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Objective To explore the effect of hypoxia on cell migration and fusion of urine-derived stem cells (USCs) in vitro, and observe the changes in cytoskeleton and cell polarity during the process. Methods After USCs were cultured under normoxia (20%) or hypoxia (3%) for 48 h, cell migration were detected by cell scratch test and Transwell assay, USCs' fusion with hepatic HP14-19 and HepG2 cells were observed and determined using confocal microscopy and flow cytometry, and structure of cytoskeleton was observed with transmission electron microscopy (TEM) and phalloidin fluorescence probe. The expression of cell polarity related proteins, RhoA, Cdc42 and Rac1 was measured with immunofluorescence staining, flow cytometry and real-time PCR. Results The USCs from the hypoxia group showed stronger migration capacity and cell fusion with hepatocytes when compared with the cells from the normoxia group. The results of TEM and phalloidin fluorescence staining revealed that hypoxia induced remodeling of cytoskeleton, and regularly and well-arranged microfilament and microtubule. The results of immunofluorescence staining, flow cytometry and real-time PCR indicated that the expression levels of cell polarity related proteins RhoA, Cdc42 and Rac1 were much higher in the hypoxia group than in the normoxia group. Conclusion Hypoxia preconditioning promotes cell migration and fusion in USCs, which may be associated with cytoskeleton remodeling and up-regulation of cell polarity.

Performance degradation assessment methods for rolling bearings under vibration signal monitoring typically involve extracting signal degradation features and inputting them directly into unoptimized assessment models. However, this method often fails to characterize degradation trends and detect early faults in bearings effectively. Moreover, it is susceptible to interference from outliers and false signal fluctuations, posing challenges for accurate performance degradation assessment. To solve the above problems, a novel performance degradation assessment method of rolling bearings based on optimized variational mode decomposition to construct the maximum information degradation feature set and improved hippopotamus optimization algorithm optimized fuzzy support vector data description is proposed. This method effectively suppresses the signal degradation feature pollution caused by the redundancy of irrelevant frequency components, realizes the screening of effective degradation feature sets, and further improves the accuracy of bearing performance degradation assessment. Through experimental verification, this research method uses early healthy rolling bearing samples to establish an assessment model, which can adaptively determine the starting point and degradation trend of bearing degradation. In comparison with other methods for performance degradation assessment under vibration monitoring, it offers distinct advantages. [ABSTRACT FROM AUTHOR]

Exploring and discovering various types of skyrmions has enriched the fundamental study and the active skyrmionics aiming at using skyrmions in spintronics due to the advantages of global stability as high-density magnetic information bit. The unique capability to introduce abundant spin structures, physical phenomena, and dynamics due to the interactions of 4f and 3d electrons push the rare-earth–transition metal (RE–TM) magnets into the research frontier again. Herein, the exotic magnetic domain configurations are discovered in traditional ThMn12-type RE–TM magnets. It is clearly demonstrated that the magnetic anisotropy alteration and magnetic coupling between the respective RE and TM sublattices are responsible for the abundant magnetic domain evolution. In particular, the field-free biskyrmions at room temperature and tunable spin texture transformation are successfully obtained via manipulating the in-plane magnetic anisotropy, which has broadened the physical mechanism and application exploration of manipulating ferrimagnetic order to generate topological spin structures in strategic rare-earth magnets. [ABSTRACT FROM AUTHOR]

The geometry of an orifice is a major determinant of nozzle internal flow and cavitation, which directly govern spray atomization and consequently affect combustion and fuel economy in internal combustion engines. In this study, simulation models of the nozzle at different angles between the normal and the injection hole inlet cross-section and the injection hole axis, as well as with different injection hole cone angles (a positive angle between the injection hole axis and its walls implies a divergent hole), were investigated by means of a previously developed numerical model that was validated based on experimental data from X-ray image technology. The results indicate that as the angle between the normal and the injection hole inlet cross-section and the injection hole axis increases, the cavitation asymmetry within the injection hole intensifies, accompanied by a decrease in the gas volume fraction. On one side of the injection hole, the hydraulic flip width expands, while, on the other side of the injection hole, the flow state gradually changes from hydraulic flip to super-cavitation flow, transitional cavitation and fully reattached flow. The divergent orifice layout intensifies cavitation, and the higher the positive injection hole cone angle, the bigger the hydraulic flip width. The convergent layout of the injection hole suppresses cavitation, and cavitation inside the nozzle disappears completely when the injection hole cone angle is less than −10°. [ABSTRACT FROM AUTHOR]

High-strength concrete (HSC) boasts excellent compressive strength and durability, making it a popular choice in various engineering applications. However, under the impact of high temperatures, HSC tends to crack easily, so it is combined with polyvinyl alcohol fiber (PVA fiber) to explore its engineering application prospect. This paper investigated the physical and mechanical characteristics of HSC reinforced with PVA fibers subjected to different heating temperatures and cooling techniques. The experimental results reveal a correlation between rising temperatures and observable changes in the specimens: a progressively lighter surface hue, an augmented frequency of cracking, and a considerable escalation in the mass loss rate, particularly after the temperature exceeds 400 °C. Regarding mechanical properties, the dynamic elastic modulus and compressive and flexural strength all decrease as the heating temperature increases. As the amount of PVA fiber rises while maintaining a steady temperature, these measurements initially show an increase followed by a decrease. The fiber contents yielding the best compressive and flexural strength are 0.2% and 0.3%, in that order. Considering the influence of cooling methods, water spray cooling has a greater impact on physical and mechanical properties than natural cooling. Furthermore, SEM was employed to scrutinize the microstructure of HSC, enhancing comprehension of the alterations in its physical and mechanical characteristics. The findings of this research offer significant information regarding the high-temperature behavior of HSC, serving as a valuable resource for guiding the design, building, and upkeep of structures that incorporate HSC. Additionally, this study will aid in advancing the progress and utilization of HSC technology. [ABSTRACT FROM AUTHOR]

Background: In this prospective cohort study, we determined the phenotypic characteristics of children with regressive autism spectrum disorder (ASD) and explored the effects of rehabilitation. Methods: We recruited 370 children with ASD aged 1.5–7 years. Based on the Regression Supplement Form, the children were assigned to two groups: regressive and non-regressive. The core symptoms and neurodevelopmental levels of ASD were assessed before and after 1 year of behavioral intervention using the Autism Diagnostic Observation Schedule (ADOS), Social Response Scale (SRS), Children Autism Rating Scale (CARS), and Gesell Developmental Scale (GDS). Results: Among the 370 children with ASD, 28.38% (105/370) experienced regression. Regression was primarily observed in social communication and language skills. Children with regressive ASD exhibited higher SRS and CARS scores and lower GDS scores than those with non-regressive ASD. After 1 year of behavioral intervention, the symptom scale scores significantly decreased for all children with ASD; however, a lesser degree of improvement was observed in children with regressive ASD than in those with non-regressive ASD. In addition, the symptom scores of children with regressive ASD below 4 years old significantly decreased, whereas the scores of those over 4 years old did not significantly improve. Children with regressive ASD showed higher core symptom scores and lower neurodevelopmental levels. Nevertheless, after behavioral intervention, some symptoms exhibited significant improvements in children with regressive ASD under 4 years of age. Conclusion: Early intervention should be considered for children with ASD, particularly for those with regressive ASD. [ABSTRACT FROM AUTHOR]

High-strength concrete (HSC) has a high compressive strength, high density, excellent durability, and seepage resistance, but its deformation ability is weak. Adding fibers can improve the physical and mechanical properties of HSC. Additionally, the HSC structure may face the threat of fire. In the process of fire extinguishing, the damage mechanism of high-temperature-resistant concrete is complicated due to the different contact conditions with water at different locations. Hence, it is essential to conduct pertinent research on the behavior of fiber-reinforced HSC with different cooling methods after high-temperature action. In this paper, polyvinyl alcohol fiber (PVA fiber) was selected to be added into the HSC to carry out high-temperature experimental research, so as to explore the apparent changes, failure pattern, and mass loss rate of the fiber-reinforced HSC using different cooling methods and analyze the influence of its residual compressive strength and flexural strength. The test results suggest that, with the increase in heating temperature, the color of the specimen's surface transitions from dark blue-gray to white, and the quantity of surface cracks on the specimen gradually rises. The mechanical strength gradually decreases as the heating temperature increases. At a consistent heating temperature, the mechanical strength initially rises, and then falls with an increase in fiber content. The maximum compressive strength and flexural strength were achieved at PVA fiber contents of 0.2% and 0.3%, respectively. For different temperatures and fiber contents, the mechanical strength after natural cooling is generally higher than that after immersion cooling. In addition, X-ray polycrystalline diffractometry (XRD) and scanning electron microscopy (SEM) tests were conducted to analyze the compositional alterations and microstructure of the fiber-reinforced HSC following high-temperature exposure, accompanied by an explanation of the factors influencing the alterations in the physical and mechanical properties. Therefore, the findings of this study can serve as a valuable reference for the utilization of HSC in engineering structures and contribute to the advancement of HSC technology. [ABSTRACT FROM AUTHOR]

Objective This study aims to investigate the feasibility and safety of Da Vinci robotic-assisted thoracoscopy for resecting mediastinal tumors in pediatric patients. Methods From November 2020 to June 2023, a total of 80 pediatric patients undergoing mediastinal tumor resection at Wuhan Children's Hospital were randomly assigned into two groups, with each group consisting of 40 participants. The control group underwent conventional thoracoscopy, while the observation group underwent Da Vinci robotic-assisted thoracoscopy. This study aimed to compare perioperative indicators between the two groups and establish learning curves based on surgical duration and intraoperative blood loss. Additionally, it assessed levels of pain mediators and stress response markers before surgery and at 24 hours post-surgery, as well as postoperative complications. Inflammatory marker levels were evaluated one month after surgery, and the children's quality of life was measured using the Pediatric Quality of Life Inventory(PedsQL) Generic Core Scales before surgery and one month post-surgery. Results The surgical duration for the observation group and the control group was(1.76 ± 0.33) hours and(2.82±0.62) hours, respectively, and the intraoperative blood loss was(49.83 ± 6.39) mL and(71.55 ± 8.19) mL, respectively. Furthermore, the post-operative drainage time, drainage volume, and hospital stay for the observation group were all lower than those for the control group(P < 0.05). After surgery, the levels of BK, 5-HT, NPY, and PGE2 in the observation group were(8.06 ± 1.06) mg/L, (170.20 ± 13.21) ng/L, (201.82 ± 13.52) mg/L, and(241.82 ± 15.32) ng/L, respectively, indicating lower levels of pain mediators, stress response markers, and inflammatory factors compared to the control group(P < 0.05). he overall incidence of complications was 2.50% in the observation group as opposed to 20.00% in the control group. Moreover, there was a statistically significant improvement in quality of life after surgery within the observation group when compared to that within the control group(P < 0.05). Conclusion Da Vinci robotic-assisted thoracoscopy demonstrates enhanced feasibility and safety in pediatric mediastinal tumor resection, thereby justifying its clinical promotion. [ABSTRACT FROM AUTHOR]

During the operational phase, complex systems are subject to various shocks, both random and continuous degradation. This coupling effect poses significant challenges for reliability assessment. The proposed method aims to provide a clear and objective evaluation of the system's reliability. In this paper, we propose a competitive failure reliability analysis method that considers the coupling effect of multiple shock processes and degradation processes. The random shocks are subdivided into external and internal shocks. The degradation increment is mainly influenced by external shocks, whereas internal shocks affect the degradation rate. The combined effect of these two shock processes accelerates the failure processes. Additionally, two different shock models are combined to create an extreme‐cumulative shock model to assess the impact of various shock processes and the degradation process on system reliability. The analysis examines the coupling effect between the degradation process and shock processes to explore the influence law between hard failure and soft failure. Subsequently, the reliability modeling of competitive failure processes is completed. Finally, practical case studies demonstrate the effectiveness and practicality of the proposed method. [ABSTRACT FROM AUTHOR]

The compensated ferrimagnetic insulator Gd3Fe5O12 (GdIG) with a magnetization compensation point (TM ∼ 286 K) near room temperature has recently gained significant attention because of its long spin transmission length and absence of Ohmic loss. However, previously reported GdIG films with perpendicular magnetic anisotropy have a TM far below room temperature, which is unfavorable for practical applications. Here, we show the tuning of TM from 268 to 303.7 K in perpendicularly magnetized 15 nm GdIG films epitaxially grown on (111) Gd3Sc2Ga3O12 by manipulating the epitaxial strain through controlling the rapid cooling temperature during the annealing process. By varying the film thickness between 5 and 40 nm, the TM of the film can be further extended to a range of 246–380 K. We have also demonstrated highly efficient switching of the GdIG spin-sublattices driven by current at room temperature in the GdIG/Pt heterostructures with various TM values, especially with TM slightly higher than 300 K. Our findings reveal potential opportunities for insulating compensated ferrimagnetic films of GdIG in the development of high-density, high-speed, and energy-efficient spintronic devices. [ABSTRACT FROM AUTHOR]

In order to study the inter flow of magnetic drive pump, the total flow field of magnetic drive pump was simulated with CFD software based on SST k-ω turbulence model, and the flow fields distribution rules of cooling channel were analyzed under different working conditions. The numerical results show that the internal flow of magnetic drive pump was disorganized under small flow condition, then the inter flow becomes gradually smooth with the increase in flux, at the same time, the area with low speed near the outlet of reflow hole and the pressure of the cool circulation channel become smaller. The pressure of cooling channel gradually decreases in flow process from deflector hole to reflow hole, and the area of low pressure is easily formed near the outlet of reflow hole.