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Abstract Sulfadoxine-pyrimethamine (SP) is a key drug recommended by the World Health Organization for the chemoprevention of malaria. However, the strategy is affected by the parasite resistance to SP. This study evaluated Plasmodium falciparum dihydrofolate reductase (Pfdhfr) and dihydropteroate synthase (Pfdhps) genes, associated with SP resistance, from 508 P. falciparum isolates imported from West African countries to Henan Province, China, during 2012–2022. High mutant prevalence of the genes Pfdhfr (94.7%) and Pfdhps (96.8%) was observed. The mutants Pfdhfr N51I, C59R, S108N, and Pfdhps A437G were at high frequency in all countries analyzed. The overall prevalence of the mutant Pfdhps K540E was low (3.4%), but with a high frequency in Liberia (24.3%). The frequency of mutants Pfdhps I431V, A581G, and A613S was 11.7%, 9.8%, and 16.2%, respectively, all of which had the highest mutant prevalence in Nigeria. The mutant Pfdhps A581G and A613S were identified in the absence of K540E. The partially resistant haplotype (I51R59N108 - G437) was the most common (72.6%), and the fully resistant haplotype (I51R59N108 - G437E540) had a low prevalence of 3.4% and mainly occurred in Liberia. No super resistant haplotype was identified. The mutant Pfdhps I431V and the octuple mutant haplotype I51R59N108 - V431A436G437G581S613 deserve more attention. In areas of high SP resistance, the intervention still reduces low birthweight and maternal anaemia. SP should continue to be used in areas of high SP resistance until more effective alternatives for malaria chemoprevention are found. It is important to continuously monitor the molecular markers associated with SP resistance to better implement intermittent preventive treatment policies in pregnancy (IPTp) and infants (IPTi).

To explore the interaction between holes and fractures in defective white sandstone, uniaxial compression tests were conducted on samples with varying horizontal distances between holes and fractures. The technique known as Digital Image Correlation (DIC) was employed to analyze the deformation patterns, while CT scanning technology was implemented to elucidate the interior crack propagation features. Discrete Element Method (DEM) simulations were performed to investigate the micro-scale fracture evolution. The findings demonstrate that load-bearing capacity and deformation resistance decreased as the horizontal hole-fracture distance increased. The failure mode transitioned from a mixed tensile-shear failure to a more rapid tensile failure. Tensile wing fractures caused by tensile failure reinforced the merging of rock bridges. Furthermore, the trajectories of fracture propagated from the outside to the inside of the rocks progressively simplify, resulting in accelerated instability and collapse. DEM simulations indicate that the augmentation of horizontal distance between holes and fractures influenced the displacement field and the orientation of micro-fractures inside the samples. The formation of micro-fractures progressively adhered to a “clusteringexpansion-coalescence” sequence along the paths of the hole-fracture structures. The maximum strength of the samples declined in a three-phase pattern: gradual decline, steep decline, and gradual decline. These findings provide valuable insights for engineering applications, such as tunnel excavation and mining operations.

With the goal of examining the micromechanics damage characteristics of freeze-thaw red sandstone under the influence of cyclic loads, a model of freeze-thaw cyclic rock particles is developed based on Discrete Element Method numerical simulation in order to investigate and study the micromechanics response mechanism of rocks under the coupling effect of freeze-thaw and cyclic loads. The findings demonstrate that lower rock elastic modulus and higher irreversible strain are driven by longer loading/unloading durations and more frequent freeze-thaw cycles. Its bearing capacity and resistance to deformation are diminished by the damage brought on by freeze-thaw; Rock anisotropy and the spatial organisation of microcracks are significantly altered by different loading techniques; In freeze-thaw rocks, the frequency and intensity of acoustic emission breaking follow the law of normal distribution. Under cyclic stress, samples exposed to several freeze-thaw cycles exhibit an escalation in large-scale fractures, accompanied by a concentrated spatial distribution of acoustic emission events. Three phases may be distinguished in the energy evolution of red sandstone: the initial, accumulation, and release phases. The energy storage capacity is compromised by freeze-thaw degradation, resulting in an elevated conversion rate of dissipative energy and rendering the energy conversion mechanism more unstable. The previously described study results possess considerable relevance for rock engineering construction and catastrophe mitigation in cold climates.

At present, the majority of deep learning-based ship object detection algorithms concentrate predominantly on enhancing recognition accuracy, often overlooking the complexity of the algorithm. These complex algorithms demand significant computational resources, making them unsuitable for deployment on resource-constrained edge devices, such as airborne and spaceborne platforms, thereby limiting their practicality. With the purpose of alleviating this problem, a lightweight and high-accuracy synthetic aperture radar (SAR) ship image detection network (LHSDNet) is proposed. Initially, GhostHGNetV2 was utilized as the feature extraction network, and the calculation amount of the network was reduced by GhostConv. Next, a lightweight feature fusion network was designed to combine shallow and deep features through lightweight convolutions, effectively preserving more information while minimizing computational requirements. Lastly, the feature extraction module was integrated through parameter sharing, and the detection head was lightweight to save computing resources further. The results from our experiments demonstrate that the proposed LHSDNet model increases mAP50 by 0.7% in comparison to the baseline model. Additionally, it illustrates a pronounced decrease in parameter count, computational demand, and model file size by 48.33%, 51.85%, and 41.26%, respectively, when contrasted with the baseline model. LHSDNet achieves a balance between precision and computing resources, rendering it more appropriate for edge device implementation.

Abstract Currently, microwave correlation imaging (MCI) is regarded as an important method to address the forward‐looking imaging problem in radar. The key step of this method is to form a spatio‐temporal two‐dimensional random radiation field through various means. However, the current methods do not consider the polarization domain, which is an important dimension of electromagnetic signals. The existing research mainly focuses on using polarized antenna elements, without incorporating polarization information into the imaging system. To fill this gap, this letter proposes the polarization microwave correlation imaging (PMCI) based on the orthogonal complement space, which performs instantaneous polarization measurements (IPM) while correlating imaging of the target. Through simulation analysis, this method can further improve the quality and anti‐interference ability of MCI. Moreover, under the condition of low time‐frequency product, the peak sidelobe level (PSL) and isolation of this method are approximately 3.5 dB and 12.5 dB higher than those of traditional instantaneous polarization measurement methods (TIPM).

Visceral leishmaniasis (VL) was widely prevalent in Henan Province in the 1950s. Through active efforts by the government, there were no local cases reported from 1984 to 2015. In 2016, local VL cases reoccurred, and there was an increasing trend of VL cases in Henan Province. To provide a scientific control of VL, an investigation was conducted in Henan Province from 2016 to 2021. The data from VL cases were obtained from the Disease Surveillance Reporting System of the Chinese Center for Disease Control and Prevention. The rK39 immunochromatographic test (ICT) and PCR assay were performed among high-risk residents and all dogs in the patients’ village. ITS1 was amplified, sequenced, and subjected to phylogenetic analyses. A total of 47 VL cases were reported in Henan Province during 2016–2021. Of the cases, 35 were local, and they were distributed in Zhengzhou, Luoyang, and Anyang. The annual average incidence was 0.008/100,000, showing an upward trend year by year (χ2 = 3.987, p = 0.046). Their ages ranged from 7 months to 71 years, with 44.68% (21/47) in the age group of 0–3 years and 46.81% (22/47) in the age group ≥15 years. The cases occurred throughout the year. The high-risk populations were infants and young children (age ≤3), accounting for 51.06% (24/47), followed by farmers at 36.17% (17/47). The ratio of males to females was 2.13:1. The positive rates of rK39 ICT and PCR were 0.35% (4/1130) and 0.21% (1/468) in the residents. The positive rates of rK39 ICT and PCR were 18.79% (440/2342) and 14.92% (139/929) in the dogs. The ITS1 amplification products in the patients and positive dogs were sequenced. The homology between the target sequence and Leishmania infantum was more than 98%. The phylogenetic analysis indicated that the patients and the positive dogs were infected by the same type of Leishmania, which was consistent with the strains in the hilly endemic areas in China. This paper showed that patients and domestic dogs were infected by the same type of L. infantum and that the positive rate in dogs was relatively high in Henan Province. Because the measures of patient treatment and culling of infected dogs were not effective in reducing VL incidence in Henan Province, it is urgent to develop new approaches for the control of VL, such as wearing insecticide-impregnated collars on dogs, treating the positive dogs, spraying insecticide for sandflies control, and improving residents’ self-protection awareness to prevent the further spread of VL in Henan Province.

Malaria remains a major public health issue in Nigeria, and Nigeria is one of the main sources of imported malaria in China. Antimalarial drug resistance is a significant obstacle to the control and prevention of malaria globally. The molecular markers associated with antimalarial drug resistance can provide early warnings about the emergence of resistance. The prevalence of antimalarial drug resistant genes and mutants, including PfK13, Pfcrt, Pfmdr1, Pfdhfr, and Pfdhps, was evaluated among the imported Plasmodium falciparum isolates from Nigeria in Henan, China, from 2012 to 2019. Among the 167 imported P. falciparum isolates, the wild-type frequency of PfK13, Pfcrt, Pfmdr1, Pfdhfr, and Pfdhps was 98.7, 63.9, 34.8, 3.1, and 3.1%, respectively. The mutation of PfK13 was rare, with just two nonsynonymous (S693F and Q613H) and two synonymous mutations (C469C and G496G) identified from four isolates. The prevalence of Pfcrt mutation at codon 74–76 decreased year-by-year, while the prevalence of pfmdr1 86Y also decreased significantly with time. The prevalence of Pfdhfr and Pfdhps mutants was high. Combined mutations of Pfdhfr and Pfdhps had a high prevalence of the quadruple mutant I51R59N108-G437 (39.0%), followed by the octal mutant I51R59N108-V431A436G437G581S613 (17.0%). These molecular findings update the known data on antimalarial drug-resistance genes and provide supplemental information for Nigeria.