Search Results (861)

Background. Cervical spondylosis is a degenerative disorder of the spine, frequently associated with chronic neck pain, reduced mobility, and functional impairment. Patients develop alterations in muscle tone, stiffness, and elasticity, which further contribute to disability. This study aimed to investigate the effects of a 14-day standardized rehabilitation program on the biomechanical and contractile properties of cervical and scapular muscles in patients with cervical spondylosis. Methods. This study used a single-group pre–post observational design on 23 patients (16 women, 7 men; mean age 61.1 ± 14.2 years) diagnosed with cervical spondylosis. All participants completed a standardized rehabilitation treatment that included cervical mobilization, stretching, isometric exercises, scapular stabilization, electrotherapy, ultrasound, thermotherapy, and balneotherapy. Muscle properties were evaluated bilaterally using the MyotonPRO^® device, measuring frequency, stiffness, decrement, relaxation time, and creep. Assessments were performed in a sitting position for the deltoid, upper trapezius and pectoralis major, both at baseline (T0) and after treatment (T1). Handgrip strength was assessed bilaterally with a handheld dynamometer. Results. The deltoid muscle showed a significant reduction in frequency (14.86 → 13.50 Hz, p = 0.034) and stiffness (306.4 → 256.1 N/m, p = 0.014) on the right side, suggesting normalization of tone and passive resistance. The upper trapezius had a significant bilateral decrease in decrement (p < 0.05), reflecting improved elasticity. The pectoralis major displayed the most consistent adaptations, with increased frequency (right side, p = 0.008), improved relaxation bilaterally (p < 0.05), and significant reductions in decrement and creep (p < 0.01). Handheld dynamometry confirmed increased handgrip strength, with a 5.4% improvement on the left side and 7.6% on the right side. Conclusions. In our study measurable changes in muscle parameters were observed following a rehabilitation program in patients with cervical spondylosis. The integration of myotonometry and dynamometry allowed objective assessment of muscle adaptations supporting the clinical value of individualized rehabilitation strategies. Full article

This work presents a notch filter architecture based on a dual-output second-generation voltage conveyor, designed with a current-mode approach. The proposed topology employs a single frequency-selective LC branch and directly uses the two voltage outputs of the DOVCII to generate a notch response without additional active stages. Analytical expressions for the transfer function, notch frequency, and quality factor are derived, highlighting independent control of the passband gain and notch parameters. A sensitivity analysis demonstrates that the notch frequency depends exclusively on the LC product with half-order sensitivities, while the quality factor is predominantly controlled by a single resistor, resulting in predictable tuning and improved tolerance to passive component variations. Transistor-level analysis of the proposed filter was carried out using a standard AMS 0.35 μm CMOS process and has been validated through both circuit-level simulations and experimental measurements using a DOVCII implementation based on the AD844 current-feedback amplifier. Prototypes operating at 100 kHz and 50 Hz notch frequencies have been implemented, the latter employing a current-mode inductance simulator to avoid bulky passive inductors. Full article

To measure temperature and pressure parameters in harsh environments such as those with high temperature and high pressure, a wireless and passive multi-grid Complementary Split-Ring Resonator and substrate integrated waveguide (MG-CSRR-SIW) structure for a temperature and pressure sensor based on microwave scattering principles and high-temperature co-fired ceramic (HTCC) technology is proposed. It can measure temperature within 25–1200 °C and pressure within 0–300 kPa. The structural design of the sensor by using high-frequency electromagnetic simulation software contributes to a linear relationship between the measured parameters and the sensor’s return loss (S11). Furthermore, the performance validation of the proposed sensor is implemented by sensor fabrication and experimentation. The test results show that the proposed sensor exhibits good performance of reliability and linearity. The temperature sensitivity is 199.33 kHz/°C and 379.75 kHz/°C in the temperature ranges of 25–475 °C and 475–1200 °C, respectively. In addition, the pressure sensitivity reaches 235.5 kHz/kPa at 800 °C. The maximum relative measurement error is 2.2% and 1.45% in regard to temperature and pressure, respectively. Full article

With the advancement of digital technology, serious games have become an essential tool for disseminating and educating individuals about cultural heritage. However, systematic empirical research remains limited with respect to how visual elements influence users’ cognitive and emotional engagement through interactive behaviors. Using the “Macau Historic Centre Science Popularization System” as a case study, this mixed-methods study investigates the mechanisms by which visual elements affect user experience and learning outcomes in digital interactive environments. Eye-tracking data, behavioral logs, questionnaires, and semi-structured interviews from 30 participants were collected to examine the impact of visual elements on cognitive resource allocation and emotional engagement. The results indicate that the game intervention significantly enhanced participants’ retention and comprehension of cultural knowledge. Eye-tracking data showed that props, text boxes, historic buildings, and the architectural light and shadow shows (as incentive feedback elements) had the highest total fixation duration (TFD) and fixation count (FC). Active-interaction visual elements showed a stronger association with emotional arousal and were more likely to elicit high-arousal experiences than passive-interaction elements. The FC of architectural light and shadow shows a positive correlation with positive emotions, immersion, and a sense of accomplishment. Interview findings revealed users’ subjective experiences regarding visual design and narrative immersion. This study proposes an integrated analytical framework linking “visual elements–interaction behaviors–cognition–emotion.” By combining eye-tracking and information dynamics analysis, it enables multidimensional measurement of users’ cognitive processes and emotional responses, providing empirical evidence to inform visual design, interaction mechanisms, and incentive strategies in serious games for cultural heritage. Full article

Concrete structures suffering from Mg²⁺ environments may suffer severe damage, which mainly has something to do with the coupled effect among Cl⁻, SO₄²⁻, and Mg²⁺. Based on a systematic review of Web of Science and Scopus database (2000–2025), we first summarized the migration behavior, reaction paths, and interaction mechanism of Cl⁻, SO₄²⁻, and Mg²⁺ in cementitious matrices. Secondly, from the perspective of Cl⁻ cyclic adsorption–desorption breaking the passivation film of steel bars, SO₄²⁻ generating expansion products leads to crack expansion, then Mg²⁺ decalcifies C-S-H and transforms into M-S-H; we analyzed the main damage mechanisms, respectively. In addition, under the coexistence conditions of three kinds of ions, the “fixation–substitution–redissolution” process and “crack–transport” coupling positive feedback mechanism further increase the development rate of damage. Then, some anti-corrosion measures, such as mineral admixtures, functional chemical admixtures, fiber reinforcements, surface coatings, and new binder systems, are summarized, and the pros and cons of different anti-corrosion technologies are compared and evaluated. Lastly, from two aspects of simulation prediction for the coupled corrosion damage mechanism and service life prediction, respectively, we have critically evaluated the advances and problems existing in the current research on the aspects of ion migration-reaction coupled models, multi-physics coupled frameworks, phase-field methods, etc. We found that there is still much work to be conducted in three respects: deepening mechanism understanding, improving prediction precision, and strengthening the connection between laboratory test results and actual projects, so as to provide theoretical basis and technical support for the durability design and anti-corrosion strategies of concrete in complex Mg²⁺ environments. Full article

This study presents a rigorous experimental investigation of in-cabin acoustic comfort across a heterogeneous set of road and special-purpose vehicles. Interior noise measurements were conducted on a total of 35 vehicles, comprising five vehicles from each of seven operational categories, grouped according to RNTR-2 regulations into three distinct vehicle classes: N1, N2, and N2G. The adopted research methodology ensures a unified, phenomenological, and experimental approach to the assessment of interior vehicle acoustics, enabling consistent data acquisition and comparative analysis across vehicle classes. Measurements were performed under both stationary and dynamic operating conditions using Class 1 precision instrumentation. The experimental results reveal systematic differences in acoustic performance between vehicle classes. While N1 and N2 vehicles generally comply with recommended comfort thresholds, N2G special-purpose vehicles exhibit significantly elevated interior noise levels, reaching up to 90 dBA during dynamic operation, together with increased variability at higher engine regimes. These findings highlight the influence of vehicle architecture, operational conditions, and mission-oriented design constraints on vibro-acoustic behavior. Passive noise control solutions based on advanced sound-absorbing and sound-insulating materials were further evaluated, demonstrating interior noise reductions of up to 10 dBA. The scientific contribution of this work lies in the establishment of a unified, reproducible methodology that enables direct cross-category comparison of in-cabin acoustic comfort while explicitly integrating special-purpose vehicles into a comfort-oriented analytical paradigm. By moving beyond regulatory compliance toward a multidimensional interpretation of acoustic comfort, the study provides a robust foundation for vehicle design optimization and supports the future development of dedicated comfort assessment standards. Full article

A composite dual-cavity passively mode-locked fiber laser based on a functionalized microsphere resonator is proposed and experimentally demonstrated. The nonlinear response of the resonator is enhanced by depositing TiO₂ film on a SiO₂ microsphere, which leads to improved mode-locking performance. The wavelength selectivity and optical field confinement of the microsphere resonator are exploited, allowing it to simultaneously serve as an intracavity narrowband filter and a nonlinear modulation element. The threshold of the mode-locked laser was measured to be as low as 34 mW, and stable mode-locked operation was achieved at a pump power of 105.7 mW, with a pulse duration of 2.8 ns, a repetition rate of 13.88 MHz, and a signal-to-noise ratio of 74.86 dB. The output spectrum exhibited a central wavelength of 1560.12 nm, a 3 dB linewidth of 0.06 nm, and a side-mode suppression ratio of 55.13 dB. This straightforward design provides an effective approach for the miniaturization of passively mode-locked fiber lasers. Full article

Silver tarnishing in museum environments depends on multiple, interacting factors that are not often studied in situ. With the aim of addressing the problem in real-world scenarios, this study presents a one-year assessment at the National Archaeological Museum of Spain, in Madrid, a museum that houses a significant collection of silver objects. Pure Ag coupons were placed in four display cases—two designs with different airtightness—and in an adjacent gallery. Tarnishing was quantified by colorimetry, gravimetry, and galvanostatic reduction, and analyzed in relation to environmental parameters (T/RH) and gaseous pollutants (H₂S, SO₂, HF, HCl, formic and acetic acids), measured with passive samplers. Coupons showed different degrees of tarnish, with annual corrosion rates ranging from IC1 (very low) to IC2 (low), without a straightforward relation to hydrogen sulfide concentrations. Electrochemical profiles and XPS on representative coupons identified Ag₂S as the dominant product, with AgCl and minor Ag₂SO₄ in the coupons exposed outside the airtight cases, indicating different contributions inside and outside the cases. Findings highlight that sulfide concentration is not the sole driver; case airtightness, internal materials, cleaning products used on adjacent areas, and, possibly, other aspects influence silver tarnishing. Full article

Background: Postoperative infections remain a major complication in spinal surgeries involving intersomatic screws, often compromising osseointegration and long-term implant stability. Questions/Purposes: This study evaluated a nanotextured titanium oxide surface with nanopillar-like morphology designed to reduce bacterial colonization while preserving mechanical integrity and promoting bone integration. Methods: Ti₆Al₄V screws were studied in three batches: control, passivated with HCl and acid mixture treatment to obtain nanotopographies on the surfaces. To create the nanotopographies, the screws were treated with a 1:1 (v/v) sulfuric acid–hydrogen peroxide solution for 2 h. Surface morphology, roughness, wettability, and surface energy were analyzed by SEM, confocal microscopy, and contact angle measurements. Corrosion and ion release were assessed electrochemically and by ICP-MS, respectively. Mechanical behavior, cytocompatibility, mineralization, and antibacterial efficacy were evaluated in vitro. Osseointegration was analyzed in rabbit tibiae after 21 days by histology and bone–implant contact (BIC). Results: The treatment produced uniform nanopillars (Ra = 0.12 µm) with increased hydrophilicity (49° vs. 102° control) and higher surface energy. Mechanical properties and fatigue resistance (~600 N, 10 million cycles) were unaffected. Corrosion currents and Ti ion release remained low. Nanopillar surfaces enhanced osteoblast adhesion and mineralization and reduced bacterial viability by >60% for most strains. In vivo, Bone Index Contact (BIC) was higher for nanopillars (52.0%) than for HCl-treated (43.8%) and control (40.1%) screws, showing a positive osseointegration trend (p > 0.005). Conclusions: The proposed acid-etching process generates a stable, scalable nanotopography with promising antibacterial and osteogenic potential while maintaining the alloy’s mechanical and chemical integrity. Clinical relevance: This simple, scalable, and drug-free surface modification offers a promising approach to reduce postoperative infections and promote bone integration in spinal implants. Full article

Social housing plays a key role in the Colombian residential market, showing a growing commitment to sustainability: currently, a high percentage of EDGE-certified homes belong to this segment. However, in hot and humid areas such as Montería, most VIS homes have deficiencies in their thermal envelopes and poor roof insulation, which leads to a heavy reliance on air conditioning. This study addresses the lack of practical and replicable methodologies for improving energy efficiency in social housing located in hot–humid climates. The research aims to develop and apply a methodological framework that integrates architectural rehabilitation strategies with quantitative evaluation using the EDGE App tool. The proposed approach was implemented in Montería, Colombia, through a case study that combines diagnostic analysis of existing housing conditions, simulation of energy-saving measures, and assessment of environmental and economic performance. A real home in Montería was used as a reference, and more than 600 simulations were carried out considering different orientations and passive strategies. Through a Pareto analysis, the three most efficient measures were identified: natural ventilation, high-solar-reflectance roofing, and moderate reduction in the U-value. Together, these measures reduced energy consumption by up to 50%, with minimal increases in construction costs (≤1.2% of the commercial value). It was also found that excessive insulation can induce unwanted nighttime heating demands, highlighting the need for adjustments to the climatic context. The results confirm the technical and economic feasibility of mass rehabilitation of VIS in hot and humid climates using standard passive measure packages, consolidating the role of the EDGE App as a key tool for guiding sustainable design, investment, and environmental certification decisions. Full article

This paper presents a precision, wide-dynamic-range leakage current sensor tailored for in-situ monitoring of aging mechanisms such as Time-Dependent Dielectric Breakdown (TDDB) in both active and passive components. The proposed architecture supports high-voltage stress and is fully monolithic, integrating a current-to-voltage front-end, tunable-gain amplifier, and a successive approximation register (SAR) analog-to-digital converter (ADC). To validate the concept, a discrete-component prototype was implemented and evaluated across a leakage current range of 1 nA to 1 $\mathsf{\mu }$A. The sensor achieves 12-bit resolution with measured integral non-linearity (INL) and differential non-linearity (DNL) within $\pm 1.5$ LSB and $\pm 0.3$ LSB, respectively. Compared to prior monitors, the design enables linear current digitization and supports high-voltage stress, features essential for accurate and scalable TDDB characterization. Applications include embedded reliability monitoring in power converters, analog building blocks, and large-scale aging test arrays. Full article

Objectives: The objective is assessing whether the placebo effect can influence the time course of recovery following a football match. Methods: Using a randomized crossover design, eighteen youth male players (age: 15.3 ± 0.5 years, stature: 178.7 ± 6.4 cm, body mass: 65.3 ± 7.6 kg, playing experience: 8.6 ± 1.5 years) completed two friendly matches, followed by placebo (PLA; sham vagus nerve stimulation) or passive rest (CON). To assess the impact of PLA, countermovement jump height (CMJ), 10 and 20 m sprint times, heart rate variability (Ln-rMSSD), static and dynamic muscle soreness, and perceived fatigue were measured at pre-match, post-match, post-recovery, and 24 h post-match. Results: Our findings indicate that match play induced substantial fatigue, with significant deteriorations [p ≤ 0.002, small-to-large effect sizes (ES)] in CMJ, 10 and 20 m sprint performance, Ln-rMSSD, muscle soreness, and perceived fatigue at post-match and post-recovery compared to pre-match (except Ln-rMSSD between pre-match and post-recovery: p = 0.151, small ES). Although no significant between-intervention differences were found for any variable at any time point (p > 0.05), effect size analysis showed moderately lower perceived fatigue (r = 0.40) and dynamic soreness (r = 0.32) in PLA compared to CON at post-recovery. Conclusions: These findings suggest that while placebo stimulation did not affect performance or heart rate variability, it may support perceptual recovery. This holds relevance for both research and practice, as including placebo conditions can help isolate psychological effects from true treatment responses, while promoting positive expectations may enhance the perceived effectiveness of recovery strategies. Full article

Urban environments, particularly university campuses, are increasingly exposed to thermal discomfort due to the Urban Heat Island (UHI) effect and intense solar radiation. This study evaluates the effectiveness of passive and hybrid cooling strategies, specifically sun-sail shading and mist cooling, in enhancing outdoor thermal comfort (OTC) in a university courtyard. The Van Dyck courtyard at the American University of Beirut, located on the East Mediterranean coast, was selected due to its heavy use between 10 am and 2 pm during summer, when ambient temperatures ranged between 32 and 36 °C and relative humidity between 21 and 33%. Thermal variations across four seating areas were analyzed using ENVI-met, a high-resolution microscale model validated against on-site data, achieving Mean Absolute Percentage Errors of 4% for air temperature and 5.2% for relative humidity. Under baseline conditions, Physiological Equivalent Temperature (PET) exceeded 58 °C, indicating severe thermal stress. Several mitigation strategies were evaluated, including three shading configurations, two mist-cooling setups, and a combined system. Results showed that double-layer shading reduced PET by 17.1 °C, mist cooling by 1.2 °C, and the combined system by 20.7 °C. Shading minimized radiant heat gain, while mist cooling enhanced evaporative cooling, jointly bringing thermal sensations closer to slightly warm–comfortable conditions. These cooling interventions also have sustainability value by reducing dependence on mechanically cooled indoor spaces and lowering campus air-conditioning demand. As passive or low-energy measures, shading and mist cooling support climate-adaptive outdoor design in heat-stressed Mediterranean environments. Full article

This study evaluated the effects of a passive upper-limb exoskeleton in agricultural work using a repeated-measures design with 24 adult males across three exoskeleton conditions (No Exo, Prototype, and Airframe), three work directions (left, front, and right), and two work distances (near and far). Outcomes included muscle activity, center of pressure travel, task completion time, perceived exertion, body part discomfort, and usability. Airframe use significantly reduced shoulder and upper-arm muscle activity by about 25–35 percent, consistent with the mechanical sharing of shoulder elevation torque. Erector spinae activity showed a compensatory increase trend, suggesting heightened trunk stabilization demands. Center of pressure varied by direction and distance, with greater excursion for leftward and far tasks, but did not differ among exoskeleton conditions, indicating preserved postural stability. Task time was unaffected by exoskeleton and distance but was longest for leftward tasks. Perceived exertion and discomfort varied by direction and distance and tended to be lower on average with Airframe. Usability differed only in the effectiveness factor, which favored Airframe. An integrated evaluation emphasizing EMG, center of pressure, and perceived fatigue, with usability as needed, is recommended for field validation. Full article

The Loop-Back Quantum Key Distribution (LB-QKD) protocol establishes a bidirectional architecture in which a single photon travels forth and back through the same optical channel. Unlike conventional one-way schemes such as BB84, Alice performs both state preparation and measurement, while Bob acts as a passive polarization modulator and reflector. This design eliminates detectors at Bob’s side, minimizes synchronization requirements, and enables compact, low-power implementations suitable for quantum-mobile and IoT platforms. An extended three-basis configuration $\{X,Y,Z\}$ is introduced, preserving the simplicity of the two-basis scheme while improving noise tolerance through enhanced orthogonality-based filtering. Analytical modeling shows that the effective protocol error decreases from $E_{\mathrm{protocol}}^{\left(2\right)}=e/2$ to $E_{\mathrm{protocol}}^{\left(3\right)}=e/3$, achieving a 33% improvement in noise resilience. Despite its slightly lower sifting efficiency ($\eta =1/6$), the total information gain reaches $G=0.26$ bits per pulse, maintaining post-sifting throughput comparable to BB84. The protocol doubles the tolerable QBER of conventional QKD, sustaining secure operation up to $22\%$ for two bases and approximately $47.58\%$ for three bases. Its passive, self-verifying architecture enhances resistance to man-in-the-middle, photon-number-splitting, and side-channel attacks, providing a scalable and energy-efficient framework for secure key distribution and authentication in next-generation mobile and distributed quantum networks. Full article