Search Results (109)

This study presents a numerical and experimental evaluation of axial load transfer mechanisms in deep foundations constructed in stratified cohesive soils in İzmir, Türkiye. A full-scale bi-directional static load test equipped with strain gauges was conducted on a barrette pile to investigate depth-dependent mobilization of shaft resistance. A finite element model was developed and calibrated using field-observed load–settlement and strain data to replicate the pile–soil interaction and deformation behavior. The analysis revealed a shaft-dominated load transfer behavior, with progressive mobilization concentrated in intermediate-depth cohesive layers. Sensitivity analysis identified the undrained stiffness (E_u) as the most influential parameter governing pile settlement. A strong polynomial correlation was established between calibrated E_u values and SPT N₆₀, offering a practical tool for preliminary design. Additionally, strain energy distribution was evaluated as a supplementary metric, enhancing the interpretation of mobilization zones beyond conventional stress-based methods. The integrated approach provides valuable insights for performance-based foundation design in layered cohesive ground, supporting the development of site-calibrated numerical models informed by full-scale testing data. Full article

Background: The atlanto-axial segment is highly mobile and, therefore, prone to instability in the setting of inflammatory disease, infection, tumor or trauma. While minimally invasive surgical (MIS) techniques have gained acceptance in the thoracolumbar spine due to their advantages over traditional approaches, their use at the atlanto-axial segment is controversial due to the surgical risk associated with its complex anatomy. To evaluate the current evidence on MIS atlanto-axial fixation, we carried out a systematic review of the literature and compared the reported results with those of open procedures. Methods: This systematic review follows PRISMA-DTA 2020 guidelines. A comprehensive search was conducted in November 2023 across PubMed/Medline, Google Scholar and clinicaltrials.gov using specific keywords related to minimally invasive atlanto-axial fixation. Data regarding study characteristics, patient demographics, surgical techniques, and outcomes were extracted from included studies. Results: This systematic review included 13 articles reporting on the results of surgery in 305 patients, in whom a total of 683 screws were inserted through a posterior MIS approach. N = 162 screws were inserted using the Harms–Goel technique, while N = 521 were placed using the Magerl technique. N = 40 screws were inserted using navigation guidance, while N = 643 were introduced with fluoroscopy assistance. Eight screws were misplaced. A Vertebral Artery (VA) injury was reported in three patients. With a mean value of 26.2 ± 15.3 months, the rate of fusion ranged between 80% and 100%. Conclusions: This study highlights the potential of MIS for posterior atlanto-axial fixation, which was achieved using Magerl transarticular screws in a large majority of cases. Despite technical challenges, MIS approaches appear to achieve satisfactory clinical and radiological outcomes with complication rates similar to those of open techniques. Future studies may help refine the indications for MIS and identify those cases better suited for open approaches. Full article

Surface-guided tram systems are increasingly being recognised not only as mobility instruments but also as agents of urban regeneration that reshape spatial and social dynamics. This study evaluates the configurational impact of the Trambesòs tram in Barcelona on accessibility, integration, and urban cohesion within the Levante del Besòs area. A Space Syntax analysis was conducted in UCL DepthmapX for axial map analysis and visual graph analysis within a 500 m radius around each station. Three typologies of intervention (site-specific, articulation axes, and saturation pieces) guided the assessment. This analysis shows that Avinguda Diagonal and Avinguda Meridiana are primary structural corridors, while stations Glòries, Ca l’Aranyó, and Pere IV recorded the highest accessibility and visual openness. The results indicate that targeted interventions have positive impacts on the Space Syntax metrics regardless of their spatial centrality, highlighting the critical role of this diverse intervention typology in shaping the study area’s spatial configuration and influencing a hierarchy of social appropriation and use. It is concluded that the Trambesòs tram and associated urban interventions have jointly enhanced centrality and permeability in key sectors, and specific peripheral enclaves have local functioning. These findings, focused on spatial and morphological patterns, may support future interventions in urban design and mobility planning. Although the analysis centres on spatial configuration, future research may integrate socioeconomic variables to broaden the understanding of regeneration processes. Full article

Accelerometers are nowadays included in almost any portable or mobile device, including smartphones, smartwatches, wrist-bands, and even smart rings. The data collected from them is therefore an ideal candidate to tackle human motion recognition, as it can easily and unobtrusively be acquired. In this work we analyze the performance of a hand-gesture classification system implemented using LSTM neural networks on a resource-constrained microcontroller platform, which required trade-offs between network accuracy and resource utilization. Using a publicly available dataset, which includes data for 20 different hand gestures recorded from 10 subjects using a wrist-worn device with a 3-axial accelerometer, we achieved nearly 90.25% accuracy while running the model on an STM32L4-series microcontroller, with an inference time of 418 ms for 4 s sequences, corresponding to an average CPU usage of about 10% for the recognition task. Full article

In addition to axial motor complications such as abnormal posture, instability, falls, and gait variability, neurodegenerative diseases like Parkinsonian syndromes include executive dysfunction, Parkinson’s disease dementia, and neuropsychiatric symptoms. These motor disorders significantly affect mobility, quality of life, and well-being. Recently, physical activity of various intensities monitored both remotely and face-to-face via digital health technologies, mobile platforms, or sensory cues has gained relevance in managing idiopathic and atypical Parkinson’s disease (PD and APD). Remote monitoring solutions, including home-based digital health assessments using semi-structured activities, offer unique advantages. Real-world gait parameters like walking speed can now be continuously assessed with body-worn sensors. Developing effective strategies to slow pathological aging and mitigate neurodegenerative progression is essential. This study presents outcomes of using digital health technologies (DHTs) for remote assessment of motor function, physical activity, and daily living tasks, aiming to reduce disease progression in PD and APD. In addition to wearable inertial sensors, clinical rating scales and digital biomarkers enhance the ability to characterize and monitor motor symptoms. By reviewing recent literature, we identified emerging trends in quantifying and intervening in neurodegeneration using tools that evaluate both remote and face-to-face physical activity. Our findings confirm that DHTs offer accurate detection of motor fluctuations and support clinical evaluations. In conclusion, DHTs represent a scalable, effective strategy for improving the clinical management of PD and APD. Their integration into healthcare systems may enhance patient outcomes, support early intervention, and help delay the progression of both motor and cognitive symptoms in aging individuals. Full article

Dog clutches are superior to synchromesh units due to much less wear caused by friction but require an external torque source to synchronize the rotation speeds. The current trend in e-mobility to use the driving motor of an electric vehicle as this source just creates another problem, which is known as torque holes. In this work, we propose a novel double-sided dog clutch that synchronizes the speeds electromagnetically by itself avoiding mechanical contact between the parts. A shift sleeve, two coils placed coaxially in their stators, and two complementary rings form an electromagnetic reluctance actuator, which is integrated inside the gearbox between two gearwheels and represents the double-sided clutch. Thus, intermediate parts between the shift sleeve and the actuator are not required. Both actuator sides can produce axial force and electromagnetic torque. However, torques and forces are generated simultaneously on both sides. Therefore, a special control algorithm is developed to keep the resulting axial force approximately equal to zero while the torque is generated in the neutral gear position. After the synchronization, the axial force is applied on the corresponding side to shift the required gear engaging the shift sleeve teeth directly with the slots of the complementary ring mounted on the gearwheel. So, an axial contact of the teeth at an unaligned state, which can lead to unsuccessful shifting, is avoided. A testrig, which includes a clutch prototype and a testing two-speed gearbox, has been designed and built. The developed theoretical ideas have been verified during the experiments under different conditions. The experiments confirm that the actuator can reduce positive and negative speed differences on both sides and subsequently shift the gear without a shift sleeve collision at misaligned angular positions. Full article

Background/Objectives: Spine mobility is essential for overall health and daily functioning. Accurate assessment of spinal mobility is necessary for diagnosing and managing orthopedic, neurological, and rheumatological disorders, particularly in patients experiencing lower back and thoracic pain. The present study evaluates the effectiveness of traditional clinical tests in comparison to the innovative photogrammetric 3D posture assessment for evaluating spinal mobility. Methods: A total of 20 patients from a medical clinic underwent tests to measure lumbar and thoracic spine mobility, including flexion, lateral incline, and axial rotation, using both conventional and 3D posture assessment methods. Results: We found strong correlations between investigated methods, which recommends photogrammetry as a reliable and effective tool for assessing posture in clinical practice. Furthermore, 3D posture assessment offers a faster approach (clinical evaluation: 2:59 ± 0.22 min vs. photogrammetry: 1:03 ± 0.01 min) and a more practical method for assessing spinal mobility, thereby enhancing the patient experience and providing clinicians with objective data for treatment planning. Conclusions: The study highlights the value of modern technologies in clinical assessment and therapeutic intervention, encouraging therapists to integrate photogrammetric methods into their daily practice to improve patient outcomes. Full article

Background and Objectives: The objective of our study was to describe the biopsychosocial profile of individuals diagnosed with axial spondyloarthritis (AxSpA) and to analyze how their clinical characteristics interact with disease activity. Materials and Methods: An observational study was conducted, involving 28 participants diagnosed with AxSpA. We evaluated clinical outcomes (perceived pain, range of motion [RoM], pressure pain threshold [PPT], and proprioceptive acuity), psychosocial outcomes (the Pain Catastrophizing Scale [PCS], Tampa Scale of Kinesiophobia [TSK-11], and the Fear-Avoidance Beliefs Questionnaire [FABQ]), and AxSpA-specific indices (the Bath Ankylosing Spondylitis Metrology Index [BASMI], Bath Ankylosing Spondylitis Functional Index [BASFI], and Bath Ankylosing Spondylitis Disease Activity Index [BASDAI]). Data were analyzed using Spearman’s correlation coefficients and simple and multiple linear regression models. Results: Cervical and lumbar RoM values were reduced compared to established normative values for the general population. Significant associations were found between perceived pain, pain catastrophizing, and FABQ scores with both BASDAI and BASFI (p < 0.05). The interaction between perceived pain and pain catastrophizing (p < 0.001) accounted for 45.7% of the variance in BASDAI, while the interaction between perceived pain and FABQ (p < 0.001) explained 52.1% of the variance in BASDAI. Conclusions: The biopsychosocial profile of patients with AxSpA is characterized by moderate-intensity perceived pain and reduced cervical and lumbar mobility. The observed associations between BASDAI, pain catastrophizing, and fear-avoidance beliefs underscore the influence of psychosocial factors on disease progression. Full article

The distributed electric tilt-rotor Unmanned Aerial Vehicle (UAV) combines the vertical take-off and landing (VTOL) capability of helicopters with the high-speed cruise performance of fixed-wing aircraft, offering a transformative solution for Urban Air Mobility (UAM). However, aerodynamic interference between rotors is a new challenge to improving their flight efficiency, especially the dynamic interactions during the transition phase of non-parallel tandem dual-rotor systems, which require in-depth investigation. This study focuses on the aerodynamic performance evolution of the tilt-rotor system during asynchronous transition processes, with an emphasis on quantifying the influence of rotor tilt angles. A customized experimental platform was developed to investigate a counter-rotating dual-rotor model with fixed axial separation. Key performance metrics, including thrust, torque, and power, were systematically measured at various tilt angles (0–90°) and rotational speeds (1500–3500 RPM). The aerodynamic coupling mechanisms between the front and rear rotor disks were analyzed. The experimental results indicate that the relative tilt angle of the dual rotors significantly affects aerodynamic interference between the rotors. In the forward tilt mode, the thrust of the aft rotor recovers when the tilt angle reaches 45°, while in the aft tilt mode, it requires a tilt angle of 75°. By optimizing the tilt configuration, the aerodynamic performance loss of the aft rotor due to rotor-to-rotor aerodynamic interference can be effectively mitigated. This study provides important insights for the aerodynamic performance optimization and transition control strategies of the distributed electric tilt-rotor UAV. Full article

Macau’s aging communities face growing challenges in meeting the needs of older residents due to rising population density and extremely limited land resources. The concentration of outdated residential buildings—home to a substantial older adult population—exacerbates issues related to age-associated physical decline. For seniors who prefer familiar environments, the spatial constraints inherent in these densely built urban areas increasingly conflict with their specific gerontological needs, indicating the urgent need for urban renewal. This study employs a multi-methodological framework to examine aging populations in Macau’s high-density urban contexts. In Phase I, questionnaire surveys combined with SPSS 26.0-based cluster analysis are employed to (1) stratify older adults according to walking behavior patterns; (2) identify subgroup-specific needs and (3) establish key demographic correlates. Based on the socio-ecological framework, Phase II implements spatial analytics through ArcGIS demarcation of pedestrian catchment areas. This phase further integrates point-of-interest (POI) distribution analysis with space syntax-derived axial map evaluations to formulate typological mobility guidelines for different age cohorts. This study outlines the community walking space requirements of older adults in Macau and explores the influence of high-density community spaces on older adults. A practical evaluation method is proposed to assess age-friendly features of urban pathways, identifying the key environmental factors and their respective impacts. These preliminary findings may inform basic planning principles and adaptive design approaches for older adult-oriented pedestrian spaces. Full article

Background and Objectives: Spondylarthritis is a complex group of inflammatory diseases closely associated with the HLA-B27 antigen. However, the role of non-HLA-B27 alleles in the disease’s pathogenesis has gained significant scholarly attention in recent years. Case presentation: This case study presents a 49-year-old male with a history of progressive inflammatory back pain, characterized by morning stiffness and restricted spinal mobility developed over several years. Initially presenting with non-specific symptoms, the patient eventually experienced persistent axial pain and deteriorating functional limitations, which required further evaluation. Radiographic imaging supported the diagnosis of ankylosing spondylitis (AS) by identifying bilateral sacroiliitis. HLA genotyping revealed a negative result for HLA-B27 but positive results for HLA-B13 and HLA-B37. This finding serves as a foundation for exploring alternative genetic factors contributing to spondylarthritis (SpA). HLA-B13 and HLA-B37 exhibit structural and functional similarities to HLA-B27, particularly in their peptide-binding grooves. This resemblance may lead to overlapping peptide repertoires and increased T cell cross-reactivity. Moreover, these alleles belong to overlapping cross-reactive groups (CREGs) and share the Bw4 epitope. This suggests that they may contribute to disease pathogenesis via similar mechanisms, such as molecular mimicry and the dysregulation of natural killer (NK) cell interactions, as observed in HLA-B27. Conclusions: This case emphasizes the necessity of expanding diagnostic criteria to incorporate non-HLA-B27 markers, particularly for patients who are HLA-B27-negative. Enhancing our understanding of the roles of alternative genetic markers can improve diagnostic accuracy, enable personalized treatment approaches, and enhance outcomes for the diverse SpA patient population. Full article

A robust and elegant approach, based on the Two-Zone Moment Analysis (TZMA) method, is proposed to assess the contributions of the mobile and stationary zones, $H_{Cm}$ and $H_{Cs}$, to the C term $H_C$ in the van Deemter equation for plate height. The TZMA method yields two formulations for $H_{Cm}$ and $H_{Cs}$, both fully equivalent in terms of $H_C$, yet offering different decompositions of the contributions from the mobile and stationary zones. The first formulation proposes an expression for the term $H_{Cs}$ that has strong similarities, but also significant differences, from the well-known and widely used one proposed by Giddings. While it addresses the inherent limitation of Giddings’ approach—namely, the complete decoupling of transport phenomena in the moving and stationary zones—it introduces the drawback of a non-unique decomposition of $H_C$. Despite this, it proves highly valuable in highlighting the limitations and flaws of Giddings’ method. In contrast, the second formulation not only properly accounts for the interaction between the moving and stationary zones, but provides a unique and consistent decomposition of $H_C$ into its components. Three different geometries are investigated in detail: the 2D triangular array of cylinders (pillar array columns), the 2D array of rectangular pillars (radially elongated pillar array columns) and the 3D face-centered cubic array of spheres. It is shown that Giddings’ approach significantly underestimates the $H_{Cs}$ term, especially for porous-shell particles. Its accuracy is limited, being reliable only when intra-particle diffusivity ($D_s$) and the zone retention factor ($k^{″}$) are very low, or when axially invariant systems are considered. Full article

Background/Objectives: Limited spinal range of motion (ROM) is linked to low back disorders, emphasizing the need to maintain mobility in the elderly. This study measured maximum spinal ROM, asymmetrical patterns, and the effects of age and muscle activation on spinal mobility. Methods: Forty healthy participants aged 50 and older were recruited. An optical motion capture system recorded three-dimensional coordinates of reflective markers placed on spinal landmarks. Asymmetry was analyzed in sidebending and axial rotation. Electromyography (EMG) data were collected bilaterally from paraspinal muscles at L3 during flexion, extension, sidebending, and axial rotation. Results: Trunk ROM averaged 111° in flexion, 38° in extension, 46° in sidebending, and 87° in axial rotation. Kinematic asymmetry was observed in sidebending and axial rotation. ROM decreased with age in flexion motion (p ≤ 0.04). EMG activity was significantly correlated with ROM data for all combined motions (p = 0.0002). The strongest EMG signal was recorded during flexion, whereas the weakest signal was observed during extension. EMG activity also correlated with kinematic asymmetry (p ≤ 0.03). Conclusions: Age and muscle activation significantly influence spinal ROM in the elderly. Lumbar kinematic asymmetry can be partially attributed to paraspinal muscle activation, underscoring the importance of analyzing asymmetrical motions in conjunction with EMG activity. Full article

The widespread use of mobile devices and desktop computers has been associated with mechanical neck symptoms, yet few studies have compared cervical kinematics and clinical symptoms between them. In this study, 15 participants (27.7 ± 4.4 years, 12 male) performed four randomly ordered 20 min tasks: two mobile (smartphone and tablet) and two desktop computer (keyboard and mouse) tasks. Kinematic variables, including neck flexion, lateral bending, axial rotation, anterior translation, and total distance moved, were measured using an optical motion capture system, while clinical symptoms, including discomfort, pain, tension, and fatigue, were assessed using a visual analog scale. Paired t-tests and linear mixed models were used for analysis. Results showed that mobile device users exhibited greater neck flexion (38.9° [32.1–45.6°] vs. −0.2° [−4.3–3.9°], p < 0.001) and anterior translation (21.0 cm [12.0–30.1] vs. 1.6 cm [−4.4–7.7], p < 0.001) compared to desktop users. All clinical symptoms were significantly higher during mobile device use (p < 0.05), with neck flexion and anterior translation strongly correlating with symptom severity. In conclusion, mobile device use leads to more severe neck symptoms compared to desktop computer use, which is associated with increased flexion and forward head posture. To reduce neck symptoms, avoiding sustained flexion and forward head positions during mobile device use is recommended. Full article

This paper introduces a novel miniaturized, four-mode, semi-flexible leaky wave Multiple-Input Multiple-Output (MIMO) antenna specifically designed to advance vehicular communication systems. The proposed antenna addresses key challenges in 5G low- and high-frequency bands, including millimeter-wave communication, by integrating innovative features such as a periodic Spoof Surface Plasmon Polariton Transmission Line (SSPP-TL) and logarithmic-spiral-like semi-circular strip patches parasitically fed via orthogonal ports. These design elements facilitate stable impedance matching and wide impedance bandwidths across operating bands, which is essential for vehicular networks. The hybrid combination of leaky wave and SSPP structures, along with a defected wide-slot ground structure and backside meander lines, enhances radiation characteristics by reducing back and bidirectional radiation. Additionally, a naturalization network incorporating chamfered-edge meander lines minimizes mutual coupling and introduces a fourth radiation mode at 80 GHz. Compact in size (14 × 12 × 0.25 mm³), the antenna achieves high-performance metrics, including S11 < −18.34 dB, dual-polarization, peak directive gains of 11.6 dBi (free space) and 14.6 dBi (on vehicles), isolation > 27 dB, Channel Capacity Loss (CCL) < 3, Envelope Correlation Coefficient (ECC) < 0.001, axial ratio < 2.25, and diversity gain (DG) > 9.85 dB. Extensive testing across various vehicular scenarios confirms the antenna’s robustness for Vehicle-to-Vehicle (V2V), Vehicle-to-Pedestrian (V2P), and Vehicle-to-Infrastructure (V2I) communication. Its exceptional performance ensures seamless connectivity with mobile networks and enhances safety through Specific Absorption Rate (SAR) compliance. This compact, high-performance antenna is a transformative solution for connected and autonomous vehicles, addressing critical challenges in modern automotive communication networks and paving the way for reliable and efficient vehicular communication systems. Full article