Search Results (40,253)

Upper extremity impairments often lead to reduced joint range of motion (ROM), making reliable assessment essential for rehabilitation planning. This study investigated the within-day and between-day reliability of the Microsoft Kinect V2 depth camera for active upper extremity ROM assessment in 30 healthy adults. Ten predefined shoulder and elbow movements were recorded, and joint angles were computed using a custom vector-based algorithm. Within-day reliability ranged from moderate to excellent (ICC: 0.754–0.953), while between-day reliability ranged from moderate to good (ICC: 0.654–0.881). Absolute reliability varies substantially across movements. The SEM% values ranged from 2.1% to 17.3% within-day and from 2.8% to 23.6% between-day. The between-day MDC values were particularly high for certain movements (e.g., >20° for shoulder extension and >50° for elbow flexion), indicating limited sensitivity to detect small clinical changes. Additionally, shoulder adduction could not be reliably analyzed in 36.7% of participants due to self-occlusion-related tracking instability, highlighting a practical limitation of the Kinect V2 for certain upper extremity movements. These findings suggest that Kinect V2-based ROM assessment demonstrates acceptable reliability for large-amplitude planar movements under controlled conditions but shows substantial limitations for rotational and occlusion-prone tasks. The device may be suitable for research or screening applications; however, caution is warranted when interpreting small changes in clinical settings. Full article

To address the durability deficiencies and limited service life of concrete structures exposed to complex service environments such as chloride attack in marine and underground engineering, this study employs fly ash (FA) and ground granulated blast-furnace slag (GGBS), typical eco-friendly materials, as functional mineral admixtures to systematically investigate the effects of their combined incorporation on the mechanical properties, durability, drying shrinkage, and microstructural characteristics of concrete. The objective is to develop a concrete material that achieves high durability while maintaining structural safety and service performance, with the additional benefit of improved resource utilization efficiency. Single-factor tests were first conducted to determine the sensitivity ranges of FA and GGBS within 10–30% for slump, compressive strength, chloride migration coefficient (RCM), and drying shrinkage. Subsequently, response surface methodology (RSM) was employed to establish quadratic regression models using FA and GGBS as independent variables and compressive strength, RCM, and drying shrinkage as response indicators. The models exhibited high fitting accuracy, and their reliability was validated through analysis of variance (ANOVA), residual analysis, and predictive performance indices. Multi-objective optimization based on the desirability function identified the optimal mix proportion as FA = 14.8% and SL = 29.3%, yielding predicted values of 56.2 MPa for 28-day compressive strength, 6.03 × 10⁻¹² m²/s for RCM, and 639 με for 90-day drying shrinkage. Microstructural analysis using SEM and MIP further revealed that the binary-blended system promotes the formation of a dense C–S–H/C–A–S–H gel network, refines pore-size distribution, and reduces pore connectivity, thereby improving long-term mechanical and durability performance. The findings provide quantitative guidance for designing high-durability, environmentally friendly concrete suitable for marine and underground engineering applications. Full article

Background: Myricetin (MYR) is a natural flavonol with antioxidant, neuroprotective, anti-inflammatory, antidiabetic, and cardioprotective activities. Still, its pharmaceutical use is limited by very low aqueous solubility (~16.6 µg/mL) and poor oral bioavailability (<10%). This study aimed to enhance the solubility and potentially improve the bioavailability of MYR by developing an amorphous nanofibrous delivery system. Methods: Electrospinning was applied to fabricate MYR-loaded nanofibers using polyvinylpyrrolidone K30 (PVP30), and the influence of key processing parameters on MYR solubility was evaluated. Nanofibers produced under selected electrospinning conditions were characterized in terms of morphology, encapsulation efficiency, and physicochemical properties. Results: X-ray powder diffraction confirmed complete amorphization of MYR within the BB5 fiber structure (distance: 12 cm, voltage: 25 kV, flow rate: 1.5 mL/h). FTIR analysis indicated hydrogen-bonding interactions between MYR hydroxyl groups and PVP30 carbonyl groups, contributing to stabilization of the amorphous form. SEM images revealed homogeneous, defect-free fibers with diameters below 400 nm, although localized MYR agglomerates were observed. Solubility and release studies demonstrated a characteristic spring-and-parachute effect, enabling rapid MYR release and maintenance of a supersaturated state. Enhanced solubility resulted in significantly improved antioxidant activity in DPPH and CUPRAC assays compared with crystalline MYR. Conclusions: Electrospun PVP30 nanofibers represent a promising platform for improving the solubility, dissolution behavior, and functional activity of poorly soluble bioactive compounds such as myricetin, supporting their potential application in pharmaceutical formulations. Full article

As the net gain of carbon by plants after accounting for respiration, vegetation net primary productivity (NPP) plays a central role in the terrestrial carbon cycle. However, a systematic and quantitative analysis of the spatiotemporal evolution and driving mechanisms of vegetation NPP on Hainan Island, a tropical region, is still lacking. Focusing on Hainan Island, this study employs an integrated approach—including the coefficient of variation, Mann–Kendall test, Hurst exponent, geographical detector, and PLS-SEM—to investigate the spatiotemporal dynamics of vegetation NPP and its underlying drivers from 2001 to 2022. The main conclusions as follows: (1) Vegetation NPP on Hainan Island showed a fluctuating upward trend from 2001 to 2022, with a mean annual increase of 3.6 g C·m⁻²·yr⁻¹, and displayed a spatial pattern of decrease from the central-southern mountainous areas toward the coastal regions. (2) NPP changes were generally stable; historically, areas showing an increasing trend exceeded those with a decreasing trend by 30.55%. In the future, the predominant projected trends are “persistent decrease” and “increase to decrease,” which together account for over 80% of the total area. (3) Topography and climate were the dominant drivers of NPP spatial heterogeneity. Elevation had the strongest explanatory power, followed by evapotranspiration and temperature. A significant, nonlinear enhancement effect was observed in the interaction between any two factors. (4) Topographic, climatic, anthropogenic, and vegetation factors all exerted direct positive effects on vegetation NPP. Anthropogenic activities also indirectly promoted NPP by influencing pathways such as vegetation growth. The conclusions of this research provide support for the implementation and evaluation of land-use planning, afforestation projects, and ecological protection and restoration measures on Hainan Island. Full article

Service encounters have long been viewed as determinants of hotel guest loyalty, yet excellent service does not always translate into repeat patronage. This study examines how green service encounters shape guest loyalty in green-certified luxury hotels in Bali, a leading sustainable tourism destination. It investigates whether green experiential value and green customer delight mediate the effect of green service encounters on green hotel loyalty. Survey data from 273 domestic repeat guests of Green Globe and Earth Check-certified luxury hotels in Bali were analyzed using partial least squares structural equation modeling (PLS-SEM). The results show that green service encounters influence loyalty primarily through green experiential value and green customer delight, with delight exerting a comparatively stronger mediating effect. The study extends green hotel loyalty research by theorizing and testing an emotion-centric, sustainability-anchored loyalty mechanism beyond traditional service-quality and satisfaction models. Managerially, the findings highlight the need for certified luxury green hotels to design green service encounters that create distinctive experiential value and delight, thereby strengthening long-term guest loyalty. Full article

This study investigates the impact of green organizational support and green self-efficacy on promoting employees’ pro-environmental behaviors, framed within Social Cognitive Theory and Social Exchange Theory. The direct and indirect impacts of green organizational support on employees’ green advocacy and pro-environmental behaviors remain insufficiently examined in the literature. This study aims to clarify the factors affecting pro-environmental behaviors within the workplace and to examine the relationship among green organizational support, green self-efficacy, green advocacy, and pro-environmental behavior. Data was gathered from 154 employees via a structured questionnaire, and the proposed model was analyzed using SmartPLS 4. The study findings demonstrate that both green organizational support and green advocacy directly and positively influence workplace pro-environmental behaviors. The impact of green self-efficacy on the eco-friendly behaviors of employees could not be validated. The results are useful for the development of sustainability strategies for organizations and the establishment of an environmentally conscious corporate culture. Full article

Zirconium hydride is susceptible to dehydrogenation at elevated temperatures. In this study, zirconium hydride was oxidized by in situ oxidation in a CO₂ atmosphere at temperatures ranging from 550 to 700 °C for 10 h. The morphology, elemental distribution, phase structure, and hydrogen barrier performance of the resulting oxide films were systematically characterized using SEM, EDS, XRD, film adhesion and microhardness tests, and dehydrogenation experiments. At 550–600 °C, the formed oxide films are thin and non-uniform, containing numerous micropores and cracks, which results in limited hydrogen barrier performance. When the oxidation temperature is increased to 650 °C, a better balance between the oxidation reaction and diffusion processes is achieved. This leads to the formation of a dense, continuous, and uniform ZrO₂ film with strong adhesion to the substrate. As a result, the initial dehydrogenation temperature increases to 660 °C, while both the dehydrogenation rate and cumulative hydrogen release are significantly reduced, indicating the best overall hydrogen resistance. However, further increasing the oxidation temperature to 700 °C causes an excessively high oxidation rate, which introduces large growth and thermal stresses. These stresses promote the formation of microcracks in the oxide film, weaken the interfacial bonding strength, and consequently reduce the hydrogen barrier performance. The results demonstrate that the hydrogen permeation resistance of the oxide film is mainly governed by film compactness, defect evolution, and interfacial integrity. Based on these findings, 650 °C is identified as the optimal processing temperature for producing a high-quality hydrogen-resistant ZrO₂ film on zirconium hydride under a CO₂ atmosphere. Full article

The development of thermostable and pH-robust endo-polygalacturonases (endo-PGases) is crucial for industrial applications such as food processing. This study aimed to engineer the thermostability of an acidic, thermophilic endo-PGase (PoxaEnPG28B) by rigidifying its flexible regions. We employed an integrated computational strategy combining molecular dynamics (MD) simulations at elevated temperatures with in silico analyses of unfolding free-energy changes to identify and design stabilizing mutations. This approach successfully yielded the mutant D249K, which exhibited a 5 °C higher optimal temperature (70 °C) and a 68.8% longer half-life at 55 °C, and it retained over 76.8% activity at 75 °C. Notably, D249K maintained the wild-type’s optimal pH (5.0) and broad pH stability (3.0–8.0). Although it is not the absolute top performer in every single metric, D249K achieves the best overall balance between thermostability and pH robustness among all reported thermophilic endo-PGases. MD simulations revealed that its enhanced stability sems from reduced global and local flexibility and a more compact structure. In juice extraction applications, D249K increased yields by up to 98.5%, significantly surpassing the wild-type. This study demonstrates the efficacy of MD-guided flexible region engineering for the GH28 family and presents D249K as a highly promising industrial biocatalyst. Full article

The increasing release of pharmaceutical pollutants, particularly antibiotics and analgesics, into aquatic environments poses a significant environmental challenge and necessitates sustainable removal strategies. In this study, lavender-derived biochar was produced by pyrolysis at 450 and 650 °C and subsequently modified with Zn²⁺ (3 and 5 mmol) via a solvothermal method. The resulting materials were evaluated as photocatalysts for the degradation of doxycycline and paracetamol in distilled water under UV-A irradiation. Structural and optical characterization (SEM–EDS, XRD, PL, FTIR) was conducted to elucidate structure–performance relationships relevant to photocatalytic activity. The sample pyrolyzed at 450 °C and modified with 5 mmol Zn²⁺ exhibited the highest photocatalytic performance, achieving degradation efficiencies of 62.78% for doxycycline (k = 0.0032 min⁻¹) and 75.19% for paracetamol (k = 0.0113 min⁻¹). The results demonstrate that controlled Zn incorporation into lavender-derived biochar enhances photocatalytic performance and highlight the role of synthesis parameters in governing catalytic behavior. This work underscores the potential of agro-waste-derived biochar as a functional matrix in sustainable photocatalytic systems. Full article

To address the problem of excessive sulfur in high-sulfur magnetite concentrates when used directly, this study systematically investigated the desulfurization behavior and mechanism during oxidative roasting. Green pellets were prepared by mixing high-sulfur iron concentrate fines with 1% bentonite, followed by roasting experiments in air at 800–1200 °C. Thermogravimetric analysis (TG), real-time flue gas analysis (DOAS), X-ray diffraction (XRD), and scanning electron microscopy–energy dispersive spectroscopy (SEM–EDS) were employed to characterize the process and products. The results show that sulfur release is mainly concentrated in two stages: intensive oxidative decomposition of FeS/FeS₂ in the range of 480–580 °C and release of reacted sulfur originally encapsulated within the pellets in the range of 940–1080 °C. It was found that alkali metal oxides CaO and MgO in the feed can fix sulfur at a high temperature. They react with released SO₂ and iron oxides to form Ca/Mg sulfate–iron oxide composite phases, such as (Ca_0.75Mg_0.25)SO₄·0.38Fe₂O₃ and (Ca_0.91Mg_0.09)SO₄·3.66Fe₂O₃·1.47MgO, which slow the SO₂ emission rate. A desulfurization ratio above 99% can be achieved when roasting at 1100 °C and above. This study clarifies the sulfur migration mechanism during the roasting of high-sulfur iron concentrate pellets, providing a theoretical basis for optimizing the roasting process to achieve efficient desulfurization and recovery of iron resources. Full article

Polyether ether ketone (PEEK) is a high-performance thermoplastic with potential applications in aerospace, automotive, and biomedical components, owing to its exceptional specific strength, thermal stability, and biocompatibility. However, its moderate hardness and limited wear resistance in dry sliding severely constrain its use in highly loaded tribological contacts. In this study, PEEK-based reinforced hybrid composites were produced utilizing a powder metallurgy technique, with reinforcement fractions of 10 wt.% graphite (Gr), boron (B), hydroxyapatite (HAp), and zirconium (Zr). The processing sequence included homogeneous wet-mixing, uniaxial cold compaction at pressures of 10–30 MPa, and sintering at 250–300 °C. The composition and microstructures were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Mechanical and tribological performances were assessed by Vickers microhardness, uniaxial compression and dry sliding wear tests. The best-performing Gr-B hybrid composite increased hardness by 240% and compressive strength by 175% compared with unreinforced PEEK. Tribologically, boron-containing PEEK demonstrated up to a 34.7% reduction in the coefficient of friction and approximately a 90% drop in wear-induced mass loss compared with unreinforced PEEK. The resulting Gr-B-reinforced PEEK hybrids are excellent choices for demanding load-bearing and tribological components like aerospace bushings, automotive sliding elements, spinal cages, and orthopedic fixation devices in biomedical applications because of their balanced combination of high hardness, superior wear resistance, and high compressive strength. Full article

Background: Voluntary activation testing quantifies the ability of the motor nervous system to produce maximal force. Laboratory assessment of ankle plantar flexor voluntary activation is common, but field testing in practical settings is limited by equipment portability. We aimed to compare plantar flexor voluntary activation and maximal voluntary contraction (MVC) using a portable device with a standardised laboratory method and evaluate the test–retest reliability of the portable protocol. Methods: We performed a pseudo-randomised, crossover design. Participants completed two protocols: (1) portable force plate testing and (2) a laboratory-based isokinetic dynamometer. Voluntary activation was assessed using twitch interpolation via tibial nerve stimulation. Differences between protocols were analysed using generalised estimating equations. Reliability was assessed with the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and coefficient of variation (CV). Results: Twenty healthy participants (8 females, 12 males; median age 28.5 years) were included. No difference between protocols was detected for voluntary activation (β = 0.6, p = 0.68). The portable protocol demonstrated good reliability (ICC = 0.85) and low measurement error (SEM = 2.56%, CV = 2.79%). Conclusions: We demonstrated that the portable protocol is a valid and reliable method for assessing plantar flexor voluntary activation. It is suitable for assessing within-subject changes over time and can reduce participant attendance burden for neurophysiological muscle testing. Full article

Artificial intelligence (AI) marketing technologies are reshaping customer engagement in service sectors, yet their performance within integrated digital ecosystems remains poorly understood. Existing research often examines AI tools in isolation, overlooking how the holistic quality of the virtual customer experience (VCE) shapes their impact on consumer decisions, particularly in intangible service contexts such as telecommunications. This study addresses this gap by investigating the influence of four AI technologies—chatbots, dynamic pricing, voice search, and visual search—on purchasing decisions, with VCE tested as a critical moderating mechanism. Using Partial Least Squares Structural Equation Modeling (PLS-SEM) and survey data from 487 telecommunications customers in Saudi Arabia, the findings confirm significant positive direct effects for all four AI tools. Moreover, the VCE significantly amplifies these individual relationships and further strengthens their combined contribution to decision quality, enabling the model to explain 71.2% of the variance in purchasing decisions. The results indicate that competitive advantage in AI-enabled service markets depends not on deploying isolated technologies, but on orchestrating a coherent, high-quality virtual experience ecosystem. By integrating the Technology Acceptance Model (TAM) and Stimulus–Organism–Response (SOR) framework, this study advances the theoretical understanding of how AI and experience design jointly enhance digital decision-making. Practically, it underscores the need for managers to prioritize integrated VCE design to drive sustainable consumption and strengthen customer loyalty in increasingly digital service environments. Full article

This study investigates the application of artificial intelligence for predicting the compressive strength of a high-performance, eco-efficient engineered cementitious composite (ECC), designated mix S8-1, A. The composite incorporates supplementary cementitious materials and alternative aggregates derived from recycled glass waste. The binder system combines waste glass powder and silica fume, while the aggregate fraction includes recycled cobalt glass. An extensive experimental program involving 14 mixtures tested at 7, 28, 56, 90, and 120 days was performed to establish the reference mechanical and rheological properties. Mix S8-1, A achieved strength class C60/75 and workability corresponding to consistency class S4. To substantiate long-term performance, microstructural and chemical analyses were conducted on specimens preserved since 2011, using scanning electron microscopy (SEM) and X-ray fluorescence (XRF). The results confirmed a stable, densified microstructure, evidencing the long-term durability of the patented ECC formulation. For predictive modeling, a shallow feedforward artificial neural network with three hidden layers was developed and trained on 70 dataset entries representing mixture proportions and curing ages. Model performance was evaluated using cross-validation, achieving a coefficient of determination (R²) of 0.968, a mean absolute error of 1.96 MPa, and a root mean square error of 2.52 MPa. The results demonstrate that AI-based approaches can accurately predict the compressive strength of high-performance, environmentally sustainable ECCs incorporating recycled glass constituents, supporting both performance optimization and resource-efficient material design. Full article

Interrater reliability is a critical aspect of measurement quality, particularly in assessments that rely on subjective judgment. However, interrater reliability estimates vary, and such variability can introduce bias or reduce the accuracy of observed scores, especially when comparing across groups or conditions. Understanding and accounting for these differences is essential when interpreting reliability in applied settings such as education, psychology, and performance evaluation. This study addresses the need for more nuanced approaches to evaluating interrater reliability across groups. Specifically, in this study, we examine generalizability theory (GT) and structural equation modeling (SEM) that enable direct testing of differences in reliability coefficients across groups. A simulation study compared a proposed method grounded in GT and SEM to the W statistic for reliability coefficient comparisons. Results demonstrate that the proposed method consistently outperforms the W statistic in terms of both Type I error control and statistical power, particularly when sample sizes are moderate to large or when variance in rater agreement exists across groups. These findings underscore the importance of explicitly modeling differences in interrater reliability and provide researchers with a more robust tool for evaluating the consistency of ratings across diverse contexts and populations. Full article