Search Results (18,631)

CD137 is a prominent costimulatory molecule of the tumor necrosis factor (TNF) receptor superfamily that activates T cells through a complex bidirectional signaling process involving CD137L. The clinical value of immunotherapies underscores the potential of CD137L/CD137 as an effective target for boosting antitumor immune responses; however, the intricate mechanisms governing these interactions have not been fully elucidated. Herein, we constructed various oligomeric states of CD137L (monomeric, dimeric, and trimeric CD137L) and explored their interactions with CD137 using molecular dynamics simulations. Our findings revealed that trimeric CD137L exhibits higher thermal stability but reduced binding affinity for CD137 compared with the dimer form, with the A’B’ loop of CD137L playing a critical role in both structural stability and promoting CD137 interactions. Notably, the formation of hexameric structures enhanced the binding affinity and stability. This study provides valuable insights into the CD137L/CD137 bidirectional signaling mechanisms, which may inform the design of next-generation CD137 agonists. Ultimately, these advancements may improve cancer immunotherapy strategies, aiming to enhance therapeutic outcomes for patients through more effective and targeted therapies. Full article

Metamorphism is a complex geologic process that is often poorly covered in introductory geology courses. This study explores the effectiveness of a video-based instructional intervention in improving student understanding of metamorphism and its relationship to plate tectonics. The intervention includes an innovative assessment procedure featuring embedded QR codes, allowing participants to complete pre- and post-tests seamlessly. Data were collected from 75 participants, with results showing modest to major improvements in conceptual understanding, particularly about geothermal gradients. However, minimal improvement was observed in questions requiring deeper knowledge of specific tectonic settings. A qualitative analysis of written responses revealed limited changes in participants’ use of key terms before and after the video intervention. These findings suggest that while video-based instruction can reinforce core concepts, greater attention is needed to address cognitive load and support learning of more challenging topics. This study underscores the importance of integrating accessible, dynamic teaching tools and refining instructional design to better engage students with metamorphic processes, which are essential to understanding Earth’s dynamic systems. Full article

This paper challenges the prevalent characterization of domesticated horses as prey species that inherently view humans as predators. Drawing on evolutionary, ethological, and cognitive evidence, we propose the “mutualistic coevolution hypothesis”, which posits that horses and humans have evolved a partnership marked by cooperation rather than fear. We critically assess the “prey hypothesis”, emphasizing a predator–prey model, which dominates equine training and the literature, and we argue that it inadequately explains horses’ morphology, behaviors, and cognitive capacities. Comparative studies on horses’ socio-cognitive skills suggest that domestication has fostered emotional, behavioral, and cognitive adaptations supporting a human–horse bond. This review examines evidence from archaeological findings and experimental research on horses’ responsiveness to human gestures, emotions, and social cues, underscoring their complex cognition and capacity for collaboration. Furthermore, morphological and behavioral analyses reveal inconsistencies in using orbital orientation or predation-related traits as evidence for categorizing horses as prey species. By emphasizing the coevolutionary dynamics underlying human–horse interactions, we advocate for replacing traditional training models centered on fear and submission with approaches that leverage horses’ mutualistic and social nature. This perspective offers insights for enhancing horse welfare and improving human–equine relationships. Full article

Thin-film thermocouple is widely used in temperature measurement because of its high temperature measurement accuracy and small size. In order to calibrate the temperature accurately with thin-film thermocouple, NiCr/NiSi thin-film thermocouple was prepared by magnetron sputtering according to the Seebeck effect. Through static calibration experiments, the Seebeck coefficient of K-wire thermocouple was found to be 39.23 μV/°C, while that of the NiCr/NiSi thin-film thermocouple was 38.89 μV/°C. Further experiments showed a Seebeck coefficient of 39.092 μV/°C for the NiCr/NiSi thin-film thermocouple, which verifies that the prepared thin-film thermocouple has good consistency and repeatability. Through the temperature measurement experiment of automobile engines, the highest stable working temperature of the engine is 107.9 °C, which further verifies that the prepared NiCr/NiSi thin-film thermocouple can have a sensitive dynamic response to temperature and high temperature measurement accuracy. Finally, the causes of experimental errors, the application prospect and existing problems of thin-film thermocouples are analyzed. Full article

Accurate spectral and radiometric calibration is critical for precise Solar Spectral Irradiance (SSI) and Aerosol Optical Depth (AOD) retrievals in ground-based observations. This study introduces a pixel-based real-time noise deduction method and evaluates its performance using laser sources, Fraunhofer dark lines, and an improved Langley plot calibration. The proposed approach addresses challenges in long-term field SSI monitoring, including spectral noise variation and frequent calibration requirements for wavelength and responsivity corrections. The pixel-based noise deduction method effectively suppresses spectral dark noise to 0 ± 0.890, outperforming temperature-based corrections by 0.6%. Wavelength accuracy tests with laser sources and Fraunhofer dark lines demonstrate high consistency, with δλ < 0.3 nm, while spectral calibration uncertainty is assessed at 0.195 nm to 0.299 nm. The improved Langley plot achieves spectral responsivity differing by only 0.80% from the standard Langley plot and enhances AOD correlation with CE318 by 0.9–2.7% (RMSE: 0.002–0.003), significantly improving AOD observation accuracy. This work advances the development of field SSI hyperspectral observation and calibration, improving the accuracy of SSI and AOD measurements and contributing to the study of environmental changes and climate dynamics. Full article

The application of lower-limb exoskeleton robots in rehabilitation is becoming more prevalent, where the precision of control and the speed of response are essential for effective movement tracking. This study tackles the challenge of optimizing both control accuracy and response speed in trajectory tracking for lower-limb exoskeleton hip robots. We introduce an optimization strategy that integrates the Sparrow Search Algorithm (SSA) with fuzzy Proportional-Integral-Derivative (PID) control. This approach addresses the inefficiencies and time-consuming process of manual parameter tuning, thereby improving trajectory tracking performance. First, recognizing the complexity of hip joint motion, which involves multiple degrees of freedom and intricate dynamics, we employed the Lagrangian method. This method is particularly effective for handling nonlinear systems and simplifying the modeling process, allowing for the development of a dynamic model for the hip joint. The SSA is subsequently utilized for the online self-tuning optimization of both the proportional and quantization factors within the fuzzy PID controller. Simulation experiments confirm the efficacy of this strategy in tracking hip joint trajectories during flat walking and standing hip flexion rehabilitation exercises. Experimental results from diverse test populations demonstrate that SSA-fuzzy PID control improves response times by 27.8% (for flat walking) and 30% (for standing hip flexion) when compared to traditional PID control, and by 6% and 2%, respectively, relative to fuzzy PID control. Regarding tracking accuracy, the SSA-fuzzy PID approach increases accuracy by 81.4% (for flat walking) and 80% (for standing hip flexion) when compared to PID control, and by 57.5% and 56.8% relative to fuzzy PID control. The proposed strategy significantly improves both control accuracy and response speed, offering substantial theoretical support for rehabilitation training in individuals with lower-limb impairments. Moreover, in comparison to existing methods, this approach uniquely tackles the challenges of parameter tuning and optimization, presenting a more efficient solution for trajectory tracking in exoskeleton systems. Full article

Based on the results of the nuclear accident response education questionnaire, we use system dynamics to develop a nuclear accident response education effectiveness evaluation model. A questionnaire survey was conducted for the pre- and post-tests of the course to understand course effectiveness and explore the interactive relationship between factors. The system dynamics is used to develop a nuclear accident response education effectiveness evaluation model. Age and education are significantly related to education and training experience (number of times), and the age, occupation, and education level are significantly related to individuals’ experience (number of times) of participating in a nuclear accident evacuation exercise. In the workshop courses, the public’s awareness of self-protection against nuclear accidents was significantly improved. Experience in educational training was significantly related to evacuation exercises. Individuals’ age and experience of participating in education and training can be used to predict their willingness to participate in evacuation exercises. Using systems thinking and analysis, an evaluation model for nuclear incident response education effectiveness is constructed as a reference for evaluating effectiveness. The designed education and training courses can increase public participation in nuclear accident response education and strengthen the cognitive benefits of response protection. Full article

Enhancing the dynamic response of Flux-Switching Permanent Magnet Synchronous Machines (FSPMSMs) is crucial for high-performance applications such as electric vehicles, renewable energy systems, and industrial automation. Conventional Proportional Integral (PI) controllers within model predictive current control (MPCC) frameworks often struggle to meet the demands of rapid transient response and precise speed tracking, particularly under dynamic operating conditions. To address these challenges, this paper presents a hybrid control strategy that integrates Sliding Mode Control (SMC) into the speed loop of MPCC, aiming to significantly improve the dynamic response and control robustness of FSPMSMs. The feasibility and effectiveness of the proposed approach are validated through high-fidelity real-time simulations using OPAL-RT Technologies’ OP5707XG simulator. Two control schemes are compared: MPCC with a PI controller in the speed loop (MPCC-PI) and MPCC with SMC in the speed loop (MPCC-SMC). Testing was conducted under various operating scenarios, including starting tests, load variations, speed ramping, and speed reversals. The results demonstrate that the MPCC-SMC strategy achieves superior dynamic performance, faster settling times, smoother transitions, and enhanced steady-state precision compared to the MPCC-PI scheme. The comparative results confirm that the MPCC-SMC method outperforms conventional MPCC strategies, making it a compelling solution for advanced motor drive applications requiring enhanced dynamic control. Full article

To address the vehicle-bridge coupling vibration issue of the Qingyuan Maglev Tourist Line, it is necessary to establish a maglev vehicle–bridge coupling dynamics simulation model that reflects the actual line conditions. Based on the vehicle and bridge structural parameters of the Qingyuan Maglev Tourist Line, this paper utilizes multi-body dynamics simulation software to create a medium–low-speed maglev vehicle dynamics model, and employs finite element software to construct a bridge model. Using the modal reduction method, the bridge finite element model is imported into the vehicle dynamics model through a rigid–flex coupling interface, establishing a medium–low-speed maglev vehicle suspension system–bridge coupling dynamics model. The accuracy of the established coupling simulation model was verified by comparing the simulation data from the coupling model with the dynamic response measured data from the Qingyuan Maglev Tourist Line. Finally, the impact of different control parameters on the vehicle–bridge coupling system was calculated, and the results indicate that selecting appropriate suspension control parameters can reduce the coupling vibration response between the maglev vehicle and the bridge. The main work of this paper is closely related to engineering, modeling based on the actual maglev line’s vehicle and bridge parameters, and validating the model through the dynamic test results of the line, laying the foundation for the suppression of maglev vehicle–bridge coupling vibration and system optimization. Full article

To address the mismatch between materials and operational speed in mine scraper conveyors under time-varying load conditions, this paper proposes a methodology for the regulation of speed based on the quantity of coal transported by the scraper conveyor. Furthermore, a vector control strategy for permanent magnet synchronous motors (PMSMs) is presented, underpinned by a global fast terminal sliding mode controller. Firstly, a calculation model for the real-time coal volume of the scraper conveyor was developed based on the double-end oblique cutting coal mining technology in fully mechanized mining operations. This model takes into account the operational condition of the shearer and the scraper conveyor. In addition, a graded speed regulation control method was introduced. Secondly, a global fast terminal controller was developed by integrating the features of linear and terminal sliding mode surfaces. An enhanced sliding mode vector control strategy for the permanent magnet drive motor of the scraper conveyor was subsequently proposed. Finally, a simulation and ground test were subsequently performed on the PMSM experimental bench and SGZ2×1200 scraper conveyor to validate the proposed control strategy. The results indicated that the proposed control strategy not only diminished the overshoot of the rotational speed and decreased the dynamic response time but also improved the anti-interference capabilities of the PMSM relative to the original PI control. Moreover, the ground test validated the feasibility of the suggested speed regulation method. Full article

On large ships, Officers on Watch (OOW) work in a demanding environment where they are confronted with stress and dynamic conditions and frequently move from one wing of the vessel to another. Therefore, a physiological monitoring system to assess the activity of their autonomic nervous system, i.e., to detect their physiological responses, stress, and fatigue, should be lightweight and portable. This paper presents a comparison of wired and portable wearable psychophysiological systems. Although the wired system offers greater precision, its complexity, poor ergonomics, and the need for a controlled setup make it less suitable for the natural working conditions of OOWs. A wireless portable system, although weaker in precision, is more suitable due to its portability, ease of use, real-time data capabilities, ability to measure anxiety, and immediate insights into physiological states during real-world use in real time. Such an application provides a wearable physiological data collection solution that, in conjunction with a mobile app and cloud platform, enables seamless data collection and processing of participants’ autonomic nervous system arousal. Full article

This study aimed to identify the critical ground motion parameters that lead to structural damage and assess their impact on the nonlinear responses of buildings. The analyses are carried out using a calibrated numerical model that was acquired within the ICONS experimental framework that represents reinforced concrete (RC) structures constructed before seismic design regulations were enforced. For the analysis, 30 seismic records were chosen based on magnitude (M), epicentral distance (R), and peak ground acceleration (PGA) for two high seismic activity areas that were observed. Eleven parameters are categorized, traditional metrics, energy-based, spectrum-based, duration-based, and fundamental metrics, and examined based on their main attributes. The results showed a strong relationship between certain seismic properties and the maximum interstory drifts of building as a damage prediction parameter. Peak ground velocity (PGV), specific energy density (SED), and Housner Intensity (HI) were found to be the most important variables in assessing the correlation with possible structural damage. Therefore, the assessment of structural damage based on nonlinear dynamic analysis should primarily incorporate PGV with the possible addition of energy- and spectrum-based metrics as the most reliable ground motion parameters for the selection of earthquake records for time history analysis. Full article

In modern marine vessels equipped with electric propulsion systems, rectifiers are commonly used as part of the setup. However, the conventional deadbeat predictive direct power control strategy for three-phase voltage source pulse-width modulation (PWM) rectifiers tends to underperform when subjected to load variations and external disturbances. To address these limitations, this paper proposes an enhanced linear active disturbance rejection control (LADRC), incorporating virtual capacitance and an improved equivalent input disturbance strategy. The integration of virtual capacitance in the LADRC is specifically applied during load transitions. Virtual capacitance is a capacitor element simulated through the control strategy. It enhances voltage stability and dynamic response capability by compensating for voltage fluctuations and power deficits in the system. By providing a virtual active power, this approach substantially improves power tracking performance, reducing the DC voltage drop and settling time by 60% and 74%, respectively. In addition, the proposed strategy is easy to implement and does not add complexity to the LADRC. Moreover, the equivalent input disturbance is refined through virtual capacitance, enabling accurate disturbance estimation. As a result, the active power ripple and current total harmonic distortion under disturbances are reduced by 44% and 40%, respectively. The stability of the proposed strategy is comprehensively analyzed, and experimental results from a prototype system validate its effectiveness and accuracy. Full article

Despite the unchanged nature of the general regulatory framework, the last decade has witnessed the emergence of new forms of governance over religious affairs at the local and provincial levels in Buenos Aires (Argentina). These initiatives constitute, on the one hand, a response to the demands presented by religious groups that were once invisible and experiencing marked demographic growth. On the other hand, they are a way of integrating religious expertise into territorial governance strategies, given the structural ineffectiveness of public policies in locally grounding them. In view of this scenario, this article will present a network and dynamic analysis of the public management of religion at the local and intermediate levels in the province of Buenos Aires. Specifically, we will give an account of the genesis of these state units, as well as the profiles of the political decision makers who direct them and the interactions between local and provincial religious affairs officials in the period of 2022–2023. Based on these data, we will evaluate the levels of innovation that these regulations present with respect to the general normative framework and the limits and advantages that they postulate in the face of the question of religious citizenship. In methodological terms, this research combines the analysis of secondary sources, participant observation, in-depth interviews, and network analysis. Full article

Rifampicin is a broad-spectrum antibiotic, active against several bacterial infections such as tuberculosis. It is a relatively large and structurally complex molecule, including numerous polar groups. Although violating several of Lipinski’s rules for efficient intestinal absorption, rifampicin shows good oral bioavailability, permeating through cell membranes in the absorption pathway and those of the target organisms. Some hypotheses have been proposed for its efficient membrane permeation, but the details are mostly unknown. In this work, the interaction of rifampicin with POPC lipid bilayers is studied using experimental biophysics methodologies and atomistic molecular dynamics simulations considering the two most prevalent ionic species at physiological pH, the anionic and the zwitterionic forms. The results show that both ionization forms of rifampicin establish favorable interactions with the membrane lipids, in agreement with the relatively high partition coefficient obtained experimentally. The results from MD simulations and isothermal titration calorimetry using different pH buffers show that the piperazine group inserts deeply in the membrane and is accompanied by a stabilization of its neutral form. The bulky nature of rifampicin and its deep insertion in the membrane lead to a strong perturbation in the lipids local order, decreasing the membrane barrier properties as evaluated from the rate of carboxyfluorescein leaching. Altogether, the comparison between the experimental and MD simulations results provides important insight regarding the rifampicin molecular features responsible for its relatively fast membrane permeation. The lipid POPC used in this study was selected as a simple membrane with relevance for different organisms across all kingdoms. Further studies using more complex lipid compositions will provide details on eventual specificities for rifampicin interaction with the membranes of distinct organisms. Full article