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  1. Article: An algorithm to detect dicrotic notch in arterial blood pressure and photoplethysmography waveforms using the iterative envelope mean method.

    Pal, Ravi / Rudas, Akos / Kim, Sungsoo / Chiang, Jeffrey N / Braney, Anna / Cannesson, Maxime

    medRxiv : the preprint server for health sciences

    2024  

    Abstract: Background and objective: Detection of the dicrotic notch (DN) within a cardiac cycle is essential for assessment of cardiac output, calculation of pulse wave velocity, estimation of left ventricular ejection time, and supporting feature-based machine ... ...

    Abstract Background and objective: Detection of the dicrotic notch (DN) within a cardiac cycle is essential for assessment of cardiac output, calculation of pulse wave velocity, estimation of left ventricular ejection time, and supporting feature-based machine learning models for noninvasive blood pressure estimation, and hypotension, or hypertension prediction. In this study, we present a new algorithm based on the iterative envelope mean (IEM) method to detect automatically the DN in arterial blood pressure (ABP) and photoplethysmography (PPG) waveforms.
    Methods: The algorithm was evaluated on both ABP and PPG waveforms from a large perioperative dataset (MLORD dataset) comprising 17,327 patients. The analysis involved a total of 1,171,288 cardiac cycles for ABP waveforms and 3,424,975 cardiac cycles for PPG waveforms. To evaluate the algorithm's performance, the systolic phase duration (SPD) was employed, which represents the duration from the onset of the systolic phase to the DN in the cardiac cycle. Correlation plots and regression analysis were used to compare the algorithm with an established DN detection technique (second derivative). The marking of the DN temporal location was carried out by an experienced researcher using the help of the 'find_peaks' function from the scipy PYTHON package, serving as a reference for the evaluation. The marking was visually validated by both an engineer and an anesthesiologist. The robustness of the algorithm was evaluated as the DN was made less visually distinct across signal-to-noise ratios (SNRs) ranging from -30 dB to -5 dB in both ABP and PPG waveforms.
    Results: The correlation between SPD estimated by the algorithm and that marked by the researcher is strong for both ABP (
    Conclusion: Our proposed IEM- based algorithm can detect DN in both ABP and PPG waveforms with low computational cost, even in cases where it is not distinctly defined within a cardiac cycle of the waveform ('DN-less signals'). The algorithm can potentially serve as a valuable, fast, and reliable tool for extracting features from ABP and PPG waveforms. It can be especially beneficial in medical applications where DN-based features, such as SPD, diastolic phase duration, and DN amplitude, play a significant role.
    Language English
    Publishing date 2024-03-07
    Publishing country United States
    Document type Preprint
    DOI 10.1101/2024.03.05.24303735
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Association of red blood cell distribution width with hospital admission and in-hospital mortality across all-cause adult emergency department visits.

    Hong, Woo Suk / Rudas, Akos / Bell, Elijah J / Chiang, Jeffrey N

    JAMIA open

    2023  Volume 6, Issue 3, Page(s) ooad053

    Abstract: Objectives: To test the association between the initial red blood cell distribution width (RDW) value in the emergency department (ED) and hospital admission and, among those admitted, in-hospital mortality.: Materials and methods: We perform a ... ...

    Abstract Objectives: To test the association between the initial red blood cell distribution width (RDW) value in the emergency department (ED) and hospital admission and, among those admitted, in-hospital mortality.
    Materials and methods: We perform a retrospective analysis of 210 930 adult ED visits with complete blood count results from March 2013 to February 2022. Primary outcomes were hospital admission and in-hospital mortality. Variables for each visit included demographics, comorbidities, vital signs, basic metabolic panel, complete blood count, and final diagnosis. The association of each outcome with the initial RDW value was calculated across 3 age groups (<45, 45-65, and >65) as well as across 374 diagnosis categories. Logistic regression (LR) and XGBoost models using all variables excluding final diagnoses were built to test whether RDW was a highly weighted and informative predictor for each outcome. Finally, simplified models using only age, sex, and vital signs were built to test whether RDW had additive predictive value.
    Results: Compared to that of discharged visits (mean [SD]: 13.8 [2.03]), RDW was significantly elevated in visits that resulted in admission (15.1 [2.72]) and, among admissions, those resulting in intensive care unit stay (15.3 [2.88]) and/or death (16.8 [3.25]). This relationship held across age groups as well as across various diagnosis categories. An RDW >16 achieved 90% specificity for hospital admission, while an RDW >18.5 achieved 90% specificity for in-hospital mortality. LR achieved a test area under the curve (AUC) of 0.77 (95% confidence interval [CI] 0.77-0.78) for hospital admission and 0.85 (95% CI 0.81-0.88) for in-hospital mortality, while XGBoost achieved a test AUC of 0.90 (95% CI 0.89-0.90) for hospital admission and 0.96 (95% CI 0.94-0.97) for in-hospital mortality. RDW had high scaled weights and information gain for both outcomes and had additive value in simplified models predicting hospital admission.
    Discussion: Elevated RDW, previously associated with mortality in myocardial infarction, pulmonary embolism, heart failure, sepsis, and COVID-19, is associated with hospital admission and in-hospital mortality across all-cause adult ED visits. Used alone, elevated RDW may be a specific, but not sensitive, test for both outcomes, with multivariate LR and XGBoost models showing significantly improved test characteristics.
    Conclusions: RDW, a component of the complete blood count panel routinely ordered as the initial workup for the undifferentiated patient, may be a generalizable biomarker for acuity in the ED.
    Language English
    Publishing date 2023-07-13
    Publishing country United States
    Document type Journal Article
    ISSN 2574-2531
    ISSN (online) 2574-2531
    DOI 10.1093/jamiaopen/ooad053
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Book ; Online: Covid19Proxy

    Rudas, Akos / Chiang, Jeffrey

    2020  

    Abstract: Proxy for Covid-19 PCR test using EHR data. ...

    Abstract Proxy for Covid-19 PCR test using EHR data.
    Keywords covid19
    Publishing date 2020-09-10
    Publishing country eu
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Machine Learning of Physiologic Waveforms and Electronic Health Record Data: A Large Perioperative Data Set of High-Fidelity Physiologic Waveforms.

    Kim, Sungsoo / Kwon, Sohee / Rudas, Akos / Pal, Ravi / Markey, Mia K / Bovik, Alan C / Cannesson, Maxime

    Critical care clinics

    2023  Volume 39, Issue 4, Page(s) 675–687

    Abstract: Perioperative morbidity and mortality are significantly associated with both static and dynamic perioperative factors. The studies investigating static perioperative factors have been reported; however, there are a limited number of previous studies and ... ...

    Abstract Perioperative morbidity and mortality are significantly associated with both static and dynamic perioperative factors. The studies investigating static perioperative factors have been reported; however, there are a limited number of previous studies and data sets analyzing dynamic perioperative factors, including physiologic waveforms, despite its clinical importance. To fill the gap, the authors introduce a novel large size perioperative data set: Machine Learning Of physiologic waveforms and electronic health Record Data (MLORD) data set. They also provide a concise tutorial on machine learning to illustrate predictive models trained on complex and diverse structures in the MLORD data set.
    MeSH term(s) Humans ; Electronic Health Records ; Machine Learning ; Clinical Relevance
    Language English
    Publishing date 2023-05-18
    Publishing country United States
    Document type Journal Article ; Review
    ZDB-ID 1006423-0
    ISSN 1557-8232 ; 0749-0704
    ISSN (online) 1557-8232
    ISSN 0749-0704
    DOI 10.1016/j.ccc.2023.03.003
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Automated large-scale prediction of exudative AMD progression using machine-read OCT biomarkers.

    Rudas, Akos / Chiang, Jeffrey N / Corradetti, Giulia / Rakocz, Nadav / Avram, Oren / Halperin, Eran / Sadda, Srinivas R

    PLOS digital health

    2023  Volume 2, Issue 2, Page(s) e0000106

    Abstract: Age-related Macular Degeneration (AMD) is a major cause of irreversible vision loss in individuals over 55 years old in the United States. One of the late-stage manifestations of AMD, and a major cause of vision loss, is the development of exudative ... ...

    Abstract Age-related Macular Degeneration (AMD) is a major cause of irreversible vision loss in individuals over 55 years old in the United States. One of the late-stage manifestations of AMD, and a major cause of vision loss, is the development of exudative macular neovascularization (MNV). Optical Coherence Tomography (OCT) is the gold standard to identify fluid at different levels within the retina. The presence of fluid is considered the hallmark to define the presence of disease activity. Anti-vascular growth factor (anti-VEGF) injections can be used to treat exudative MNV. However, given the limitations of anti-VEGF treatment, as burdensome need for frequent visits and repeated injections to sustain efficacy, limited durability of the treatment, poor or no response, there is a great interest in detecting early biomarkers associated with a higher risk for AMD progression to exudative forms in order to optimize the design of early intervention clinical trials. The annotation of structural biomarkers on optical coherence tomography (OCT) B-scans is a laborious, complex and time-consuming process, and discrepancies between human graders can introduce variability into this assessment. To address this issue, a deep-learning model (SLIVER-net) was proposed, which could identify AMD biomarkers on structural OCT volumes with high precision and without human supervision. However, the validation was performed on a small dataset, and the true predictive power of these detected biomarkers in the context of a large cohort has not been evaluated. In this retrospective cohort study, we perform the largest-scale validation of these biomarkers to date. We also assess how these features combined with other EHR data (demographics, comorbidities, etc) affect and/or improve the prediction performance relative to known factors. Our hypothesis is that these biomarkers can be identified by a machine learning algorithm without human supervision, in a way that they preserve their predictive nature. The way we test this hypothesis is by building several machine learning models utilizing these machine-read biomarkers and assessing their added predictive power. We found that not only can we show that the machine-read OCT B-scan biomarkers are predictive of AMD progression, we also observe that our proposed combined OCT and EHR data-based algorithm outperforms the state-of-the-art solution in clinically relevant metrics and provides actionable information which has the potential to improve patient care. In addition, it provides a framework for automated large-scale processing of OCT volumes, making it possible to analyze vast archives without human supervision.
    Language English
    Publishing date 2023-02-15
    Publishing country United States
    Document type Journal Article
    ISSN 2767-3170
    ISSN (online) 2767-3170
    DOI 10.1371/journal.pdig.0000106
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Book ; Online: Multimodal Clinical Pseudo-notes for Emergency Department Prediction Tasks using Multiple Embedding Model for EHR (MEME)

    Lee, Simon A. / Jain, Sujay / Chen, Alex / Biswas, Arabdha / Fang, Jennifer / Rudas, Akos / Chiang, Jeffrey N.

    2024  

    Abstract: In this work, we introduce Multiple Embedding Model for EHR (MEME), an approach that views Electronic Health Records (EHR) as multimodal data. This approach incorporates "pseudo-notes", textual representations of tabular EHR concepts such as diagnoses ... ...

    Abstract In this work, we introduce Multiple Embedding Model for EHR (MEME), an approach that views Electronic Health Records (EHR) as multimodal data. This approach incorporates "pseudo-notes", textual representations of tabular EHR concepts such as diagnoses and medications, and allows us to effectively employ Large Language Models (LLMs) for EHR representation. This framework also adopts a multimodal approach, embedding each EHR modality separately. We demonstrate the effectiveness of MEME by applying it to several tasks within the Emergency Department across multiple hospital systems. Our findings show that MEME surpasses the performance of both single modality embedding methods and traditional machine learning approaches. However, we also observe notable limitations in generalizability across hospital institutions for all tested models.
    Keywords Computer Science - Computation and Language
    Subject code 006
    Publishing date 2024-01-31
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  7. Article ; Online: Imputation of the continuous arterial line blood pressure waveform from non-invasive measurements using deep learning.

    Hill, Brian L / Rakocz, Nadav / Rudas, Ákos / Chiang, Jeffrey N / Wang, Sidong / Hofer, Ira / Cannesson, Maxime / Halperin, Eran

    Scientific reports

    2021  Volume 11, Issue 1, Page(s) 15755

    Abstract: In two-thirds of intensive care unit (ICU) patients and 90% of surgical patients, arterial blood pressure (ABP) is monitored non-invasively but intermittently using a blood pressure cuff. Since even a few minutes of hypotension increases the risk of ... ...

    Abstract In two-thirds of intensive care unit (ICU) patients and 90% of surgical patients, arterial blood pressure (ABP) is monitored non-invasively but intermittently using a blood pressure cuff. Since even a few minutes of hypotension increases the risk of mortality and morbidity, for the remaining (high-risk) patients ABP is measured continuously using invasive devices, and derived values are extracted from the recorded waveforms. However, since invasive monitoring is associated with major complications (infection, bleeding, thrombosis), the ideal ABP monitor should be both non-invasive and continuous. With large volumes of high-fidelity physiological waveforms, it may be possible today to impute a physiological waveform from other available signals. Currently, the state-of-the-art approaches for ABP imputation only aim at intermittent systolic and diastolic blood pressure imputation, and there is no method that imputes the continuous ABP waveform. Here, we developed a novel approach to impute the continuous ABP waveform non-invasively using two continuously-monitored waveforms that are currently part of the standard-of-care, the electrocardiogram (ECG) and photo-plethysmogram (PPG), by adapting a deep learning architecture designed for image segmentation. Using over 150,000 min of data collected at two separate health systems from 463 patients, we demonstrate that our model provides a highly accurate prediction of the continuous ABP waveform (root mean square error 5.823 (95% CI 5.806-5.840) mmHg), as well as the derived systolic (mean difference 2.398 ± 5.623 mmHg) and diastolic blood pressure (mean difference - 2.497 ± 3.785 mmHg) compared to arterial line measurements. Our approach can potentially be used to measure blood pressure continuously and non-invasively for all patients in the acute care setting, without the need for any additional instrumentation beyond the current standard-of-care.
    MeSH term(s) Arterial Pressure ; Blood Pressure Determination/methods ; Cohort Studies ; Deep Learning ; Female ; Humans ; Hypertension/physiopathology ; Hypotension/physiopathology ; Intensive Care Units/statistics & numerical data ; Male ; Middle Aged ; Pulse Wave Analysis
    Language English
    Publishing date 2021-08-03
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-021-94913-y
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Automated Identification of Incomplete and Complete Retinal Epithelial Pigment and Outer Retinal Atrophy Using Machine Learning.

    Chiang, Jeffrey N / Corradetti, Giulia / Nittala, Muneeswar Gupta / Corvi, Federico / Rakocz, Nadav / Rudas, Akos / Durmus, Berkin / An, Ulzee / Sankararaman, Sriram / Chiu, Alec / Halperin, Eran / Sadda, Srinivas R

    Ophthalmology. Retina

    2022  Volume 7, Issue 2, Page(s) 118–126

    Abstract: Objective: To assess and validate a deep learning algorithm to automatically detect incomplete retinal pigment epithelial and outer retinal atrophy (iRORA) and complete retinal pigment epithelial and outer retinal atrophy (cRORA) in eyes with age- ... ...

    Abstract Objective: To assess and validate a deep learning algorithm to automatically detect incomplete retinal pigment epithelial and outer retinal atrophy (iRORA) and complete retinal pigment epithelial and outer retinal atrophy (cRORA) in eyes with age-related macular degeneration.
    Design: In a retrospective machine learning analysis, a deep learning model was trained to jointly classify the presence of iRORA and cRORA within a given B-scan. The algorithm was evaluated using 2 separate and independent datasets.
    Participants: OCT B-scan volumes from 71 patients with nonneovascular age-related macular degeneration captured at the Doheny-University of California Los Angeles Eye Centers and the following 2 external OCT B-scans testing datasets: (1) University of Pennsylvania, University of Miami, and Case Western Reserve University and (2) Doheny Image Reading Research Laboratory.
    Methods: The images were annotated by an experienced grader for the presence of iRORA and cRORA. A Resnet18 model was trained to classify these annotations for each B-scan using OCT volumes collected at the Doheny-University of California Los Angeles Eye Centers. The model was applied to 2 testing datasets to assess out-of-sample model performance.
    Main outcomes measures: Model performance was quantified in terms of area under the receiver operating characteristic curve (AUROC) and area under the precision-recall curve (AUPRC). Sensitivity, specificity, and positive predictive value were also compared against additional clinician annotators.
    Results: On an independently collected test set, consisting of 1117 volumes from the general population, the model predicted iRORA and cRORA presence within the entire volume with nearly perfect AUROC performance and AUPRC scores (iRORA, 0.61; 95% confidence interval [CI] [0.45, 0.82]: cRORA, 0.83; 95% CI [0.68, 0.95]). On another independently collected set, consisting of 60 OCT B-scans enriched for iRORA and cRORA lesions, the model performed with AUROC (iRORA: 0.68, 95% CI [0.54, 0.81]; cRORA: 0.84, 95% CI [0.75, 0.94]) and AUPRC (iRORA: 0.70, 95% CI [0.55, 0.86]; cRORA: 0.82, 95% CI [0.70, 0.93]).
    Conclusions: A deep learning model can accurately and precisely identify both iRORA and cRORA lesions within the OCT B-scan volume. The model can achieve similar sensitivity compared with human graders, which potentially obviates a laborious and time-consuming annotation process and could be developed into a diagnostic screening tool.
    MeSH term(s) Humans ; Retrospective Studies ; Retinal Degeneration/pathology ; Macular Degeneration/pathology ; Retinal Pigment Epithelium/pathology ; Machine Learning ; Atrophy
    Language English
    Publishing date 2022-08-19
    Publishing country United States
    Document type Journal Article
    ISSN 2468-6530
    ISSN (online) 2468-6530
    DOI 10.1016/j.oret.2022.08.016
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article: SLIViT: a general AI framework for clinical-feature diagnosis from limited 3D biomedical-imaging data.

    Avram, Oren / Durmus, Berkin / Rakocz, Nadav / Corradetti, Giulia / An, Ulzee / Nitalla, Muneeswar G / Rudas, Akos / Wakatsuki, Yu / Hirabayashi, Kazutaka / Velaga, Swetha / Tiosano, Liran / Corvi, Federico / Verma, Aditya / Karamat, Ayesha / Lindenberg, Sophiana / Oncel, Deniz / Almidani, Louay / Hull, Victoria / Fasih-Ahmad, Sohaib /
    Esmaeilkhanian, Houri / Wykoff, Charles C / Rahmani, Elior / Arnold, Corey W / Zhou, Bolei / Zaitlen, Noah / Gronau, Ilan / Sankararaman, Sriram / Chiang, Jeffrey N / Sadda, Srinivas R / Halperin, Eran

    Research square

    2023  

    Abstract: We present SLIViT, a deep-learning framework that accurately measures disease-related risk factors in volumetric biomedical imaging, such as magnetic resonance imaging (MRI) scans, optical coherence tomography (OCT) scans, and ultrasound videos. To ... ...

    Abstract We present SLIViT, a deep-learning framework that accurately measures disease-related risk factors in volumetric biomedical imaging, such as magnetic resonance imaging (MRI) scans, optical coherence tomography (OCT) scans, and ultrasound videos. To evaluate SLIViT, we applied it to five different datasets of these three different data modalities tackling seven learning tasks (including both classification and regression) and found that it consistently and significantly outperforms domain-specific state-of-the-art models, typically improving performance (ROC AUC or correlation) by 0.1-0.4. Notably, compared to existing approaches, SLIViT can be applied even when only a small number of annotated training samples is available, which is often a constraint in medical applications. When trained on less than 700 annotated volumes, SLIViT obtained accuracy comparable to trained clinical specialists while reducing annotation time by a factor of 5,000 demonstrating its utility to automate and expedite ongoing research and other practical clinical scenarios.
    Language English
    Publishing date 2023-11-21
    Publishing country United States
    Document type Preprint
    DOI 10.21203/rs.3.rs-3044914/v2
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: A machine learning algorithm to increase COVID-19 inpatient diagnostic capacity.

    Goodman-Meza, David / Rudas, Akos / Chiang, Jeffrey N / Adamson, Paul C / Ebinger, Joseph / Sun, Nancy / Botting, Patrick / Fulcher, Jennifer A / Saab, Faysal G / Brook, Rachel / Eskin, Eleazar / An, Ulzee / Kordi, Misagh / Jew, Brandon / Balliu, Brunilda / Chen, Zeyuan / Hill, Brian L / Rahmani, Elior / Halperin, Eran /
    Manuel, Vladimir

    PloS one

    2020  Volume 15, Issue 9, Page(s) e0239474

    Abstract: Worldwide, testing capacity for SARS-CoV-2 is limited and bottlenecks in the scale up of polymerase chain reaction (PCR-based testing exist. Our aim was to develop and evaluate a machine learning algorithm to diagnose COVID-19 in the inpatient setting. ... ...

    Abstract Worldwide, testing capacity for SARS-CoV-2 is limited and bottlenecks in the scale up of polymerase chain reaction (PCR-based testing exist. Our aim was to develop and evaluate a machine learning algorithm to diagnose COVID-19 in the inpatient setting. The algorithm was based on basic demographic and laboratory features to serve as a screening tool at hospitals where testing is scarce or unavailable. We used retrospectively collected data from the UCLA Health System in Los Angeles, California. We included all emergency room or inpatient cases receiving SARS-CoV-2 PCR testing who also had a set of ancillary laboratory features (n = 1,455) between 1 March 2020 and 24 May 2020. We tested seven machine learning models and used a combination of those models for the final diagnostic classification. In the test set (n = 392), our combined model had an area under the receiver operator curve of 0.91 (95% confidence interval 0.87-0.96). The model achieved a sensitivity of 0.93 (95% CI 0.85-0.98), specificity of 0.64 (95% CI 0.58-0.69). We found that our machine learning algorithm had excellent diagnostic metrics compared to SARS-CoV-2 PCR. This ensemble machine learning algorithm to diagnose COVID-19 has the potential to be used as a screening tool in hospital settings where PCR testing is scarce or unavailable.
    MeSH term(s) Adult ; Aged ; Area Under Curve ; Betacoronavirus ; COVID-19 ; COVID-19 Testing ; Clinical Laboratory Techniques/methods ; Clinical Laboratory Techniques/standards ; Coronavirus Infections/diagnosis ; Humans ; Inpatients ; Los Angeles ; Machine Learning ; Mass Screening/methods ; Mass Screening/standards ; Middle Aged ; Pandemics ; Pneumonia, Viral/diagnosis ; Polymerase Chain Reaction ; Retrospective Studies ; SARS-CoV-2
    Keywords covid19
    Language English
    Publishing date 2020-09-22
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2267670-3
    ISSN 1932-6203 ; 1932-6203
    ISSN (online) 1932-6203
    ISSN 1932-6203
    DOI 10.1371/journal.pone.0239474
    Database MEDical Literature Analysis and Retrieval System OnLINE

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