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Pyriproxyfen (PPF) has been shown to affect the pupal stage and ecdysone levels in holometabolous insects, such as silkworms and mealworms. It remains unknown whether it affects hemimetabolous insects with their hormone levels in insects lacking a pupal stage. In this laboratory study, bioassays were conducted to investigate the effects of varying doses of PPF on Aphis craccivora Koch (Hemiptera: Aphididae). Ultraperformance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) was used to determine the types and titers of juvenile hormone (JH) and 20-hydroxyecdysone (20E). Additionally, the effects of PPF on A. craccivora reproduction and molting, as well as its influence on relevant gene expression, were examined. The results revealed LC50 and LC90 values of 3.84 and 7.49 mg/l for PPF, respectively, after 48 h of exposure. The results demonstrated a significant reduction in the titer of JH III and a significant increase in the titer of 20E following treatment with PPF. However, there was no significant decrease observed in the titer of JH III skipped bisepoxide (JH SB3). A sublethal concentration of PPF was found to inhibit Krüppel homolog 1 (kr-h 1) gene expression and reduce aphid reproduction, but it did not significantly impact ecdysone receptor expression and aphid molting. The results of this study demonstrate that PPF exhibits a lethal effect on aphids, thereby providing an effective means of control. Additionally, sublethal concentrations of PPF have been found to inhibit the JH in aphids, resulting in a decline in their reproductive ability and achieving the desired control objectives. [ABSTRACT FROM AUTHOR]

As a hot topic in the field of computer vision, video action recognition has great application potential, such as intelligent monitoring, data recommendation and virtual reality. However, although convolutional neural network has achieved great success in the field of image classification, it has not ushered in its "AlexNet" moment in the field of action recognition, and temporal modeling is still the key and challenge of video action recognition. Aiming at the problem that spatiotemporal feature can not be fully used in video action recognition, a spatiotemporal feature enhancement network for action recognition is proposed. First of all, we designed a novel temporal feature aggregation module to enhance the short-range temporal features and enhance action related features. Then, we present a grouping convolution superposition module to expand the receptive field of temporal features and improve the learning ability of the network to long-term temporal and spatial features. Finally, experiments are conducted on the public action datasets UCF-101 and HMDB-51, and the experimental results demonstrate that the proposed method in this paper effectively enhances the fusion of spatiotemporal features and achieves high accuracy. [ABSTRACT FROM AUTHOR]

Due to the widespread use of lithium-ion batteries, evaluations of the flammability and explosive characteristics of carbon dust materials as anodes require attention. Carbon dust often reaches the micron/nano scale, and dust particle state and explosion risk generated in different industrial scenarios are different, which is in urgent need of research. Nanoscale dust has relatively static coagulation properties and shows characteristics of dispersion and reagglomeration under a certain airflow. The particle size characteristics affect its thermodynamic characteristics and various consequence parameters of dust explosion. The oxidation and combustion characteristics are mainly affected by dust particle size distribution characteristics. The apparent activation energy is mainly affected by the proportion of small and medium-sized particles and pre-exponential index factor is mainly affected by the dust overall average particle size and specific surface area. The explosion consequence parameters are affected by the thermodynamic parameters, by the disturbance state, particle distribution degree of dust cloud and other factors, which affect the heat radiation and heat transfer process to some extent resulting in different explosion consequence parameters. Due to the agglomeration characteristics of nano-level dust, the minimum ignition energy and minimum ignition temperature of nano-level dust are generally smaller than that of micron level dust. [ABSTRACT FROM AUTHOR]

Objectives The current study aimed to assess myocardial microcirculation dysfunction via cardiac magnetic resonance (CMR) first-pass perfusion imaging in children with Duchenne muscular dystrophy (DMD). Methods In total, 67 children with DMD and 15 controls who underwent contrast-enhanced CMR first-pass perfusion imaging were enrolled in this study. CMR first-pass perfusion and late gadolinium enhancement (LGE) sequences were acquired. Further, the global, regional, and coronary artery distribution area perfusion indexes (PI), upslope (%BL), maximum signal intensity (MaxSI), time to maximum signal intensity (TTM), and baseline SI were analysed. The perfusion parameters of the LGE positive (+), LGE negative (−), and control groups were compared. Pearson correlation analysis was performed to assess the association between myocardial microcirculation and conventional cardiac function and LGE parameters. Results The LGE+ group had a significantly lower global and apical-ventricular MaxSI than the control group (all P  <  .05). The left anterior descending arterial (LAD), left circumflex coronary arterial (LCX), and right coronary arterial (RCA) segments of the LGE+ group had a lower upslope and MaxSI than those of the control group (all P  <  .05). The LAD segments of the LGE− group had a lower MaxSI than those of the control group (41.10 ± 11.08 vs 46.36 ± 13.04; P  <  .001). The LCX segments of the LGE− group had a lower PI and upslope than those of the control group (11.05 ± 2.84 vs 12.46 ± 2.82; P  =  .001; 59.31 ± 26.76 vs 68.57 ± 29.99; P  =  .002). Based on the correlation analysis, the upslope, MaxSI, and TTM were correlated with conventional cardiac function and LGE extent. Conclusions Paediatric patients with DMD may present with microvascular dysfunction. This condition may appear before LGE and may be correlated with coronary artery blood supply and LGE extent. Advances in knowledge First-pass perfusion parameters may reveal the status of myocardial microcirculation and reflect the degree of myocardial injury at an earlier time in DMD patients. Perfusion parameters should be analysed not only via global or base, middle, and apical segments but also according to coronary artery distribution area, which may detect myocardial microvascular dysfunction at an earlier stage, in DMD patients with LGE−. [ABSTRACT FROM AUTHOR]