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Recently emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants may pose a threat to immunity. A systematic landscape of neutralizing antibodies against emerging variants is needed. We systematically searched for studies that evaluated neutralizing antibody titers induced by previous infection or vaccination against SARS-CoV-2 variants and collected individual data. We identified 106 studies meeting the eligibility criteria. Lineage B.1.351 (beta), P.1 (gamma) and B.1.617.2 (delta) significantly escaped natural infection–mediated neutralization, with an average of 4.1-fold (95% confidence interval [CI]: 3.6–4.7-fold), 1.8-fold (1.4–2.4-fold), and 3.2-fold (2.4–4.1-fold) reduction in live virus neutralization assay, while neutralizing titers against B.1.1.7 (alpha) decreased slightly (1.4-fold [95% CI: 1.2–1.6-fold]). Serum from vaccinees also led to significant reductions in neutralization of B.1.351 across different platforms, with an average of 7.1-fold (95% CI: 5.5–9.0-fold) for nonreplicating vector platform, 4.1-fold (3.7–4.4-fold) for messenger RNA platform, and 2.5-fold (1.7–2.9-fold) for protein subunit platform. Neutralizing antibody levels induced by messenger RNA vaccines against SARS-CoV-2 variants were similar to, or higher, than that derived from naturally infected individuals. [ABSTRACT FROM AUTHOR]

Mechanical agitation was usually applied to improve the fluidization quality of the fluidized bed. This study aimed to explore the effect of agitation on the fluidization characteristics and separation effect of a gas–solid separation fluidized bed. On the basis of the multiple reference frame model, the fluidized bed under mechanical agitation was simulated, where the symmetrical motion pattern of the bed particles was identified. Furthermore, when the agitation speed w was below 75 rpm, the fluidization quality was improved gradually with the lower density fluctuation variance of 0.06 g/cm3. Finally, under the appropriate operating conditions (fluidization number of 1.2, w = 75 rpm), raw coal was separated in a fluidized bed, and the yield of cleaned coal was 41.30% with an ash content of 14.27%. Moreover, the probable error was as low as 0.105 g/cm3, indicating the strong separation performance of the gas–solid separation fluidized bed with an agitator. [Display omitted] • Gas–solid separation fluidized bed with blade stirrer studied via CFD and experiments. • 3D model of a fluidized bed was established through CFD simulation. • Mechanical agitation effect on fluidization and separation verified experimentally. • Theoretical basis to promote gas–solid separation fluidized beds' industrial use. [ABSTRACT FROM AUTHOR]

Background To assess the case fatality risk (CFR) of COVID-19 in mainland China, stratified by region and clinical category, and estimate key time-to-event intervals. Methods We collected individual information and aggregated data on COVID-19 cases from publicly available official sources from 29 December 2019 to 17 April 2020. We accounted for right-censoring to estimate the CFR and explored the risk factors for mortality. We fitted Weibull, gamma, and log-normal distributions to time-to-event data using maximum-likelihood estimation. Results We analyzed 82 719 laboratory-confirmed cases reported in mainland China, including 4632 deaths and 77 029 discharges. The estimated CFR was 5.65% (95% confidence interval [CI], 5.50–5.81%) nationally, with the highest estimate in Wuhan (7.71%) and lowest in provinces outside Hubei (0.86%). The fatality risk among critical patients was 3.6 times that of all patients and 0.8–10.3-fold higher than that of mild-to-severe patients. Older age (odds ratio [OR], 1.14 per year; 95% CI, 1.11–1.16) and being male (OR, 1.83; 95% CI, 1.10–3.04) were risk factors for mortality. The times from symptom onset to first healthcare consultation, to laboratory confirmation, and to hospitalization were consistently longer for deceased patients than for those who recovered. Conclusions Our CFR estimates based on laboratory-confirmed cases ascertained in mainland China suggest that COVID-19 is more severe than the 2009 H1N1 influenza pandemic in hospitalized patients, particularly in Wuhan. Our study provides a comprehensive picture of the severity of the first wave of the pandemic in China. Our estimates can help inform models and the global response to COVID-19. [ABSTRACT FROM AUTHOR]

We conducted two surveys to evaluate the health‐seeking behaviors of individuals with acute respiratory infections (ARI) during the COVID‐19 outbreak in Wuhan, China. Among 351 participants reporting ARI (10.3%, 351/3,411), 36.5% sought medical assistance. Children were more likely to seek medical assistance than other age‐groups (66.1% vs. 28.0%‐35.1%). This population‐based study demonstrates that the majority of patients with ARI symptoms did not seek medical assistance during the COVID‐19 outbreak in Wuhan. These findings may be used to refine the estimates of disease burden and clinical severity of COVID‐19 and to plan for health resources allocation. [ABSTRACT FROM AUTHOR]

The membrane structure is a flexible structure, which is easy to vibrate or even relax under dynamic load. Engineering accident analysis shows that the relaxation of membrane structure is more likely to lead to structural failure. In this article, the impact load problem is combined with the flexible structure to analyze the impact of hailstone impact load on the dynamic response of membrane structure. First, the umbrella membrane stretching device was designed and manufactured, and the hailstone impact test was carried out on the umbrella membrane structure with polyvinyl chloride membrane material. Dynamic response data, tension relaxation of side cables and vibration deformation of umbrella membrane structures impacted by hailstones with different sizes and different characteristic points were obtained. In the numerical analysis, the form-finding analysis of umbrella membrane structure is carried out by finite element method, and the transient impact analysis is conducted in LS-DYNA. Finally, the reliability of the research results is verified by comparing the numerical and experimental results. The general laws and conclusions are drawn and the disaster-causing mechanism of membrane structure impacted by hailstone is revealed. On the whole, although the probability of hailstone destroying the membrane material directly is very small, it will relax the membrane structure and affect the safety of membrane structure. The conclusions of this article provide a theoretical basis for the design and maintenance of membrane structures. [ABSTRACT FROM AUTHOR]

A robust discontinuous Galerkin (DG) finite element method is proposed for elasticity problems with interfaces, where the continuity across the interfaces is weakly enforced by using Nitsche's method. We employ a weighting for the interfacial consistency terms arising in the Nitsche variational form and present a detailed finite element formulation of this DG method. The stabilization parameter is evaluated by solving element level generalized eigenvalue problem for higher-order elements. Consequently, we give the choice of the weighting parameter that results in an estimate for the stabilization parameter such that the method remains well behaved in the pathological cases. The accuracy and robustness of the proposed method are then demonstrated through several numerical examples. [ABSTRACT FROM AUTHOR]

Objectives: The long-term dynamics of antibody responses in patients with influenza A(H7N9) virus infection are not well understood.Methods: We conducted a longitudinal serological follow-up study in patients who were hospitalized with A(H7N9) virus infection, during 2013-2018. A(H7N9) virus-specific antibody responses were assessed by hemagglutination inhibition (HAI) and neutralization (NT) assays. A random intercept model was used to fit a curve to HAI antibody responses over time. HAI antibody responses were compared by clinical severity.Results: Of 67 patients with A(H7N9) virus infection, HAI antibody titers reached 40 on average 11 days after illness onset and peaked at a titer of 290 after three months, and average titers of ≥80 and ≥40 were present until 11 months and 22 months respectively. HAI antibody responses were significantly higher in patients who experienced severe disease, including respiratory failure and acute respiratory distress syndrome, compared with patients who experienced less severe illness.Conclusions: Patients with A(H7N9) virus infection who survived severe disease mounted higher antibody responses that persisted for longer periods compared with those that experienced moderate disease. Studies of convalescent plasma treatment for A(H7N9) patients should consider collection of donor plasma from survivors of severe disease between 1 and 11 months after illness onset. [ABSTRACT FROM AUTHOR]

Lead-free perovskite is a non-toxic and environmentally friendly material, which plays an increasingly significant role in photodetection, luminescence, photovoltaics and so on. In this paper, a single-component white light emission is successfully achieved through the co-doping of Sb3+, Mn2+ and Tb3+ in Cs 2 NaInCl 6. The photoluminescent mechanism is proved through the spectra measurements and decay dynamics. The addition of Sb3+ could activate the self-trapped exciton (STE) emission of the matrix (blue light at 450 nm). The efficient energy transfer from STE emission could realize red light emission of Mn2+, and green light emission of Tb3+. The single-component white light emission is obtained with the Commission Internationale de L'Eclairage of (0.31, 0.35), high color rendering index of 88.1 and correlated color temperature of 6394 K. Finally, the prepared white light emitting diodes demonstrate high performance and excellent stability. This provides a new idea for development of lead-free perovskite white luminescent materials in display and lighting applications. • The blue self-trapping exciton emission of Cs 2 NaInCl 6 is significantly enhanced through the sensitivity of Sb3+ ions. • The efficient energy transfer channels from matrix to Mn2+ and Tb3+ ions promote the formation of white light emission. • The prepared white light-emitting diodes display high performance and excellent stability. [ABSTRACT FROM AUTHOR]

The high power extraction of wind farms necessitates a comprehensive optimization system encompassing precise and efficient layout design and cooperative control. This study applies a novel ANN-based power prediction framework to resolve the layout optimization combined with the genetic algorithm, then composes a double-layer machine learning framework for the control optimization incorporating Bayesian machine learning. Three wind scenarios and control schemes are accounted for to investigate their impacts on the actual power benefits of the layout and control optimizations, respectively. The study shows that the divergence of wind resources will lead to more evenly scattered turbine arrangements for each direction sector in the optimized layout but may weaken the functionality of layout design in annual power rise owing to the compromise between different wind directions. Under the spread wind scenario, the spread optimized layout may narrow the space for the power enhancement of the yaw control, whereas the unidirectional optimized layout may give rise to a more considerable power gain from the yaw control. Row-based control shows desirable performance in the regular aligned layout, while column-based control is recommended for irregularly optimized layouts, particularly for unidirectional optimized ones. The spread optimized layout will widen the gap of power improvement between the column-based and independent controls, thus weakening the advantage of the column-based control. [ABSTRACT FROM AUTHOR]

This paper presents a data-driven wind farm layout optimization framework that uses a machine learning wake model that considers physical control stages. The machine learning wake model is trained using well-validated Computational Fluid Dynamics (CFD) simulation data, and consists of thousands of sub-models, each of which is an artificial neural network (ANN) wake model. The ANN wake models are trained separately for low-speed and high-speed inflows to ensure high accuracy of the predictions, with less than 2% error compared to CFD simulations. The accuracy and efficiency of the framework are validated, and the results show better agreement with CFD simulation than an analytical wake model developed in recent years. A parametric study on the number of wind turbines in the Horns Rev wind farm demonstrates that more wind turbines can be added with a minor decrease in average power, with more even and staggered layouts. Under full-wake uniform inflow, the selected analytical wake model exhibits a power prediction error of 5%–8%, while the differences between optimal layouts searched by different wake models range from 2% to 8%. When introducing a wider range of inflow direction sectors, the discrepancy between optimal layout performances decreases. [ABSTRACT FROM AUTHOR]