Search Results (1,077)

This paper focuses on the sealing failure problem of double-lip seal rings for high-speed ball bearings used in unmanned aerial vehicles. By using ANSYS 2023R1 software, a thermal–stress–wear coupled finite element model was established. Taking the contact pressure and volume loss due to wear as indicators to evaluate sealing performance, this study analyzed the influence of lip seal structural parameters on sealing performance, performed response surface optimization of the seal structure parameters and conducted a comparative test on lip seals before and after optimization. The research results show that the contact pressure at the main lip of the lip seal was the greatest, which was 0.79 MPa, and the volume loss due to wear lip seal was 7.94 × 10⁻⁷ mm³. Optimal sealing performance is achieved when the seal lip inclination angle is 41.68°, the middle width of the lip seal is 0.153 mm, the main lip height is 0.179 mm, the spring center distance is 0.37 mm and the radial interference is 0.0034 mm. After optimization, the grease leakage rate of the sealing ring decreased by 48% compared to before optimization. Full article

Molecular chaperones, especially heat shock proteins (HSPs) have vital functions in cells’ responses to stress. Here, we cloned and sequenced the complete complementary DNA encoding HSP90 (MjHSP90) from the shrimp Marsupenaeus japonicus. The MjHSP90 cDNA comprised 3162 bp, including a 2172 bp coding region encoding a 724 amino acid-protein (predicted molecular mass = 83.12 kDa). Homology and phylogenetic analyses showed that MjHSP90 was highly conserved and most homologous to Litopenaeus vannamei HSP90. MjHSP90 is expressed in all tested tissues, with high expression in gill tissue and the hepatopancreas. Cold stress significantly upregulated MjHSP90 expression in the gill and hepatopancreas (p < 0.05). Following RNA interference knockdown of MjHSP90, the cold stress-related death rate of the shrimp increased significantly, accompanied by significantly upregulated expression of apoptosis-related genes Mjcaspase-3 and Mjbcl-2 (p < 0.05) and an increase in the number of apoptotic cells. The results indicated that MjHSP90 might play a pivotal role in the shrimp’s immune response to cold stress. Full article

Poliovirus represents an oncolytic agent for human glioblastoma—one of the most aggressive types of cancer. Since interference of viruses with metabolic and redox pathways is often linked to their pathogenesis, drugs targeting metabolic enzymes are regarded as potential enhancers of oncolysis. Our goal was to reveal an imprint of poliovirus on the metabolism of glioblastoma cell lines and to assess the dependence of the virus on these pathways. Using GC-MS, HPLC, and Seahorse techniques, we show that poliovirus interferes with amino acid, purine and polyamine metabolism, mitochondrial respiration, and glycolysis. However, many of these changes are cell line- and culture medium-dependent. 2-Deoxyglucose, the pharmacologic inhibitor of glycolysis, was shown to enhance the cytopathic effect of poliovirus, pointing to its possible repurposing as an enhancer of oncolysis. Inhibitors of polyamine biosynthesis, pyruvate import into mitochondria, and fatty acid oxidation exhibited antiviral activity, albeit in a cell-dependent manner. We also demonstrate that poliovirus does not interfere with the production of superoxide anions or with levels of H₂O₂, showing an absence of oxidative stress during infection. Finally, we showed that a high rate of poliovirus replication is associated with fragmentation of the mitochondrial network, pointing to the significance of these organelles for the virus. Full article

Horizontal well fracturing is vital for low-permeability tight oil reservoirs, but multi-fracture effectiveness is hampered by stress shadowing and fluid-rock interactions, particuarly in optimizing fracture geometry and conductivity under different sequencing strategies. While previous studies have addressed aspects of pore pressure and stress effects, a comprehensive comparison of sequencing strategies using fully coupled models capturing the intricate seepage–stress–damage interactions remains limited. This study employs a novel 2D fully coupled XFEM model to quantitatively evaluate three fracturing approaches: simultaneous, sequential, and alternating. Numerical results demonstrate that sequential and alternating strategies alleviate stress interference, increasing cumulative fracture length by 20.6% and 26.1%, respectively, versus conventional simultaneous fracturing. Based on the research findings, fracture width reductions are 30.44% (simultaneous), 18.78% (sequential), and 7.21% (alternating). As fracture width directly governs conductivity—the critical parameter determining hydrocarbon flow efficiency—the alternating strategy’s superior width preservation (92.79% retention) enables optimal conductivity design. These findings provide critical insights for designing fracture networks with targeted dimensions and conductivity in tight reservoirs and offer a practical basis to optimize fracture sequencing design. Full article

With the development of underground space in urban areas, the demand for tunneling through existing railways is increasing. The adverse effects of cut-blasting during the construction of tunnels under crossing existing railways are investigated. Combined with the principle of blasting seismic wave superposition, LS-DYNA numerical simulation is used to analyze the seismic wave superposition law under different superposition methods. This study also investigates the vibration reduction effect of millisecond blasting for cut-blasting under the different classes of surrounding rocks. The results show that the vibration reduction forms of millisecond blasting can be divided into separation and interference of waveform. Based on the principle of superposition of blasting seismic waves, vibration reduction through wave interference is further divided. At the same time, a new vibration reduction mode is proposed. This vibration reduction mode can significantly improve construction efficiency while improving damping efficiency. The new vibration reduction mode can increase the vibration reduction to 80% while improving construction efficiency. Additionally, there is a significant difference in the damping effect of different classes of surrounding rock on the blasting seismic wave. Poor-quality surrounding rock enhances the attenuation of seismic wave velocity and peak stress in the surrounding rock. In the Zhongliangshan Tunnel, a tunnel cut-blasting construction at a depth of 42 m, the best vibration reduction plan of Class III is 3 ms millisecond blasting, in which the surface points achieve separation vibration reduction. The best vibration reduction plan of Class V is 1 ms millisecond blasting, in which the surface points achieve a new vibration reduction mode. During the tunnel blasting construction process, electronic detonators are used for millisecond blasting of the cut-blasting. This method can reduce the vibration effects generated by blasting. The stability of the existing railway is ultimately guaranteed. This can improve construction efficiency while ensuring construction safety. This study can provide significant guidance for the blasting construction of the tunnel through the railway. Full article

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a major pest of soybean fields. While high-temperature stress induced by global warming can initially suppress aphid populations, these pests may eventually adapt, leading to more severe infestations and crop damage. Heat shock proteins (HSPs), which are upregulated in response to heat stress to protect aphid development, also confer tolerance to other abiotic stressors, including insecticides. To investigate the role of HSPs in insecticide resistance in A. glycines, we analyzed the expression profiles of three AgHsp90 genes (AgHsp75, AgHsp83, and AgGrp94) following exposure to high temperatures and insecticides. Functional validation was performed using RNA interference (RNAi) to silence AgHsp90 genes. Our results demonstrated that AgHsp90 genes were significantly upregulated under both heat and insecticide stress conditions. Furthermore, after feeding on dsRNA of AgHsp90 genes, mortality rates of A. glycines significantly increased when exposed to imidacloprid and lambda-cyhalothrin. This study provides evidence that AgHsp90 genes play a crucial role in mediating thermal tolerance and insecticide resistance in A. glycines. Full article

This review article aims to provide an overview of superconducting magnetic quantum sensors and their applications in the biomedical field, particularly in the neurological field. These quantum sensors are based on superconducting quantum interference devices (SQUIDs), the operating principles of which will be presented along with the most relevant characteristics. Emphasis will be placed on the magnetic flux and magnetic field noise, which are essential for applications, especially brain investigations requiring ultra-high magnetic field sensitivity. The main configurations of SQUID magnetometers used for highly sensitive applications will be shown, stressing their design aspects. In particular, the configurations based on the superconducting flux transformer and the multiloop will be explained. We will discuss the most critical application of SQUID magnetometers, magnetoencephalography, which measures the weak magnetic signals produced by neuronal currents. Starting from the realization of a multichannel system for magnetoencephalography, we will present an accurate comparison with recent systems using optically pumped magnetometers. Finally, we will discuss the main clinical applications of magnetoencephalography. Full article

Fiber Bragg grating (FBG) exhibits strong resistance to electromagnetic interference and excellent linear strain response, making it highly promising for structural health monitoring (SHM) in pavement. This research investigates the strain transfer characteristics of embedded FBG in pavement structure and materials by using the relevant theoretical models. Results indicate adhesive layer thickness and sheath modulus are the primary factors influencing the strain transfer coefficient. A thinner adhesive layer and high modulus of sheath enhance the coefficient. Additionally, the strain distribution of sheath significantly affects the transfer efficiency. When the stress level near the grating region is lower than the both ends, the coefficient increases and even exceeds 1, which typically occurs under multi-axle conditions. As for asphalt mixture, high temperature leads to lower efficiency, while accumulated plastic strain improves it. Although the increased load frequency results a higher strain transfer coefficient, the magnitude of this change is negligible. By employing polynomial fitting to the sheath strain distribution, the boundary condition of theoretical equation could be removed. The theoretical and numerical results of strain transfer coefficient for pavement embedded FBG demonstrate good consistency, indicating the polynomial fitting is adoptable for the theoretical calculation with non-uniform strain distribution. This study utilizes the FEM to clarify the evolution of FBG strain transfer in pavement structures and materials, providing a theoretical basis for the design and implementation of embedded FBG in pavement. Full article

The functional role of MAPKK genes in potato (Solanum tuberosum L.) under high-temperature stress remains unexplored, despite their critical importance in stress signaling and yield protection. We characterized StMAPKK1, a novel group D MAPKK localized to plasma membrane/cytoplasm. Quantitative real-time polymerase chain reaction (qRT-PCR) revealed cultivar-specific upregulation in potato (‘Atlantic’ and ‘Desiree’) leaves under heat stress (25 °C, 30 °C, and 35 °C). Transgenic lines overexpressing (OE) StMAPKK1 exhibited elevated antioxidant enzyme activity, including ascorbate peroxidase (APX), catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD), mitigating oxidative damage. Increased proline and chlorophyll accumulation and reduced oxidative stress markers, hydrogen peroxide (H₂O₂) and malondialdehyde (MDA), indicate improved cellular redox homeostasis. The upregulation of key antioxidant and heat stress-responsive genes (StAPX, StCAT1/2, StPOD12/47, StFeSOD2/3, StMnSOD, StCuZnSOD1/2, StHSFA3 and StHSP20/70/90) strengthened the enzymatic defense system, enhanced thermotolerance, and improved photosynthetic efficiency, with significant improvements in net photosynthetic rate (Pn), transpiration rate (E), and stomatal conductance (Gs) under heat stress (35 °C) in StMAPKK1-OE plants. Superior growth and biomass (plant height, plant and its root fresh and dry weights, and tuber yield) accumulation, confirming the positive role of StMAPKK1 in thermotolerance. Conversely, RNA interference (RNAi)-mediated suppression of StMAPKK1 led to a reduction in enzymatic activity, proline content, and chlorophyll levels, exacerbating oxidative stress. Downregulation of antioxidant-related genes impaired ROS scavenging capacity and declines in photosynthetic efficiency, growth, and biomass, accompanied by elevated H₂O₂ and MDA accumulation, highlighting the essential role of StMAPKK1 in heat stress adaptation. These findings highlight StMAPKK1’s potential as a key genetic target for breeding heat-tolerant potato varieties, offering a foundation for improving crop resilience in warming climates. Full article

Hierarchical surface structuring is a critical aspect of advanced materials design, impacting fields ranging from optics to biomimetics. Among several laser-based methods for complex structuring of photo-responsive surfaces, the broadband vectorial interferometry proposed here offers unique performances. Such a method leverages a polychromatic laser source, an unconventional choice for holographic encoding, to achieve deterministic multiscale surface structuring through interference light patterning. Azopolymer films are used as photosensitive substrates. By exploring the interaction between optomechanical stress modulations at different spatial periodicities induced within the polymer bulk, we demonstrate the emergence of hierarchical Fourier surfaces composed of multiple deterministic levels. These structures range from sub-micrometer to tens of micrometers scale, exhibiting a high degree of control over their morphology. The experimental findings reveal that the optical encoding scheme significantly influences the resulting topographies. The polarization light patterns lead to more regular and symmetric hierarchical structures compared to those obtained with intensity patterns, underscoring the role of vectorial light properties in controlling surface morphologies. The proposed method is fully scalable, compatible with more complex recording schemes (including multi-beam interference), and it is applicable to a wide range of advanced technological fields. These include optics and photonics (diffractive elements, polarimetric devices), biomimetic surfaces, topographical design, information encoding, and anti-counterfeiting, offering a rapid, reliable, and versatile strategy for high-precision surface structuring at a submicrometric scale. Full article

The proliferation of telecommunication devices in recent decades has resulted in a substantial increase in exposure risk to manmade radiofrequency electromagnetic fields (RF-EMFs) for both animals and plants. The physiological effects of these exposures remain to be fully elucidated. In this study, we measured and analyzed the chlorophyll fluorescence rise kinetics of lettuce plants in the presence of RF-EMFs and after a short drought treatment. The analysis of the fluorescence data was conducted using two different strategies: a conventional JIP test and a novel machine learning-assisted anomaly-detection approach. Our results suggest that exposure to RF-EMFs weakens the plant’s hormetic responses induced by drought treatment, both in terms of the response’s magnitude and its extent. These findings provide further evidence supporting the hypothesis that RF-EMFs interfere with plant stress responses. Full article

Nanoplastics (NPs), an emerging class of environmental pollutants, are increasingly recognized for their potential to interfere with critical cellular processes. Autophagy, a conserved degradative pathway essential for maintaining cellular homeostasis and adaptation to stress, has recently become a focal point of nanotoxicology research. This review synthesizes current evidence on the interactions between NPs and autophagic pathways across diverse biological systems. Findings indicate that NPs can trigger autophagy as an early cellular response; however, prolonged exposure may lead to autophagic dysfunction, contributing to impaired cell viability and disrupted signaling. Particular attention is given to the physiochemical properties of NPs such as size, surface charge, and polymer type, which influence cellular uptake and intracellular trafficking. We also highlight key mechanistic pathways, including oxidative stress and mTOR modulation. Notably, most available studies focus almost exclusively on polystyrene (PS)-based NPs, with limited data on other types of polymers, and several reports lack comprehensive assessment of autophagic flux or downstream effects. In conclusion, a better understanding of NP–autophagy crosstalk—particularly beyond PS—is crucial to evaluate the real toxic potential of NPs and guide future research in human health and nanotechnology. Full article

The totem-pole bridgeless power factor correction (PFC) circuit based on the triangular current mode (TCM) in the front-end PFC of a switching power supply has the advantage of realizing zero-voltage switching (ZVS) in the full working range. However, the TCM control based on the critical conduction mode (CRM) further increases the inductance current ripple, and the traditional input voltage AC sampling circuit increases the circuit complexity and device cost. Therefore, this paper studies the corresponding improvement technology from two dimensions. Firstly, the coordinated interleaved parallel technology is employed to design the system’s overall control-improvement strategy. This approach not only achieves full working-range ZVS but also reduces both the inductor current ripple and power device stress. Simultaneously, an optimized input voltage sampling circuit is designed to accommodate varying voltage requirements of control chip pins. This circuit demonstrates strong synchronization in both voltage and phase sampling, and the structural characteristics of the optocoupler can also suppress electrical signal interference. Finally, a 600 W totem-pole bridgeless PFC prototype is developed. The experimental results demonstrate the effectiveness of the proposed improved method. The prototype efficiency peak reaches 97.3%. Full article

In high-voltage transmission lines, insulators subjected to prolonged electromechanical stress are prone to zero-value defects, leading to insulation failure and posing significant risks to power grid reliability. The conventional detection method of spark gap is vulnerable to environmental interference, while the emerging electric field distribution-based techniques require complex instrumentation, limiting its applications in scenes of complex structures and atop tower climbing. To address these challenges, this study proposes an electroluminescent sensing strategy for zero-value insulator identification based on the electroluminescence of ZnS:Cu. Based on the stimulation of electrical stress, real-time monitoring of the health status of insulators was achieved by applying the composite of epoxy and ZnS:Cu onto the connection area between the insulator steel cap and the shed. Experimental results demonstrate that healthy insulators exhibit characteristic luminescence, whereas zero-value insulators show no luminescence due to a reduced drop in electrical potential. Compared with conventional detection methods requiring access of electric signals, such non-contact optical detection method offers high fault-recognition accuracy and real-time response capability within milliseconds. This work establishes a novel intelligent sensing paradigm for visualized condition monitoring of electrical equipment, demonstrating significant potential for fault diagnosis in advanced power systems. Full article

Hypochlorous acid (HClO) serves as a biological mediator and is widely utilized as a disinfectant in food processing and water treatment. However, excessive HClO residues in food and environmental water raise concerns due to the potential formation of carcinogenic chlorinated byproducts and disinfection byproducts (DBPs). Despite its importance, traditional methods for HClO detection often involve complex sample preparation, sophisticated instrumentation, and skilled operators. Herein, we report an aggregation-induced emission (AIE) small molecule fluorescent probe (NYV) that integrates colorimetric and ratiometric fluorescence responses for the detection of HClO. This probe exhibits high sensitivity, with a detection limit of 0.35 $\mathsf{\mu }$M, a rapid response time of 1 min, and a wide linear range (0–142.5 $\mathsf{\mu }$M), along with anti-interference capabilities, making it suitable for real-time monitoring. Furthermore, we have developed a portable solid-state sensor based on probe NYV for the rapid visual detection of HClO. The potential applications of this probe in real sample analysis and bioimaging experiments are demonstrated. Our findings contribute to the development of innovative fluorescent probes for HClO detection, with broad applications in food safety, environmental monitoring, and biomedical research on oxidative stress and ferroptosis. Full article