Search Results (40)

Blood flow restriction training (BFRT) offers notable advantages, including simplicity and time efficiency. However, no meta-analysis has yet comprehensively evaluated its effects on glucose and lipid metabolism in overweight or obese adults. This meta-analysis examines the potential efficacy of BFRT in improving glycemic and lipid control in overweight/obese adults. The literature was searched in six databases, with the search period up to 31 March 2025. A total of eight randomized controlled trials involving 267 participants were identified. Data were analyzed using Stata 18.0 and RevMan 5.4 with random effects models. Outcomes included fasting blood glucose (FBG), homeostasis model assessment of insulin resistance (HOMA-IR), and lipid profiles, and risk of bias and publication bias (Egger’s test) were assessed. BFRT significantly reduced FBG (Hedges’ g = −1.13, 95% CI: −1.65 to −0.62, p < 0.01; I² = 66.34%) and HOMA-IR (Hedges’ g = −0.98, 95% CI: −1.35 to −0.61, p < 0.01; I² = 17.33%) compared with the controls. However, no significant changes were observed in lipid profiles. Our analysis demonstrates that BFRT exhibits the favorable effect of improving glucose metabolism in overweight/obese adults; however, current evidence does not support significant advantages of BFRT for lipid metabolism improvement. Full article

To meet the rapid maneuverability and lightweight demands of micro-nano satellites, a space micro solid thruster using 3D-printed short glass fiber reinforced polyamide 6 (PA6GF) composites was developed. Thruster shells with wall thicknesses of 4, 3, and 2.5 mm were designed, and ground ignition tests were conducted to monitor chamber pressure and shell temperature. Compared with conventional metallic thrusters, PA6GF composites have exhibited excellent thermal insulation and sufficient mechanical strength. Under 8 MPa and 2773 K ignition conditions, the shell thickness was reduced to 2.5 mm and could withstand pressures up to 10.37 MPa. These results indicate that PA6GF composites are well-suited for space micro solid thrusters with inner diameters of 15–70 mm, offering new possibilities for lightweight space propulsion system design. Full article

What drives corporate dividend policy remains an unsettled issue, largely due to data limitations, as many privately held firms do not need to disclose their financial reports publicly. We examine and compare the dividend policies of firms with three distinct ownership structures—publicly held stock insurers, privately held stock insurers, and mutual insurers—within the U.S. property-liability insurance industry. Our findings indicate that publicly held insurers are more likely to distribute dividends and tend to pay higher dividends compared to privately held insurers, with mutual insurers paying the least in the matched sample. We found that mutual insurers’ dividend policies are more sensitive to cash flow, whereas stock insurers’ policies are more responsive to profits. We show that private insurers have significantly less smoothness in dividend policies. Our findings highlight the significant role that ownership structure plays in shaping corporate dividend policies. Full article

Ceramic samples of CuCr_1−xY_xO₂ (x = 0–0.02) were synthesized via the high temperature solid-state reaction method, and the influence of Y³⁺ doping on their microstructure and antiferromagnetic phase transitions was systematically investigated. Y³⁺ doping increased the unit cell volume from 130.928 ų for x = 0 to 131.147 ų for x = 0.0200, and the average grain size decreased from 3.38 μm for x = 0 to 4.27 μm for x = 0.0200. The Cr and Y elements maintained +3 valence, while the Cu element had +1 valence. All samples showed obvious paramagnetism when the temperature was higher than 140 K. When the temperature continued to decrease, the lattice expansion changed the bond length and bond angle of the Cr-O-Cr bond, resulting in a change in the superexchange interaction, and the magnetic susceptibility increased significantly, gradually showing antiferromagnetism. The T_N of the undoped sample was about 46 K, the T_N of the doped sample with x = 0.0175 was about 21 K, and the T_N of other doped samples was about 30 K. This result indicates that Y³⁺ doping enhanced the antiferromagnetism of the sample but also weakened its antiferromagnetic stability. Full article

Aeromonas veronii is a foodborne pathogen commonly found in contaminated crayfish. In this study, the effects of ultrasound combined with plasma-activated water (US-PAW) against A. veronii and on the flavour of crayfish were investigated to evaluate their impact on crayfish preservation. In vitro, US and PAW showed a significantly synergistic inhibition against A. veronii growth and biofilm reformation at 7 min. Furthermore, PAW disrupted the membrane integrity of A. veronii, accompanied by enhanced outer membrane permeability, with bacteria exhibiting distortion, deformation, and the accelerated leakage of intracellular substances, which US-PAW further promoted. Additionally, US-PAW increased the intracellular levels of reactive oxygen species and hydrogen peroxide, disrupting cellular homeostasis. This resulted in a significant decrease in the activities of SOD and GSH, as well as a reduction in the intracellular ATP concentration and the activities of MDH and SDH. The results indicated that US-PAW treatment impairs the ability of A. veronii cells to generate sufficient energy to resist external stress, ultimately leading to bacterial death due to the inability to maintain normal physiological functions. According to the bacterial cell count and GC-MS analysed, US-PAW treatment increased the storage period of crayfish (infected with A. veronii) by 2 days, while reducing sulphur-containing volatiles within 24.64% during 6 days of storage at 4 °C. These conclusions provide a theoretical foundation for the industrial application of US-PAW to preserve crayfish. Full article

Although the extrudate swelling, melt fracture, and extrusion deformation of polymer micro-catheters in traditional extrusion molding can be eliminated via the double-layer gas-assisted extrusion (DL-GAE) method, some failure problems are generated under unreasonable process conditions. To ascertain the reasons for failure in DL-GAE molding of polymer micro-catheters, the influences of the interaction between the melt and double assisted gas on the DL-GAE molding of polymer micro-catheters were experimentally and numerically studied. Meanwhile, a DL-GAE die and experimental system were designed and constructed. We analyzed the influence laws of the melt and assisted gas on the DL-GAE molding of polymer micro-catheters, as well as reasons for the molding’s failure. Our studies demonstrate that under the condition of stable DL-GAE, as the melt flow rate increases, the wall thickness and diameter of polypropylene (PP) micro-catheters increase. When the melt flow rate continuously increases, the stability of the assisted gas is destroyed, resulting in the failure of DL-GAE. In addition, under synchronized pressures of a double gas-assisted layer, the diameters of the micro-catheters increase, but their wall thickness decreases. Under an individual pressure increase of the outer gas-assisted layer, surface bump defects are generated. Under an individual pressure increase of the inner gas-assisted layer, the diameters of PP micro-catheters swell prominently until they break. Therefore, although DL-GAE can eliminate extrusion problems of polymer micro-catheters, it is suggested that reasonable process parameters for the melt and double assisted gas should be satisfied and matched. This work can provide significant technical support for the DL-GAE of polymer micro-catheters during manufacture. Full article

Organic matter (OM) is the primary carrier for the generation and occurrence of shale oil and gas. The combination of sequence stratigraphy and elemental geochemistry plays a crucial role in the study of organic matter enrichment mechanisms in marine shale, but it is rarely applied to terrestrial lacustrine basins. As a product of the last large-scale lake transgression in the Sichuan Basin, the Early Jurassic Lianggaoshan Formation (LGS Fm.) developed multiple organic-rich shale intervals, which is a good example for studying the OM enrichment in lacustrine basins. Based on a high-resolution sequence stratigraphic framework, the evolutionary process of terrestrial debris input, redox conditions, and paleo-productivity during the sedimentary period of the Lianggaoshan Formation lacustrine shale at different stages of lake-level variations has been revealed. The main controlling factors for OM enrichment and the establishment of their enrichment patterns have been determined. Sequence stratigraphy studies have shown that there are three third-order lake transgression-lake regression (T-R) cycles in the LGS Formation. The total organic carbon content (TOC) is higher in the TST cycle, especially in the T-R3 cycle, and lower in the RST cycle. There are differences in the redox conditions, paleo-productivity, terrestrial detrital transport, and OM accumulation under the influence of lacustrine shale deposition in different system tracts. The results indicate that changes in lake level have a significant impact on the reducibility of bottom water and paleo-productivity of surface seawater, but have a relatively small impact on the input of terrestrial debris. In the TST cycle, the reducibility of bottom water gradually increases, and the paleo-productivity gradually increases, while in the RST cycle, the opposite is true. Within the TST cycle, the OM accumulation is mainly influenced by paleo-productivity and redox condition of bottom water, with moderate input of terrestrial debris playing a positive role. In the RST cycle, the redox condition of bottom water is the main inducing factor for OM enrichment, followed by paleo-productivity, while terrestrial input flux plays a diluting role, which is generally not conducive to OM accumulation. Full article

As a habitat for waterbirds, wetlands are key to their survival, reproduction and development. Waterbirds usually prefer breeding, wintering and resting in fixed locations. Siberian cranes (Grus leucogeranus), which are highly dependent on wetlands, have long fed on farmland at migratory stopover sites. To explore the reason for this phenomenon, the time budgets of Siberian crane populations stopping over on farmland or in wetland habitats were studied and compared in this study. The results showed that the farmlands visited by the Siberian cranes are rich in food resources and have experienced low levels of disturbance. The temporal distribution of feeding behavior on farmland (53.50%) was greater than that in wetland habitats (31.96%). The variations in warning, flying and walking behavior on farmland were less than those in wetlands. The feeding efficiency on farmland was significantly greater than that in wetlands. Therefore, Siberian cranes transiting the Songnen Plain leave wetland habitats and stop over on farmland, representing a behavior that occurs more than just occasionally. Instead, they change their foraging habitat choices based on the optimal foraging theory. As a transit feeding area for Siberian cranes, farmland poses a significant risk, and the restoration of wetland habitats and food resources is still needed. This study can provide theoretical support for the conservation of rare and endangered species (the Siberian crane) and the management of stopover sites. Full article

Multi-hole pressure probes are crucial for turbomachinery flow measurements, yet conventional data processing methods often lack generalization for complex flows. This study introduces an innovative approach by integrating machine learning techniques with the structural risk minimization (SRM) principle, significantly enhancing the generalization capability of regression models. A comprehensive framework has been developed, combining SRM-based machine learning regression methods, such as ridge regression and kernel ridge regression, with hyperparameter optimization and S-fold cross-validation, to ensure robust model selection and accuracy. Validated using the McCormick function and applied to VKI-RG transonic turbine cascade measurements, the SRM-based methods demonstrated superior performance over traditional empirical risk minimization approaches, with lower error ratios and higher $R^2$ values. Novel insights from SHAP analysis revealed subtle but significant differences in aerodynamic parameters, including a $0.63122°$ discrepancy in exit flow angle predictions, guiding the probe design and calibration strategies. This study presents a holistic workflow for improving multi-hole pressure probe measurements under high-subsonic conditions, representing a meaningful enhancement over traditional empirical methods and providing valuable references for practical applications. Full article

The shared energy storage device acts as an energy hub between multiple microgrids to better play the complementary characteristics of the microgrid power cycle. In this paper, the cooperative operation process of shared energy storage participating in multiple island microgrid systems is researched, and the two-stage research on multi-microgrid operation mode and shared energy storage optimization service cost is focused on. In the first stage, the output of each subject is determined with the goal of profit optimization and optimal energy storage capacity, and the modified grey wolf algorithm is used to solve the problem. In the second stage, the income distribution problem is transformed into a negotiation bargaining process. The island microgrid and the shared energy storage are the two sides of the game. Combined with the non-cooperative game theory, the alternating direction multiplier method is used to reduce the shared energy storage service cost. The simulation results show that shared energy storage can optimize the allocation of multi-party resources by flexibly adjusting the control mode, improving the efficiency of resource utilization while improving the consumption of renewable energy, meeting the power demand of all parties, and realizing the sharing of energy storage resources. Simulation results show that compared with the traditional PSO algorithm, the iterative times of the GWO algorithm proposed in this paper are reduced by 35.62%, and the calculation time is shortened by 34.34%. Compared with the common GWO algorithm, the number of iterations is reduced by 18.97%, and the calculation time is shortened by 22.31%. Full article

The shear stirrups and bend-up reinforcement in ultra-high-performance concrete (UHPC) beams could potentially be excluded due to the superior mechanical properties of UHPC. This paper reports the new findings of an experimental research into the factors that influence the shear behavior of non-stirrup UHPC beams. Fourteen beams were tested in shear, comprising twelve non-stirrup UHPC beams and two normal concrete (NC) beams reinforced with stirrups. The test variables included the steel fiber volume content (2.0%, 1.5%, and 0%), the shear span-to-effective-depth ratio (1.2, 1.8, 2.0, and 3.1), beam width (150 mm and 200 mm), and beam height (300 mm, 350 mm, and 400 mm). The results demonstrated that the steel fiber volume content had a significant influence on the shear behavior of the non-stirrup UHPC beams. The failure modes of the beams without steel fibers were typically brittle, whereas those reinforced with steel fibers exhibited ductile failure. The shear resistance of the beams could be significantly enhanced by the addition of steel fibers in the concrete mix. Furthermore, the post-cracking load-bearing performance of the beams could also be markedly improved by the addition of steel fibers. In addition, the shear span-to-effective-depth ratio had a considerable impact on the failure mode and the ultimate shear strength of the tested beams. The contribution of steel fibers to the shear capacity of the UHPC beams was observed to increase as the shear span-to-effective-depth ratio increased. The French standard formulae tended to overestimate the contribution of steel fibers, and the calculation results were found to be more accurate for UHPC beams with a moderate shear span-to-effective-depth ratio (around 2.0). Moreover, the French standard formulae demonstrated greater accuracy at a larger beam height for calculating the contribution of UHPC matrix. Full article

This paper addresses the problems of valve-turning operation in rescue environments where a wheeled mobile manipulator (WMM) is employed, including the possible occurrence of large internal forces. Rather than attempting to obtain the exact position of the valve, this paper presents a solution to two main problems in robotic valve-turning operations: the radial position deviation between the rotation axes of the tool and the valve handle, which may cause large radial forces, and the possible axial displacement of the valve handle as the valve turns, which may lead to large axial forces. For the former problem, we designed a compliant end-effector with a tolerance of approximately 3.5° (angle) and 9.7 mm (position), and provided a hybrid passive/active compliance method. For the latter problem, a passivity-based force tracking algorithm was employed. Combining the custom-built compliant end-effector and the passivity-based control method can significantly reduce both the radial and the axial forces. Additionally, for valves with different installation types and WMMs with different configurations, we analyzed the minimum required number of actuators for valve turning. Simulation and experimental results are presented to show the effectiveness of the proposed approach. Full article

The development and utilization of wind energy is of great significance to the sustainable development of China’s economy and the realization of the “dual carbon” goal. Under typhoon conditions, the randomness and volatility of wind speed significantly impact the energy efficiency and design of wind turbines. This paper analyzed the changes in wind speed and direction using the BFAST method and Hurst index based on data collected at 10 m, 30 m, 50 m, and 70 m heights from a wind power tower in Yancheng, Jiangsu Province. Furthermore, the paper examined the causes of wind speed and direction changes using wind speed near the typhoon center, distance from the typhoon center to the wind tower, topographic data, and mesoscale system wind direction data. The conclusions drawn are as follows: (i) Using the BEAST method, change points were identified at 10 m, 30 m, 50 m, and 70 m heights, with 5, 5, 6, and 6 change points respectively. The change points at 10 m, 30 m, and 50 m occurred around node 325, while the change time at 70 m was inconsistent with other heights. Hurst index results indicated stronger inconsistency at 70 m altitude compared to other altitudes. (ii) By analyzing the wind direction sequence at 10 m, 30 m, 50 m, and 70 m, it was found that the wind direction changes follow the sequence Southeast (SE)—East (E)—Southeast (SE)—Southwest (SW)—West (W)—Northwest (NW). Notably, the trend of wind direction at 70 m significantly differed from other altitudes during the wind speed strengthening and weakening stages. (iii) Wind speed at 10 m and 70 m altitudes responded differently to the distance from the typhoon center and the wind near the typhoon center. The correlation between wind speed and the distance to the typhoon center was stronger at 10 m than at 70 m. The surface type and the mesoscale system’s wind direction also influenced the wind speed and direction. This study provides methods and theoretical support for analyzing short-term wind speed changes during typhoons, offering reliable support for selecting wind power forecast indicators and designing wind turbines under extreme gale weather conditions. Full article

Active power-assist lower limb exoskeleton robots aim to enhance wearer assistance while ensuring wearer comfort and simplifying the exoskeleton’s design and control. This study proposes an active assistance method known as Equivalent Force on Connection (EFOC). The EFOC method effectively addresses the limitations encountered in conventional Joint Torque Proportional Compensation (JTPC) approaches. These limitations include the necessity for exoskeleton robot configurations to align with human limb structures for parallel assistance at each lower limb joint, as well as the exoskeleton’s inability to contribute a greater proportion of assistance due to the excessive load on specific skeletal and muscular structures, resulting in wearer discomfort. Furthermore, the effectiveness of the EFOC method is evaluated and validated for assistance during both the stance and swing phases of single-leg movements. Finally, the proposed EFOC method is implemented on a hydraulic-driven lower limb exoskeleton robot to assist wearers in squatting, stepping, and jumping locomotion. The experimental results demonstrate that the proposed EFOC method can effectively achieve the desired assistance effect. Full article

With the development of Chinese society, there is an increasing demand for emissions reduction and the stable operation of the power grid. Regional comprehensive energy supply systems have entered the public’s view owing to their advantages of reducing capacity, unified dispatch, improving efficiency, and reducing energy consumption. This paper focuses on a system under construction in Chongqing, which adopts a combined gas tri-supply (combined cooling, heat, and power, CCHP) and dynamic ice storage cooling system as the research object. By establishing a mathematical model for the simulation research, this study examines the start–stop priority sequence of the gas tri-supply subsystem and the heat pump subsystem under the ice storage priority strategy in winter and summer and proposes corresponding optimization solutions. By comparing the annual operating energy consumption of the system, we conclude that the gas tri-supply composite system has good economic efficiency and peak-shaving capability, indicating that regional gas tri-supply composite systems have great application potential in the future. The proposed optimized operation strategy and simulated energy consumption calculation provide theoretical guidance for the construction and operation of both this project and similar projects. Full article