Quantitative regulation of electron-phonon coupling.

Electron-phonon (e-p) coupling plays a crucial role in various physical phenomena, and regulation of e-p coupling is vital for the exploration and design of high-performance materials. However, the current research on this topic lacks accurate quantification, hindering further understanding of the underlying physical processes and its applications. In this work, we demonstrate quantitative regulation of e-p coupling, by pressure engineering andin-situspectroscopy. We successfully observe both a distinct vibrational mode and a strong Stokes shift in layered CrBr3, which are clear signatures of e-p coupling. This allows us to achieve precise quantification of the Huang-Rhys factorSat the actual sample temperature, thus accurately determining the e-p coupling strength. We further reveal that pressure efficiently regulates the e-p coupling in CrBr3, evidenced by a remarkable 40% increase inSvalue. Our results offer an approach for quantifying and modulating e-p coupling, which can be leveraged for exploring and designing functional materials with targeted e-p coupling strengths.

Imparting Chemiresistor with Humidity-Independent Sensitivity toward Trace-Level Formaldehyde via Substitutional Doping Platinum Single Atom.

The modification of metal oxides with noble metals is one of the most effective means of improving gas-sensing performance of chemiresistors, but it is often accompanied by unintended side effects such as sensor resistance increases up to unmeasurable levels. Herein, a carbonization-oxidation method is demonstrated using ultrasonic spray pyrolysis technique to realize platinum (Pt) single atom (SA) substitutional doping into SnO2 (named PtSA-SnO2 ). The substitutional doping strategy can obviously enhance gas-sensing properties, and meanwhile decrease sensor resistance by two orders of magnitude (decreased from ≈850 to ≈2 MΩ), which are attributed to the tuning of band gap and fermi-level position, efficient single atom catalysis, and the raising of adsorption capability of formaldehyde, as validated by the state-of-the-art characterizations, such as spherical aberration-corrected scanning transmission electron microscopy (Cs -corrected STEM), in situ diffuse reflectance infrared Fourier transformed spectra (in situ DRIFT), CO temperature-programmed reduction (CO-TPR), and theoretical calculations. As a proof of concept, the developed PtSA-SnO2 sensor shows humidity-independent (30-70% relative humidity) gas-sensing performance in the selective detection of formaldehyde with high response, distinguishable selectivity (8< Sformaldehyde /Sinterferant <14), and ultra-low detection limit (10 ppb). This work presents a generalized and facile method to design high-performance metal oxides for chemical sensing of volatile organic compounds (VOCs).

Messenger RNAs in the Whole Blood of Male and Females after Acute Ischemic Stroke using Bioinformatics.

Objective: This study aimed to identify and analyze gender-specific differences in mRNA expression in the peripheral whole blood of acute ischemic stroke (AIS) patients using bioinformatics. Methods: mRNA expression data from the peripheral whole blood of AIS patients were obtained from GEO datasets. Male stroke-related mRNAs (M-mRNAs) and female stroke-related mRNAs (F-mRNAs) were identified using GEO2R. The biological functions of M-mRNAs and F-mRNAs were evaluated using GO and KEGG databases, and protein-protein interaction networks were created. Results: A total of 39 M-mRNAs (36 upregulated and 3 downregulated) were expressed in the peripheral whole blood of male AIS patients, while 44 F-mRNAs (38 upregulated and 6 downregulated) were expressed in the peripheral whole blood of female AIS patients. Twelve genes were found to overlap among the differentially expressed genes. KEGG pathway analysis revealed enrichment in S. aureus infection-related genes among the differentially expressed genes. Conclusions: This study identified gender-specific mRNA expression differences in the peripheral whole blood of AIS patients. The findings provide important insights into the molecular mechanisms underlying AIS in males and females.

Temperature-Sensitive Materials for Oil and Gas Drilling Applications.

With the vigorous development of the petroleum industry, improving the efficiency of oil and gas exploitation has become an important issue. Temperature-sensitive materials show great potential for application in the development and production of oil and gas fields due to their unique temperature-responsive properties. This paper reviews the application of temperature-sensitive materials in oil and gas drilling and introduces the characteristics of three types of temperature-sensitive materials: N-substituted acrylamide polymers, amphiphilic block copolymers, and peptides. Because these materials can change their physical state at specific temperatures, this paper discusses in detail the role of various temperature-sensitive materials as plugging agent, thickener, oil displacing agent, flocculant, and tackifier in oil and gas field operations, as well as the mechanism of action and performance of temperature-sensitive materials in practical oil and gas drilling operations. As we have not yet seen relevant similar literature, this paper aims to discuss the innovative application of temperature-sensitive materials in the oil and gas drilling process, and at the same time points out the problems in the current research and applications as well as future development directions. Through analysis and comparison, we provide an efficient and environmentally friendly materials selection option for the petroleum industry in order to promote the progress and sustainable development of oil and gas extraction processes.

[Relationship Between the Migration of Endogenous Neural Stem Cells and the Pattern of Change in Immune Cell Phenotypes in the Microenvironment After Intracerebral Hemorrhage in Rats]. / å¤§é¼ è„‘å‡ºè¡€åŽå† æºæ€§ç¥žç»å¹²ç»†èƒžè¿ç§»å’Œå¾®çŽ¯å¢ƒä¸­å ç–«ç»†èƒžè¡¨åž‹å˜åŒ–è§„å¾‹çš„å ³ç³».

Objective: Intracerebral hemorrhage (ICH), the second most common type of stroke, can cause long-lasting disability in the afflicted patients. The study was conducted to examine the patterns of change in endogenous neural stem cells (eNSCs) and in the regenerative microenvironment after ICH, to observe the relationship between the migration of eNSCs and the pattern of change in the polarization state of immune cells in the microenvironment, and provide a research basis for research on clinical nerve repair. Methods: The collagenase injection method was used for modeling. The ICH model was induced in adult female Sprague-Dawley (SD) rats by injecting type VII collagenase (2 U) into the brain tissue of rats. All the experimental rats weighed 280-300 g. In order to simulate the ICU at different time points, including the acute phase (within 1 week), subacute phase (1-3 weeks), and the chronic phase (over 3 weeks), brain tissues were harvested at 3 day post injection (3 DPI), 10 DPI, 20 DPI, and 30 DPI to evaluate the modeling effect. Immunofluorescence staining of the brain tissue sections was performed with DCX antibody to observe the pattern of change in the migration of eNSCs in the brain tissue at different time points. Immunofluorescence staining of brain tissue sections was performed with CD206 antibody and CD86 antibody for respective observation of the pattern of change in pro-inflammatory (M1-type) and anti-inflammatory (M2-type) immune cells in the regenerative microenvironment of the brain tissue after ICM. Results: Spontaneous ICH was successfully induced by injecting type Ⅶ collagenase into the brain tissue of SD rats. The volume of the hematoma formed started to gradually increase at 3 DPI and reached its maximum at 10 DPI. After that, the hematoma was gradually absorbed and was completely absorbed by 30 DPI. Analysis of the pattern of changes in eNSCs in the brain tissue showed that a small number of eNSCs were activated at 3 DPI, but very soon their number started to decrease. By 10 DPI, eNSCs gradually began to increase. A large number of eNSCs migrated to the hemorrhage site at 20 DPI. Then the number of eNSCs decreased significantly at 30 DPI (P<0.01). Analysis of the immune microenvironment of the brain tissue showed that pro-inflammatory (M1 type) immune cells increased significantly at 10 and 20 DPI (P<0.01) and decreased at 30 DPI. Anti-inflammatory (M2 type) immune cells began to increase gradually at 3 DPI, decreased significantly at 20 DPI (P<0.05), and then showed an increase at 30 DPI. Conclusion: After ICH in rats, eNSCs migrating toward the site of ICH first increase and then decrease. The immune microenvironment demonstrates a pattern of change in which inflammation is suppressed at first, then promoted, and finally suppressed again. Inflammation may have a stimulatory effect on the migration of eNSCs, but excessive inflammatory activation has an inhibitory effect on the differentiation and further activation of eNSCs. After ICH, the early stage of repair and protection (10 d) and the subacute phase (20 d) may provide the best opportunities for intervention.

Biomimetic Charge-Neutral Anion Receptors for Reversible Binding and Release of Highly Hydrated Phosphate in water.

Control of phosphate capture and release is vital in environmental, biological, and pharmaceutical contexts. However, the binding of trivalent phosphate (PO43-) in water is exceptionally difficult due to its high hydration energy. Based on the anion coordination chemistry of phosphate, in this study, four charge-neutral tripodal hexaurea receptors (L1 - L4), which were equipped with morpholine and PEG terminal groups to enhance their solubility in water, were synthesized to enable the pH-triggered phosphate binding and release in aqueous solutions. Encouragingly, the receptors were found to bind PO43- anion in a 1:1 ratio via hydrogen bonds in 100% water solutions, with L1 exhibiting the highest binding constant (1.2´103 M-1). These represent the first neutral anion ligands to bind phosphate in 100% water and demonstrate the potential for phosphate capture and release in water through pH-triggered mechanisms, mimicking native phosphate binding proteins. Furthermore, L1 can also bind multiple bioavailable phosphate species, which may serve as model systems for probing and modulating phosphate homeostasis in biological and biomedical researches.

Tough while Recyclable Plastics Enabled by Monothiodilactone Monomers.

The current scale of plastics production and the attendant waste disposal issues represent an underexplored opportunity for chemically recyclable polymers. Typical recyclable polymers are subject to the trade-off between the monomer's polymerizability and the polymer's depolymerizability as well as insufficient performance for practical applications. Herein, we demonstrate that a single atom oxygen-by-sulfur substitution of relatively highly strained dilactone is an effective and robust strategy for converting the "non-recyclable" polyester into a chemically recyclable polymer by lowering the ring strain energy in the monomer (from 16.0 kcal mol-1 in dilactone to 9.1 kcal mol-1 in monothiodilactone). These monothio-modification monomers enable both high/selective polymerizability and recyclability, otherwise conflicting features in a typical monomer, as evidenced by regioselective ring-opening, minimal transthioesterifications, and quantitative recovery of the pristine monomer. Computational and experimental studies demonstrate that an n→π* interaction between the adjacent ester and thioester in the polymer backbone has been implicated in the high selectivity for propagation over transthioesterification. The resulting polymer demonstrates high performance with its mechanical properties being comparable to some commodity polyolefins. Thio-modification is a powerful strategy for enabling conversion of six-membered dilactones into chemically recyclable and tough thermoplastics that exhibit promise as next-generation sustainable polymers.

Crystal Structure Prediction via Efficient Sampling of the Potential Energy Surface.

The crystal structure prediction (CSP) has emerged in recent years as a major theme in research across many scientific disciplines in physics, chemistry, materials science, and geoscience, among others. The central task here is to find the global energy minimum on the potential energy surface (PES) associated with the vast structural configuration space of pertinent crystals of interest, which presents a formidable challenge to efficient and reliable computational implementation. Considerable progress in recent CSP algorithm developments has led to many methodological advances along with successful applications, ushering in a new paradigm where computational research plays a leading predictive role in finding novel material forms and properties which, in turn, offer key insights to guide experimental synthesis and characterization. In this Account, we first present a concise summary of major advances in various CSP methods, with an emphasis on the overarching fundamentals for the exploration of the PES and its impact on CSP. We then take our developed CALYPSO method as an exemplary case study to give a focused overview of the current status of the most prominent issues in CSP methodology. We also provide an overview of the basic theory and main features of CALYPSO and emphasize several effective strategies in the CALYPSO methodology to achieve a good balance between exploration and exploitation. We showcase two exemplary cases of the theory-driven discovery of high-temperature superconducting superhydrides and a select group of atypical compounds, where CSP plays a significant role in guiding experimental synthesis toward the discovery of new materials. We finally conclude by offering perspectives on major outstanding issues and promising opportunities for further CSP research.

Interference tunable second harmonic generation for two-dimensional materials in layered structures.

We experimentally study the tunability of second harmonic generation (SHG) from a two-dimensional (2D) material in a 2D material/dielectric film/substrate layered structure. Such tunability arises from two interferences: one is between the incident fundamental light and its reflected light, and the other is between the upward second harmonic (SH) light and the reflected downward SH light. When both interferences are constructive, the SHG is maximally enhanced; it becomes attenuated if either of them is destructive. The maximal signal can be obtained when both interferences are perfectly constructive, which can be realized by choosing a highly reflective substrate and an appropriate thickness for a dielectric film that has a large difference in its refractive indices at the fundamental and the SH wavelengths. Our experiments demonstrate variations of three orders of magnitude in the SHG signals from a monolayer MoS2/TiO2/Ag layered structure.

P2X7Rs: new therapeutic targets for osteoporosis.

Increasing evidence suggests that both the occurrence and progression of osteoporosis are associated with inflammation, especially in primary osteoporosis. The maintenance of skeletal homeostasis is dependent on the complex regulation of bone metabolism. Numerous evidence suggested that purinoceptor networks are essential for bone homeostasis. In this review, the relationship between inflammation and the development of osteoporosis and the role of P2X7 receptor (P2X7R) in regulating the dynamic regulation of bone reconstruction were covered. We also discussed how P2X7R regulates the balance between resorption and bone formation by osteoblasts and reviewed the relevance of P2X7R polymorphisms in skeletal physiology. Finally, we analyzed potential targets of P2X7R for osteoporosis.

Stability of H3O at extreme conditions and implications for the magnetic fields of Uranus and Neptune.

The anomalous nondipolar and nonaxisymmetric magnetic fields of Uranus and Neptune have long challenged conventional views of planetary dynamos. A thin-shell dynamo conjecture captures the observed phenomena but leaves unexplained the fundamental material basis and underlying mechanism. Here we report extensive quantum-mechanical calculations of polymorphism in the hydrogen-oxygen system at the pressures and temperatures of the deep interiors of these ice giant planets (to >600 GPa and 7,000 K). The results reveal the surprising stability of solid and fluid trihydrogen oxide (H3O) at these extreme conditions. Fluid H3O is metallic and calculated to be stable near the cores of Uranus and Neptune. As a convecting fluid, the material could give rise to the magnetic field consistent with the thin-shell dynamo model proposed for these planets. H3O could also be a major component in both solid and superionic forms in other (e.g., nonconvecting) layers. The results thus provide a materials basis for understanding the enigmatic magnetic-field anomalies and other aspects of the interiors of Uranus and Neptune. These findings have direct implications for the internal structure, composition, and dynamos of related exoplanets.

Temperature-Sensitive Modified Bentonite Based on NIPAM for Drilling Fluid: Experimental and Molecular Simulation Studies.

Bentonite is an important component of drilling fluid, whose quality directly affects the safety and economic benefits of water-based drilling fluid. In order to effectively cope with temperature changes, the development of temperature-sensitive modified bentonite is of great significance. In this study, a temperature-sensitive modified bentonite based on NIPAM with excellent temperature sensitivity was developed through intercalation modification. The temperature-sensitive bentonite (CMC-B-NIPAM) was prepared by grafting N-isopropyl acrylamide (NIPAM) onto the surface of calcium bentonite through the dehydration condensation of silane coupling agent KH570 after the intercalation of sodium Carboxymethyl Cellulose (CMC). The synthesis indexes of CMC-B and CMC-B-NIPAM were optimized by the single-factor method. CMC-B-NIPAM was characterized by XRD and FTIR. The temperature sensitivity, rheology, suspensibility, and expansion capacity of CMC-B-NIPAM dispersion were investigated. The results showed that CMC-B-NIPAM had good temperature sensitivity, and the rheological properties of its dispersion showed characteristics of steady flow and temperature thickening in the range of 40-70 °C. A molecular simulation model was established to observe the microsynthesis mechanism of temperature-sensitive modified bentonite based on NIPAM. The results of this study show that CMC-B-NIPAM drilling fluid has the function of ensuring the stability of drilling fluid flow patterns compared to traditional drilling fluids.

Performance-Advantaged Stereoregular Recyclable Plastics Enabled by Aluminum-Catalytic Ring-Opening Polymerization of Dithiolactone.

Chemically recyclable polymers that can depolymerize into their constituent monomers are attractive candidates to replace non-recyclable petroleum-derived plastics. However, the physical properties and mechanical strengths of depolymerizable polymers are commonly insufficient for practical applications. Here we demonstrate that by proper ligand design and modification, aluminum complexes can catalyse stereoretentive ring-opening polymerization of dithiolactone, yielding highly isotactic polythioesters with molar masses up to 45.5 kDa. This material can form crystalline stereocomplex with a Tm of 94.5 °C, and exhibits mechanical performances comparable to petroleum-based low density polyethylene. Exposure of the polythioester to aluminum precatalyst used to synthesized it resulted in depolymerization to pristine chiral dithiolactone. Experimental and computational studies suggest that aluminum complexes have appropriate binding affinity with sulfide propagating species, thereby avoiding catalyst poisoning and minimizing epimerization reactions, which has not been accessible using other metal catalysts. Overall, aluminum catalysis provides access to performance-advantaged stereoregular recyclable plastics as a promising alternative to petrochemical plastics, thus incentivizing improved plastic sustainability.

Precision Synthesis of Polypeptides via Living Anionic Ring-Opening Polymerization of N-Carboxyanhydrides by Tri-thiourea Catalysts.

The chemistry of α-amino acid N-carboxyanhydrides (NCAs) has a history of over 100 years, but precise and efficient ring-opening polymerization methods for NCAs remain highly needed to facilitate the studies of polypeptides─that is, mimics of natural proteins─in various disciplines. Moreover, the universally accepted NCA polymerization mechanisms are largely limited to the "amine" and the "activated monomer" mechanisms, and the anionic ring-opening polymerization of NCAs has so far not been invoked. Herein, we show an unprecedented anion-binding catalytic system combining tripodal tri-thiourea with sodium thiophenolate that enables the fast and selective anionic ring-opening polymerization of NCAs. This method leads to the precision construction of various polypeptides with living polymerization behavior and is evidenced by narrow molecular weight distributions (Mw/Mn < 1.2), chain extension experiments, and minimal "activated monomer" pathway. Calculations and experimental results elucidate a living anionic polymerization mechanism, and high selectivities for monomer propagation relative to other deleterious side reactions, such as the "activated monomer" pathway, are attributed to the enhanced stabilization of the propagating carbamate anion, which is enforced by an intramolecular hydrogen bond within the tri-thiourea structure.

Particle Swarm Predictions of a SrB8 Monolayer with 12-Fold Metal Coordination.

Materials containing planar hypercoordinate motifs greatly enriched the fundamental understanding of chemical bonding. Herein, by means of first-principles calculations combined with global minimum search, we discovered the two-dimensional (2D) SrB8 monolayer, which has the highest planar coordination number (12) reported so far in extended periodic materials. In the SrB8 monolayer, bridged B8 units are forming the boron monolayer consisting of B12 rings, and the Sr atoms are embedded at the center of these B12 rings, leading to the Sr@B12 motifs. The SrB8 monolayer has good thermodynamic, kinetic, and thermal stabilities, which is attributed to the geometry fit between the size of the Sr atom and cavity of the B12 rings, as well as the electron transfer from Sr atoms to electron-deficient boron network. Placing the SrB8 monolayer on the Ag(001) surface shows good commensurability of the lattices and small vertical structure undulations, suggesting the feasibility of its experimental realization by epitaxial growth. Potential applications of the SrB8 monolayer on metal ions storage (for Li, Na, and K) are explored.

Near-infrared narrow-band minus filter based on a Mie magnetic dipole resonance.

The traditional minus filter is composed of many layers of thin films, which makes it difficult and complicated to manufacture. It is sensitive to incident light angle and polarization. Here, we propose a near-infrared narrow-band minus filter with a full width at half maximum around 5 nm made of all-dielectric Si-SiO2 structures without any ohmic loss. The stop band transmittance of the proposed filter is close to 0, while its broad pass band transmittance is as high as 90% in the work wavelength range. Theoretical analysis shows that the transmission dip originated from magnetic dipole resonance: Its position can be tuned from 1.3 µm to 1.8 µm by changing the thickness of Si structure, and the proposed structure is insensitive to changes in incident light angle and polarization angle. We further studied its potential applications as a refractive index sensor. The sensitivity of dip1 and dip2 are as high as 953.53 nm/RIU and 691.09 nm/RIU, while their figure of merit is almost unchanged: 59.59 and 115.18, respectively.

Zeeman Effect in Centrosymmetric Antiferromagnetic Semiconductors Controlled by an Electric Field.

Centrosymmetric antiferromagnetic semiconductors, although abundant in nature, seem less promising than ferromagnets and ferroelectrics for practical applications in semiconductor spintronics. As a matter of fact, the lack of spontaneous polarization and magnetization hinders the efficient utilization of electronic spin in these materials. Here, we propose a paradigm to harness electronic spin in centrosymmetric antiferromagnets via Zeeman spin splitting of electronic energy levels-termed as the spin Zeeman effect-which is controlled by an electric field. By symmetry analysis, we identify 21 centrosymmetric magnetic point groups that accommodate such a spin Zeeman effect. We further predict by first principles that two antiferromagnetic semiconductors, Fe_{2}TeO_{6} and SrFe_{2}S_{2}O, are excellent candidates showcasing Zeeman splittings as large as ∼55 and ∼30 meV, respectively, induced by an electric field of 6 MV/cm. Moreover, the electronic spin magnetization associated to the splitting energy levels can be switched by reversing the electric field. Our Letter thus sheds light on the electric-field control of electronic spin in antiferromagnets, which broadens the scope of application of centrosymmetric antiferromagnetic semiconductors.

Disproportionation of SO_{2} at High Pressure and Temperature.

Materials once suffered at high-pressure and high-temperature (HPHT) conditions often exhibit exotic phenomena that defy conventional wisdom. The behaviors of sulfur dioxide (SO_{2}), one of the archetypal simple molecules, at HPHT conditions have attracted a great deal of attention due to its relevance to the S cycle between deep Earth and the atmosphere. Here we report the discovery of an unexpected disproportionation of SO_{2} via bond breaking into elemental S and sulfur trioxide (SO_{3}) at HPHT conditions through a jointly experimental and theoretical study. Measured x-ray diffraction and Raman spectroscopy data allow us to solve unambiguously the crystal structure (space group R3[over ¯]c) of the resultant SO_{3} phase that shows an extended framework structure formed by vertex-sharing octahedra SO_{6}. Our findings lead to a significant extension of the phase diagram of SO_{2} and suggest that SO_{2}, despite its abundance in Earth's atmosphere and ubiquity in other giant planets, is not a stable compound at HPHT conditions relevant to planetary interiors, providing important implications for elucidating the S chemistry in deep Earth and other giant planets.

A symmetry-orientated divide-and-conquer method for crystal structure prediction.

Crystal structure prediction has been a subject of topical interest but remains a substantial challenge especially for complex structures as it deals with the global minimization of the extremely rugged high-dimensional potential energy surface. In this paper, a symmetry-orientated divide-and-conquer scheme was proposed to construct a symmetry tree graph, where the entire search space is decomposed into a finite number of symmetry dependent subspaces. An artificial intelligence-based symmetry selection strategy was subsequently devised to select the low-lying subspaces with high symmetries for global exploration and in-depth exploitation. Our approach can significantly simplify the problem of crystal structure prediction by avoiding exploration of the most complex P1 subspace on the entire search space and has the advantage of preserving the crystal symmetry during structure evolution, making it well suitable for predicting the complex crystal structures. The effectiveness of the method has been validated by successful prediction of the candidate structures of binary Lennard-Jones mixtures and the high-pressure phase of ice, containing more than 100 atoms in the simulation cell. The work therefore opens up an opportunity toward achieving the long-sought goal of crystal structure prediction of complex systems.

Early predictors of severe COVID-19 among hospitalized patients.

BACKGROUND: Limited research has been conducted on early laboratory biomarkers to identify patients with severe coronavirus disease (COVID-19). This study fills this gap to ensure appropriate treatment delivery and optimal resource utilization. METHODS: In this retrospective, multicentre, cohort study, 52 and 64 participants with severe and mild cases of COVID-19, respectively, were enrolled during January-March 2020. Least absolute shrinkage and selection operator and binary forward stepwise logistic regression were used to construct a predictive risk score. A prediction model was then developed and verified using data from four hospitals. RESULTS: Of the 50 variables assessed, eight were independent predictors of COVID-19 and used to calculate risk scores for severe COVID-19: age (odds ratio (OR = 14.01, 95% confidence interval (CI) 2.1-22.7), number of comorbidities (OR = 7.8, 95% CI 1.4-15.5), abnormal bilateral chest computed tomography images (OR = 8.5, 95% CI 4.5-10), neutrophil count (OR = 10.1, 95% CI 1.88-21.1), lactate dehydrogenase (OR = 4.6, 95% CI 1.2-19.2), C-reactive protein OR = 16.7, 95% CI 2.9-18.9), haemoglobin (OR = 16.8, 95% CI 2.4-19.1) and D-dimer levels (OR = 5.2, 95% CI 1.2-23.1). The model was effective, with an area under the receiver-operating characteristic curve of 0.944 (95% CI 0.89-0.99, p < 0.001) in the derived cohort and 0.8152 (95% CI 0.803-0.97; p < 0.001) in the validation cohort. CONCLUSION: Predictors based on the characteristics of patients with COVID-19 at hospital admission may help predict the risk of subsequent critical illness.