47 research outputs found
Fine-Grained Assessment of COVID-19 Severity Based on Clinico-Radiological Data Using Machine Learning
Background: The severe and critical cases of COVID-19 had high mortality rates. Clinical features, laboratory data, and radiological features provided important references for the assessment of COVID-19 severity. The machine learning analysis of clinico-radiological features, especially the quantitative computed tomography (CT) image analysis results, may achieve early, accurate, and fine-grained assessment of COVID-19 severity, which is an urgent clinical need. Objective: To evaluate if machine learning algorithms using CT-based clinico-radiological features could achieve the accurate fine-grained assessment of COVID-19 severity. Methods: The clinico-radiological features were collected from 78 COVID-19 patients with different severities. A neural network was developed to automatically measure the lesion volume from CT images. The severity was clinically diagnosed using two-type (severe and non-severe) and fine-grained four-type (mild, regular, severe, critical) classifications, respectively. To investigate the key features of COVID-19 severity, statistical analyses were performed between patients’ clinico-radiological features and severity. Four machine learning algorithms (decision tree, random forest, SVM, and XGBoost) were trained and applied in the assessment of COVID-19 severity using clinico-radiological features. Results: The CT imaging features (CTscore and lesion volume) were significantly related with COVID-19 severity (p < 0.05 in statistical analysis for both in two-type and fine-grained four-type classifications). The CT imaging features significantly improved the accuracy of machine learning algorithms in assessing COVID-19 severity in the fine-grained four-type classification. With CT analysis results added, the four-type classification achieved comparable performance to the two-type one. Conclusions: CT-based clinico-radiological features can provide an important reference for the accurate fine-grained assessment of illness severity using machine learning to achieve the early triage of COVID-19 patients
Interpretable Machine Learning for COVID-19:An Empirical Study on Severity Prediction Task
The black-box nature of machine learning models hinders the deployment of
some high-accuracy models in medical diagnosis. It is risky to put one's life
in the hands of models that medical researchers do not fully understand.
However, through model interpretation, black-box models can promptly reveal
significant biomarkers that medical practitioners may have overlooked due to
the surge of infected patients in the COVID-19 pandemic.
This research leverages a database of 92 patients with confirmed SARS-CoV-2
laboratory tests between 18th Jan. 2020 and 5th Mar. 2020, in Zhuhai, China, to
identify biomarkers indicative of severity prediction. Through the
interpretation of four machine learning models, decision tree, random forests,
gradient boosted trees, and neural networks using permutation feature
importance, Partial Dependence Plot (PDP), Individual Conditional Expectation
(ICE), Accumulated Local Effects (ALE), Local Interpretable Model-agnostic
Explanations (LIME), and Shapley Additive Explanation (SHAP), we identify an
increase in N-Terminal pro-Brain Natriuretic Peptide (NTproBNP), C-Reaction
Protein (CRP), and lactic dehydrogenase (LDH), a decrease in lymphocyte (LYM)
is associated with severe infection and an increased risk of death, which is
consistent with recent medical research on COVID-19 and other research using
dedicated models. We further validate our methods on a large open dataset with
5644 confirmed patients from the Hospital Israelita Albert Einstein, at S\~ao
Paulo, Brazil from Kaggle, and unveil leukocytes, eosinophils, and platelets as
three indicative biomarkers for COVID-19.Comment: 14 pages, 10 figure
Novel biosensor fabrication methodology based on processable conducting polyaniline nanoparticles
This work investigates polyaniline (PANI) nanoparticles, (synthesised using dodecylbenzenesulphonic acid (DBSA) as a dopant), as a novel, highly processable, non-diffusional mediating species in an enzyme biosensing application. These nanoparticles are readily dispersed in aqueous media which helps overcome some of the processability issues traditionally associated with polyaniline.
Modification of screen-printed electrodes was readily achieved with these aqueous nanoparticle dispersions, where the nanoparticles were simply cast by a drop-coating method onto the surface. After suitable pH adjustment, it was shown that horseradish peroxidase (HRP) enzyme could be added to the dispersion, and cast simultaneously with the conducting polyaniline. This effective fabrication method involves no electrochemical steps, and as such is easily amenable to mass production. The feasibility of casting enzyme with polyaniline nanoparticles is demonstrated in this short communication. More accurate deposition of protein-containing inks onto screen-printed carbon working electrodes could in the future transfer the drop-coating protocol from manual deposition to largescale production by mechanical methods such as ink-jet printing
Insight-HXMT observations of Swift J0243.6+6124 during its 2017-2018 outburst
The recently discovered neutron star transient Swift J0243.6+6124 has been
monitored by {\it the Hard X-ray Modulation Telescope} ({\it Insight-\rm HXMT).
Based on the obtained data, we investigate the broadband spectrum of the source
throughout the outburst. We estimate the broadband flux of the source and
search for possible cyclotron line in the broadband spectrum. No evidence of
line-like features is, however, found up to . In the absence of
any cyclotron line in its energy spectrum, we estimate the magnetic field of
the source based on the observed spin evolution of the neutron star by applying
two accretion torque models. In both cases, we get consistent results with
, and peak luminosity of which makes the source the first Galactic ultraluminous
X-ray source hosting a neutron star.Comment: publishe
Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite
As China's first X-ray astronomical satellite, the Hard X-ray Modulation
Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15,
2017, is a wide-band (1-250 keV) slat-collimator-based X-ray astronomy
satellite with the capability of all-sky monitoring in 0.2-3 MeV. It was
designed to perform pointing, scanning and gamma-ray burst (GRB) observations
and, based on the Direct Demodulation Method (DDM), the image of the scanned
sky region can be reconstructed. Here we give an overview of the mission and
its progresses, including payload, core sciences, ground calibration/facility,
ground segment, data archive, software, in-orbit performance, calibration,
background model, observations and some preliminary results.Comment: 29 pages, 40 figures, 6 tables, to appear in Sci. China-Phys. Mech.
Astron. arXiv admin note: text overlap with arXiv:1910.0443
GRANDMA and HXMT Observations of GRB 221009A -- the Standard-Luminosity Afterglow of a Hyper-Luminous Gamma-Ray Burst
GRB 221009A is the brightest Gamma-Ray Burst (GRB) detected in more than 50
years of study. In this paper, we present observations in the X-ray and optical
domains after the GRB obtained by the GRANDMA Collaboration (which includes
observations from more than 30 professional and amateur telescopes) and the
Insight-HXMT Collaboration. We study the optical afterglow with empirical
fitting from GRANDMA+HXMT data, augmented with data from the literature up to
60 days. We then model numerically, using a Bayesian approach, the GRANDMA and
HXMT-LE afterglow observations, that we augment with Swift-XRT and additional
optical/NIR observations reported in the literature. We find that the GRB
afterglow, extinguished by a large dust column, is most likely behind a
combination of a large Milky-Way dust column combined with moderate
low-metallicity dust in the host galaxy. Using the GRANDMA+HXMT-LE+XRT dataset,
we find that the simplest model, where the observed afterglow is produced by
synchrotron radiation at the forward external shock during the deceleration of
a top-hat relativistic jet by a uniform medium, fits the multi-wavelength
observations only moderately well, with a tension between the observed temporal
and spectral evolution. This tension is confirmed when using the extended
dataset. We find that the consideration of a jet structure (Gaussian or
power-law), the inclusion of synchrotron self-Compton emission, or the presence
of an underlying supernova do not improve the predictions, showing that the
modelling of GRB22109A will require going beyond the most standard GRB
afterglow model. Placed in the global context of GRB optical afterglows, we
find the afterglow of GRB 221009A is luminous but not extraordinarily so,
highlighting that some aspects of this GRB do not deviate from the global known
sample despite its extreme energetics and the peculiar afterglow evolution.Comment: Accepted to ApJL for the special issue, 37 pages, 23 pages main text,
6 tables, 13 figure