the connection between gradients and rotation is the residual stress, and a scaling for the rotation from conversion of free energy to macroscopic flow is calculated.
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Affiliation(s)
- J E Rice
- PSFC, MIT, Cambridge, Massachusetts 02139, USA
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Ince-Cushman A, Rice JE, Reinke M, Greenwald M, Wallace G, Parker R, Fiore C, Hughes JW, Bonoli P, Shiraiwa S, Hubbard A, Wolfe S, Hutchinson IH, Marmar E, Bitter M, Wilson J, Hill K. Observation of self-generated flows in tokamak plasmas with lower-hybrid-driven current. Phys Rev Lett 2009; 102:035002. [PMID: 19257362 DOI: 10.1103/physrevlett.102.035002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Indexed: 05/27/2023]
Abstract
In Alcator C-Mod discharges lower hybrid waves have been shown to induce a countercurrent change in toroidal rotation of up to 60 km/s in the central region of the plasma (r/a approximately <0.4). This modification of the toroidal rotation profile develops on a time scale comparable to the current redistribution time (approximately 100 ms) but longer than the energy and momentum confinement times (approximately 20 ms). A comparison of the co- and countercurrent injected waves indicates that current drive (as opposed to heating) is responsible for the rotation profile modifications. Furthermore, the changes in central rotation velocity induced by lower hybrid current drive (LHCD) are well correlated with changes in normalized internal inductance. The application of LHCD has been shown to generate sheared rotation profiles and a negative increment in the radial electric field profile consistent with a fast electron pinch.
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Affiliation(s)
- A Ince-Cushman
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, 77 Massachusetts Avenue, NW16, Cambridge, Massachusetts 02139, USA
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Ward WR, Hughes JW, Faull WB, Cripps PJ, Sutherland JP, Sutherst JE. Observational study of temperature, moisture, pH and bacteria in straw bedding, and faecal consistency, cleanliness and mastitis in cows in four dairy herds. Vet Rec 2002; 151:199-206. [PMID: 12211391 DOI: 10.1136/vr.151.7.199] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
A study of four dairy farms showed that much of the straw stored for bedding was too wet (over 15 per cent moisture content). Most of the beds, including their top surfaces, were damp (above 75 per cent relative humidity). The temperature of the surface of most of the straw beds was related to the air temperature, many being below 15 degrees C, but below the surface the temperatures of most beds reached between 15 degrees C and 45 degrees C within about a week of their being renewed. Bacterial counts also reached a plateau within one to two weeks. The pH of the top layers of straw was usually between 8.5 and 9.5. Adding lime daily to the top layer of the straw failed to raise the pH to levels at which Escherichia coli and Streptococcus uberis do not survive. Most of the counts of E coli and faecal streptococci in the top layers of straw were above 10(6) colony-forming units/g. Counts of E coli and S uberis were much higher in the beds of early lactation cows than in those of dry cows. Many of the early lactation cows were heavily and persistently contaminated with faeces. Dry cows were much cleaner. Groups of cows with firmer faeces were also cleaner. The farm with the lowest incidence of mastitis had the cleanest cows and the most satisfactory beds.
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Affiliation(s)
- W R Ward
- Division of Farm Animal Studies, University of Liverpool, Veterinary Teaching Hospital, Leahurst, Neston
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Abstract
Women who smoke and take oral contraceptives (OCs) have significantly increased risk of cardiovascular disease, but the exact mechanismsfor the increased risk are not known. Cardiovascular reactivity to psychological stress may be one mechanism for the enhanced risk, but the small number of studies examining whether OC users who smoke have greater reactivity have produced mixed results. The purpose of this study was to examine the effect of chronic cigarette smoking, acute nicotine administration, and OC use on cardiovascular and lipid reactivity. Sixty healthy women, half of whom had been using OCs for at least the previous 6 months, participated in the study. Approximately two thirds were smokers and were randomized to be tested after either a 12-hr nicotine deprivation or administration of nicotine gum. One third were nonsmokers. Heart rate, blood pressure, and lipid measures were taken at rest, during a videotaped speech task, and during recovery from the task. Results indicated that, among OC nonusers, there was no effect of smoking status or nicotine administration on cardiovascular reactivity. However, among OC users, nonsmokers had significantly greater heart rate and diastolic blood pressure reactivity to stress. These data show that acute nicotine administration, in the form of nicotine gum, has no effect on cardiovascular or lipid stress reactivity in women. However OC use among nonsmoking women is associated with greater cardiovascular reactivity to stress.
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Affiliation(s)
- S G West
- Pennsylvania State University, USA
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Abstract
Arterialized and venous blood was compared to determine if the arterialization procedure enhances the detection of stress-related changes in catecholamines. Lipid and hematologic measures were also compared for possible distortion by arterialization. Fifteen men completed two stressors. Indwelling venous catheters were placed retrograde in each hand, and the right hand was warmed to a constant temperature. Blood samples were taken simultaneously from both hands, and plasma catecholamines were determined. Arterialization increased baseline epinephrine; there were no effects of arterialization on catecholamines during stress, nor in lipid or hematologic measures during baseline or stress. Thus, arterialization of blood results in small increases in resting epinephrine levels, but does not obscure lipid measures. More importantly, arterialization of venous blood does not enhance the detection of stress-related changes in catecholamines.
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Affiliation(s)
- C M Stoney
- Department of Psychology, Ohio State University, Columbus 43210-1222, USA.
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Abstract
OBJECTIVE The purpose of this study was to examine the relationships between depressed mood and parasympathetic control of the heart in healthy men and women at rest and during two stressors. METHODS Fifty-three healthy college students completed a laboratory stress protocol that included a baseline resting period, a challenging speech task, and a forehead cold pressor task. Depressed mood was assessed using the Beck Depression Inventory (BDI). Parasympathetic cardiac control was measured as the high-frequency (0.12-0.40 Hz) component (HF) of heart rate variability using power spectrum analysis. Blood pressure, respiration rate, and respiration amplitude were measured simultaneously. RESULTS Participants were categorized as having a high or low depressed mood on the basis of median splits of their BDI scores. Those in the high depressed mood group had significantly greater reductions in HF during the speech task and significantly smaller increases in HF during the forehead cold pressor task than those in the low depressed mood group. Women had significantly greater reductions in HF during the speech task and smaller increases in HF during the forehead cold pressor task than men. However, gender and depressed mood did not interact to predict changes in HF. CONCLUSIONS Depressed mood is related to the magnitude of decrease in parasympathetic cardiac control during stressors in healthy men and women. These findings extend those of previous studies, in which a similar phenomenon was observed among patients with cardiac disease. Because the participants in this study were healthy, the relationship between depressed mood and parasympathetic cardiac control does not seem to be secondary to cardiovascular disease.
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Affiliation(s)
- J W Hughes
- Ohio State University, Columbus 43210-1222, USA
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Abstract
In the current study, we examined lipid and cardiovascular responses to an acute stressor among men with and without a parental history of myocardial infarction. 37 men were selected from a large group who completed medical history questionnaires and interviews. Twenty-two men who denied parental history of heart disease (negative parental history) were compared with 15 men with one or both parents who had suffered a myocardial infarction (positive parental history). Total cholesterol, high- and low-density lipoprotein cholesterol, triglycerides, heart rate, and blood pressure were measured at rest and during a videotaped speech stressor. Positive parental history men had significantly higher low-density lipoprotein cholesterol levels and blood pressure at baseline, significantly lower high-density lipoprotein cholesterol levels at baseline, and significantly larger total cholesterol and low-density lipoprotein cholesterol reactivity, relative to negative parental history men. Because parental history is a risk factor for subsequent cardiovascular morbidity and mortality, these data suggest that lipid reactivity to stress may be biologically important.
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Affiliation(s)
- C M Stoney
- Department of Psychology, Ohio State University, Columbus 43210-1222, USA.
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Rearwin DT, Tang JH, Hughes JW. Causes of blindness among Navajo Indians: an update. J Am Optom Assoc 1997; 68:511-7. [PMID: 9279051] [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] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND The causes of blindness among Navajo Indians, an ethnically distinct community within the United States, were last studied in 1982. This article presents an updated report on the causes of blindness among the Navajo. METHODS Staff optometrists at each of the hospitals and clinics on the Navajo Reservation collected information for each affected eye: date of onset, cause, blinding process, and best visual acuity. In terms of the total number of eyes affected, it was found that the most frequently encountered etiology was trauma, followed by congenital causes, diabetes mellitus, primary open-angle glaucoma, age-related macular degeneration, and trachoma. CONCLUSIONS Considering raw numbers as well as preventability, it is suggested that trauma, diabetes mellitus, and primary open-angle glaucoma be targeted for a focused intervention of patient-as well as public-education aimed at reducing blindness from these causes.
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Affiliation(s)
- D T Rearwin
- Southern California College of Optometry, Fullerton, USA
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Faull WB, Hughes JW, Clarkson MJ, Downham DY, Manson FJ, Merritt JB, Murray RD, Russell WB, Sutherst JE, Ward WR. Epidemiology of lameness in dairy cattle: the influence of cubicles and indoor and outdoor walking surfaces. Vet Rec 1996; 139:130-6. [PMID: 8863400 DOI: 10.1136/vr.139.6.130] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.5] [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: 02/02/2023]
Abstract
A survey of cubicles and indoor and outdoor walking surfaces on 37 farms served by four veterinary practices in Somerset, Cheshire, Wirral and west. Wales was carried out in 1989 to 1991. A study of the space requirements of Friesian/Holstein cows at pasture showed that they required approximately 240 cm x 120 cm lying space and a further 60 cm lunging space for rising. By these standards, 87 per cent of the cubicles were too short and 50 per cent were too wide or too narrow. Over 1500 observations on cows lying down, rising and standing indicated that only 12 per cent of the cubicles permitted real freedom of movement; 91 per cent of top partition rails were judged to be too low and 70 per cent of bottom rails too low or too high. In addition, the kerb was very high in 76 per cent of the cubicles. As a result, 10 per cent of cows appeared moderately or severely restricted when lying down, 33 per cent when rising and 55 per cent when standing. Over 2000 cubicle beds were also studied; 75 per cent had a concrete base and of those, 63 per cent were judged to have too little bedding and 11 per cent next to none. Higher incidences and prevalences of lameness were associated with limited borrowing space (P < 0.01) low bottom rails (P < 0.05), high kerbs (P < 0.05) and inadequate bedding (P < 0.01). Of 3190 walking surfaces, only 25 per cent were classified as satisfactory in the first winter and 34 per cent in the second. In general, surfaces in silage bays were too rough and those in other sites were too smooth. The farms with the smoothest indoor walking surfaces had a significantly higher incidence of lameness (P < 0.01). Of 3335 outdoor walking surfaces only 25 per cent were classified as satisfactory, and 70 per cent were too rough. The incidence of lameness was not significantly related to these findings.
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Affiliation(s)
- W B Faull
- Department of Veterinary Clinical Science and Animal Husbandry, University of Liverpool, Leahurst, Neston, South Wirral
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Murray RD, Downham DY, Clarkson MJ, Faull WB, Hughes JW, Manson FJ, Merritt JB, Russell WB, Sutherst JE, Ward WR. Epidemiology of lameness in dairy cattle: description and analysis of foot lesions. Vet Rec 1996; 138:586-91. [PMID: 8799985 DOI: 10.1136/vr.138.24.586] [Citation(s) in RCA: 174] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Information from 37 dairy farms, in four regions of England and Wales provided data on 8991 lesions and the preventive trimming of 4837 cows' feet. Of the total of 13,828 forms returned, veterinary surgeons treated 32 per cent and farmers or stockmen 46 per cent. Of the 8645 lesions associated with episodes of lameness, lesions in the hindlimbs accounted for 92 per cent, of which 65 per cent were in the outer claw, 20 per cent in the skin and 14 per cent in the inner claw. Sole ulcers (40 per cent) and white line lesions (29 per cent) were the predominant diseases of horn, and digital dermatitis (40 per cent) was the most common disease of the skin. Subjective assessments showed that sandcrack, penetration of the sole by foreign bodies and interdigital necrobacillosis were associated with the most severe cases of lameness. There was a significant seasonal effect in the reporting of lesions.
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Affiliation(s)
- R D Murray
- Department of Veterinary Clinical Science and Animal Husbandry, University of Liverpool, Neston, South Wirral
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Clarkson MJ, Downham DY, Faull WB, Hughes JW, Manson FJ, Merritt JB, Murray RD, Russell WB, Sutherst JE, Ward WR. Incidence and prevalence of lameness in dairy cattle. Vet Rec 1996; 138:563-7. [PMID: 8795183 DOI: 10.1136/vr.138.23.563] [Citation(s) in RCA: 196] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A survey was made of 37 dairy farms in Wirral, mid-Cheshire, mid-Somerset and Dyfed, Wales, to assess the incidence and prevalence of lameness in the cows between May 1989 and September 1991. The incidence was obtained from records made whenever a cow was examined for lameness or received preventive foot-trimming. The mean annual incidence was 54.6 new cases per 100 cows with a range from 10.7 to 170.1 and the mean values during summer and winter were 22.9 and 31.7, respectively. The prevalence of lameness was measured by regular visits at which locomotion was scored on a scale of 1 to 5, and the prevalence of lameness was calculated for each visit as the proportion of cows with scores of 3 or more. The mean annual prevalence over the whole period was 20.6 per cent with a range from 2.0 to 53.9 per cent for the 37 farms. The mean prevalences during summer and winter were 18.6 and 25.0 per cent, respectively. The prevalence measured at a single visit in midsummer or midwinter was significantly correlated with the mean prevalence over the whole corresponding period and may be useful as an assessment of the extent of lameness in a herd and the efficacy of control measures. There was evidence that training farmers to recognise early cases of lameness and request veterinary treatment resulted in a marked reduction in the duration of cases of lameness.
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Affiliation(s)
- M J Clarkson
- Department of Veterinary Clinical Science and Animal Husbandry, University of Liverpool, Veterinary Teaching Hospital, Neston, South Wirral
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Abstract
Lying down and other behavioural activities of dairy cows were studied for three 24-hour periods in a straw yard. The cows spent a total of 13.6 hours in the straw yard and lay down for 9.7 hours. The lying down time in one observation was 10.8 hours and this period may be considered ideal because there was little disturbance during that observation. Significantly more time was spent lying down at night than in the day and significantly more time was spent lying down and ruminating than standing up and ruminating. The total time spent lying down was significantly positively correlated with the time spent lying down and ruminating. Ten hours or more spent lying down may be adequate for proper rest in dairy cattle. Straw yards are better than many cubicles for lying and a longer period spent lying down may be important for the prevention of lameness in dairy cows.
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Affiliation(s)
- S S Singh
- Department of Veterinary Clinical Science and Animal Husbandry, University of Liverpool, Leahurst, Neston, South Wirral
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Singh SS, Ward WR, Lautenbach K, Hughes JW, Murray RD. Behaviour of first lactation and adult dairy cows while housed and at pasture and its relationship with sole lesions. Vet Rec 1993; 133:469-74. [PMID: 8310615 DOI: 10.1136/vr.133.19.469] [Citation(s) in RCA: 62] [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] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The times spent lying down and standing by first lactation and adult cows while they were housed and while they were at pasture were studied and related during the period of housing to the incidence of sole lesions in first lactation cows. First lactation cows lay down for a shorter time in the early housing period than later. First lactation and adult cows lay down for longer when at pasture. Maximum lying time was significantly longer and the frequency of lying lower on pasture than indoors. The times spent lying and standing and the frequency of lying were related to the incidence of sole lesions. Rumination time was not related to the occurrence of sole lesions although there were significant variations in rumination behaviour while the animals were housed and at pasture. The patterns of lying and other activities of first lactation and adult cows while they were housed were quite different from those while they were at pasture.
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Affiliation(s)
- S S Singh
- Department of Veterinary Clinical Science and Animal Husbandry, University of Liverpool Veterinary Field Station, Leahurst, Neston, South Wirral
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Abstract
OBJECTIVE To determine the proportion of patients with suspected proliferative diabetic retinopathy who did not receive the recommended follow-up ophthalmological evaluation and care, and to examine associations between various patient characteristics and the failure to obtain care. RESEARCH DESIGN AND METHODS The study cohort included all Navajo Indians identified by a retrospective review of records who had proliferative diabetic retinopathy diagnosed at an Indian Health Service Optometry Clinic between 1 October 1985 and 30 September 1988. Follow-up data were obtained by medical record reviews and by interviews with subjects. RESULTS Of 69 patients identified, 57 of 61 living patients were interviewed. Twenty-three (40.4%) had failed to obtain recommended follow-up. The RR for incomplete treatment among those without a vehicle in the household compared with those with a vehicle was 1.91 (95% CI 1.32-2.76). Other factors associated with incomplete treatment were female sex and marital status other than currently married. Twelve (21%) patients answered "no" to the question, "Have you been told that diabetes was affecting your eyes?" Eight of 38 (21%) who confirmed that they had been told that diabetes was affecting their eyes responded "no" to the question, "Do you think that diabetes is affecting your eyes?" However, the answers to these questions did not distinguish between patients who obtained or did not obtain recommended care. CONCLUSIONS Interventions to increase the proportion of Navajo Indians with diabetic retinopathy who receive appropriate ophthalmologic care must address the issue of transportation.
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Affiliation(s)
- J R Sugarman
- Navajo Area Indian Health Science, Shiprock, New Mexico
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Sternlieb G, Hughes JW. Demographics and housing in America. Popul Bull 1986; 41:1-35. [PMID: 12314155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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Abstract
A zero-grazed herd of approximately 400 cows had a significant mastitis problem associated with Escherichia coli and Streptococcus uberis during a study over three and a half years. Dry cow therapy and post-milk teat dipping effectively controlled staphylococci and the bulk milk cell count averaged less than 400 X 10(3) cells/ml, but over 1800 clinical cases of mastitis occurred over this period, 32 per cent of which were associated with E coli and 25 per cent with Str uberis. Only 8 per cent of the cases associated with E coli showed obvious systemic disturbance and 75 per cent were cured following penicillin and streptomycin treatment. The incidence was highest during spring and summer when the housed cows were dirtiest. Gross teat-end contamination came mainly from sources other than cubicle bedding, and changing the bedding from sawdust to sand did not alter the incidence of clinical mastitis. It was not possible to maintain adequate cleanliness either inside or outside the parlour, nor maintain a trouble-free milking apparatus. The costs of mastitis in this herd during one year are calculated.
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Sternlieb G, Hughes JW. Some economic effects of recent migration patterns on central cities. Res Popul Econ 1981; 3:189-207. [PMID: 12265060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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Lancaster RJ, Coup MR, Hughes JW. Toxicity of arsenic present in lakeweed. N Z Vet J 1971; 19:141-5. [PMID: 5289114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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