Search Results (3,296)

Cognitive tasks play a pivotal role in posture control among young adults. This study examined how concurrent cognitive tasks alter balance stability and sensory integration during single-leg stance by analyzing center-of-pressure trajectories and wavelet spectra to elucidate the neurobehavioral mechanisms underlying dual-task balance degradation. A cohort of 24 young adults completed both single postural control tasks and dual cognitive–postural tasks on a force plate. COP data and wavelet decomposition energy were computed and analyzed. The results revealed significant differences between the dual-task and single-task groups for Lxy, Ly, Vxy, and Vy (p < 0.05). Energy content analysis showed that the dual-task group had significantly different energy ratios across four frequency bands along the x-axis (p < 0.05). Our findings showed that dual-task conditions impair postural control in young adults, increasing anteroposterior sway and altering mediolateral energy patterns. This suggests a shift toward proprioceptive reliance during cognitive division, revealing cognitive–postural interference. These results support using dual-task assessments for fall risk evaluation and inform interventions for populations requiring cognitive–motor integration. Full article

In this study, a dynamically tunable terahertz device based on a VO₂–graphene hybrid metasurface is proposed, which realizes the dual functions of ultra-wideband absorption and efficient transmission through VO₂ phase transformation. At 345 K (metallic state), the device attains an absorption efficiency exceeding 90% (average 97.06%) in the range of 2.25–6.07 THz (bandwidth 3.82 THz), showing excellent absorption performance. At 318 K (insulated state), the device achieves 67.66–69.51% transmittance in the 0.1–2.14 THz and 7.51–10 THz bands while maintaining a broadband absorption of 3.6–5.08 THz (an average of 81.99%). Compared with traditional devices, the design breaks through the performance limitations by integrating phase change material control with 2D materials. The patterned graphene design simplifies the fabrication process. System analysis reveals that the device is polarization-insensitive and tunable via graphene Fermi energy and relaxation time. The device’s excellent temperature response and wide angular stability provide a novel solution for terahertz switching, stealth technology, and sensing applications. Full article

To address environmental pollution issues and optimize the utilization of waste biomass resources, this study proposes a novel eco-friendly sound-absorbing material based on maple leaf waste and tests its sound absorption performance. The fibers were extracted from maple leaf waste through a wet decomposition and grinding process. Metallurgical microscopy was employed to observe the microstructural characteristics of maple leaf fibers to identify the potential synergistic effect. The effects of two key factors—sample thickness and mass density—on sound absorption performance were investigated. The sound absorption coefficients were measured using the transfer function method in a dual-microphone impedance tube to evaluate their sound-absorbing performance. Experimental results demonstrate that the prepared maple leaf fibers, as acoustic materials, exhibit excellent acoustic performance across a wide frequency range, with an average sound absorption coefficient of 0.7. Increasing sample thickness improves the sound absorption coefficient in low- and mid-frequency ranges. Additionally, increased sample mass density was found to enhance acoustic performance in low- and mid-frequency bands. This study developed an eco-friendly material with lightweight and efficient acoustic absorption properties using completely biodegradable maple leaf waste. The results provide high-performance, economical, and ecologically sustainable solutions for controlling building and traffic noise while promoting the development of eco-friendly acoustic materials. Full article

Objectives: The current study aimed to summarize the current evidence on vertical control provided by the bonded rapid palatal expander (BRPE) in pediatric patient populations within 6 months after expansion. Methods: Relevant studies were screened independently by two researchers from the eight databases MEDLINE (PubMed), Web of Science, SCOPUS, Embase, Cochrane, LILACS (Latin American and Caribbean Health Sciences Literature), LIVIVO and Google Scholar, and supplemented by a manual search of the reference lists from studies selected for full-manuscript reading. Relevant data from lateral cephalograms taken pre- and post-expansion was extracted. A meta-analysis was performed with RStudio and a risk of bias assessment of the included articles was completed. Results: Ten relevant studies were included for data extraction, although most had a high risk of bias. The meta-analysis revealed that within 6-month retention after BRPE treatment, there were (1) slight increases in total (0.83 mm), upper (0.57 mm), and lower (0.70 mm) facial height; (2) minimum change in the palatal plane angulation (−0.01°); (3) minimum change in the occlusal angulation (−0.04°); and (4) minimal mandibular plane angulation changes with 0.01° increase in SN-GoGn angle, 0.71° increase in SN-MP angle, 0.17° increase in FMA, and 0.82° increase in PP-GoGn angle. Conclusion: Current evidence indicates that BRPEs may not control or reduce the vertical dimension significantly within 6 months after expansion. Further high-quality studies, particularly on hyperdivergent patients, are needed to clarify whether bonded expanders offer advantages over traditional banded expanders in management of the vertical dimension. Full article

The use of questionnaire survey results as a clinical diagnostic method for schizophrenia lacks a certain degree of objectivity; thus, markers of schizophrenia in different brain signals have been widely investigated. The objective of this investigation was to explore potential markers of schizophrenia by investigating nonequilibrium features in magnetoencephalography (MEG) signals. We propose a new method to quantify the nonequilibrium features of MEG signals: the multiscale permutation time irreversibility (MsPTIRR) index. The results revealed that the MsPTIRR indices of the MEG recordings of patients with schizophrenia were significantly lower than those of the healthy controls (HCs). Moreover, the MsPTIRR indices of the MEG recordings of patients with schizophrenia and HCs differed significantly in the frontal, occipital, and temporal lobe regions. Furthermore, the MsPTIRR indices of the MEG recordings differed significantly between patients with schizophrenia and HCs in the $\theta$, $\alpha$ and $\beta$ bands. Abnormal nonequilibrium features mined in MEG recordings using the MsPTIRR index may be used as potential markers for schizophrenia, assisting in the clinical diagnosis of this disorder. Full article

To address the challenges of insufficient response speed and robustness in optical attitude control systems under highly dynamic disturbances and internal uncertainties, a composite control strategy is proposed in this study. By integrating the proposed piecewise sliding control (P-SMC) with the improved active disturbance rejection control (ADRC), this strategy achieves complementary performance, which can not only suppress the disturbance but also converge to a bounded region fast. Under highly dynamic disturbances, the improved extended state observer (ESO) based on the EKF achieves rapid response with amplified state observations, and the Nonlinear State Error Feedback (NLSEF) generates a compensation signal to actively reject disturbances. Simultaneously, the robust sliding mode control (SMC) suppresses the effects of system nonlinearity and uncertainty. To address chattering and overshoot of the conventional SMC, this study proposes a novel P-SMC law which applies distinct reaching functions across different error bands. Furthermore, the key parameters of the composite scheme are globally optimized using the particle swarm optimization (PSO) algorithm to achieve Pareto-optimal trade-offs between tracking accuracy and disturbance rejection robustness. Finally, MATLAB simulation experiments validate the effectiveness of the proposed strategy under diverse representative disturbances. The results demonstrate improved performance in terms of response speed, overshoot, settling time and control input signals smoothness compared to conventional control algorithms (ADRC, C-ADRC, T-SMC-ADRC). The proposed strategy enhances the stability and robustness of optical attitude control system against internal uncertainties of system and sensor measurement noise. It achieves bounded-error steady-state tracking against random multi-source disturbances while preserving high real-time responsiveness and efficiency. Full article

β-Hydroxy-β-methylbutyrate (HMB), a natural metabolite derived from the essential amino acid leucine, is primarily recognised for its anabolic and anti-catabolic effects on skeletal muscle tissue. Recent studies indicate that HMB may also play a role in influencing the structural organisation of extracellular matrix (ECM) components, particularly collagen, which is crucial for maintaining the mechanical integrity of connective tissues. In this investigation, bovine type I collagen was polymerised in the presence of two concentrations of HMB (0.025 M and 0.25 M) to explore its potential function as a molecular modulator of fibrillogenesis. The morphology of the resulting collagen fibres and their molecular architecture were examined using atomic force microscopy (AFM) and Fourier-transform infrared (FTIR) spectroscopy. The findings demonstrated that lower levels of HMB facilitated the formation of more regular and well-organised fibrillar structures, exhibiting increased D-band periodicity and enhanced stabilisation of the native collagen triple helix, as indicated by Amide I and III band profiles. Conversely, higher concentrations of HMB led to significant disruption of fibril morphology and alterations in secondary structure, suggesting that HMB interferes with the self-assembly of collagen monomers. These structural changes are consistent with a non-covalent influence on interchain interactions and fibril organisation, to which hydrogen bonding and short-range electrostatics may contribute. Collectively, the results highlight the potential of HMB as a small-molecule regulator for soft-tissue matrix engineering, extending its consideration beyond metabolic supplementation towards controllable, materials-oriented modulation of ECM structure. Full article

Cognitive deficiencies are significant factors affecting aviation piloting capabilities. However, due to the limited stability resulting from the insufficient appeal of traditional attention or memory cognitive training, multi-task gamified cognitive training (MTGCT) may be more beneficial in generating far transfer effects in task performance. This study explores the enhancement effects of simulated flight operation capabilities based on visuo-spatial attention and working memory MTGCT. Additionally, we explore the neurophysiological impacts through changes in EEG power spectral density (PSD) characteristics and brain asymmetry, and whether these impacts exhibit a certain retention effect. This study designed a 28-day simulated flight operation capability enhancement experiment. In addition, the behavioral performance and EEG signal changes in 28 college students (divided into control and training groups) were analyzed. The results indicated that MTGCT significantly enhanced simulated flight operational capabilities, and the neural framework formed by physiological changes remains effective for at least two weeks. The physiological changes included a decrease in the $\theta$ band PSD and an increase in the $\alpha$ band PSD in the frontal and parietal lobes due to optimized cognitive resource allocation, as well as the frontal $\theta$ band leftward asymmetry and the frontoparietal $\alpha$ band rightward asymmetry due to the formation of neural activity patterns. These findings support, to some extent, the feasibility and effectiveness of using MTGCT as a periodic training method to enhance the operational and cognitive abilities of aviation personnel. Full article

In future 6G systems, integrated sensing and communication (ISAC) in the terahertz (THz) band are emerging as a key technology. Photomixing-based approaches offer advantages for the generation and control of THz waves due to their wide bandwidth and frequency tunability. This paper proposes and experimentally demonstrates a THz-band ISAC system that employs high-speed wavelength tunable lasers. Leveraging the rapid wavelength tunability of the laser, the system simultaneously generates a frequency-modulated continuous-wave (FMCW) radar signal and a frequency-shift keying (FSK) communication signal. Experimental results show successful ranging with a centimeter-level distance measurement error using a 7.9 GHz sweep-bandwidth THz-FMCW signal. The system achieves a short repetition period of 800 ns, significantly enhancing real-time performance in dynamic environments. Moreover, 2FSK communication at 2 Gbit/s was demonstrated without the use of an external modulator, achieving a BER below the HD-FEC threshold. These results confirm that radar and communication functionalities can be integrated into a single transmitter. The proposed system contributes to reducing system complexity and cost and offers a promising solution for 6G applications. Full article

Erbium (${\mathrm{Er}}^{3+}$) emitters are relevant for optical applications due to their narrow emission line directly in the telecom C-band due to the ⁴I_13/2 → ⁴I_15/2 transition at 1.54 μm. Additionally, they are promising candidates for future quantum technologies when embedded in thin film silicon-on-insulator (SOI) to achieve fabrication scalability and CMOS compatibility. In this paper we integrate Er³⁺ emitters in SOI metasurfaces made of closely spaced arrays of nanodisks, to study their spontaneous emission via room and cryogenic temperature confocal microscopy, off-resonance and in-resonance photoluminescence excitation at room temperature and time-resolved spectroscopy. This work demonstrates the possibility to adopt CMOS-compatible and fabrication-scalable metasurfaces for controlling and improving the collection efficiency of the spontaneous emission from the Er³⁺ transition in SOI and that they could be adopted in similar technologically advanced materials. Full article

This study evaluated the impact of biochar on the growth of strawberry plants, combining visual and proximal sensing monitoring. The plants were rooted in soil enriched with biochar, derived from pyrolysis of soft wood at 550 °C and applied in two doses (2 and 15 g/L), and after physical activation with CO₂ at 900 °C; there was also a treatment with no biochar (unaltered). Visual monitoring was based on data logging twice per week of plants’ height and number of flowers and ripe fruits. Proximal sensing monitoring involved a system including a low-cost multispectral camera and a Raspberry Pi 4. The camera acquired nadiral images hourly in three spectral bands (550, 660, and 850 nm), allowing calculation of the normalized difference vegetation index (NDVI). After three months, control plants reached a height of 12.3 ± 0.4 cm, while those treated with biochar and activated biochar grew to 18.03 ± 1.0 cm and 17.93 ± 1.2 cm, respectively. NDVI values were 0.15 ± 0.11 for control plants, increasing to 0.26 ± 0.03 (+78%) with biochar and to 0.28 ± 0.03 (+90%) with activated biochar. In conclusion, biochar application was beneficial for strawberry plants’ growth according to both visual and proximal-sensed measures. Further research is needed to optimize the integration of visual and proximal sensing monitoring, also enhancing the measured parameters. Full article

Diffractive sail components may be used in part or whole for in-space propulsion and attitude control. A sun-facing hybrid diffractive solar sail having reflective front facets and transmissive side facets is described. This hybrid design seeks to minimize the undesirable scattering from side facets. Predictions of radiation pressure are compared for analytical geometrical optics and numerical finite difference time domain approaches. Our calculations across a spectral irradiance band from 0.5 to 3 μm suggest the transverse force in a sun facing configuration reaches 48% when the refractive index of the sail material is 1.5. Diffraction measurements at a representative optical wavelength of 633 nm support our predictions. Full article

Paddy rice grain variety classification is essential for quality control, as different rice varieties exhibit significant variations in quality attributes, affecting both food security and market value. The integration of hyperspectral imaging with machine learning presents a promising approach for precise classification, though challenges remain in managing the high dimensionality and variability of spectral data, along with the need for model interpretability. To address these challenges, this study employs a CNN-Transformer model that incorporates Standard Normal Variate (SNV) preprocessing, Competitive Adaptive Reweighted Sampling (CARS) for feature wavelength selection, and interpretability analysis to optimize the classification of hybrid indica paddy rice grain varieties. The results show that the CNN-Transformer model outperforms baseline models, achieving an accuracy of 95.33% and an F1-score of 95.40%. Interpretability analysis reveals that the model’s ability to learn from key wavelength features is significantly stronger than that of the comparison models. The key spectral bands identified for hybrid indica paddy rice grain variety classification lie within the 400–440 nm, 580–700 nm, and 880–960 nm ranges. This study demonstrates the potential of hyperspectral imaging combined with machine learning to advance rice variety classification, providing a powerful and interpretable tool for automated rice quality control in agricultural practices. Full article

Background/Objectives: Orthodontic appliances disrupt oral biofilm homeostasis, leading to an increase in plaque and disease risk. Elastomeric modules (EMs) promote bacterial growth due to their material composition. Surface coatings have been developed to reduce bacterial colonization. We evaluated the mechanical, antimicrobial, and cell viability properties of a chitosan coating for EMs. Methods: EMs were coated with chitosan (CS) and chitosan-glutaraldehyde (CS-GTA) to assess antimicrobial and cell viability. Uncoated EMs were used as a control. These surface-coated modules were characterized and analyzed with Fourier transform infrared (FTIR) and Raman spectroscopy, and tensile testing. Antibacterial activity was assessed by colony-forming units (CFU) counts after incubation. Cell viability was tested with gingival fibroblasts using the MTT assay. ANOVA, Tukey, Kolmogorov–Smirnov, and Kruskal–Wallis tests were used for statistical analysis. Results: Raman spectra of the chitosan coatings showed characteristic molecular vibration bands. ANOVA revealed a significant difference in mechanical properties between the materials and between the control and the CS-GTA groups, confirmed by the Tukey post hoc test. No significant difference was observed between the groups in the Yield Stress test. All the coated groups showed reduced CFU counts in the antibacterial assay. The average cell viability of the coated groups was 85% and 89%. Conclusions: We synthesized CS and GTA-cross-linked chitosan coatings. The coatings did not affect the mechanical properties of the elastomeric modules. The chitosan and glutaraldehyde-cross-linked CS coatings inhibited bacterial growth. No significant differences were observed in antibacterial activity between the CS and the GTA-crosslinked chitosan coatings. Full article

This study introduces the Normalized Difference Gamma Ray Index (NDGRI), a novel spectral composite derived from Sentinel 2 imagery for mapping elevated natural gamma radiation in semi-arid and arid basins. We hypothesized that water-sensitive spectral indices correlate with gamma-ray hotspots in arid regions of Mongolia, where natural radionuclide distribution is influenced by hydrological processes. Leveraging historical car-borne gamma spectrometry data collected in 2008 across the Sainshand and Zuunbayan uranium project areas, we evaluated twelve spectral bands and five established moisture-sensitive indices against radiation heatmaps in Naarst and Zuunbayan. Using Pearson and Spearman correlations alongside two percentile-based overlap metrics, indices were weighted to yield a composite performance score. The best performing indices (MI—Moisture Index and NDSII_1—Normalized Difference Snow and Ice Index) guided the derivation of ten new ND constructs incorporating SWIR bands (B11, B12) and visible bands (B4, B8A). The top performer, NDGRI = (B4 − B12)/(B4 + B12) achieved a precision of 62.8% for detecting high gamma-radiation areas and outperformed benchmarks of other indices. We established climatological screening criteria to ensure NDGRI reliability. Validation at two independent sites (Erdene, Khuvsgul) using 2008 airborne gamma ray heatmaps yielded 76.41% and 85.55% spatial overlap accuracy, respectively. Our results demonstrate that NDGRI effectively delineates gamma radiation hotspots where moisture-controlled spectral contrasts prevail. The index’s stringent acquisition constraints, however, limit the temporal availability of usable scenes. NDGRI offers a rapid, cost-effective remote sensing tool to prioritize ground surveys in uranium prospective basins and may be adapted for other radiometric applications in semi-arid and arid regions. Full article