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This work studies the asymptotic dynamics of classical solutions of a multi-strain diffusive epidemic model in spatially heterogeneous environments. Results on the nonexistence of coexistence endemic equilibria are established. Moreover, explicit conditions on the parameters range which guarantee the extinctions of some strains of the disease are examined. In particular, we establish that the competition-exclusion principle occurs when the population diffuses very fast and one strain uniquely maximizes the ratio of the spatial average of transmission rate over that of the recovery rate. However, several strains of the disease may coexist when either: (i) the population diffuses very slowly, (ii) or a subgroup diffuses very slowly and the other subgroup diffuses very fast. In these two scenarios, the asymptotic profiles of the coexistence endemic equilibria with respect to the diffusion rates of the population are presented. In particular, we observe a spatial segregation of the infected populations when they diffuse very slowly. [ABSTRACT FROM AUTHOR]

The shuttle effect of lithium‐sulfur (Li−S) batteries and the poor conductivity of sulfur (S) and lithium polysulfide severely limit their practical applications. Currently, compounding carbon materials with S is one of the effective ways to solve this problem. Therefore, green, low‐cost chestnut inner shell biochar (CISC) with graded porous structure was used as the S carrier in this experiment, and carbon nanotubes (CNTs) coating was employed as the S protective layer to improve the electrical conductivity and inhibit the shuttle effect. The results showed that the CISC prepared in this experiment had a relatively high specific surface area (1135.11 m2 g−1), and the S loading rate was as high as 65.72 %. The graded porous structure and high specific surface area of CISC can increase the loading rate of S and thus increase the battery capacity. Meanwhile, the naturally contained O and N elements can improve the chemisorption of S. The initial discharge capacity of the CISC@S/CNTs battery at 0.1 C is 967.3 mAh g−1, and the capacity retention rate is 74.3 % after 500 cycles. The unique composite structure improves the battery's electrical conductivity, reduces the dissolution of polysulfides, and enhances the battery cycle stability. [ABSTRACT FROM AUTHOR]

The transient responses of a rectangular thin plate with a pair of edges simply supported and a pair of edges clamped, which is mounted on a viscoelastic foundation modelled by the fractional-order standard linear solid model, under the rectangular pulse and ramp step loads are studied in this paper. In order to describe the complicated history-dependent mechanical behavior of the actual foundation more accurately, the fractional-order standard linear solid model is adopted and the corresponding complex elastic modulus is derived. The complex natural frequency and mode shape of the thin plate with a pair of edges simply supported and a pair of edges clamped are obtained by solving the fractional-order differential equation. Then, by using the mode superposition method, the displacement transient responses are obtained by three methods, namely, the analytical solution in term of Mittag–Leffler function, the semi-analytic solutions by numerical inverse transform and the complete numerical solution. The numerical examples are provided and the reliability are verified by the comparison of three methods. Based on numerical results, the effects of the fractional-order and the viscosity coefficients of the foundation on the transient response are discussed. It is found that influences of the fractional-order are different from that of viscosity coefficient and are of peculiar property. [ABSTRACT FROM AUTHOR]

Maintaining a healthy status is crucial for the successful captive breeding of endangered alpine musk deer (Moschus chrysogaster, AMD), and captive breeding programs are beneficial to the ex-situ conservation and wild population recovery of this species. Meanwhile, the gut microbiota is essential for host health, survival, and environmental adaptation. However, changes in feeding environment and food can affect the composition and function of gut microbiota in musk deer, ultimately impacting their health and adaptation. Therefore, regulating the health status of wild and captive AMD through a non-invasive method that targets gut microbiota is a promising approach. Here, 16S rRNA gene sequencing was employed to reveal the composition and functional variations between wild (N = 23) and captive (N = 25) AMD populations. The results indicated that the gut microbiota of wild AMD exhibited significantly higher alpha diversity (P < 0.001) and greater abundance of the phylum Firmicutes, as well as several dominant genera, including UCG-005, Christensenellaceae R7 group, Monoglobus, Ruminococcus, and Roseburia (P < 0.05), compared to captive AMD. These findings suggest that the wild AMD may possess more effective nutrient absorption and utilization, a more stable intestinal microecology, and better adaption to the complex natural environment. The captive individuals displayed higher metabolic functions with an increased abundance of the phylum Bacteroidetes and certain dominant genera, including Bacteroides, Rikenellaceae RC9 gut group, NK4A214 group, and Alistipes (P < 0.05), which contributed to the metabolic activities of various nutrients. Furthermore, captive AMD showed a higher level of 11 potential opportunistic pathogens and a greater enrichment of disease-related functions compared to wild AMD, indicating that wild musk deer have a lower risk of intestinal diseases and more stable intestinal structure in comparison to captive populations. These findings can serve as a valuable theoretical foundation for promoting the healthy breeding of musk deer and as a guide for evaluating the health of wild-released and reintroduced musk deer in the future. Key points: • Wild and captive AMD exhibit contrasting gut microbial diversity and certain functions. • With higher diversity, certain bacteria aid wild AMD's adaptation to complex habitats. • Higher potential pathogens and functions increase disease risk in captive AMD. [ABSTRACT FROM AUTHOR]

Using skid-mounted natural gas to hydrogen generator in hydrogen refueling station can significantly reduce the cost of hydrogen. In 2021, China successfully built the first 250 Nm3/h on-site skid-mounted natural gas to hydrogen generator, which was successfully debug-ed in Foshan, providing hydrogen products with purity ≥99.999% for FCVs. This paper summarized the technological process and development, analyzed the risk and the safety design of skid-mounted natural gas to hydrogen generator. Several key factors affecting compactness are analyzed, including process and technical route, reforming reformer and catalyst, heat exchange network, heat exchanger and steam generation system, PSA unit and overall integrated design, etc. In addition, innovative strategies to optimize the compactness of the device are given from the aspects of process flow, reforming reformer and steam generation system.The suggestions are put forward for the development and application of on-site skid-mounted natural gas to hydrogen generator. • The first 250 Nm3/h on-site skid-mounted natural gas to hydrogen generator in China. • The technological process and development of skid-mounted natural gas to hydrogen generator. • The risk analysis and safety design of skid-mounted natural gas to hydrogen generator. • Several key influencing factors and strategies to optimize the compactness. • Cost estimation and competitiveness of skid-mounted natural gas to hydrogen generator. [ABSTRACT FROM AUTHOR]

With the idea of analyzing awareness as potential for knowledge, we propose a novel semantics for awareness logic. Expressivities of languages with different combinations of modalities for this semantics are investigated. We explore the properties of our semantics and compare our model with Fagin & Halpern model and the model by Heifetz et al. in partitional settings. A series of equivalence results are established from the comparison. Finally, we provide two axiomatizations for implicit knowledge and explicit knowledge, respectively, and prove soundness and completeness for them. [ABSTRACT FROM AUTHOR]

The uncertainty of high penetration of renewable energy brings challenges to the safe and stable operation of a power system; the virtual synchronous compensation (VSCOM) can shift the demand and compensate real-time discrepancy between generation and demand, and can improve the active support ability for the power system. This paper proposes a novel capacity allocation strategy using VSCOM for renewable energy stations based on fuzzy constraints. Firstly, the basic framework of the VSCOM is constructed with energy storage and reactive power generator (SVG) unit. Secondly, the inertia and standby capacity requirements of high penetration of renewable energy system are modeled; on this basis, a capacity allocation model of each sub unit of the VSCOM is developed, and the investment economy and stable support needs are considered. Thirdly, the uncertainty set of wind power output is defined based on the historical data to find a decision that minimizes the worst-case expected where the worst case should be taken. Finally, the simulation results show that the proposed optimal sizing strategy can effectively take advantage of stability and economy, and the VSCOM can meet the inertia support demand of 98.6% of a high proportion of renewable energy systems. [ABSTRACT FROM AUTHOR]

Early‐stage photoaging is characterized by skin laxity and wrinkling, which are mainly attributable to the ultraviolet (UV) irradiation‐mediated imbalance between matrix metalloproteinase (MMP) production and collagen degradation. Injectable platelet‐rich fibrin (i‐PRF) is a novel blood concentrate with potential effects on photoaging. Over the past few decades, platelet‐rich plasma (PRP) has been widely researched and used in different clinical fields as a first‐generation platelet concentrate. The aim of this study was to compare the antiphotoaging effects of i‐PRF in UVA‐irradiated human dermal fibroblasts with those of PRP by examining cell proliferation, migration and apoptosis, ROS generation, MMP‐1 and collagen I levels. The activation of the TGF‐β/Smad signaling pathway by i‐PRF and PRP was also investigated using western blotting. The results showed that i‐PRF was more effective than PRP in promoting cell proliferation and migration. Moreover, i‐PRF reduced ROS generation and cell apoptosis more effectively than PRP. With respect to the mechanism of collagen I upregulation, stronger stimulation of the TGF‐β/Smad signaling pathway and greater suppression of MMP‐1 expression were achieved by i‐PRF than by PRP. Our results suggest that i‐PRF can be a promising substitute for PRP in alleviating UVA‐induced photoaging and should be explored further for its anti‐photoaging properties. [ABSTRACT FROM AUTHOR]

On-site hydrogen production through steam-methane reforming (SMR) from city gas or natural gas is believed to be a cost-effective way for hydrogen-based infrastructure due to high cost of hydrogen transportation. In recent years, there have been a lot of on-site hydrogen fueling stations under design or construction in China. This study introduces current developments and technology prospects of skid-mounted SMR hydrogen generator. Also, technical solutions and economic analysis are discussed based on China's first on-site hydrogen fueling station project in Foshan. The cost of hydrogen product from skid-mounted SMR hydrogen generator is about 23 CNY/kg with 3.24 CNY/Nm3 natural gas. If hydrogen price is 60 CNY/kg, IRR of on-site hydrogen fueling station project reaches to 10.8%. While natural gas price fall to 2.3 CNY/Nm3, the hydrogen cost can be reduced to 18 CNY/kg, and IRR can be raised to 13.1%. The conclusion is that skid-mounted SMR technology has matured and is developing towards more compact and intelligent design, and will be a promising way for hydrogen fueling infrastructures in near future. • Development status and future expectation of hydrogen refueling stations and fuel cell vehicles in China. • On-site hydrogen generator can significantly reduce the cost of hydrogen. • Technical composition and global development status of On-site hydrogen generator form natural gas. • China's first on-site natural gas to hydrogen refueling station in Foshan. [ABSTRACT FROM AUTHOR]

We considered an SIS functional partial differential model cooperated with spatial heterogeneity and lag effect of media impact. The wellposedness including existence and uniqueness of the solution was proved. We defined the basic reproduction number and investigated the threshold dynamics of the model, and discussed the asymptotic behavior and monotonicity of the basic reproduction number associated with the diffusion rate. The local and global Hopf bifurcation at the endemic steady state was investigated theoretically and numerically. There exists numerical cases showing that the larger the number of basic reproduction number, the smaller the final epidemic size. The meaningful conclusion generalizes the previous conclusion of ordinary differential equation. [ABSTRACT FROM AUTHOR]

Shotcrete has been widely applied in construction projects such as tunnels, mining tunnels, and slope protection due to its unique construction method. This study investigates the synergistic effect of basalt fiber and supplementary cementitious materials on the properties of basalt fiber sprayed cementitious composites (BFSCC). The toughening effect of basalt fiber was evaluated through basic mechanical property tests and three-point bending toughness tests, with P-CMOD curves obtained. The pumpability of BFSCC was assessed using an ICAR rheometer, and microscopic mechanisms were explored through SEM testing. Experimental results indicate that both fiber length and dosage increase the dynamic yield stress of BFSCC. Specifically, compared to the control group, the addition of 18 mm fibers at a volume fraction of 0.25% increases the dynamic yield stress by 241 Pa. Additionally, the incorporation of 20% fly ash reduces the dynamic yield stress of BFSCC by approximately 45%. The adverse effects of fibers on the workability and easiness of BFSCC can be mitigated by adding supplementary cementitious materials. Basalt fibers significantly contribute to the early compressive and flexural strength of BFSCC. At an age of 1 day, 12 mm fibers at 0.15% volume fraction increase compressive strength by 19%, while 18 mm fibers at 0.25% volume fraction show the highest enhancement in flexural performance, reaching approximately 39%. Research on fracture performance reveals that basalt fibers enhance the initial cracking load and fracture toughness of BFSCC, retarding crack propagation and imparting ductility to the fracture process. The fracture energy of BFSCC with 18 mm basalt fibers reaches 167.1 N/m, representing a 24% improvement compared to the control group. A predictive model for fiber dosage and length fracture parameters was established using response surface methodology, achieving a prediction accuracy of 0.94 with good correlation. SEM images show hydration products adhering to fiber surfaces, forming protruding particles that increase internal friction, thereby inhibiting and altering the development direction of microcracks. • Synergistic effects between fibers and fly ash enhance the workability of BFSCC. • Crack initiation load increases with higher fiber volume fraction and length. • Basalt fibers dissipate energy through pullout and rupture processes. • Basalt fibers alleviate stress at the crack tips, impeding crack propagation. [ABSTRACT FROM AUTHOR]

The international hydrogen supply chain has been commercialized and promoted hydrogen trade. With the global energy transition, the two are expected to play a more important role and make hydrogen become a major international energy trade category similar to natural gas and LNG. This paper considers importing two hydrogen sources to Huizhou of China through MCH-TOL hydrogen storage technology from Saudi Arabia, which are produced from Natural gas + CCS and from renewable energy sources. It is estimated that the costs of dehydrogenation and purification after landing are 27.6 CNY/kgH 2 and 32.7 CNY/kgH 2 respectively, which are difficult to be competitive. Therefore, the strategy and goal of cost reduction are proposed. It is expected to control the costs of dehydrogenation and purification to less than 25 CNY/kgH 2 , and explore the feasibility of developing large-scale and economically competitive hydrogen import business in China. • Composition, development status and prospect of international hydrogen supply chain and global hydrogen export. • Select suitable liquid organic hydrogen carrier for hydrogen trans -ocean transportation. • Introduce the hydrogenation and dehydrogenation processes of Methylcyclohexane - Toluene hydrogen storage technology. • Cost estimation and competitiveness analysis of importing hydrogen from Saudi Arabia to Huizhou, Guangdong, China. • Provide strategic suggestions for China to reduce the cost of importing hydrogen from overseas. [ABSTRACT FROM AUTHOR]

Summary: Network has become an indispensable part of public life. To improve network utilization, network performance, network quality, and enhance network security, precise prediction of network traffic is an indispensable method and basis for solving the above problems. In order to accurately predict the network traffic, a novel combination prediction model for network traffic is proposed. In this model, local mean decomposition (LMD), bidirectional long short‐term memory (BiLSTM), and Bayesian optimization algorithm are combined. First, the LMD method decomposes the network traffic time series to obtain several product function (PF) components and a residual by LMD. Then, each PF component and residual is predicted with BiLSTM model. Meanwhile, the Bayesian optimization algorithm is introduced to optimize the hyperparameters of BiLSTM. Finally, the predicted value of each PF component and residual is linearly superimposed to obtain the final predicted value. Through the study of two groups of actual network traffic datasets and compared with a variety of state‐of‐the‐art prediction models, the proposed model has a preferable prediction results by comparison of the results. [ABSTRACT FROM AUTHOR]

In underwater acoustic target parameter estimation, the cross-spectrum method estimates the velocity of the target by the interference structure of the cross-correlated fields in two ranges. However, with the increase in interference in the marine environment, the performance of conventional cross-spectrum target velocity estimation methods gradually declines or even fails. To solve this problem, a cross-spectrum histogram method that combines the multi-line spectrum characteristics of the target is proposed in this paper. First, each frequency point of all line spectra is compensated by the cross-spectrum compensation method. Then the target velocity estimation value is obtained by performing probability distribution statistics on the velocity estimation results for all frequency points. Under different signal-to-noise ratios, simulations and experiments are carried out to verify the effectiveness of the proposed method. The results show that the proposed method is still effective in estimating the target velocity when the conventional method fails. [ABSTRACT FROM AUTHOR]

Higher alcohols synthesis (HAS) from syngas (CO/H 2) has attracted widespread attention, while the low selectivity and poor stability of the catalysts mainly stumbled its industrial application. In the work, Ni–Co alloy nanoparticles (NPs) derived from Co 1-x Ni x Al 2 O 4 loaded on the SiO 2 with large specific surface area were prepared; and during reaction, the highly dispersed Ni–Co alloys were self-optimized to Ni–Co alloy@Co–Co 2 C. Importantly, Ni–Co alloy@Co–Co 2 C can be regenerated through oxidation - reduction - self-optimization process. Characteristic results indicated that the structural liberalization during the reaction process inhibited the loss of Ni, regulated and balanced the dual active sites of the catalyst and the Ni–Co alloys were regenerated after the re-oxidation and re-reduction process. The optimized catalyst exhibited excellent catalytic performance, including a high total selectivity to alcohols of 39.3% and an excellent catalytic stability at 250 °C, 3.5 MPa (H 2 /CO = 2) and a space velocity of 6000 mL (g cat h)−1. In addition, the Ni–Co alloy@Co–Co 2 C catalyst after stability test could recover its original catalytic performance after re-oxidation and re-reduction. The renewable characteristics and superior catalytic performance of Ni–Co alloy@Co–Co 2 C made the catalyst to be one of the potential industrial catalysts for HAS. [Display omitted] • The interaction between Ni–Co inhibited the sintering of the active components. • The formation of Co–Co 2 C on the surface suppressed the loss of active components. • Ni–Co alloys were regenerated after the re-oxidation and re-reduction process. • Renewable catalyst could recover its original catalytic performance. [ABSTRACT FROM AUTHOR]

Gut microbiota forms a unique microecosystem and performs various irreplaceable metabolic functions for ruminants. The gut microbiota is important for host health and provides new insight into endangered species conservation. Forest musk deer (FMD) and alpine musk deer (AMD) are typical small ruminants, globally endangered due to excessive hunting and habitat loss. Although nearly 60 years of captive musk deer breeding has reduced the hunting pressure in the wild, fatal gastrointestinal diseases restrict the growth of captive populations. In this study, 16S rRNA high-throughput sequencing revealed the differences in gut microbiota between FMD and AMD based on 166 fecal samples. The alpha diversity was higher in FMD than in AMD, probably helping FMD adapt to different and wider habitats. The ß-diversity was higher between adult FMD and AMD than juveniles and in winter than late spring. The phylum Firmicutes and the genera Christensenellaceae R7 group, Ruminococcus, Prevotellaceae UCG-004, and Monoglobus were significantly higher in abundance in FMD than in AMD. However, the phylum Bacteroidetes and genera Bacteroides, UCG-005, Rikenellaceae RC9 gut group, and Alistipes were significantly higher in AMD than FMD. The expression of metabolic functions was higher in AMD than in FMD, a beneficial pattern for AMD to maintain higher energy and substance metabolism. Captive AMD may be at higher risk of intestinal diseases than FMD, with higher relative abundances of most opportunistic pathogens and the expression of disease-related functions. These results provide valuable data for breeding healthy captive musk deer and assessing their adaptability in the wild. Key points: • Alpha diversity of gut microbiota was higher in FMD than that in AMD • Expression of metabolic and disease-related functions was higher in AMD than in FMD [ABSTRACT FROM AUTHOR]

[Display omitted] • The chemical state of Co0 in the active pairs could be adjusted by changing the doping amount of Ni. • The nanoparticles of Co-Ni bimetals converted to a core shell structure of Ni@Co. • Coδ+ in the active pairs of Coδ+/Co0 were obtained via the interaction between Co and perovskite. • The active pair Coδ+ and Co0 synergistically boosted the formation of higher alcohols. Higher alcohols synthesis (HAS) from syngas (CO + H 2) is much attractive, but achieving a high selectivity of alcohols is still challenging due to the difficult balance between dissociative adsorption and associative adsorption of CO. In this work, a series of Coδ+/Co0 tailored by nickel and CaTiO 3 catalysts derived from a series of perovskite pre-catalyst Ca 0.6 La 0.4 Ti 0.6 Co 0.4-x Ni x O 3 were prepared and applied to HAS. Highly dispersed Co-Ni bimetals on CaTiO 3 were formed after reduction owing to the uniform distribution of nickel and cobalt ions in the perovskite phase. Through the reduction process, the bimetallic nanoparticles of Co-Ni with Co enriched in surface and Ni in core are produced. In addition, Coδ+ in the active pairs of Coδ+/Co0 were obtained via the interaction between Co and perovskite; and the chemical state of Co0 in the active pairs was tuned by the interaction between nickel and cobalt. The resulted catalyst showed excellent selectivity to higher alcohols with the total alcohols as high as 45.34 %. The higher alcohols reached 70.29 wt% at 270 °C, 3.0 MPa and a GHSV of 3900 mL g−1h−1 with H 2 /CO = 2/1. [ABSTRACT FROM AUTHOR]

Nowadays, core-shell structures have attracted considerable attention as microwave absorbers (MAs) due to the synergistic effect between dielectric and magnetic loss. Herein, core-shell Fe 3 Al@polypyrrole (Fe 3 Al@PPy) composites were successfully fabricated by the thermit reaction and chemical oxidation polymerization method with the assistance of ammonium persulfate and p-toluene sulfonic acid. Due to the regulation of the impedance matching by the electromagnetic coupling and core-shell structure, the Fe 3 Al@PPy composites showed enhanced electromagnetic wave (EMW) absorption performance compared with the pure Fe 3 Al. Furthermore, the thickness of the PPy shell increased from 0.23 µm to 1.50 µm as the addition of pyrrole (Py) increased from 0.25 mL to 1.0 mL. Meanwhile, the core-shell Fe 3 Al@PPy composites exhibited the optimal wave absorption performance when the PPy shell thickness was 0.80 µm, and the reflection loss (RL) could reach − 40.53 dB with the thickness of 2.0 mm at 13.3 GHz. This work provides a new idea for the design of large-scale electromagnetic (EM) coupled MAs with core-shell structures. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Revolutionizing National Park zoning in China with keystone species. • Habitat suitability of 16 wildlife in Kunlun area exhibits heterogeneity with MaxEnt. • KMNP's boundary and functional zoning were optimized, outperforming the selected area. National parks in China play a vital role in preserving biodiversity, protecting endangered species, maintaining ecological balance, and promoting sustainable development amid global biodiversity decline. Boundary delimitation and functional zoning within these parks are crucial for preserving ecosystem integrity and species diversity. In the case study of Kunlun Mountains National Park (KMNP, Qinghai section), an extensive wildlife background survey yielded 4,523 occurrence records (3,921 after optimization) for 16 nationally protected wildlife species. Using the ecological niche model, this study aimed to explore the boundary range, functional zoning, and protection gap areas within KMNP by simulating the suitable spatial distribution of wildlife species, taking into account their protection and endangered statuses. The findings indicated that the primary habitat for key protected species in KMNP mainly occupied meadow and steppe in terms of vegetation types, along with grassland and unused land in terms of land use types, with average annual precipitation from 200 mm to 400 mm, elevations ranging from 4,100 m to 4,700 m, and average annual temperatures from −4.5℃ to −2℃. The suitable distribution of different wildlife species in the Kunlun Mountains area showed variations, mainly concentrated in the southwestern, central, and southeastern regions. The optimized KMNP covered around 49,800 km2, a 16.3 % reduction from the selected area, with the core protection zone at 16,300 km2 and the general control zone at 33,200 km2. The suitability of 93.75 % (15/16) species within the core protection area of KMNP was higher comparing to the optimized area, selected area, and Mangya-Golmud-Dulan area, indicating that the boundary delimitation and functional zoning of KMNP were highly rational. The boundary range and functional zoning method developed in this study provide a crucial scientific foundation for KMNP's conservation and management, and valuable guidance for national park construction, ecosystem preservation, biodiversity conservation, and the promotion of key species' reproduction and survival on the Qinghai-Tibet Plateau, with promising future applications. [ABSTRACT FROM AUTHOR]

Plant diseases caused by plant viruses and pathogens seriously affect crop yield and quality, and it is very difficult to control them. The discovery of new leads based on natural products is an important way to innovate pesticides. Based on the resveratrol is a kind of natural phytoalexin, but it cannot be used as candidate for the development of new drug due to its poor druggability. The phenolic hydroxyl groups in the resveratrol structure are easily destroyed by oxidation, in order to improve its stability, ester formation is the most commonly used modification method in drug design. Their structures were characterized by 1H NMR, 13C NMR and HRMS. The activity against tobacco mosaic virus (TMV) of these ester derivatives has been tested for the first time. The bioassay results showed part of the target compounds exhibited good to excellent in vivo activities against TMV. The optimum compounds III-2 (inhibitory rates of 50, 53, and 59% at 500 μg/mL for inactivation, curative, and protection activities in vivo, respectively), III-4 (inhibitory rates of 57, 59, and 51% at 500 μg/mL, respectively), and II-5 (inhibitory rates of 54, 52, and 51% at 500 μg/mL, respectively) displayed higher activity than commercial plant virucide ribavirin (inhibitory rates of 38, 37, and 40% at 500 μg/mL, respectively). Compounds I-9 and I-10 also showed excellent activities. The systematic study provides strong evidence that these simple resveratrol derivatives could become potential TMV inhibitors. The novel concise structure provides another new template for antiviral studies. [ABSTRACT FROM AUTHOR]

Ultrasound attenuation coefficient estimation (ACE) has great diagnostic potential for fatty liver detection and assessment. In a previous study, we proposed a reference phantom-free ACE method, called reference frequency method (RFM), which does not require a calibrated phantom for normalization. The power of each frequency component can be normalized by the power of an adjacent frequency component in the spectrum to cancel system-dependent effects such as focusing and time gain compensation (TGC). RFM demonstrated accurate ACE in both phantom and in in-vivo liver studies. However, our study also showed that the robustness and penetration of RFM were affected by noise in the ACE signals. Here we propose a noise suppression (NS) and a signal-to-noise ratio (SNR) quality control method to reduce the influence of noise on ACE-RFM performance. The proposed methods were tested in harmonic ACE because harmonic imaging is a more frequently used mode than fundamental imaging for abdominal applications. After applying the NS and SNR control methods, the noise-induced bias for attenuation estimation in harmonic ACE was effectively reduced, leading to significantly improved effective penetration depth. The proposed methods directly measure the noise spectrum of the ultrasound system, which can also be adapted to other spectrum-based ACE methods, such as the reference phantom method and the spectra shift method. [ABSTRACT FROM AUTHOR]

Objective: To quantitatively evaluate the effectiveness of Fangcang shelter hospitals, designated hospitals, and the time interval from illness onset to diagnosis toward the prevention and control of the COVID-19 epidemic.Methods: We used SEIAR and SEIA-CQFH warehouse models to simulate the two-period epidemic in Wuhan and calculate the time dependent basic reproduction numbers (BRNs) of symptomatic infected individuals, asymptomatic infected individuals, exposed individuals, and community-isolated infected individuals. Scenarios that varied in terms of the maximum numbers of open beds in Fangcang shelter hospitals and designated hospitals, and the time intervals from illness onset to hospitals visit and diagnosis were considered to quantitatively assess the optimal measures.Results: The BRN decreased from 4.50 on Jan 22, 2020 to 0.18 on March 18, 2020. Without Fangcang shelter hospitals, the cumulative numbers of cases and deaths would increase by 18.58 and 51.73%, respectively. If the number of beds in the designated hospitals decreased by 1/2 and 1/4, the number of cumulative cases would increase by 178.04 and 92.1%, respectively. If the time interval from illness onset to hospital visit was 4 days, the number of cumulative cases and deaths would increase by 2.79 and 6.19%, respectively. If Fangcang shelter hospitals were not established, the number of beds in designated hospitals reduced 1/4, and the time interval from visiting hospitals to diagnosis became 4 days, the cumulative number of cases would increase by 268.97%.Conclusion: The declining BRNs indicate the high effectiveness of the joint measures. The joint measures led by Fangcang shelter hospitals are crucial and need to be rolled out globally, especially when medical resources are limited. [ABSTRACT FROM AUTHOR]

Mutation of the K-Ras gene has been widely found in non-small cell lung cancer. Compared with other mutations of lung cancer, the drugs cannot effectively target mutant K-Ras. However, the mitosis of cancer cells is vulnerable to external interference. Our previous study showed that electromagnetic fields (MFs) could suppress cell proliferation. In this article, a cell proliferation model based on the A549 cell line was established while considering the effects of MFs. In addition, the parameters of the A549 cell proliferation model were regressed by the finite difference method and verified by numerical simulation. Based on the calculations, the density of the A549 cells reflects the trend of measured data from optical microscopy. This approach not only helps reveal the mechanism of MFs on cancer cells but also suggests a new way to predict the effects of magnetic stimulation on cancer inhibition. [ABSTRACT FROM AUTHOR]

Ultrasound vascular imaging based on ultrafast plane wave imaging and singular value decomposition (SVD) clutter filtering has demonstrated superior sensitivity in blood flow detection. However, ultrafast ultrasound vascular imaging is susceptible to electronic noise due to the weak penetration of unfocused waves, leading to a lower signal-to-noise ratio (SNR) at larger depths. In addition, incoherent clutter artifacts originating from strong and moving tissue scatterers that cannot be completely removed create a strong mask on top of the blood signal that obscures the vessels. Herein, a method that can simultaneously suppress the background noise and incoherent artifacts is proposed. The method divides the tilted plane or diverging waves into two subgroups. Coherent spatial compounding is performed within each subgroup, resulting in two compounded data sets. An SVD-based clutter filter is applied to each data set, followed by a correlation between the two data sets to produce a vascular image. Uncorrelated noise and incoherent artifacts can be effectively suppressed with the correlation process, while the coherent blood signal can be preserved. The method was evaluated in wire-target simulations and phantom, in which around 7–10-dB SNR improvement was shown. Consistent results were found in a flow channel phantom with improved SNR by the proposed method (39.9 ± 0.2 dB) against conventional power Doppler (29.1 ± 0.6 dB). Last, we demonstrated the effectiveness of the method combined with block-wise SVD clutter filtering in a human liver, breast tumor, and inflammatory bowel disease data sets. The improved blood flow visualization may facilitate more reliable small vessel imaging for a wide range of clinical applications, such as cancer and inflammatory diseases. [ABSTRACT FROM AUTHOR]

The nematode worm Caenorhabditis elegans is a model organism widely used in biological research on genetics, development, neuroscience, and aging. Microinjection is an effective and widely adopted method to create transgenetic worms, perform ribonucleic acid (RNA) interference of certain genes, and introduce different types of molecules into specific locations inside a worm body. Based on microfluidics and robotic micromanipulation techniques, we develop a robotic system for automated microinjection of C. elegans with greatly improved injection speed and success rate over traditional manual microinjection. A double-layer microfluidic device with computer-controlled pneumatic valves is developed for automated on-chip loading, immobilization, injection, and downstream sorting of single worms. A new autofocusing-based contact detection algorithm is proposed to find the optimal injection position along the depth direction of the microscope field of view. The direction and location of the needle tip are reliably identified using an image processing algorithm. Through experiments on 240 worms, the system demonstrates automated injection at a speed of 6 worms/min (9.97 s/worm) with a presorting operation success rate of 78.8% (postsorting operation success rate: 100%), which are more than 23 times faster and 1.6 times higher than the speed (0.25 worm/min) and success rate (30%) of a proficient human operator, respectively. With the superior performance, this system will enable new large-scale gene- and molecule-screening studies on C. elegans that cannot be fulfilled by the conventional microinjection technique. Note to Practitioners—In the worm biology community, there are thousands of research laboratories worldwide that routinely cope with worm microinjection experiments. This article aims to present the functionality and performance of our automated robotic system for high-speed worm injection. Using the robotic system, a large number of C. elegans can be loaded into the microfluidic device for continuous worm immobilization and injection. A user-friendly graphical user interface (GUI) is developed to allow an operator to monitor the injection process on a computer screen, select the injection location inside the worm body (through computer mouse clicking), and direct the system (through keyboard input) for downstream sorting of the successfully injected worms for further culture. Given its unique features, such as high injection speed, high level of automation, and high success/survival rates, this system holds great potential to liberate worm researchers from the tedious manual injection process and provide unparalleled injection throughput and consistency. [ABSTRACT FROM AUTHOR]

Wild-caught animals must cope with drastic lifestyle and dietary changes after being induced to captivity. How the gut microbiome structure of these animals will change in response receives increasing attention. The plateau zokor (Eospalax baileyi), a typic subterranean rodent endemic to the Qinghai-Tibet plateau, spends almost the whole life underground and is well adapted to the environmental pressures of both plateau and underground. However, how the gut microbiome of the plateau zokor will change in response to captivity has not been reported to date. This study compared the microbial community structure and functions of 22 plateau zokors before (the WS group) and after being kept in captivity for 15 days (the LS group, fed on carrots) using the 16S rRNA gene via high-throughput sequencing technology. The results showed that the LS group retained 973 of the 977 operational taxonomic units (OTUs) in the WS group, and no new OTUs were found in the LS group. The dominant bacterial phyla were Bacteroides and Firmicutes in both groups. In alpha diversity analysis, the Shannon, Sobs, and ACE indexes of the LS group were significantly lower than those of the WS group. A remarkable difference (P < 0.01) between groups was also detected in beta diversity analysis. The UPGMA clustering, NMDS, PCoA, and Anosim results all showed that the intergroup difference was significantly greater than the intragroup difference. And compared with the WS group, the intragroup difference of the gut microbiota in the LS group was much larger, which failed to support the assumption that similar diets should drive convergence of gut microbial communities. PICRUSt revealed that although some functional categories displayed significant differences between groups, the relative abundances of these categories were very close in both groups. Based on all the results, we conclude that as plateau zokors enter captivity for a short time, although the relative abundances of different gut microbiota categories shifted significantly, they can maintain almost all the OTUs and the functions of the gut microbiota in the wild. So, the use of wild-caught plateau zokors in gut microbial studies is acceptable if the time in captivity is short. [ABSTRACT FROM AUTHOR]

• High-Surface-Area Biocarbon: KOH activation yields porous LPSC. • N/O co-doping enhances the adsorption of LiPS. • The unique structure of LPSC@S/CNTs electrodes enhances battery cycling stability. Practical applications of lithium-sulfur batteries (LSBs) are limited due to the shuttle effect and the low conductivity of sulfur (S) and lithium polysulfide (LiPS). Currently, porous carbon materials doped with heteroatoms show extraordinary potential in this regard. Therefore, using KOH activation, we successfully prepared porous London Plane seed stems biochar (LPSC) with nitrogen and oxygen co-doping as the S carrier. We used carbon nanotubes (CNTs) as electrode coatings to improve the conductivity and suppress the shuttle effect. The results showed that the LPSC@S/CNTs composite electrode had an initial discharge capacity of 1090.4 mAh g−1 at 0.05 C. Furthermore, the capacity remained at 86.0 % after 300 cycles. This study provides a promising and sustainable approach to high-performance energy storage solutions. [ABSTRACT FROM AUTHOR]

One‐pot transformation of monomer mixtures into block copolymers remains a key challenge. Herein, a metal‐free route to prepare block copolymers from monomer mixtures by a hydroxyl functionalized ionic liquid of 3‐(2‐hydroxyl‐ethyl)‐1‐methylimidazolium bromide (HEMIMB) is described. HEMIMB can bridge two catalytic cycles including ring‐opening alternating copolymerization (ROAC) of phthalic anhydride (PA) with epoxides and ring‐opening polymerization (ROP) of L‐lactide (LA), and enable a selective copolymerization from PA, LA, and epoxides. The selective copolymerization depends on the presence of PA in mixed feedstocks, exhibits the first ROAC of PA with epoxides and then ROP of LA to the formation of block polyesters in one‐pot strategy. This work is beneficial to the development of metal‐free catalysts for sequence‐controlled polymerization that enable block architectures from mixtures of monomers. [ABSTRACT FROM AUTHOR]

Shanghai is one of the fastest growing regions of hydrogen energy in China. This paper researched feasible hydrogen sources in both internal and external Shanghai. This study comes up 9 hydrogen production methods and 6 transportation routes, ultimately forms 12 hydrogen supply solutions according to local conditions. The total cost in each solution is estimated including processes of hydrogen production, treatments, storage and transportation based on different transport distance. The results indicate that hydrogen supply cost is above 50 CNY/kgH 2 for external hydrogen sources after long-distance transportation to Shanghai, such as hydrogen production from coal in Inner Mongolia and from renewables in Hebei. The total cost of on-site hydrogen production from natural gas can be controlled under 40 CNY/kgH 2. When the price of wind power reduces to 0.5 CNY/kWh, hydrogen production from offshore wind power cooperating with hydrogen pipeline network has the greatest development potential for Shanghai hydrogen supply. • Coming up 12 hydrogen supply solutions according to local conditions in Shanghai. • Technical and economically analysis for each hydrogen supply solution. • Industrial off-gas and natural gas are suitable for short-term hydrogen sources. • Offshore wind power has the greatest potential as future hydrogen source. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) ultrasound shear wave elastography (SWE) has been widely used for soft tissue properties assessment. Given that shear waves propagate in three dimensions (3D), extending SWE from 2D to 3D is important for comprehensive and accurate stiffness measurement. However, implementation of 3D SWE on a conventional ultrasound scanner is challenging due to the low volume rate (tens of Hertz) associated with limited parallel receive capability of the scanner's hardware beamformer. Therefore, we developed an external mechanical vibration-based 3D SWE technique allowing robust 3D shear wave tracking and speed reconstruction for conventional scanners. The aliased shear wave signal detected with a sub-Nyquist sampling frequency was corrected by leveraging the cyclic nature of the sinusoidal shear wave generated by the external vibrator. Shear wave signals from different sub-volumes were aligned in temporal direction to correct time delays from sequential pulse-echo events, followed by 3D speed reconstruction using a 3D local frequency estimation algorithm. The technique was validated on liver fibrosis phantoms with different stiffness, showing good correlation (r = 0.99, p < 0.001) with values measured from a state-of-the-art SWE system (GE LOGIQ E9). The phantoms with different stiffnesses can be well-differentiated regardless of the external vibrator position, indicating the feasibility of the 3D SWE with regard to different shear wave propagation scenarios. Finally, shear wave speed calculated by the 3D method correlated well with magnetic resonance elastography performed on human liver (r = 0.93, p = 0.02), demonstrating the in vivo feasibility. The proposed technique relies on low volume rate imaging and can be implemented on the widely available clinical ultrasound scanners, facilitating its clinical translation to improve liver fibrosis evaluation. [ABSTRACT FROM AUTHOR]

Contrast microbubble (MB)-based super-resolution ultrasound microvessel imaging (SR-UMI) overcomes the compromise in conventional ultrasound imaging between spatial resolution and penetration depth and has been successfully applied to a wide range of clinical applications. However, clinical translation of SR-UMI remains challenging due to the limited number of MBs detected within a given accumulation time. Here, we propose a Kalman filter-based method for robust MB tracking and improved blood flow speed measurement with reduced numbers of MBs. An acceleration constraint and a direction constraint for MB movement were developed to control the quality of the estimated MB trajectory. An adaptive interpolation approach was developed to inpaint the missing microvessel signal based on the estimated local blood flow speed, facilitating more robust depiction of microvasculature with a limited amount of MBs. The proposed method was validated on an ex ovo chorioallantoic membrane and an in vivo rabbit kidney. Results demonstrated improved imaging performance on both microvessel density maps and blood flow speed maps. With the proposed method, the percentage of microvessel filling in a selected blood vessel at a given accumulation period was increased from 28.17% to 74.45%. A similar SR-UMI performance was achieved with MB numbers reduced by 85.96%, compared to that with the original MB number. The results indicate that the proposed method substantially improves the robustness of SR-UMI under a clinically relevant imaging scenario where SR-UMI is challenged by a limited MB accumulation time, reduced number of MBs, lowered imaging frame rate, and degraded signal-to-noise ratio. [ABSTRACT FROM AUTHOR]

The construction of a graft copolymer is an effective method to modify the properties of CO2-based aliphatic polycarbonate (CO2-APC) for meeting specific needs. Herein, we describe a facile route for the synthesis of CO2-based APC-graft-polystyrene copolymers using a "grafting from" strategy. Firstly, the copolymerization of CO2 and epichlorohydrin (ECH) was performed for the synthesis of the APC of poly(CO2/ECH). Then, a functionalized-APC can be prepared by the substitution reaction of poly(CO2/ECH) and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) that can serve as a precursor for the graft compolymer of P(CO2/ECH)-g-polystyrene via nitroxide-mediated radical polymerization (NMRP). The intermediates at each step and final graft copolymers were characterized using 1H NMR, GPC, DSC and TG analyses. [ABSTRACT FROM AUTHOR]

Owing to the well-defined porous structure and unique charge characteristics, ionic covalent organic polymers (ICOPs) are promising for gas capture, storage, drug delivery, adsorption and separation. Herein, we report a new ICOP that was synthesized via a simple Suzuki coupling reaction by introducing a monomer of 1-(3,5-dibromo-phenyl)-4-methyl-1H-[1,2,4]triazole-4-iodo iodide ionic liquid into a polymer framework. The as-prepared ICOP exhibited high adsorption capacity to methyl blue (MB) in aqueous solution because of the ion exchange of the ICOP with anionic dyes in aqueous solution. The adsorption equilibrium of the ICOP to MB with a concentration of 400 mg L−1 can be achieved within 20 min, which is much faster than that of non-ionic COPs. Moreover, the ICOP exhibits high stability with a removal rate of above 85% for MB after 10 consecutive cycles. It is also demonstrated that the ICOP is efficient for the selective adsorption of mixed dyes of MB with rhodamine B (RB) or methyl orange (MO) in aqueous solution. This work bodes well for the rational design of ICOPs to real-life applications in sewage treatment. [ABSTRACT FROM AUTHOR]

Tumor angiogenesis plays an important role during breast tumor growth. However, conventional Doppler has limited sensitivity to detect small blood vessels, resulting in a large overlap of Doppler features between benign and malignant tumors. An ultrasensitive ultrasound microvessel imaging (UMI) technique was recently developed. To evaluate the performance of UMI, we studied 44 patients with 51 breast masses. Tumor pathology served as the gold standard: 28 malignancies and 23 benignities. UMI provided a significant improvement in depicting smaller vessels compared with conventional Doppler. The microvessel morphologies observed on UMI were associated with tumor benign/malignant classification. The diagnostic accuracy of correct Breast Imaging Reporting and Data System (BI-RADS) classification rate (BI-RADS ≥4a: test positive; BI-RADS ≤3: test negative) as a fraction of total mass population was improved by 16% after combining conventional ultrasound with UMI compared with using conventional ultrasound alone. This improvement indicates the potential of UMI in reducing unnecessary benign biopsies and avoiding missed malignant biopsies. [ABSTRACT FROM AUTHOR]

We propose a susceptible-exposed-infected-recovered-susceptible (SEIRS) reaction-diffusion model, where the disease transmission and recovery rates can be spatially heterogeneous. The basic reproduction number (R 0) is connected with the principal eigenvalue of a linear cooperative elliptic system. Threshold-type results on the global dynamics in terms of R 0 are established. The monotonicity of R 0 with respect to the diffusion rates of the exposed and infected individuals, which does not hold in general, is established in several cases. Finally, the asymptotic profile of the endemic equilibrium is investigated when the diffusion rate of the susceptible individuals is small. Our results reveal the importance of the movement of the exposed and recovered individuals in disease dynamics, as opposed to most of previous works which solely focused on the movement of the susceptible and infected individuals. [ABSTRACT FROM AUTHOR]

Ship detection using optical satellite imagery is of great significance in many applications such as traffic surveillance, pollution monitoring, etc. So far, a lot of ship detection methods have been developed for images covering open sea, offshore area and harbors. Compared to the ship detection in sea and offshore area, it is more difficult to detect ships in inland river due to several challenges. First of all, many ships in inland river are clustered together and hard to be separated from each other. Secondly, ships lying alongside the pier are very likely to be recognized as part of the pier. Thirdly, ships in inland river is usually smaller than those in the sea. A hierarchical method is proposed to detect the ships in inland river in this paper. The Regions of Interest (ROIs) are firstly extracted based on water–land segmentation using multi-spectral information. Then two kinds of ship candidates are extracted based on the panchromatic band. The isolated ships are detected by analyzing the shape of connected components and the clustered ships are detected by using mixtures multi-scale Deformable Part Models (DPM) and Histogram of Oriented Gradient (HOG). At last, a Back Propagation Neural Network (BPNN) is trained to classify the ship candidates using the multi-spectral bands. The experiments using Quickbird satellite images show that our approach is effective in ship detection and performs particularly well in separating the ships clustered together and staying alongside the pier. • The Regions of Interest (ROIs) are firstly extracted based on water–land segmentation using multi-spectral information. • Two kinds of ship candidates are extracted based on the panchromatic band. • Backpropagation Neural Network (BPNN) is trained and used to classify the ship candidates using the multi-spectral bands. [ABSTRACT FROM AUTHOR]

Ultrasound microvessel imaging (UMI) based on the combination of singular value decomposition (SVD) clutter filtering and ultrafast plane wave imaging has recently demonstrated significantly improved Doppler sensitivity, especially to small vessels that are invisible to conventional Doppler imaging. Practical implementation of UMI is hindered by the high computational cost associated with SVD and low blood signal-to-noise ratio (SNR) in deep regions of the tissue due to the lack of transmit focusing of plane waves. Concerning the high computational cost, an accelerated SVD clutter filtering method based on randomized SVD (rSVD) and randomized spatial downsampling (rSD) was recently proposed by our group, which showed the feasibility of real-time implementation of UMI. Concerning the low blood flow SNR in deep imaging regions, here we propose a noise suppression method based on noise debiasing that can be easily applied to the accelerated SVD method to bridge the gap between real-time implementation and high imaging quality. The proposed method experimentally measures the noise-induced bias by collecting the noise signal using the identical imaging sequence as regular UMI, but with the ultrasound transmission turned off. The estimated bias can then be subtracted from the original power Doppler (PD) image to obtain effective noise suppression. The feasibility of the proposed method was validated under different ultrasound imaging parameters [including transmitting voltages and time-gain compensation (TGC) settings] with a phantom experiment. The noise-debiased images showed an increase of up to 15.3 and 13.4 dB in SNR as compared to original PD images on the blood flow phantom and an in vivo human kidney data set, respectively. The proposed noise suppression method has negligible computational cost and can be conveniently combined with the previously proposed accelerated SVD clutter filtering technique to achieve high quality, real-time UMI imaging. [ABSTRACT FROM AUTHOR]

The quest to eradicate poverty, central to the United Nations Sustainable Development Goals (SDGs), poses a significant global challenge. Advancement in sustainable rural development is critical to this effort, requiring the seamless integration of environmental, economic, and governmental elements. Previous research often omits the complex interactions among these factors. Addressing this gap, this study evaluates sustainable rural development in China by examining the interconnection between agricultural production and government-led poverty reduction, with annual rainfall considered an influential factor of climate change impacts on these sectors and overall sustainability. Utilizing a Meta-frontier entropy network dynamic Directional Distance Function (DDF) within an exogenous Data Envelopment Analysis (DEA) model, we categorize China's 27 provinces into southern and northern regions according to the Qinling-Huaihe line for a comparative study of environmental, economic, and governmental efficiency. This innovative approach overcomes the limitations of previous static analyses. The findings reveal: (1) Rainfall, as an exogenous variable, significantly affects agricultural production efficiency. (2) The overall efficiency in both southern and northern regions increases when accounting for rainfall. (3) Government effectiveness in poverty reduction is comparatively lower in the northern region than in the southern region when rainfall is considered. These insights underscore the importance of including climatic variables in sustainable development policies and emphasize the need for region-specific strategies to bolster resilience against climatic challenges. [ABSTRACT FROM AUTHOR]

The lithium‐sulfur (Li−S) batteries have a high theoretical specific capacity of 1675 mAh ⋅ g−1 and have become the most promising high‐energy storage system for the next generation batteries technology. However, their applications are hindered by insulated feature and volume expansion of sulfur, as well as the "shuttle effect" of polysulfides. MXenes own metallic conductivity and strong ability of polysulfides adsorption. Besides, their unique two‐dimensional (2D) structure, large specific surface area, abundant functional groups, and adjustability are beneficial to overcome the drawbacks of the sulfur cathode. In this review, different mainstream preparation methods and excellent properties of MXenes are summarized. Significant achievements and recent progress of MXene‐based cathodes and interlayers applied to Li−S cathodes are concluded later. Finally, the challenges, possible solutions and potential applications of MXenes for Li−S batteries are also presented. [ABSTRACT FROM AUTHOR]

• The research explored the trend of rheological properties of BFSCC during construction stages of mixing and spraying. • The study assessed the regulatory patterns governing the changes in time-dependent rheological parameters of fresh BFSCC. • Novel prediction models were established to regulate the rheological parameters of BFSCC at different construction stages. In the application of modern sprayed cementitious composites, more specific requirements have been proposed for crack resistance, toughness, and durability. By adding fibers with high strength and toughness to the cementitious matrix, the resulting composite material can exhibit excellent mechanical properties. Currently, the commonly used fiber materials of sprayed cementitious composites include steel fiber, polypropylene fiber, basalt fiber. As a type of green and sustainable building material, basalt fiber has been widely used in various engineering projects. In the field of sprayed cementitious composites (SCC), the addition of chopped basalt fibers can enhance its toughness and cracking resistance. However, fiber inclusion may also lead to reduced workability and equipment clogging. Therefore, the rheological behavior of basalt fiber sprayed cementitious composites (BFSCC) under mixing and spraying stages of construction become critical and essential to be fully investigated. In order to simulate the actual engineering application environment of BFSCC, a mortar spraying machine and ICAR rheometer were used to evaluate the variation of key rheological parameters under mixing and spraying stages of construction. The yield stress, plastic viscosity, and thixotropic indices of BFSCC under the influences of basalt fiber characteristics, i.e., type, content and hybrid length, were investigated. The time-dependent rheological behavior of BFSCC was also evaluated. The results indicated that there were significant differences on rheological behaviors under mixing and spraying stages of construction when the basalt fiber was introduced. The spraying process yielded a much higher static and dynamic yield stresses of BFSCC compared with those of mixing stage. Under the same fiber volume content, the plastic viscosity of BFSCC increased first and then decreased with an increase in fiber length in both stages, reaching a maximum at 12 mm. The time-dependent changes in the thixotropic index decreased first and then increased with an increase in time in both the mixing and spraying stages. A prediction model on rheological parameters for BFSCC under mixing and spraying stages was established in accordance with fiber characteristics. [ABSTRACT FROM AUTHOR]

Accurate segmentation of lesions in medical images is a key step to assist clinicians in diagnosis and analysis. Most studies combine the Transformer model with CNN at a single scale or use the highest-level feature tensor extracted by CNN as input to Transformer without fully exploiting Transformer's potential. In addition, for the problems of structural boundary blurring, heterogeneous textures, etc., in medical images, most existing methods pay attention to using contour information to solve this problem but simply fuse the contour information and ignore the potential relationship between the regions and the contours. We propose the DPCTN network based on the traditional encoding–decoding structure, consisting of the CNN, Transformer dual backbone networks and parallel attention mechanisms, to achieve accurate segmentation in medical image lesions. Local and global multiscale feature information is extracted by CNN and Transformer. The Transformer block of channel cross fusion can implement multiscale information fusion of the high-level local features and reduce the impact of the redundant information. The dual backbone feature fusion module effectively couples the local and global high-level feature information. The decoder refines and enriches the boundary and regional features, layer by layer, to achieve effective supervision of the boundary and region. Considering the possible dimension collapse in the attention mechanism, a novel three branch transposed self-attention module is designed to reduce the information loss caused by feature pooling. To verify the effectiveness of our proposed method, subjective and objective comparative experiments and ablation experiments were performed on four medical segmentation tasks, polyps, skin lesions, glands and breast tumors. A large number of experimental results show that our method is superior to the current state-of-the-art method, reduces the standard deviation and is more robust. Source code is released at https://github.com/sd-spf/DPCTN. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new structure was designed by surface solid reaction among Al, La, Co and TiO 2. • Co0-Co2+ active sites were formed due to the formation of CoAl 2 O 4 and Co metal. • TiO 2 was covered by the La oxides to inhibit its agglomeration in the HAS process. • Co/TiO 2 doped by La and Al showed excellent selectivity for higher alcohols. The conversion of syngas (CO + H 2) to advanced oxygenated compounds is a promising strategy for the production of fuel and high-value chemicals, in which regulation of Co0-Co2+ active pairs is of great challenge to the performance of catalysts. In this work, Co-based catalysts supported on TiO 2 modified by La and Al were designed and a novel Co metal-CoAl 2 O 4 active structure was constructed through surface solid reaction to facilitate the higher alcohol synthesis (HAS) from syngas. The results show that the formation of CoAl 2 O 4 by the interaction between Co and Al is conducive to maintaining the stability of Co2+ in catalyst and promoting the coupling of the intermediate CH x * and CO*. Besides, the promoters La and Al are uniformly dispersed on the surface of the catalyst, and inhibit the sintering of the active sites. As a result, the catalyst modified by Al and La exhibits the conversion rate of syngas almost three times as high as that of bare Co/TiO 2 catalyst, and the selectivity of total alcohols reached 39.1% at 270 °C. A new feasible strategy of solid reaction on TiO 2 provides an interesting way to create Co0-Co2+ active pairs for syngas conversion to higher alcohols. [ABSTRACT FROM AUTHOR]

Ultrasound attenuation coefficient estimation (ACE) has diagnostic potential for clinical applications such as differentiating tumors and quantifying fat content in the liver. The two commonly used ACE methods in the ultrasound array imaging system are the spectral shift method and the reference-phantom-based methods. The spectra shift method estimates the central frequency downshift along depth, whereas the reference-phantom-based methods use a well-calibrated phantom to cancel system dependent effects in attenuation estimation. In this study, we propose a novel system-independent ACE technique based on spectra normalization of different frequencies. This technique does not require a reference phantom for normalization. The power of each frequency component is normalized by the power of an adjacent frequency component in the spectrum to cancel system-dependent effects, such as focusing and time gain compensation (TGC). This method is referred to as the reference frequency method (RFM), and its performance has been evaluated in phantoms and in vivo liver studies. The RFM technique can be applied to various transducer geometries (e.g., linear or curved arrays) with different beam patterns (e.g., focused or unfocused). [ABSTRACT FROM AUTHOR]

Eutectic freeze crystallization was developed to recover sodium erythorbate (NaE) from wastewater at pHs 4.1, 5.3, and 6.5. Two substances (A and B) were sequentially recovered from the samples. The recovery rate of substance A was 2.06, 1.83, and 3.03 g/L at pHs 4.1, 5.3, and 6.5, respectively; while that of B was 5.51, 3.09, and 3.26 g/L at the corresponding pHs. The analysis results of the two recovered substances indicated that substance A was mostly Na2SO4·10H2O, while substance B was mainly NaE. Salt recovery was most successful at pH 4.1 with the purity of recovered NaE reaching 87.53 wt%. Moreover, the chemical oxygen demand and electric conductivity of the ice were far smaller than the initial wastewater. The concentration effect was minimal due to the formation of Na2SO4·10H2O and NaE crystals. This combined crystallization strategy can potentially become an economic technology to recover NaE from wastewater. Practitioner pointsSegregation of NaE and Na2SO4·10H2O during the freeze crystallization process.Recovering 5.53 kg NaE with the purity of 87.53 wt% from 1 m3 wastewater.Decreasing chemical oxygen demand and electric conductivity of wastewater through freeze crystallization technology. [ABSTRACT FROM AUTHOR]

A functional differential model of SEIS-M type with two time delays, representing the response time for mass media to cover the current infection and for individuals' behavior changes to media coverage, was proposed to examine the delayed media impact on the transmission dynamics of emergent infectious diseases. The threshold dynamics were established in terms of the basic reproduction number R 0 . When there are no time delays, we showed that if the media impact is low, the endemic equilibrium is globally asymptotically stable for R 0 > 1 , while the endemic equilibrium may become unstable and Hopf bifurcation occurs for some appropriate conditions by taking the level of media impact as bifurcation parameter. With two time delays, we comprehensively investigated the local and global bifurcation by considering the summation of delays as a bifurcation parameter, and theoretically and numerically examined the onset and termination of Hopf bifurcations from the endemic equilibrium. Main results show that either the media described feedback cycle, from infection to the level of mass media and back to disease incidence, or time delays can induce Hopf bifurcation and result in periodic oscillations. The findings indicate that the delayed media impact leads to a richer dynamics that may significantly affect the disease infections. [ABSTRACT FROM AUTHOR]

Reduction of nitrogen (N2) under ambient conditions and understanding the mechanism have been hugely challenging problems for decades. Herein, we for the first time report that N,P co-doped hierarchical porous carbon (NPC) can serve as an electrocatalyst for the nitrogen reduction reaction (NRR) in an acid aqueous solution under ambient conditions. The faradaic efficiency (FE) and yield of production of NH3 on the NPC electrode reached as high as 4.2% and 0.97 μg h−1 mg-1cat., respectively. Furthermore, the electrocatalytic NRR mechanism on the NPC electrode was undoubtedly confirmed by electrochemical in situ Fourier transform infrared spectroscopy, and follows an associative pathway. These results are predicted to offer a new platform in the rational design and synthesis of highly efficient electrocatalysts for the NRR under ambient conditions. [ABSTRACT FROM AUTHOR]

Ultrasound super-resolution (SR) microvessel imaging technologies are rapidly emerging and evolving. The unprecedented combination of imaging resolution and penetration promises a wide range of preclinical and clinical applications. This paper concerns spatial quantization error in SR imaging, a common issue that involves a majority of current SR imaging methods. While quantization error can be alleviated by the microbubble localization process (e.g., via upsampling or parametric fitting), it is unclear to what extent the localization process can suppress the spatial quantization error induced by discrete sampling. It is also unclear when low spatial sampling frequency will result in irreversible quantization errors that cannot be suppressed by the localization process. This paper had two goals: 1) to systematically investigate the effect of quantization in SR imaging and establish principles of adequate SR imaging spatial sampling that yield minimal quantization error with proper localization methods and 2) to compare the performance of various localization methods and study the level of tolerance of each method to quantization. We conducted experiments on a small wire target and on a microbubble flow phantom. We found that the Fourier analysis of an oversampled spatial profile of the microbubble signal could provide reliable guidance for selecting beamforming spatial sampling frequency. Among various localization methods, parametric Gaussian fitting and centroid-based localization on upsampled data had better microbubble localization performance and were less susceptible to quantization error than peak intensity-based localization methods. When spatial sampling resolution was low, parametric Gaussian fitting-based localization had the best performance in suppressing quantization error, and could produce acceptable SR microvessel imaging with no significant quantization artifacts. The findings from this paper can be used in practice to help intelligently determine the minimum requirement of spatial sampling for robust microbubble localization to avoid adding or even reduce the burden of computational cost and data storage that are commonly associated with SR imaging. [ABSTRACT FROM AUTHOR]

Contrast-enhanced ultrasound (CEUS) imaging has great potential for use in many new ultrasound clinical applications. We recently proposed a novel CEUS imaging sequence, Hadamard-encoded multipulses (HEM), to improve the signal-to-noise ratio (SNR) and the contrast-to-tissue ratio (CTR) as compared to other classic CEUS methods. HEM increases microbubble responses by using longer coded transmit pulses and the fast polarity change between coded pulses. In this study, we propose to combine the HEM pulse with multiplane wave (MW) imaging technique to further improve CEUS imaging SNR and contrast-to-noise ratio. During MW-HEM transmissions, the microbubbles undergo multiple fast pulse polarity changes, leading to significantly improved microbubble nonlinear responses, and thus further enhanced SNR and CTR as compared to HEM alone or other CEUS sequences. This improvement may facilitate more robust CEUS imaging for deep abdominal organs and the heart. [ABSTRACT FROM AUTHOR]

Combining atomistic simulations and continuum modeling, the effects of misfit dislocations on strain relaxation and subsequently self-rolling of strain-engineered nanomembranes have been investigated. Two representative material systems including (GaN/In0.5Ga0.5N) of wurtzite lattice and II–VI materials (CdTe/CdTe0.5S0.5) of zinc-blend lattice were considered. The atomistic characteristics of dislocation and the resulting lattice distorting were first determined by generalized-stacking-fault energy profile and disregistry function obtained through Peierls-Nabarro model. Those properties were then used to calculate the accurate mismatch strain of those nanomembranes with the presence of dislocations, and as inputs into von-Karman shell theory to quantitatively evaluate the effects on self-rolling curvature and anisotropy. The theoretical results were further confirmed by atomistic simulations of different crystal geometries and dislocation configurations. Our results provide essential theoretical insights towards prediction and design of rollup configurations for strain-engineered nanomembranes containing crystalline defects. [ABSTRACT FROM AUTHOR]

Shear wave elastography methods are able to accurately measure tissue stiffness, allowing these techniques to monitor the progression of hepatic fibrosis. While many methods rely on acoustic radiation force to generate shear waves for 2-D imaging, probe oscillation shear wave elastography (PROSE) provides an alternative approach by generating shear waves through continuous vibration of the ultrasound probe while simultaneously detecting the resulting motion. The generated shear wave field in in vivo liver is complicated, and the amplitude and quality of these shear waves can be influenced by the placement of the vibrating probe. To address these challenges, a real-time shear wave visualization tool was implemented to provide instantaneous visual feedback to optimize probe placement. Even with the real-time display, it was not possible to fully suppress residual motion with established filtering methods. To solve this problem, the shear wave signal in each frame was decoupled from motion and other sources through the use of a parameter-free empirical mode decomposition before calculating shear wave speeds. This method was evaluated in a phantom as well as in in vivo livers from five volunteers. PROSE results in the phantom as well as in vivo liver correlated well with independent measurements using the commercial General Electric Logiq E9 scanner. [ABSTRACT FROM PUBLISHER]