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Summary Background Stroke is a leading cause of death and disability worldwide. Despite considerable improvements in diagnosis and treatment, little is known about the short-term and long-term prognosis after a first stroke in low-income and middle-income countries, including China. We aimed to assess the short-term and long-term risk of recurrent stroke and mortality after a first stroke for each of the major pathological stroke types. Methods This population-based cohort study included adults aged 35–74 years without disability who were recruited to the China Kadoorie Biobank (CKB). A baseline survey was conducted in ten geographical areas (five urban, five rural) in China, and participants had clinical measurements recorded. Participants were followed up by monitoring death registries and by electronic linkage to health registries and health insurance claims databases, with follow-up until Jan 1, 2017. Participants were excluded from analyses if they had a previous history of stroke, transient ischaemic attack, or ischaemic heart disease at baseline. All incidences of fatal and non-fatal stroke during the study period were recorded by type (ischaemic stroke, intracerebral haemorrhage, subarachnoid haemorrhage, and unspecified type). Primary outcome measures were 28-day mortality, recurrent stroke, major vascular events (recurrent stroke, myocardial infarction, or vascular death), vascular mortality, and all-cause mortality. Findings Of 512 715 individuals in the CKB, 489 586 participants without previous ischaemic heart disease and stroke at recruitment were included, of whom 45 732 (42 073 [92%] confirmed by brain imaging) had a stroke during the study period. The mean age was 59·3 years (SD 9·8) for participants who had a stroke (54% women) and 50·8 years (10·3) for participants with no stroke (60% women). 36 588 (80%) of the incident cases of stroke were ischaemic stroke, 7440 (16%) were intracerebral haemorrhage, 702 (2%) were subarachnoid haemorrhage, and 1002 (2%) were an unspecified stroke type. 28-day mortality was 3% (95% CI 3–4) for ischaemic stroke, 47% (46–48)for intracerebral haemorrhage, 19% (17–22; 52% for rural areas and 32% for urban areas) subarachnoid haemorrhage, and 24% (22–27) for unspecified stroke. Among participants who survived stroke at 28 days, 41% (41–42) had recurrent stroke at 5 years (ischaemic stroke 41% [41–42], intracerebral haemorrhage 44% [42–46], subarachnoid haemorrhage 22% [18–27], unspecified stroke type 40% [35–44]) and mortality at 5 years was 17% ([17–18] ischaemic stroke 16% [15–16], intracerebral haemorrhage 28% [26–29], subarachnoid haemorrhage 16% [12–20], unspecified stroke type 15% [12–19]). After a first ischaemic stroke, 91% of recurrent strokes were also ischaemic stroke; after an intracerebral haemorrhage, 56% of recurrent strokes were intracerebral haemorrhage, and 41% of recurrent strokes were ischaemic stroke. Interpretation After a first stroke, the risk of recurrence or death within 5 years was high among this population of Chinese adults. Urgent improvements to secondary prevention of stroke in China are needed to reduce these risks. Funding Wellcome Trust, Medical Research Council, British Heart Foundation, Cancer Research UK, Kadoorie Charitable Foundation, Chinese Ministry of Science and Technology, National Natural Science Foundation of China. Copyright © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.

Multiferroic material bismuth ferrite (BiFeO3 = BFO) and Ho-substitution (Bi1-xHoxFeO3, x = 0.05, 0.10, 0.15, 0.20) thin films were successfully fabricated on silicon (110) substrates by the sol-gel approach. The doping-Ho effects on crystal structure, surface morphology and magnetic property were investigated. The X-ray diffraction (XRD) revealed that the Ho-substitution thin films underwent a phase transition from the rhombohedral to the orthorhombic structure. The changes in Ho-substitution and pure BFO surface appearance were analyzed using the Field Emission Scanning Electron Microscopy (SEM). Meanwhile, the saturation magnetization (Ms) of Ho-substitution samples obtained remarkable augment with the increase in Ho-doping due to the enhancement of superexchange interactions between Fe-O-Fe and spatial modulation for helical structure destruction. The heightening of superexchange interactions is attributed to the reduction of oxygen vacancies because of Ho3+ ions in a stable status.

Experimental test of a 3D parameterized vane cascade with non-axisymmetric endwall was conducted by using the particle image velocimetry (PIV) and five-hole probe. Both the straight annular cascade with axisymmetric endwall (denoted by Ref) and the negatively bowed cascade with non-axisymmetric endwall (denoted by Opt) were tested. Here, the Opt design was obtained through optimization based on Computational Fluid Dynamics (CFD), by combining the techniques of section profiling, compound lean and non-axisymmetric endwall [1] . The results showed that, the pressure distributions of blade surface at 10%, 50% and 90% spans of CFD results and experimental data are in good agreement. The trends of total pressure coefficient at cascade outlet (denoted by C p t ) and outlet flow angle (denoted by α 1 ) were well matched; the C p t of Opt design was shown increased by 0.47%, and 0.41% in experiment and CFD simulations, respectively. The contours of C p t showed that the profile loss of Opt design is significantly reduced and the secondary loss region gets closer to hub and shroud. By tracking the secondary vortices near the hub of cascades, the affected area of secondary flow of Opt design was confirmed to be smaller when compared to that of the Ref design; but the size of passage vortex near the cascade exit was increased. The results of PIV and five-hole probe were consistent; they both confirmed that the combined parameterization of both blade and endwalls is effective in reducing the affected area of secondary flow and the profile loss of the low-aspect-ratio vane cascade.

To date, intermediate hosts of SARS-CoV-2 remain obscure and controversial. Several studies have shown that SARS-CoV-2-related pangolin coronavirus (Pangolin-CoV) has a high sequence similarity to SARS-CoV-2 and might be the initial source of SARS-CoV-2; however, the biological characteristics of Pangolin-CoV are still largely unknown. In this study, we evaluated the pathogenicity and transmissibility of Pangolin-CoV in Syrian golden hamsters

Since December 2019, coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a great challenge to the world's public health system. Nosocomial infections have occurred frequently in medical institutions worldwide during this pandemic. Thus, there is an urgent need to construct an effective surveillance and early warning system for pathogen exposure and infection to prevent nosocomial infections in negative-pressure wards. In this study, visualization and construction of an infection risk assessment of SARS-CoV-2 through aerosol and surface transmission in a negative-pressure ward were performed to describe the distribution regularity and infection risk of SARS-CoV-2, the critical factors of infection, the air changes per hour (ACHs) and the viral variation that affect infection risk. The SARS-CoV-2 distribution data from this model were verified by field test data from the Wuhan Huoshenshan Hospital ICU ward. ACHs have a great impact on the infection risk from airborne exposure, while they have little effect on the infection risk from surface exposure. The variant strains demonstrated significantly increased viral loads and risks of infection. The level of protection for nurses and surgeons should be increased when treating patients infected with variant strains, and new disinfection methods, electrostatic adsorption and other air purification methods should be used in all human environments. The results of this study may provide a theoretical reference and technical support for reducing the occurrence of nosocomial infections.

The particulate matter (PM) in livestock houses, one of the primary sources of atmospheric PM, is not only detrimental to the respiratory health of animals and farmworkers but also poses a threat to the public environment and public health and warrants increased attention. In this study, we investigated the variation in the pulmonary microbiome and metabolome in broiler chickens exposed to PM collected from a broiler house. We examined the pulmonary microbiome and metabolome in broilers, observing that PM induced a visible change in α and β diversity. A total of 66 differential genera, including unclassified_f_Ruminococcaceae and Campylobacter, were associated with pulmonary inflammation. Untargeted metabolomics was utilised to identify 63 differential metabolites induced by PM and correlated with differential bacteria. We observed that PM resulted in injury of the broiler lung and disruption of the microbial community, as well as causing changes in the observed metabolites. These results imply that perturbations to the microbiome and metabolome may play pivotal roles in the mechanism underlying PM-induced broiler lung damage.

Reducing the crystal size and creating intra/inter-crystalline mesoporosity or macroporosity are two options to enhance the mass transportation efficiency in microporous zeolites. In this study, an improved aerosol-assisted hydrothermal method was used to synthesize small-crystal Titanium silicalite-1 (TS-1) with low template amount. By using a more concentrated template agent the particle size of the TS-1 crystal can be reduced from 350-800 nm to 230–270 nm. A well-dispersion of the Ti species can be achieved under optimized synthesis condition. A post-treatment with tetrapropyl ammonium hydroxide (TPAOH) was used to further improve the diffusion property. The mesopore volumes and external surface areas are significantly increased due to the formation of the intracrystalline voids. All the TS-1 samples were evaluated in propene epoxidation. The conversion of H2O2 and the selectivity of Propylene Oxide are 99.9% and 98%, which are improved as compared to those of the parent TS-1.

With the ever-increasing turbine inlet temperature and blade loadings, the thermal management for the endwall of gas turbines is gaining wide attention. Specifically, the increasing blade loadings intensify the cross flows and the blade-endwall interactions, making the design of turbine endwalls operating in such harsh thermal environments a really challenging problem. To resolve such a problem, we propose a novel non-axisymmetric endwall, which is shaped both near the blade leading edge and between the two adjacent blades. The effectiveness of the proposed non-axisymmetric endwall is well demonstrated on a typical large-turning-angle gas turbine with a purge slot. More specifically, in order to obtain a solution that can achieve a good balance between the gas turbine aerodynamic and thermal performance, we carry out three separate optimizations for the non-axisymmetric endwall. The aerodynamic loss, the film cooling effectiveness and the heat transfer coefficient are taken as the objective functions, respectively, for the optimization process. The optimal solution aiming to minimize the heat transfer coefficient achieves the most desirable performance. This solution substantially reduces both the aerodynamic loss and thermal loads at the turbine endwall, since it is effective to suppress both the horseshoe vortex and the cross flows. Furthermore, through a fundamental flow-thermal analysis of the three optimal solutions, an insight into the effects of non-axisymmetric endwall on gas turbine aero-thermal performance is obtained and guidelines for the aero-thermal design of non-axisymmetric endwalls are provided.

The point-by-point scanning mechanism of photoacoustic microscopy (PAM) results in low-speed imaging, limiting the application of PAM. In this work, we propose a method to improve the quality of sparse PAM images using convolutional neural networks (CNNs), thereby speeding up image acquisition while maintaining good image quality. The CNN model utilizes attention modules, residual blocks, and perceptual losses to reconstruct the sparse PAM image, which is a mapping from a 1/4 or 1/16 low-sampling sparse PAM image to a latent fully-sampled one. The model is trained and validated mainly on PAM images of leaf veins, showing effective improvements quantitatively and qualitatively. Our model is also tested using in vivo PAM images of blood vessels of mouse ears and eyes. The results suggest that the model can enhance the quality of the sparse PAM image of blood vessels in several aspects, which facilitates fast PAM and its clinical applications.

Nano-sized zeolite Beta aggregates with interparticle mesopores were synthesized by the aerosol-assisted method. The amorphous powders in the Na 2 O–Al 2 O 3 −SiO 2 system, which was obtained from an aerosol drying process, were used as the precursor. The zeolite was crystallized in a high concentration system with high alkalinity. This can not only improve the autoclave utilization and the crystallization rate, but also reduce the amount of both template and waste water. The obtained zeolite Beta is spherical nano-aggregates with interparticle mesopores. It shows high BET surface area and good Al species distribution. The study on crystallization process indicated that the precursor gradually dissolved under the strong alkaline condition and the nano-sized zeolite crystals were formed in the liquid phase as time prolonged. Therefore, the transformation mechanism mainly followed the liquid-phase mechanism. More importantly, the zeolite beta synthesized by aerosol-assisted method exhibited good catalytic activity and stability in the cracking reaction of 1,3,5-TIPB.

Influenza A virus has caused intermittent pandemics with potentially devastating consequences in human populations. Under natural conditions, influenza virus is mainly spread person-to-person through the air; however, in studies of influenza virology, the virus is typically intranasally instilled in the form of large liquid droplets. The dynamics of influenza virus infection and real-time progression of respiratory tract infection are still poorly understood, partly due to a lack of available efficient replication-competent viruses that stably express a reporter gene. To address this limitation, we constructed a replication-competent influenza A virus carrying a Gaussia luciferase reporter gene in the NA segment of the viral genome (IAV-Gluc). The recombinant virus (IAV-Gluc) stably expressed Gaussia luciferase, and the viral load in lungs was proportional to the fluorescence intensity. Although IAV-Gluc was less virulent than wild-type virus (PR8), it efficiently infected and replicated within murine lungs and was pathogenic in mice. After challenging guinea pigs with the equivalent doses of virus using two different methods, namely, intranasal (IN) inoculation and aerosol exposure (AR), it was found that the animals subjected to IN inoculation showed greater virus deposition in the lungs (12.27%) than those subjected to AR (1.34%), although the latter group exhibited more rapid viral replication within 48 h. Combining the results of live-animal imaging and traditional techniques used to measure viral titer, we identified additional differences between IN inoculation and AR. For example, IN inoculation caused the virus to distribute in a punctate pattern throughout the lungs, whereas virus delivered through AR showed an even distribution pattern, which increased the efficiency of viral replication. Indeed, the replication efficiency of the AR group was 11,073-fold higher than the original deposition amount after 48 h, whereas that of the IN group was only 15.4-fold higher than the original deposition amount after 24 h.

This work reports the one-pot synthesis of N-doped onion-like carbon coated Sn nanocapsules by the arc discharge method. Due to the cooperation of the Sn nanoparticles, onion-like carbon shell and the doping of N in carbon shell, the nanocapsules show good electrochemical performance as anode materials for lithium ion batteries, exhibiting excellent cycling stability of 902.8 mA h g−1 at 0.1 A g−1 after 1000 cycles and bearing superior rate capability with average reversible capacity of 428.6 mA h g−1 at 20 A g−1.

Time and energy saving synthesis method is crucial to the scale up applications of energy conversion and storage materials. In this report, we demonstrate a convenient and novel approach to fabricate the highly crystalline ZnMn2O4 nanoparticles as anode materials for Li rechargeable batteries. Pure phase ZnMn2O4 samples can be feasibly obtained under different calcination temperature from the precursor via combustion assisted coprecipitation method. Various techniques are used to characterize the structure and morphology of the products. Sample gained at 800 °C exhibits the best electrochemical property for lithium ion batteries. A reversible specific capacity of 716 mAh g−1 can be retained under a current density of 100 mA g−1 after 90 circles. Even the current density elevated up to 1000 mA g−1, the reversible capacity of the material still can be kept as high as 500 mAh g−1 after 1200 cycles. The outstanding performance compared to the other samples benefits from its good crystallinity and uniform dispersion with appropriate particle size.

Y-doped Li2Fe1⿿xYxSiO4/C (x = 0, 0.02, 0.04) composites are successfully synthesized via a sol-gel method. X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectrometry and UV-visible spectroscopy are used to investigate the effect of yttrium doping on the characteristics of Li2FeSiO4/C. The results show that yttrium (Y) does enter the crystal structure of Li2FeSiO4 and negligibly affect the morphology of the composites as well as the structural properties of the coated carbon. The electrochemical performance is evaluated by galvanostatic charge-discharge and electrochemical impedance spectra. Li2Fe0.98Y0.02SiO4/C exhibits the best rate capability and cycle stability among the three samples. The enhanced electrochemical performance is attributed to its enhanced electronic conductivity, higher lithium ion diffusion coefficient and better structure stability due to the proper amount of Y doping in Fe sites.

An aero-mechanical multidisciplinary optimization was carried out for a high-speed centrifugal impeller, SRV2-O, by integrating a Self-adaptive Multi-Objective Differential Evolution (SMODE) algorithm, RANS solver technique, Finite Element Method (FEM), and data mining technique of analysis of variance (ANOVA). Specifically, the optimization of the impeller was conducted for the maximization of isentropic efficiency and the minimization of maximum stress. During optimization, constraints were imposed on the total pressure ratio at the optimization point and the mass flow rate at the choked point as well. Where, the former constraint intends to guarantee the working capability of the impeller while the latter tries to fix the working range. After optimization, six optimal Pareto solutions are finally obtained. The isentropic efficiency of the optimal solutions is increased by 2.07% at most while the maximum stress is decreased by 6.36% at most among the Pareto solutions. The better performance of optimal designs was demonstrated through detailed aerodynamic and mechanical analysis. Then, the ANOVA is used to explore the effects of variables on performance function in design space, it is found that, the design variables located at the meridian channel and the leading edge of the full blade have significant effect on aerodynamic performance. These variables are crucial to reduce the loss caused by shock wave at impeller inlet and the leakage flow at blade tip. Meanwhile, the design variables located near the leading edge of full blade root section have great effect on strength performance, as they are effective to decrease the bend of blades and thus reduce the maximum stress. Thereby, the better aeromechanical performance can be achieved by dedicated adjustment on the curves of both the shroud of meridional channel and leading edge of full blade. The results of ANOVA are consistent with the aero-mechanical analysis. Therefore, the effectiveness of aero-mechanical optimization and data mining framework is demonstrated.

ZnFe2O4 nano particles as an anode material for lithium ion batteries are prepared by the glycine-nitrate combustion method. The mixture of styrene butadiene rubber and sodium carboxyl methyl cellulose (SBR/CMC) with the weight ratio of 1:1 is used as the binder for ZnFe2O4 electrode. Compared with the conventional polyvinylidene-fluoride (PVDF) binder, the SBR/CMC binder is much cheaper and environment benign. More significantly, this water soluble binder significantly improves the rate capability and cycle stability of ZnFe2O4. A discharge capacity of 873.8 mAh g−1 is obtained after 100 cycles at the 0.1C rate, with a very little capacity fading rate of 0.06% per cycle. Studies show that the SBR/CMC binder enhances the adhesion of the electrode film to the current collector, and constructs an effective three-dimensional network for electrons transport. In addition, the SBR/CMC binder helps to form a uniform SEI film thus prohibiting the formation of lithium dendrite. Electrochemical impedance spectroscopy shows that the SBR/CMC binder lowers the ohmic resistance of the electrode, depresses the formation of SEI film and facilitates the charge transfer reactions at the electrode/electrolyte interface. These advantages highlight the potential applications of SBR/CMC binder in lithium ion batteries.