Search Results (13,561)

Despite the increasing adoption of desktop virtual reality (VR) in higher education, the specific instructional efficacy of 3D interactive prompts remains inadequately understood. This study examines how such prompts—specifically dynamic spatial annotations and 3D animated demonstrations—influence learning outcomes within a desktop virtual learning environment (DVLE). Employing a quasi-experimental design integrated with eye-tracking and multimodal learning analytics, university students were assigned to either an experimental group (DVLE with 3D prompts) or a control group (basic DVLE) while completing physics tasks. Data collection encompassed eye-tracking metrics (fixation heatmaps, pupil diameter and dwell time), post-test performance (assessing knowledge comprehension and spatial problem-solving), and cognitive load ratings. Results indicated that the experimental group achieved significantly superior learning outcomes, particularly in spatial understanding and dynamic reasoning, alongside optimized visual attention patterns—characterized by shorter initial fixation latency and prolonged fixation on key 3D elements—and reduced cognitive load. Eye-tracking metrics were positively correlated with post-test scores, confirming that 3D prompts enhance learning by improving spatial attention guidance. These findings demonstrate that embedding 3D interactive prompts in DVLEs effectively directs visual attention, alleviates cognitive burden, and improves learning efficiency, offering valuable implications for the design of immersive educational settings. Full article

This study aimed to develop and characterize novel 3D-printed chitosan methacryloyl (CSMA) hydrogel-functionalized nano-hydroxyapatite/polycaprolactone (nHA/PCL) scaffolds for controlled release of bone marrow mesenchymal stem cell-exosomes (BMSC-Exos), with the objective of enhancing osteogenic and angiogenic capabilities in vitro. We fabricated a biomimetic, highly porous scaffold composed of nHA/PCL using high-temperature fused deposition modeling. An interfacial bioactive layer was formed via ultraviolet-induced crosslinking of CSMA hydrogel on the scaffold and loaded bone marrow mesenchymal stem cell-exosomes. We characterized the composite scaffold to evaluate its physicochemical properties, cytocompatibility, cell migration ability, osteogenic capacity, and angiogenic capacity. The 3D-printed 20%nHA/PCL scaffold has a porosity of approximately 75%, with its surface containing four elements: carbon, oxygen, calcium, and phosphorus. The compressive strength is (13.76 ± 1.33) MPa. The CSMA hydrogel exhibits good injectability and degrades slowly over time. Exosomes with a negative charge are released slowly within the extracellular matrix hydrogel. The contact angle of the scaffold material is below 90 degrees, and the hemolysis rate is below 5%. In vitro assays demonstrated that the nHA/PCL-CSMA-Exos composite exhibited excellent biocompatibility, markedly enhanced cell proliferation and migration, and robust pro-angiogenic and osteogenic activity. The fabricated nHA/PCL-CSMA-Exos composite scaffolds demonstrated excellent physicochemical properties, biocompatibility, and cell migration ability, promoting angiogenesis, bone tissue formation and mineralization. Full article

Recent research suggests that artificial intelligence (AI) tools allow EFL (English as a Foreign Language) learners to exert greater control over their language-learning process. Furthermore, these tools enhance their language skills by providing them with elements often absent in traditional classroom settings, such as autonomy and individual pace of learning. Specifically, AI-based tools, such AI chatbots, have the potential to facilitate learning and streamline tasks for both students and instructors in language-learning contexts. These digital companions (i.e., chatbots) can be methodically crafted and equipped with the required essential materials to support students in practising language skills independently, regardless of time or location. The current study presents an experiment conducted with undergraduate students at a university in Saudi Arabia to assess the effectiveness of a customised AI chatbot, WritePro (GPT-4), in improving their writing skills. Learners in the experimental group were instructed to use WritePro to navigate through their writing stages, focusing their queries on four key components: content and organisation, grammar mechanics, vocabulary usage, and sentence structure. The findings showed that WritePro serves as an effective tool for EFL learners to overcome several challenges in developing writing competencies. Therefore, the significance of these findings lies in the potential of AI tools to enable EFL instructors to effectively integrate chatbots into classroom instruction, supporting the development of students’ writing skills. Furthermore, these findings can be used as a basis for advocacy with university policymakers regarding the use of AI chatbots in language classrooms. Full article

Pearl millet, an African-origin crop with exceptional heat tolerance, maintains normal flowering and seed production even under extremely high temperatures. The MADS-box transcription factor family plays a central role not only in floral organs, but also in abiotic stress responses. However, its specific function in pearl millet’s heat stress response remains unclear. In this study, a total of 63 MADS-box genes were identified. These genes were classified into five subfamilies and distributed across seven chromosomes, with chromosome 6 containing the highest number (12 genes). Additionally, expression analysis revealed that 53 MADS-box genes exhibited increased expression levels following heat stress under high-temperature conditions. Differential expression analysis identified five key MADS-box genes responding to heat stress. Further analysis of their expression trends using qRT-PCR revealed that the expression levels of these genes first increased and then decreased after heat stress treatment, with differences in the timing of peak expression among different genes. PMA1G07218.1 was selected for further functional characterization, which exhibited a significant response to heat stress treatment and reached a peak at 6 h. Subcellular localization analysis confirmed that the encoded protein is exclusively nuclear-localized. Through the yeast one-hybrid method (Y1H), we found that PMA1G07218.1 interacts by binding to the AG cis-acting element of F-box gene PMA1G04890.1. These findings provide valuable insight into the role of MADS-box genes in the high-temperature stress response of pearl millet, highlighting PMA1G07218.1 as a promising candidate for enhancing thermotolerance in this species. Full article

Modern robotic tasks often require interaction with the surrounding elements in the workspace. In some high-precision tasks, it is essential to stabilize the contact force on a smooth yet rigid surface, which can be modeled as a unilateral constraint. This challenge becomes increasingly complex in the presence of disturbances. This study addresses these issues using a robust fuzzy force-position controller that combines the approximation capabilities of fuzzy inference systems with the nonlocal properties of fractional operators. The proposed approach extends the error integration to include proportional-integral-derivative (PID) components of the position error, along with the integral of the contact force error. This formulation leverages the orthogonality between force and velocity subspaces to achieve accurate force-position stabilization. Additionally, an adaptive mechanism enhances closed-loop performance and robustness. The effectiveness of the proposed controller is validated through analytical derivations and simulations, thereby demonstrating its reliability in constrained environments. Full article

To address the inherent defects in the fabrication of AlCrN titanium alloy coatings and enhance interfacial bonding strength as well as tribological performance, an AlCrN coating was employed as an absorption layer and subjected to laser shock processing to form an AlCrN/TC4 transition layer. Subsequently, a secondary AlCrN coating was deposited to construct a gradient coating architecture. The surface and cross-sectional morphologies and elemental distributions under varying laser energies were systematically investigated, and the influence of laser energy on the adhesion and wear resistance of the gradient coatings was analyzed. The results demonstrate that with increasing laser impact energy, the thickness of the AlCrN/TC4 transition layer gradually decreases from 3.75 μm to 1.32 μm, accompanied by significant changes in elemental distribution across the surface and cross-section. The interfacial bonding strength of the gradient coating increases substantially from 13.6 N to 43.3 N, while the average friction coefficient rises from 0.436 to 0.507. Concurrently, the wear track depth is reduced, and the wear rate decreases from 86.46 × 10⁻⁵ mm³/(N·m) to 7.67 × 10⁻⁵ mm³/(N·m). Laser shock peening promotes elemental diffusion, enabling the formation of a diffusion-aided interlayer. The incorporation of this diffused zone facilitates the successful construction of a high-quality TC4 titanium alloy gradient coating, effectively broadening the film–substrate interface, enhancing surface hardness, and significantly improving both interfacial adhesion and wear resistance. Full article

As one of the most representative cultural heritages, traditional Chinese opera is characterized by highly refined symbolic contexts and stylized narrative structures. Nevertheless, the contemporary generation often struggles with its abstract expression and language, leading to declining attendance. In addition, urbanization and digital entertainment have squeezed out its living spaces, increasing demand for more diverse experiences. To address these issues, this study conducts a systematic and thematically categorized review of the literature, exploring how extended reality (XR) reshapes the spatial and experiential representation of opera culture. Drawing upon the reality–virtuality continuum and spatial computing as theoretical foundations, the research investigates the features, workflows, and cultural adaptability of augmented reality (AR), virtual reality (VR), and mixed reality (MR), identifying how each modality of XR supports distinct modes of space generation and audience engagement. Through comparative analysis, we propose three XR-based approaches for reinterpreting Chinese opera: AR for theatrical spaces visualization, VR for performative narratives embodiment, and MR for opera cultural elements superposition. Overall, the research clarifies that XR can be used as a comprehensive medium to enhance replicability and user perception, contributing to the preservation and communication of humanity’s traditional culture. Full article

This study investigated the characterization and application of organoclay formulations in a chemoautotrophic biofloc system. Organoclays were produced using the calcination method and bentonite, chitosan, corn, and tapioca starches as ingredients. Thermogravimetric analysis confirmed the high thermal stability of bentonite, whereas biopolymers (tapioca, chitosan, and corn starch) exhibited greater thermal sensitivity and a lower residual mass. Scanning electron microscopy revealed that organoclays had increased porosity (4–21 µm) compared to bentonite, while energy-dispersive spectroscopy confirmed the retention of key chemical elements. X-ray diffraction and Fourier-transform infrared spectroscopy indicated structural modifications due to thermal processing. In aqueous conditions, bentonite and organoclays disaggregated into particles with sizes between 0.76 and 1.24 μm. Based on these physicochemical properties, three formulations were selected for nitrification trials due to their stability in water, O1 (bentonite + tapioca), O2 (bentonite + tapioca + chitosan), and O6 (bentonite + corn starch), along with a 100% bentonite treatment and a control group (C) supplemented with inorganic salts and artificial Needlona^® substrates. All treatments achieved full nitrification within 37 days, with O1 exhibiting the best performance by maintaining ammonia and nitrite levels within safe thresholds. These findings suggest that organoclays, particularly O1, can enhance nitrification stability, providing a promising strategy for water quality management in intensive aquaculture systems. Full article

While collaborative robots are designed to enable flexible and safe human–robot interactions, their comparatively low structural stiffness poses a challenge for high-precision machining and heavy-assembly tasks. Addressing this limitation is essential for enhancing their performance and improving their overall efficiency in manufacturing processes. This paper proposes an approach for enhancing the stiffness by means of situational coupling of two collaborative robots. Therefore, an analysis is conducted to determine the kinematic limitations of coupled collaborative robots. The stiffness of coupled collaborative robots is then modeled using the finite element method. Furthermore, experimental stiffness measurements of a single collaborative robot are conducted to establish a quantitative reference, which is both to validate the model and to quantify the stiffness enhancement achieved through coupling. On the basis of the combined experimental and numerical results, it is demonstrated that the approach of coupling has the potential to enhance stiffness by up to 37.19 times in comparison with a solitary collaborative robot. Full article

Pesticides are applied to promote performances in the agricultural field, sustaining crop productivity by counteracting the damages induced by pests and weeds. Under conditions of uncontrolled application, their negative influences exerted on soil, water and biodiversity mean contamination of food and impact on human health. The reactive oxygen species generation induced by pesticides impair the antioxidant protective ability. For humans, pesticides can have cytotoxic, carcinogenic, and mutagenic potential. They can be classified relying on the chemical structure or on the targeted organism. Optical sensors are based on UV-Vis absorption, fluorescence, chemiluminescence, surface plasmon resonance or Raman scattering. Based on their coloring features, nanomaterials are used in optical sensing platforms. They impart high specific surface area, small sizes, facility of surface modification by biorecognition elements (enzyme, antibody, aptamer, molecularly-imprinted polymer) and promote sensitivity and selectivity in biosensing platforms. The present paper highlights the performances of the optical sensing platforms in pesticide assay. Relevant novel applications are discussed critically, following the attempts to improve analytical features of chemical and biochemical sensors. Critical comparison of the techniques is performed in the last section. Advances in nanofabrication like the inclusion of novel nanomaterials and optimizing data interpretation by integration of algorithms can further enhance performances. Full article

Bio-inspired flow-sensing and actuation mechanisms offer a promising path for enhancing the stability of flapping-wing flying robots (FWFRs) operating in dynamic and noisy environments. This study introduces a bio-inspired sensing and actuation feather unit (SAFU) that mimics the covert feathers of falcons and serves simultaneously as a distributed flow sensor and an adaptive actuation element. Each electromechanical feather (EF) passively detects airflow disturbances through deflection and actively modulates its flaps through an embedded actuator, enabling real-time aerodynamic adaptation. A reduced-order bond-graph model capturing the coupled aero-electromechanical dynamics of the FWFR wing and SAFU is developed to provide a physics-based training environment for a proximal policy optimization (PPO) based reinforcement learning controller. Through closed-loop interaction with this environment, the PPO policy autonomously learns control actions that regulate feather displacement, reduce airflow-induced loads, and improve dynamic stability without predefined control laws. Simulation results show that the PPO-driven SAFU achieves fast, well-damped responses with rise times below 0.5 s, settling times under 1.4 s, near-zero steady-state error across varying gust conditions and up to 50% alleviation of airflow-induced disturbance effects. Overall, this work highlights the potential of bio-inspired sensing-actuation architectures, combined with reinforcement learning, to serve as a promising solution for future flapping-wing drone designs, enabling enhanced resilience, autonomous flow adaptation, and intelligent aerodynamic control during operations in gusts. Full article

Background: In recent years, virtual consultations have emerged as a crucial approach for continuity of chronic care provision, indicating a promising avenue for the future of smart healthcare systems. However, reversions to in-person care highlight persistent limitations, despite notable advantages of remote modalities. In parallel, recent developments in artificial intelligence (AI) indicate the potential to enhance remote chronic care, but user perceptions of such assistance and the corresponding human factors remain underexplored. Objective: This mixed methods study aims to better understand the virtual consultation experiences and attitudes toward AI-assisted tools in remote care among patients with noncommunicable chronic conditions and their healthcare professionals (HCPs). It conducts an in-depth examination of the associated human–computer interaction and usability elements of virtual consultations and of potential AI assistance. Methods: Public and Patient Involvement was integrated to run pilots and refine documentations. Semi-structured interviews with patients (n = 10), focus groups with HCPs (n = 15), and an online survey (n = 83) were conducted. Qualitative data was analysed through a reflexive thematic approach. The survey comprised the Telehealth Usability Questionnaire (TUQ) and bespoke items on user AI views, and the data was used to triangulate the qualitative findings. Nonparametric Kruskal–Wallis tests and ε² effect sizes compared TUQ and AI views scores between current and former virtual consultation user groups. Results: Seven themes emerged from the qualitative data, which were supported by the quantitative findings. The statistical analyses resulted in a mean TUQ total score of 90.6 (SD = 15.0), which indicates high usability and user satisfaction; however, they failed to detect a difference between groups (p > 0.05; ε² = 0.002–0.032). There was a clear preference for hybrid models, while a lack of empathy was identified during remote interactions. While a notable proportion of users indicated a literacy gap towards AI use in healthcare settings, they expressed cautious openness towards AI assistance, contingent upon transparency, human oversight, and data integrity; indicating a potential gap between competence to judge the technology and willingness to use it. Significant differences in views on AI assistance across groups failed to be detected (p > 0.05; ε² = 0.005–0.065). Conclusions: Virtual consultations for chronic conditions are widely usable and acceptable, particularly through hybrid approaches. Addressing empathic engagement, holistic patient status, and transparent AI integration can enhance clinical quality and user experiences during remote interactions. However, the low statistical power and failure to detect a difference between groups (likely due to the small sample size) indicate the need for caution when interpreting the quantitative findings. There is also the implicit need to address potential AI literacy gap among users, indicating the need for robust safeguard measures. This study has also identified evidence-based assistive AI features that can potentially enhance virtual consultations. These insights can inform the co-design of evidence-based virtual care platforms, policies and supportive AI tools to sustain remote chronic care delivery. Full article

Coprime arrays enable enhanced degrees of freedom through the construction of virtual array equivalent signals. However, the presence of large “holes” leads to discontinuous co-arrays, which severely hampers direction-of-arrival (DOA) estimation techniques that rely on uniform array structures. This paper explores the practical application of co-array domain signal processing for underwater acoustic coprime arrays. We propose a novel array configuration based on coprime minimum disordered pairs, enabling the formation of continuously connected co-arrays without interpolating. To address the challenge of limited snapshots in underwater environments, DOA estimation can be achieved by utilizing traditional multipath matching pursuit (MMP) algorithms under the proposed continuous co-array implementation scheme. In practical applications, physical array element failures are inevitable, and faulty elements can create holes in the originally continuous co-array. While interpolation techniques can mitigate small gaps, their performance deteriorates significantly in the presence of large holes or uneven data distribution. To overcome these limitations, we introduce a sparse signal recovery (SSR) method using a fragment array data validation technique for sparse DOA estimation with an underwater acoustic coprime array. Based on the designed continuous array expansion scheme, the resulting continuous co-array is used to map the positions of element failures, revealing the gaps in the co-array. A validation model is established for partially continuous sub-arrays within the discontinuous co-array, enabling signal direction estimation based on the fragmented array validation. Both simulation and sea trial results confirm that the proposed approach maximizes the utilization of co-array elements without relying on interpolation or prediction, offering a robust solution for scenarios involving sensor failures. Full article

The transient electromagnetic (TEM) method is a key detection and monitoring technology for safe coal-mine production. Surface TEM depth penetration is limited by real geological conditions and transmitter–receiver hardware performance. Compared with the surface TEM method, the tunnel TEM method can enhance the depth of exploration to some extent, but it is constrained by the limited working space of the roadway, which makes it difficult to perform the area-wide and multi-line data acquisition, and thus the lateral detection resolution is directly compromised. Consequently, either surface or tunnel TEM alone suffers inherent limitations. The multidimensional surface and surface-to-tunnel TEM method employs a single large-loop transmitter and records electromagnetic (EM) signals both on the surface and in the tunnel, enabling joint data interpretation. The joint TEM observation method effectively addresses the limitations by using a single observation mode, with the goal of achieving high-precision detection. To investigate the detection capabilities of the joint surface and surface-to-tunnel TEM method, we propose a three-dimensional (3D) joint surface and surface-to-tunnel TEM forward modeling method based on the spectral element method (SEM). The SEM, using high-order vector basis functions, enables high-precision modeling of TEM responses with complex geo-electric earth models. The accuracy of the SEM is validated through comparisons with one-dimensional (1D) TEM semi-analytical solutions. To further reveal TEM response characteristics and multi-dimensional resolution under joint surface and tunnel detection modes, we construct several typical 3D geo-electric earth models and apply the SEM algorithm to simulate the TEM responses. We systematically analyze the horizontal and vertical resolution of 3D earth model targets at different decay times. The numerical results demonstrate that surface multi-line TEM surveying can accurately delineate the lateral extent of the target body, while vertical in-tunnel measurements are crucial for identifying the top and bottom interfaces of geological targets adjacent to the tunnel. Finally, the theoretical modeling results demonstrate that compared to individual TEM methods, the multi-dimensional joint surface and tunnel TEM observation yields superior target spatial information and markedly improves TEM detection efficacy under complex conditions. The 3D TEM forward modeling based on the SEM provides the theoretical foundation for subsequent 3D inversion and interpretation of surface-to-surface and surface-to-tunnel joint TEM data. Full article

A novel resonant-type defected ground structure (DGS) featuring a modified internal structure is proposed to enhance the suppression of cross-polarized (XP) radiation of rectangular microstrip antennas (RMAs) on slot-type DGS. Specifically, integrating periodic circular metal structure (PCS) into the slot-type DGS, which has been demonstrated to reduce RMA XP levels and minimize the space occupied by defects. As a resonant-type DGS, the embedding of the PCS enables the excitation of the entire DGS by the fringe field of the patch. The coupling between the fringe field and the PCS-type DGS results in a significant alteration of the field distribution of the high-order mode TM₀₂, thereby effectively suppressing the XP radiation generated by TM₀₂ mode. This structural concept originates from the unique control capabilities of periodic structures over electromagnetic field propagation, with the objective of optimizing the symmetry of the substrate field distribution inside the defect region. Compared to slot-type DGS, the periodic structure enables more electromagnetic fields to couple into the slot from the non-radiating side and disperse among each metal element, generating resonance in the TM₀₂ mode field. Experiments demonstrate the H-plane co-cross polarization isolation exceeds 25 dB across an azimuth range exceeding 200°, with peak XP suppression reaching 20 dB. This performance is at the forefront of resonant-type DGSs. Full article