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Animal models of COVID-19 facilitate the development of vaccines and antivirals against SARS-CoV-2. The efficacy of antivirals or vaccines may differ in different animal models with varied degrees of disease. Here, we introduce a mouse model expressing human angiotensin-converting enzyme 2 (ACE2). In this model, ACE2 with the human cytokeratin 18 promoter was knocked into the Hipp11 locus of C57BL/6J mouse by CRISPR – Cas9 (K18-hACE2 KI). Upon intranasal inoculation with high (3 × 105 PFU) or low (2.5 × 102 PFU) dose of SARS-CoV-2 wildtype (WT), Delta, Omicron BA.1, or Omicron BA.2 variants, all mice showed obvious infection symptoms, including weight loss, high viral loads in the lung, and interstitial pneumonia. 100% lethality was observed in K18-hACE2 KI mice infected by variants with a delay of endpoint for Delta and BA.1, and a significantly attenuated pathogenicity was observed for BA.2. The pneumonia of infected mice was accompanied by the infiltration of neutrophils and pulmonary fibrosis in the lung. Compared with K18-hACE2 Tg mice and HFH4-hACE2 Tg mice, K18-hACE2 KI mice are more susceptible to SARS-CoV-2. In the antivirals test, REGN10933 and Remdesivir had limited antiviral efficacies in K18-hACE2 KI mice upon the challenge of SARS-CoV-2 infections, while Nirmatrelvir, monoclonal antibody 4G4, and mRNA vaccines potently protected the mice from death. Our results suggest that the K18-hACE2 KI mouse model is lethal and stable for SARS-CoV-2 infection, and is practicable and stringent to antiviral development.

IntroductionTo explore the distribution of Isthmin-1 (ISM1) level and its association with isolated post-challenge hyperglycemia (IPH).MethodsA total of 522 participants without a history of diabetes were invited to attend a standard 75g 2-h oral glucose tolerance test (OGTT), and 71 subjects were further invited for a 3-h oral minimal model test. Insulin sensitivity and β-cell function were evaluated using both HOMA and estimated from OGTT. Circulating ISM1 levels were determined by a commercially available ELISA kit.ResultsA total of 76 (14.6%) participants were diagnosed as IPH, accounting for 61.3% of the newly diagnosed diabetes. ISM1 levels were significantly higher in men than in women (1.74 ng/mL versus 0.88 ng/mL). The inverse correlation between ISM1 and β-cell function and IPH was only significant in men. After multivariate adjustment, per unit increment in ISM1 was associated with 0.68-fold (95% CI: 0.49-0.90) reduced odds ratio (OR) of IPH in men. Compared to men with the lowest ISM1 levels, the adjusted OR of IPH with the highest ISM1 levels decreased by 73% (95% CI: 0.11-0.61). Moreover, incorporation of ISM1 into the New Chinese Diabetes Risk Score (NCDRS) model yielded a substantial improvement in net reclassification improvement of 58% (95% CI: 27%-89%) and integrated discrimination improvement of 6.4% (95% CI: 2.7%-10.2%) for IPH.ConclusionsISM1 was significantly and independently associated with IPH, and serves as a feasible biomarker for the early identification of men with high risk of IPH.

Air contamination stands as a formidable obstacle to China’s social-economic progress, significantly impacting citizen well-being and living conditions. The endeavor to forecast air quality accurately, which carries substantial societal implications, has become increasingly crucial particularly within Chinese urban agglomeration. Recent deep learning approaches have significantly enhanced the modeling of complex spatial-temporal correlations within air quality data, primarily by treating the data as a dispersion process. Unfortunately, a substantial portion of previous research has neglected the impact of heterogeneity in air quality data within urban agglomeration on the predictions. Moreover, these studies haven’t adequately modeled and disentangled air quality data specific to individual cities and that originating from other cities within the urban agglomeration. To improve forecasting performance, we propose a novel forecasting model predicated on the Gaussian Decoupled Representation Extractor, engineered to forecast air quality within urban agglomeration. The model, using a data-driven approach, segregates the air-quality time series by quantifying and decoding the heterogeneous constituents of time, location, and origin variables embedded in air-quality data. It incorporates a dual attention mechanism to apprehend the spatial-temporal dependencies to air-quality. The efficacy of the model is corroborated using a data set from urban agglomeration in Hunan Province. Through extensive experiments, it is demonstrated that compared with the baselines, our model has shown an improvement, with a reduction of 11.2% in MAE and 8.97% in RMSE respectively.

Highlights Novel double-network (DN) ion-conducting hydrogel (ICH) based on a poly(ionic liquid)/MXene/poly(vinyl alcohol) system (named PMP DN ICH) was synthesized using freeze–thawing and ionizing radiation technology. The PMP DN ICH possesses a multiple cross-linking mechanism and exhibits outstanding ionic conductivity (63.89 mS cm−1), excellent temperature resistance (−60–80 °C) and decent mechanical performance. The well-designed PMP DN ICH shows considerable potential in wearable sensing, energy storage, and energy harvesting.

Summary: Background: Non-high-density lipoprotein cholesterol (non-HDL-c) was a strong risk factor for incident cardiovascular diseases and proved to be a better target of lipid-lowering therapies. Recently, gut microbiota has been implicated in the regulation of host metabolism. However, its causal role in the variation of non-HDL-c remains unclear. Methods: Microbial species and metabolic capacities were assessed with fecal metagenomics, and their associations with non-HDL-c were evaluated by Spearman correlation, followed by LASSO and linear regression adjusted for established cardiovascular risk factors. Moreover, integrative analysis with plasma metabolomics were performed to determine the key molecules linking microbial metabolism and variation of non-HDL-c. Furthermore, bi-directional mendelian randomization analysis was performed to determine the potential causal associations of selected species and metabolites with non-HDL-c. Findings: Decreased Eubacterium rectale but increased Clostridium sp CAG_299 were causally linked to a higher level of non-HDL-c. A total of 16 microbial capacities were found to be independently associated with non-HDL-c after correcting for age, sex, demographics, lifestyles and comorbidities, with the strongest association observed for tricarboxylic acid (TCA) cycle. Furthermore, decreased 3-indolepropionic acid and N-methyltryptamine, resulting from suppressed capacities for microbial reductive TCA cycle, functioned as major microbial effectors to the elevation of circulating non-HDL-c. Interpretation: Overall, our findings provided insight into the causal effects of gut microbes on non-HDL-c and uncovered a novel link between non-HDL-c and microbial metabolism, highlighting the possibility of regulating non-HDL-c by microbiota-modifying interventions. Funding: A full list of funding bodies can be found in the Sources of funding section.

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) has been spreading globally for over 2 years, causing serious contagious disease and incalculable damage. The introduction of vaccines has slowed the spread of SARS‐CoV‐2 to some extent, but there remains a need for specific and effective treatment. The high chemical diversity and safety profiles of natural products make them a potential source of effective anti‐SARS‐CoV‐2 drugs. Cotton plant is one of the most important economic and medical crops and is the source of a large number of antiviral phytochemicals. In this work, we used SARS‐CoV‐2 main protein (Mpro) as the target to identify potential anti‐SARS‐CoV‐2 natural products in cotton. An in vitro assay showed that of all cotton tissues examined, cotton flower extracts (CFs) exhibited optimal inhibitory effects against Mpro. We proceeded to use the CF metabolite database to screen natural Mpro inhibitors by combining virtual screening and biochemical assays. We identified that several CF natural products, including astragalin, myricitrin, and astilbin, significantly inhibited Mpro with half‐maximal inhibitory concentrations (IC50s) of 0.13, 10.73, and 7.92 μm, respectively. These findings may serve as a basis for further studies into the suitability of cotton as a source of potential therapeutics for SARS‐CoV‐2.

Abstract Outbreaks of coronaviruses (CoVs), especially severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), have posed serious threats to humans and animals, which urgently calls for effective broad‐spectrum antivirals. RNA‐dependent RNA polymerase (RdRp) plays an essential role in viral RNA synthesis and is an ideal pan‐coronaviral therapeutic target. Herein, based on cryo‐electron microscopy and biochemical approaches, gossypol (GOS) is identified from 881 natural products to directly block SARS‐CoV‐2 RdRp, thus inhibiting SARS‐CoV‐2 replication in both cellular and mouse infection models. GOS also acts as a potent inhibitor against the SARS‐CoV‐2 variant of concern (VOC) and exerts same inhibitory effects toward mutated RdRps of VOCs as the RdRp of the original SARS‐CoV‐2. Moreover, that the RdRp inhibitor GOS has broad‐spectrum anti‐coronavirus activity against alphacoronaviruses (porcine epidemic diarrhea virus and swine acute diarrhea syndrome coronavirus), betacoronaviruses (SARS‐CoV‐2), gammacoronaviruses (avian infectious bronchitis virus), and deltacoronaviruses (porcine deltacoronavirus) is showed. The findings demonstrate that GOS may serve as a promising lead compound for combating the ongoing COVID‐19 pandemic and other coronavirus outbreaks.

Fe3C filled carbon nanotubes (CNTs) self-organized into flexible-film-morphologies (buckypapers) have been proposed for numerous applications, these include flexible data-storage-devices, exchange-bias, spin-based-systems, flexible ferromagnetic-electrodes and others. However, despite the important progress, the significant concentration of Cl-containing-hydrocarbons which is needed for the buckypaper-growth (i.e. 1 to 10 ml) represents still an important challenge for industrial-production.Here we report the experimental-growth-parameters needed for the nucleation and growth of flexible Fe3C-filled-CNT buckypapers, under very-low-concentrations of dichlorobenzene, as low as 0.05 ml.By carefully estimating both the heating- and cooling-rate parameters of the chosen chemical-vapor-deposition (CVD) reactor, we demonstrate the identification of two active-growth-regions which allow for the simultaneous nucleation and growth of ferromagnetically-filled buckypapers. The obtained films comprise of selectively grown single-wall (active-region-1) and multiwall (active-region-2) CNTs. The simultaneous growth of the two types of buckypapers within the same reactor is discussed and attributed to the dynamics of dichlorobenzene-pyrolysis, which appears to yield a higher concentration of Cl-radicals in the active-region-1. In the buckypapers grown in the latter (active-region-1) we highlight an unusual separation between the first (inner) and second CNT-cylinders, with the HRTEM analyses revealing an anomalously-large interlayer-distance varying from ∼ 1.6 to ∼ 6.6 nm (an effective void between two CNT-cylinders).

We report a novel investigation of the effects of sulfur-precursor concentration on the morphological, structural and magnetic properties of vertically aligned mm-long films of carbon nanotubes (CNTs) filled with Fe3C nanowires. Fabrication was carried out by sublimation and pyrolysis of ferrocene/sulfur mixtures in the presence of 0.65 ml of dichlorobenzene within a custom designed chemical vapour deposition (CVD) reactor, under an Ar flow of 10-100 ml/min. The employed quantity of sulfur was found to have an important impact on the structural properties of the as grown CNTs, yielding either few wall CNTs (FWCNTs) or multiwall CNTs (MWCNTs) in presence of 0.4 mg or 1.2 mg of sulfur (category 1,2). Appearance of RBM (radial breathing modes) bands with variable intensities, was demonstrated in category-1 samples by both point and mapping Raman spectroscopy. Further, an additional broad band indicative of a chlorine/sulfur-induced amorphization of the CNT-walls was detected. Structural manipulation of category-1 and-2 samples was sought through annealing, in an attempt to create carbon-sulfur phases. The latter system has been indeed recently identified as a possible superconductor, under certain conditions of doping. Our findings highlight two different regimes of carbon-sulfur manipulation of the CNT-layers which involve 1) the nucleation of covalent carbon-sulfur phases at T∼150 °C -300 °C, with appearance of Raman bands at 1250 cm−1 and 1450 cm−1 and 2) an enhancement of the CNT-defectiveness (D and D’ bands) at T∼600 °C.

Controlling Bernal (AB) to rhombohedral (ABC) stacking-transitions has recently become an important goal towards manipulation of the electronic properties of highly- oriented-pyrolytic-graphite (HOPG) and graphene.In this letter we report a novel investigation of AB to ABC stacking transitions in exfoliated-HOPG-lamellae with variable thickness. The samples were produced by employing I) an edge-tape-exfoliation-method to extrude lamellae of ∼ 80–140 μm thickness and 2) a manual-exfoliation-method, which yielded samples of ∼ 300–450 μm thickness. Characterization was carried out by employing Raman-point/mapping-spectroscopy in certain selected defective-regions of the samples. We demonstrate an abrupt enhancement of the rhombohedral-phase-content within dense- and thick-staircase-sublattices, indicative of a possible crucial role of the sublattice-defect-thickness in preventing ABC to AB post-exfoliation stacking-relaxation. Relaxation of the produced ABC stacks was then found after approximately four weeks from exfoliation (in thick lamellae).

A surface plasmon resonance (SPR) refractive index sensing technique based on the optimal pre-and post-selection (PPS) is put forward. The intensity contrast ratio (ICR) is introduced to estimate the precision of this sensing technique. Compared with the traditional sensing techniques, our method shows that the ICR can be improved by about two orders of magnitude with optimal pre-and post-selected states. It is also proved that our sensing technique has a large tolerance for the metal film thickness and the incident angle. Remarkably, the method greatly reduces the cost of experiments, which is significant for promoting the widespread applications of SPR sensors.

Background: The collagenase encoding gene col was cloned into a pP43NMK vector and amplified in Escherichia coli JM109 cells. The shuttle vector pP43NMK was used to sub-clone the col gene to obtain the vector pP43NMK-col for the expression of collagenase in Bacillus subtilis WB600. The enzyme was characterized and the composition of the expression medium and culture conditions were optimized. Methods: The expressed recombinant enzyme was purified by ammonium sulfate, ultrafiltration, and through a nickel column. The purified collagenase had an activity of 9405.54 U/mg. Results: The recombinant enzyme exhibited optimal activity at pH 9.0 and 50 °C. Catalytic efficiency of the recombinant collagenase was inhibited by Fe3+ and Cu2+, but stimulated by Co2+, Ca2+, Zn2+, and Mg2+. The optimal conditions for its growth were at pH 7.0 and 35 °C, using 15 g/L of fructose and 36 g/L of yeast powder and peptone mixture (2:1) at 260 rpm with 11% inoculation. The maximal extracellular activity of the recombinant collagenase reached 2746.7 U/mL after optimization of culture conditions, which was 2.4-fold higher than that before optimization. Conclusions: This study is a first attempt to recombinantly express collagenase in B. subtilis WB600 and optimize its expression conditions, its production conditions, and possible scale-up.

New strategies to rapidly develop broad-spectrum antiviral therapies are urgently required for emerging and re-emerging viruses. Host-targeting antivirals (HTAs) that target the universal host factors necessary for viral replication are the most promising approach, with broad-spectrum, foresighted function, and low resistance. We and others recently identified that host dihydroorotate dehydrogenase (DHODH) is one of the universal host factors essential for the replication of many acute-infectious viruses. DHODH is a rate-limiting enzyme catalyzing the fourth step in de novo pyrimidine synthesis. Therefore, it has also been developed as a therapeutic target for many diseases relying on cellular pyrimidine resources, such as cancers, autoimmune diseases, and viral or bacterial infections. Significantly, the successful use of DHODH inhibitors (DHODHi) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection further supports the application prospects. This review focuses on the advantages of HTAs and the antiviral effects of DHODHi with clinical applications. The multiple functions of DHODHi in inhibiting viral replication, stimulating ISGs expression, and suppressing cytokine storms make DHODHi a potent strategy against viral infection.

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) enriched eggs are popular for their enrichment of PUFAs, but their freshness and quality are prone to decline with time, particularly if storage conditions are not well maintained. Home storage is the last but a neglected important tach in eggs supply chain, but few studies are available on the egg storage in the home stage. This study aimed to evaluate the internal quality change of both n-3 PUFAs enriched and conventional eggs by simulating eggs stored at consumers’ home in refrigeration and under room temperature. The egg quality indices (Haugh unit, yolk index, weight, and albumen pH) were adopted and analyzed for both storage conditions. Wireless sensor network (WSN) was used for real-time monitoring of the temperature and humidity during storage. The results showed that temperature, humidity and time of storage all have an influence on the freshness of both n-3 PUFAs enriched and conventional eggs and there is no significant difference happened to n-3 PUFAs enriched eggs and conventional eggs. Refrigeration can decelerate the quality deterioration of both n-3 PUFAs enriched and conventional eggs and consumers should be educated about how to maintain the internal quality of eggs during home storage.

Introduction: To explore the distribution of Isthmin-1 (ISM1) level and its association with isolated post-challenge hyperglycemia (IPH). Methods: A total of 522 participants without a history of diabetes were invited to attend a standard 75g 2-h oral glucose tolerance test (OGTT), and 71 subjects were further invited for a 3-h oral minimal model test. Insulin sensitivity and b-cell function were evaluated using both HOMA and estimated from OGTT. Circulating ISM1 levels were determined by a commercially available ELISA kit. Results: A total of 76 (14.6%) participants were diagnosed as IPH, accounting for 61.3% of the newly diagnosed diabetes. ISM1 levels were significantly higher in men than in women (1.74 ng/mL versus 0.88 ng/mL). The inverse correlation between ISM1 and b-cell function and IPH was only significant in men. After multivariate adjustment, per unit increment in ISM1 was associated with 0.68-fold (95% CI: 0.49-0.90) reduced odds ratio (OR) of IPH in men. Compared to men with the lowest ISM1 levels, the adjusted OR of IPH with the highest ISM1 levels decreased by 73% (95% CI: 0.11-0.61). Moreover, incorporation of ISM1 into the New Chinese Diabetes Risk Score (NCDRS) model yielded a substantial improvement in net reclassification improvement of 58% (95% CI: 27%-89%) and integrated discrimination improvement of 6.4% (95% CI: 2.7%-10.2%) for IPH. Conclusions: ISM1 was significantly and independently associated with IPH, and serves as a feasible biomarker for the early identification of men with high risk of IPH. [ABSTRACT FROM AUTHOR]

Abstract Malaria is a potentially fatal infective illness caused due to parasites that belong to the Plasmodium genus, which are transferred to humans with the help of the stings of affected female Anopheles mosquitoes, and it persists as a serious public wellness problem worldwide. Cordia myxa is a medicinal plant that possesses various medicinal characteristics like antimicrobial, anti-inflammation, antioxidant, and antidiabetic activities, which makes it an important natural resource for the therapy of different maladies in traditional medicine. In this investigation, a certain network pharmacology method has been utilized to identify the potent active components, possible targets as well as signaling pathways present in C. myxa in relation to malaria therapy. The active compounds were submitted to molecular docking approaches to validate their successful activity against the potential targets. The study concluded that three constituents named cosmosiin, stigmastanol, robinetin, and quercetin were highly active and could regulate the expression of Interleukin 6 (IL6) and Cysteine-aspartic acid protease 3 (CASP3), which may act as a potential therapeutic target for malaria treatment. These analyses are validated by molecular dynamics simulation which reflects on the overall structural stability of the intermolecular conformation and interactions. These results can also be witnessed in simulation-based trajectories binding free energies, which concluded the significant role of electrostatic and van der Waals energies in total intermolecular interactions. Finally, we utilized machine learning to predict the anti-malarial activity of C. myxa compounds, comparing them with approved drugs. Using the Chemprop model and MAIP predictions, we assessed ten compounds, revealing their potential as lead anti-malarial agents. This study establishes a groundwork for comprehending the function of the anti-malaria action of C. myxa.

Abstract Purpose To assess the clinical efficacy of arthroscopic treatment for posterior cruciate ligament (PCL) tibial avulsion fractures using high-intensity suture binding combined with button plate suspension fixation. Methods We retrospectively analyzed clinical data from 32 patients with PCL tibial avulsion fractures treated at our hospital from July 2020 to August 2023. We recorded operation time, intraoperative and postoperative complications, and used imaging to assess fracture reduction and healing. Pain and knee function were evaluated using the Visual Analogue Scale (VAS), range of knee motion, Lysholm score, and International Knee Documentation Committee (IKDC) score. Study Design Case series; Level of evidence, 4. Results All patients were followed for 6 to 18 months, averaging 13.6 months. All incisions healed successfully without postoperative complications. X-rays taken on the first postoperative day showed satisfactory fracture reduction. Three-month post-surgery imaging confirmed healed fractures and no internal fixation failures. At the final follow-up, knee function was well recovered, with only one patient exhibiting a positive posterior drawer test of degree I. Furthermore, the mean VAS score was 0. 5 (range 0.0 to 1.0), active knee extension was 2. 2° (range 0.0 to 5.0), and active knee flexion was 137.7° (range 130.0 to 145.0). The mean Lysholm score was 91.5(range 89.3 to 94.0), and the IKDC score averaged 83.8 ± 3.7, and these outcomes showed statistically significant improvement from preoperative levels (P

Abstract Neoadjuvant immunochemotherapy (NAIC) achieves superior clinical benefits over neoadjuvant chemotherapy (NAC) in multiple types of human cancers, including gastric adenocarcinoma (GAC). However, it is poorly understood how the malignant epithelial cells and tumor immune microenvironment (TIME) might respond distinctly to NAIC and NAC that underlies therapeutic efficacy. Here treatment‐naive and paired tumor tissues from multiple centers were subjected to pathological, immunological, and transcriptomic analysis. NAIC demonstrated significantly increased rate of pathological complete response compared to NAC (pCR: 25% vs. 4%, p

Change detection is a crucial remote sensing (RS) application because it can locate the interesting changed regions and provide corresponding time-series information with multitemporal RS images acquired in the same region. Synthetic aperture radar (SAR), with the advantages of all-day and all-weather conditions, can achieve high-resolution imaging from long operation distances. Moreover, the coherence imaging characteristics of the SAR system cause the attained complex-value images to be more sensitive to ground surface features. Traditional intensity-based change detection methods merely use the intensity difference between multitemporal images; thus, the results only reflect the significant landmark changes, such as seismic disasters and flood disasters. In this article, we use the coherent imaging characteristics of the SAR complex images to detect very subtle changes, such as vehicle tracks and footprints. Specifically, coherent change detection based on amplitude and phase generates a difference image utilizing the repeat-pass repeat-geometry SAR images, while the global attention-based convolutional neural network achieves automatic subtle change track extraction from the difference images. The experimental results based on our measured airborne SAR data demonstrate that our proposed method reduces the sensitivity of the detectable changed region from the meter level to the centimeter level, further providing our method with the ability to detect very subtle changes, such as vehicle tire tracks or footprints by human activities. This subtle change detection capability can be used for the search and rescue of vehicles and personnel lost in the field.

Abstract Background Since arthroscopy was discovered to treat acromioclavicular joint injury, people have had great interest and attention to this beautiful and minimally invasive operation, and related research has been increasing worldwide. At present, there is no bibliometric and visualized analysis in this field. The purpose of this study is to explore the research hotspots and trends of arthroscopic treatment of acromioclavicular joint injury through bibliometric and visualized analysis and look forward to the future development direction of clinical practice. Methods The publications on arthroscopic treatment of acromioclavicular joint injury diseases from its establishment to April 2023 were obtained from the Web of Science (WOS) Core Collection database. CiteSpace, VOSviewer, Scimago graphica and Origin were used for bibliometric and visualized analysis. Results This study included a total of 330 publications. The number of publications tends to increase every year. The USA has the most significant number of publications and citations. Imhoff AB is the most relevant scholar with the largest number of publications in this field, and the scholar with the highest citation and average citations is Mazzocca AD. Tech Univ Munich, Rush University and Charite are the three institutions with the greatest contribution. Tech Univ Munich, Rush University and Charite are the three institutions with the greatest contribution. In addition, “Arthroscopy-the Journal of Arthroscopic and Related Surgery” and “American Journal of Sports Medicine” are the institutions with the most significant number of publications and average citations, respectively. The most common keywords are “acromioclavicular joint dislocation,” “arthroscopic resection,” “arthroscopic reconstruction” and “coracoclavicular ligament.” Conclusion The number of publications shows a steady upward trend as a whole. However, there is still a lack of cooperation among countries, institutions and scholars around the world, so various countries, institutions and scholars need to strengthen academic exchanges and expand the field of cooperation, so as to promote further research and development in related fields. However, minimally invasive methods such as arthroscopy are still the hotspots and frontiers in the treatment of acromioclavicular joint injury in the future.

Dedicated to synchronously acquiring large-area, high-precision, and multi-scale ocean wind and wave information, a novel concept of a spaceborne ocean microwave dual-function integrated sensor is proposed in this paper. It integrates the functions of a scatterometer and SAR by sharing a single phased-array antenna. An overview of the scientific requirements and motivations for the sensor are outlined firstly. In order to fulfill the observation requirements of both the functions, the constraints on the system parameters such as frequency, antenna size, and incidence angle are analyzed. Then, the selection principles of these parameters are discussed within the limitations of antenna area, bandwidth, available time, and cost. Additionally, the constraints on the time sequence of transmitting and receiving pulses are derived to ensure that there is no conflict when the two functions operate simultaneously. Subsequently, a method for jointly designing the pulse repetition frequency (PRF) of both the functions is introduced, along with zebra maps to verify its effectiveness. At the end of the paper, the system and performance parameters of the sensor are given for further insight into it.

In the fabrication of a proton exchange membrane fuel cell electrode, the catalyst layers (CLs) are coated onto either a gas diffusion medium or a membrane. The deposition method of the catalyst ink plays an important role in the structure of the CL, which directly affects its electrochemical performance. Ultrasonic spraying is a method commonly employed for depositing catalyst ink onto the membrane, and the consequent droplet size is correlated to the microstructure of the CLs. In this study, a two-dimensional nozzle model that vibrates at an ultrasonic frequency was developed to simulate the spraying process of the catalyst ink. The volume of the fluid method with dynamic meshing was used. Parametric studies were carried out to gain insights into the atomization process. It was found that measures such as increasing the nozzle amplitude and frequency, and selecting the surface tension and viscosity of the catalyst ink within a proper range, are conducive to obtaining finer droplets and narrower droplet size distribution. Simulation results of non-Newtonian fluids with different viscosity ranges show that the ink fluid with higher viscosity and low shear rate improves the spray quality. This observation is consistent with the results of Newtonian fluids with different viscosities. [ABSTRACT FROM AUTHOR]

High-resolution airborne synthetic aperture radar imaging requires long synthetic aperture time (LSAT). However, the LSAT invalidates the Fresnel approximation in the traditional autofocusing method, leaving a residual signal phase in the motion error. To solve the problem, a signal-reconstruction-based phase gradient autofocus (SR-PGA) and a subimage resampling (SIR) methods are proposed. They are developed on the hyperbolic model. First, a subaperture division strategy divides the full-aperture high-order error into multiple low-order subaperture errors (SPEs). Then, the SR-PGA is developed to estimate the SPE, in which the precise deramping is reconstructed to eliminate the residual signal phase in the SPE. Third, the SIR is proposed to eliminate residual Doppler-variant shift of the adjacent subimages, improving the accuracy of the SPE combination. Finally, simulation and actual data processing verify the effectiveness and validity of the algorithm.