Search Results (223)

This paper presents an electromechanical coupling model integrating an equivalent magnetic network (EMN) model of a dual three-phase permanent magnet synchronous motor (DTP-PMSM) with the dynamic model of a helical planetary gear transmission system. Using this model, this study analyzes the dynamic characteristics of an electric drive system, specifically motor phase current, electromagnetic torque, and gear meshing force, under self-fault-tolerant control strategies. Simulation and experimental results demonstrate that the self-fault-tolerant control strategy enables rapid fault tolerance during open-phase faults, significantly reducing system fault recovery time. Meanwhile, compared to the open-phase faults conditions, the self-fault-tolerant control effectively suppresses most harmonic components within the system; only the second harmonic amplitude of the electromagnetic torque exhibited an increase. This harmonic disturbance propagates to the gear system through electromechanical coupling, synchronously amplifying the second harmonic amplitude in the gear system’s vibration response. This study demonstrates that self-fault-tolerant control strategies significantly enhance the dynamic response performance of the electric drive system under open-phase faults conditions. Furthermore, this study also investigates the electromechanical coupling mechanism through which harmonics generated by this strategy affect the gear system’s dynamic response, providing theoretical support for co-optimization electromechanical coupling design and fault-tolerant control in high-reliability electric drive transmission systems. Full article

After a ship suffers an external strike, the system is often in a poor state of battle damage. Currently, the support capacity of the system in all aspects decreases dramatically, the operation interval narrows, and it is not easy to ensure the completion of the long-term mission chain, especially when it involves impact loads, which is more significant. Given this, this paper proposes a restoration strategy for the power system of battle-damaged ships based on the long-term mission chain. First, the Ship Power System (SPS) is modelled and analyzed to obtain the multi-case operating characteristics of various types of loads, including impact loads under the mission chain. Second, the frequency and power support capability of energy storage is mined and quantified, and the limitations of its frequency support, power interaction, and other multi-operating states are characterized, based on which the multi-operating state switching strategy of the system containing energy storage is formed, to enhance the active support capability of the system. Subsequently, a frequency response model of the system is established. This model takes into account the support provided by energy storage, analyzes the dynamic evolution of system frequency under the disturbance of directly connected impact loads. Based on this analysis, the safe operating boundary of the system is identified. Finally, a two-stage SPS optimization model is proposed based on the above, and the effectiveness and superiority of this paper’s strategy are verified through simulation analysis of typical scenarios and comparison of multiple strategies. Full article

Mitochondria maintain cellular homeostasis through the dynamic balance of fusion and fission, which relies on nuclear-encoded mitochondrial fusion proteins, mitofusins 1 and 2 (Mfn1, Mfn2). Changes in Mfn1 and Mfn2 expression significantly affect mitochondrial fusion and fission, thereby affecting cellular metabolism. This study investigated the effect of Mfn1 expression on cell proliferation, apoptosis, and mitochondrial function by overexpressing Mfn1 (in OE-Mfn1 cells) and silencing Mfn1 using short hairpin RNA (shRNA) (in shMfn1 cells). Cell proliferation capacity, mitochondrial membrane potential, and mitochondrial ATP content were measured. To investigate the effects of Mfn1 on cellular metabolism and epigenetic modifications, the levels of metabolites α-KG, A-CoA, and SAM, as well as the levels of cellular methylation and acetylation, were detected by ELISA. Differentially expressed genes and metabolites were assessed by RNA-seq and LC-MS. This study demonstrates that alterations in Mfn1 gene expression can significantly affect mitochondrial metabolism and cell proliferation and apoptosis. In addition, Mfn1 affects the expression of genes encoding enzymes that are responsible for histone methylation and acetylation, thereby regulating these modifications. These findings provide a theoretical basis for further elucidation of the mechanisms by which Mfn1 affects cell proliferation, regulates metabolites, and modulates chromatin epigenetic modification. Full article

The incidence of fatal anaphylaxis is increasing, but there is still no recognized “golden standard” for forensic diagnosis. Due to its non-specific symptoms, especially cardiovascular symptoms without cutaneous changes, it can easily be misdiagnosed as acute myocardial infarction. Here, we established rat models (n = 12) of fatal anaphylaxis (FA), acute myocardial infarction (AMI), and coronary atherosclerosis with anaphylaxis (CAA). The untargeted metabolomics of plasma and 16S rRNA sequencing of fecal matter was performed, and a random forest was used to identify potential biomarkers. Three metabolites (tryptophan, trans-3-indole acrylic acid, and imidazole acetic acid) and three microbial genera (g_Prevotellaceae_Ga6A1_group, g_UCG_008, and g_Eubacterium_hallii_group) were identified as potential biomarkers for distinguishing anaphylaxis and non-anaphylaxis. The classification model of plasma metabolites showed a much better discriminatory performance than that of microbial genus, serum IgE, and tryptase. The performance of the microbial genera was superior to the serum IgE but inferior to the serum tryptase. Forensic samples of fatal anaphylaxis and non-anaphylaxis deaths (n = 12) were collected for untargeted metabolomics detection. The results showed that among the three identified metabolic biomarkers, tryptophan has better stability in cadaveric blood samples. Its diagnostic performance (AUC = 87.1528) was superior to serum IgE and tryptase, making it more suitable as a postmortem biomarker of fatal anaphylaxis. Full article

The association of gut microbiota with lymph node tuberculosis (LNTB) remains unexplored. This study employed metagenomic sequencing and plasma metabolomics analyses to investigate the role of gut microbiota in LNTB patients. Significant alterations in gut microbial diversity were observed in LNTB patients, characterized by a notable reduction in bacterial taxa involved in short-chain fatty acid (SCFA) synthesis, including Ruminococcus, Faecalibacterium, Roseburia, and Blautia, compared to healthy individuals. KEGG pathway analysis further revealed that gut dysbiosis could negatively impact SCFA biosynthesis and metabolism. Plasma metabolomics demonstrated disruptions in metabolites associated with SCFA synthesis and inflammation pathways in the LNTB group. Integrated analysis indicated significant correlations between specific gut microbiota (Blautia, Butyricicoccus, Coprococcus, Ruminococcus, Bacteroides, Clostridium) and plasma metabolites, including α-benzylbutyric acid, acetic acid, and succinic acid. Our findings demonstrate that gut microbiota dysbiosis and related metabolic dysfunction significantly reduce SCFA production in LNTB patients, potentially identifying novel therapeutic targets for LNTB management. Full article

Arc scanning synthetic aperture radar (ArcSAR) can achieve high-resolution panoramic imaging and retrieve submillimeter-level deformation information. To monitor buildings in a city scenario, ArcSAR must be lightweight; have a high resolution, a mid-range (around a hundred meters), and low power consumption; and be cost-effective. In this study, a novel high-resolution wide-beam single-chip millimeter-wave (mmwave) ArcSAR system, together with an imaging algorithm, is presented. First, to handle the non-uniform azimuth sampling caused by motor motion, a high-accuracy angular coder is used in the system design. The coder can send the radar a hardware trigger signal when rotated to a specific angle so that uniform angular sampling can be achieved under the unstable rotation of the motor. Second, the ArcSAR’s maximum azimuth sampling angle that can avoid aliasing is deducted based on the Nyquist theorem. The mathematical relation supports the proposed ArcSAR system in acquiring data by setting the sampling angle interval. Third, the range cell migration (RCM) phenomenon is severe because mmwave radar has a wide azimuth beamwidth and a high frequency, and ArcSAR has a curved synthetic aperture. Therefore, the fourth-order RCM model based on the range-Doppler (RD) algorithm is interpreted with a uniform azimuth angle to suit the system and implemented. The proposed system uses the TI 6843 module as the radar sensor, and its azimuth beamwidth is 64°. The performance of the system and the corresponding imaging algorithm are thoroughly analyzed and validated via simulations and real data experiments. The output image covers a 360° and 180 m area at an azimuth resolution of 0.2°. The results show that the proposed system has good application prospects, and the design principles can support the improvement of current ArcSARs. Full article

Hypoxia leads to endothelial dysfunction and increased blood–brain barrier (BBB) permeability, promoting the incidence of diseases such as stroke and acute high-altitude illness. Brain microvascular endothelial cells (BMECs) are important structural and functional components of the BBB; however, the molecular changes that occur in BMECs during hypoxia remain unknown. We reported the molecular and functional changes in BMECs under hypoxia through whole-transcriptome sequencing, small RNA microarray, TMT quantitative proteomic, and untargeted metabolomic analyses. We found that hypoxia affected pathways such as ncRNA processing, the HIF-1 signaling pathway, the cell cycle, DNA replication, glucose metabolism, protein synthesis, and inflammation pathways. ncRNA processing was significantly downregulated. However, the levels of some miRNAs, tRNAs, tsRNAs, snoRNAs, lncRNAs, and circRNAs were significantly upregulated under hypoxia. These results suggest that ncRNAs may play an important role in oxidative stress and cellular adaptation to hypoxia, helping us understand the pathological process of BBB injury and providing potential targets for the treatment of BBB-related cerebrovascular diseases. Full article

When the shield machines are constructed in soft soil, excavation may be impeded by the accumulation of cutter head mud. Geological conditions and shield construction are identified as the main factors for cutter head mud formation, based on analysis of its mechanism. In addition to traditional metrics, the imperforation area in the cutter head center is incorporated into the analysis of shield construction factors. The Analytic Hierarchy Process (AHP) is utilized to establish a risk assessment model for shield cutter head mud cake, determining the weight of each sub-factor and enabling a preliminary risk assessment of mud cake occurrence. This study applies Analytic Hierarchy Process (AHP) to classify the factors affecting shield mud by using the Mawan cross-sea channel construction project (Moon Bay Avenue along the Yangtze River) as a case study. Each factor is scored and weighted according to established scoring criteria and evaluation formulas, and then the results of the risk of shield mud cake in the Mawan tunnel are obtained. Moreover, field observations validate the proposed risk model, with the derived risk index demonstrating strong alignment with actual data. Full article

Alginate oligosaccharides (AOSs) have been shown to be effective in enhancing crop growth. However, their functions in horticulture crops and growth-promoting mechanisms remain insufficiently characterized. This study employed pot cultivation experiments to investigate the effects of AOS root drenching (0, 15, 30, 45 mg·L⁻¹) on tomato (Solanum lycopersicum L.) seedling growth, photosynthetic performance, and phytohormone accumulation. The results showed that AOS promoted the leaf count per plant, leaf area of the youngest fully expanded leaves, shoot and root dry mass, chloroplast pigment contents and photosynthetic rate of tomato seedlings. And the 30 mg·L⁻¹ treatment consistently showed optimal efficacy, in which tomato seedlings also exhibited a significantly longer total root length, a larger root surface area and a greater number of root tips compared to the control. Phytohormone profiling revealed that AOS differentially regulated shoot/root phytohormones as follows: increasing auxins/cytokinins (CKs)/GA₁₉ content in shoots and Indole-3-acetic acid (IAA)/CKs/1-aminocyclopropane-1-carboxylic acid (ACC) content in roots, while decreasing root Jasmonic acid (JA)/5-deoxystrigol (5DS) contents. Finally, these findings demonstrate that AOS enhances tomato growth by coordinately reprogramming phytohormone homeostasis. Full article

Coal mines play an important role in the global energy supply. Monitoring the displacement of open-pit mines is crucial to preventing geological disasters, such as landslides and surface displacement, caused by high-intensity mining activities. In recent years, multi-temporal Synthetic Aperture Radar Interferometry (InSAR) technology has advanced and become widely used for monitoring the displacement of open-pit mines. However, the scattering characteristics of surfaces in open-pit mining areas are unstable, resulting in few coherence points with uneven distribution. Small BAseline Subset InSAR (SABS-InSAR) technology struggles to extract high-density points and fails to capture the overall displacement trend of the monitoring area. To address these challenges, this study focused on the Shengli West No. 2 open-pit coal mine in eastern Inner Mongolia, China, using 201 Sentinel-1 images collected from 20 May 2017 to 13 April 2024. We applied both SBAS-InSAR and distributed scatterer InSAR (DS-InSAR) methods to investigate the surface displacement and long-term behavior of the open-pit coal mine over the past seven years. The relationship between this displacement and mining activities was analyzed. The results indicate significant land subsidence was observed in reclaimed areas, with rates exceeding 281.2 mm/y. The compaction process of waste materials was the main contributor to land subsidence. Land uplift or horizontal displacement was observed over the areas near the active working parts of the mines. Compared to SBAS-InSAR, DS-InSAR was shown to more effectively capture the spatiotemporal distribution of surface displacement in open-pit coal mines, offering more intuitive, comprehensive, and high-precision monitoring of open-pit coal mines. Full article

To address the issues of poor Co²⁺ regeneration and limited interfacial electron transfer in heterogeneous catalytic systems, this study proposes the synthesis of highly efficient and stable Co₃O₄/ZnO composites through the pyrolysis–oxidation reaction of Co/Zn MOFs for the degradation of rhodamine B (RhB) using activated peroxymonosulfate (PMS). The results confirmed that the catalyst exhibited a high electron transfer capacity, and the synergistic effect between the bimetals enhanced the reversible redox cycle of Co³⁺/Co²⁺. Under optimal conditions, complete removal of RhB was achieved in just 6 min using the Co₃O₄/ZnO composite, which demonstrated excellent stability after five cycles. Furthermore, the catalyst exhibited a high degradation efficiency in real water samples with a total organic carbon (TOC) removal rate of approximately 65% after 60 min. The electrochemical measurements, identification of active species, and X-ray photoelectron spectroscopy (XPS) analysis revealed that non-radicals (¹O₂ and direct charge transfer) played a major role in the degradation of RhB. Finally, the potential mechanisms and degradation pathways for RhB degradation using this catalyst were systematically investigated. This study opens new avenues for the development of efficient and stable PMS catalysts, and provides insights into the preparation of other emerging metal oxides. Full article

Bacterial chemoreceptors sense extracellular stimuli and drive bacteria toward a beneficial environment or away from harm. Their ligand-binding domains (LBDs) are highly diverse in terms of sequence and structure, and their ligands cover various chemical molecules that could serve as nitrogen, carbon, and energy sources. The mechanism of how this diverse range of LBDs senses different ligands is essential to signal transduction. Previously, we reported that the chemoreceptor MCP2201 from Comamonas testosteroni CNB-1 sensed citrate and L-malate, altered the ligand-free monomer–dimer equilibrium of LBD to citrate-bound monomer (with limited monomer) and L-malate-bound dimer, and triggered positive and negative chemotactic responses. Here, we present our findings, showing that D-malate binds to MCP2201, induces LBD dimerization, and triggers the chemorepellent response exactly as L-malate did. A single site mutation, T105A, can alter the D-malate-bound LBD dimer into a monomer–dimer equilibrium and switch the negative chemotactic response to D-malate to a positive one. Differences in attractant-bound LBD oligomerization, such as citrate-bound wildtype LBD monomer and D-malate-bound T105A dimer, indicated that LBD oligomerization is a consequence of signal transduction instead of a trigger. Our study expands our knowledge of chemoreceptor-sensing ligands and provides insight into the evolution of bacterial chemoreceptors. Full article

This work is a continuation of our previous research. We successfully produce low-carbon gear steel containing trace tellurium (Te) through industrial production line (EAF-LF-VD-CC), and we investigate the effects of a trace Te addition on the precipitation of MnS inclusions in sulfur-containing gear steel billets, the machinability of rods, and the high-temperature vacuum carburizing performance of rods. This study demonstrates that the addition of trace Te in steel can be achieved in industrial production without causing disruptions in the steelmaking process. The Te addition effectively induces spheroidization and refinement of MnS inclusions in industrial cast billets, showing good consistency with laboratory Te alloying experimental results. Furthermore, the Te addition reduces the deformation rate of MnS inclusions during industrial rolling processes. Benefiting from the spheroidization of MnS inclusions, the chip-breaking performance during the machining of Te-containing rods is significantly optimized, along with substantial improvement in machined surface roughness. The industrial rods exhibit excellent grain stability during 960 °C high-temperature vacuum carburizing, with carburizing rates significantly enhanced compared to conventional gear steels. This work comprehensively demonstrates the multifaceted effects of Te treatment on gear steel properties, particularly providing valuable references for developing high-temperature carburizing gear steels. Full article

Due to its sensitivity to cold temperatures, cucumber growth is substantially constrained by suboptimal temperature stress in northern China’s off-season production systems. Suboptimal temperatures severely repress the nutrient absorption, growth, and yield formation of vegetables in solar greenhouses during winter and early spring in China. Alginate oligosaccharides (AOSs) are anionic acidic polysaccharides derived from brown algae, known for promoting plant growth and alleviating abiotic stress. In this study, we aimed to investigate the effects of different nutrient solution concentrations combined with AOS on the growth and nutrient uptake of cucumber seedlings under suboptimal temperatures (15/8 °C, day/night). Potted ‘Jinchun 4’ cucumber seedlings grown in coconut coir were treated with 0.5×, 1.0×, or 1.5× strength of Hoagland solution alone (N0.5, N1, N1.5), or with 30 mg·L⁻¹ AOS (A0.5, A1, A1.5). The results showed that the growth attributes and nitrogen (N) accumulation of cucumber plants of N1 and N1.5 were significantly higher than those of N0.5. Additionally, plants of A0.5 exhibited significantly higher plant height, chlorophyll a content, root surface area, root volume, root vitality, N metabolism enzyme (NR, GDH, GS) activities, and N accumulation, than those under N0.5, N1, or N1.5. Moreover, compared to A0.5, the net photosynthetic rate, total root length, root surface area, root N content, leaf nitrate reductase activity, root glutamate dehydrogenase activity, and N accumulation of A1 and A1.5 were significantly higher than those of A0.5. Correlation analysis revealed strong linkages between root morphology traits and tissue N content. In summary, under suboptimal temperature conditions, the application of AOS improved cucumber seedlings’ nutrient absorption and growth more efficiently than merely raising nutrient levels, as it enhanced root surface area, root vitality, and N metabolic enzyme activities. Full article

In response to the increasingly severe energy consumption problem and to promote energy saving and emission reduction, this study aims to design and apply an energy management system platform based on artificial intelligence (AI) technology. The system adopts sensor technology and data acquisition equipment to monitor various types of energy consumption in buildings in real time, efficiently process and predict these data through machine learning algorithms, and finally visualize the results. The system is functionally complete, completing the process from data collection to visualization, the cloud platform’s construction, and finally a full energy management platform. Various machine learning methods are applied to energy management by predicting the chilled water energy meter return temperature of the central air-conditioning system and comparing its performance. Among the various types of regression algorithms, the mean-square error (MSE) of decision tree regression is 0.36, the MSE of support vector regression (SVR) is 0.09, the MSE of K-nearest neighbor (KNN) regression is 0.57, and the MSE of extreme gradient boosting (XGBoost) regression is 0.32. The SVR, the XGBoost regression, and the decision tree regression perform better in various indices. Full article