Search Results (78)

Nowadays, Fused Filament Fabrication (FFF) 3D printing offers promising opportunities for the customized manufacturing of ankle–foot orthoses (AFOs) targeted towards rehabilitation purposes. Polypropylene (PP) represents an ideal candidate in orthotic applications due to its light weight and superior mechanical properties, offering an excellent balance between flexibility, chemical resistance, biocompatibility, and long-term durability. However, Additive Manufacturing (AM) of AFOs based on PP remains a major challenge due to its limited bed adhesion and high shrinkage, especially for making large parts such as AFOs. The primary innovation of the present study lies in the optimization of FFF 3D printing parameters for the fabrication of functional, patient-specific orthoses using PP, a material still underutilized in the AM of medical devices. Firstly, a thorough thermomechanical characterization was conducted, allowing the implementation of a (thermo-)elastic material model for the used PP filament. Thereafter, a Taguchi design of experiments (DOE) was established to study the influence of several printing parameters (extrusion temperature, printing speed, layer thickness, infill density, infill pattern, and part orientation) on the mechanical properties of 3D-printed specimens. Three-point bending tests were conducted to evaluate the strength and stiffness of the samples, while additional tensile tests were performed on the 3D-printed orthoses using a home-made innovative device to validate the optimal configurations. The results showed that the maximum flexural modulus of 3D-printed specimens was achieved when the printing speed was around 50 mm/s. The most significant parameter for mechanical performance and reduction in printing time was shown to be infill density, contributing 73.2% to maximum stress and 75.2% to Interlaminar Shear Strength (ILSS). Finally, the applicability of the finite element method (FEM) to simulate the FFF process-induced deflections, part distortion (warpage), and residual stresses in 3D-printed orthoses was investigated using a numerical simulation tool (Digimat-AM^®). The combination of Taguchi DOE with Digimat-AM for polypropylene AFOs highlighted that the 90° orientation appeared to be the most suitable configuration, as it minimizes deformation and von Mises stress, ensuring improved quality and robustness of the printed orthoses. The findings from this study contribute by providing a reliable method for printing PP parts with improved mechanical performance, thereby opening new opportunities for its use in medical-grade additive manufacturing. Full article

In the name of God and profit, Jorge Álvares, the first Portuguese to set foot in China, arrived in 1513 and opened a new chapter for missionary work. One of the most significant forms of “Sino-Portuguese” decorative art, ivory sculpture, is closely linked to the Portuguese mission in the Orient and serves as a witness to encounters between different cultures and religions. This study focuses on representative Sino-Portuguese ivory sculptures of the Virgin and Child from the Late Ming period through a detailed analysis of iconography and a comparative visual critique with European prototypes and Guanyin representations to discuss the significance of missionary visual imagery in cultural interactions. The ivory sculpture of the Virgin and Child is not merely an image; it is a physical object with both material and visual characteristics, acquiring its religious significance during the missionary process. The present study aims to present its artistic hybridity and demonstrate how the Chinese carvers make the Sino-Portuguese “speak” different visual languages, leading to different interpretations. It also reflects the cultural translation that occurs in the complex process of religious contact. In this space of ‘culture in between’, Christianity has been able to transcend cultural and religious boundaries. Full article

Post-stroke hemiplegia often leads to gait asymmetry, mobility reduction, and increased fall risk. Foot Drop Stimulation (FDS) is used in rehabilitation to improve dorsiflexion and gait patterns. Through cyclogram-based analysis, this retrospective study evaluated the effectiveness of FDS in enhancing inter-limb gait symmetry in 21 post-stroke hemiplegic individuals following 10 sessions of treadmill training combined with FDS. Participants underwent 3D gait analysis pre- and post-intervention, performed by means of optical motion capture system, from which spatiotemporal and cyclogram features of the hip, knee, and ankle were computed. FDS was found to significantly improve dynamic range of motion (ROM) of the affected side at hip (+5%) and knee (+9%) joints. Cyclogram analysis showed that FDS reduced inter-limb hip asymmetry (orientation: 13.35° to 10.65°, Trend Symmetry Index: 19.09° to 15.46°), though no improvements were observed at the ankle. FDS with treadmill training improved hip and knee symmetry, supporting cyclogram-based assessments for gait rehabilitation and highlighting the need for targeted ankle interventions. Further research is needed to explore long-term effects and optimize rehabilitation strategies. Full article

Wearable inertial measurement units (IMUs) have been widely used in human movement analysis outside the laboratory. However, the IMU-based orientation estimation remains challenging, particularly in scenarios involving relatively fast movements. Increased sampling rate has the potential to improve accuracy, but it also increases power consumption and computational complexity. The relationship between sampling frequencies and accuracies remains unclear. We thus investigated the specific influence of IMU sampling frequency on orientation estimation across a spectrum of movement speeds and recommended sufficient sampling rates. Seventeen healthy subjects wore IMUs on their thigh, shank, and foot and performed walking (1.2 m/s) and running (2.2 m/s) trials on a treadmill, and a motion testbed with an IMU was used to mimic high-frequency cyclic human movements up to 3.0 Hz. Four widely used IMU sensor fusion algorithms computed orientations at 10, 25, 50, 100, 200, 400, 800, and 1600 Hz and were compared with marker-based optical motion capture (OMC) orientations to determine accuracy. Results suggest that the sufficient IMU sampling rate for walking is 100 Hz, running is 200 Hz, and high-speed cyclic movements is 400 Hz. The accelerometer sampling rate is less important than the gyroscope sampling rate. Further, accelerometer sampling rates exceeding 100 Hz even resulted in decreased accuracy because excessive orientation updates using distorted accelerations and angular velocity introduced more error than merely using angular velocity. These findings could serve as a foundation to inform wearable IMU development or selection across a spectrum of human gait movement speeds. Full article

Background/Objectives: As a representative anatomic ankle ligament repair technique, the Broström procedure continues to be modified to reach better clinical outcomes, superior mechanical stability, early rehabilitation, and minimal risk of recurrent instability. This study aimed to evaluate the intermediate-term clinical outcomes after the modified Broström procedure (MBP) with suture-tape augmentation for chronic lateral ankle instability. Methods: Ninety-four patients with chronic lateral ankle instability were followed for ≥3 years after MBP augmented with suture tape. The patient-reported clinical outcomes were evaluated with the Foot and Ankle Outcome Score (FAOS) and the Foot and Ankle Ability Measure (FAAM). The changes in mechanical ankle stability were evaluated with physical examination and periodic stress radiography. The changes in static and dynamic postural control ability were assessed with the single-leg stance test and Biodex posturography. Results: FAOS and FAAM scores significantly improved from preoperative means of 52.6 and 54.2 points to 91.8 and 90.5 points at final follow-up, respectively (p < 0.001). Talar tilt angle and anterior talar translation significantly improved from preoperative means of 15.4° and 14.3 mm to 2.7° and 4.5 mm at final follow-up, respectively (p < 0.001). Two patients (2.1%) complained of a recurrence of mechanical and functional instability. One patient (1.1%) showed non-specific inflammation related to a suture tape. Balance retention time significantly improved from a preoperative mean of 3.7 to 6.4 s at final follow-up (p < 0.001), with a non-significant side-to-side difference. The overall stability index significantly improved from a preoperative mean of 3.7 to 1.9 at final follow-up (p < 0.001), with a significant side-to-side difference. Conclusions: The MBP augmented with suture tape appears to be an effective surgical technique for chronic lateral ankle instability. Through anatomic repair of attenuated ankle ligaments and suture-tape augmentation, this modified procedure can provide reliable stability and minimal risk of recurrent instability. In addition, static and dynamic postural control ability may be improved through continuous proprioceptive-oriented rehabilitation following surgery. Full article

High-fidelity simulations are used to study the stability of a coupled parachute–payload system in different configurations. A 8.53 m ring–slot canopy is attached to two separate International Organization for Standardization (ISO) container payloads representing a Twenty Foot Equivalent (TEU). To minimize risk and as an alternative to a relatively expensive traditional test program, a multi-phase design and evaluation program using computational tools validated for uncoupled parachute system components was completed. The interaction of the payload wake suspended at different locations and orientations below the parachute were investigated to determine stability characteristics for both subsonic and supersonic freestream conditions. The DoD High-Performance Computing Modernization Program CREATE^TM-AV Kestrel suite was used to perform CFD and fluid–structure interaction (FSI) simulations using both delayed detached-eddy simulations (DDES) and implicit Large Eddy Simulations (iLES). After analyzing the subsonic test cases, the simulations were used to predict the coupled system’s response to the supersonic flow field during descent from a high-altitude deployment, with specific focus on the effect of the payload wake on the parachute bow shock. The FSI simulations included structural cable element modeling but did not include aerodynamic modeling of the suspension lines or suspension harness. The simulations accurately captured the turbulent wake of the payload, its coupling to the parachute, and the shock interactions. Findings from these simulations are presented in terms of code validation, system stability, and drag performance during descent. Full article

This research aimed to investigate morphological parameters (body mass, height, BMI) of medallists at the World Masters Orienteering Championships (WMOC), alongside their sports achievements and results. Fifty medallists from the 2022 WMOC, aged 35 to 80, were surveyed using a questionnaire, with non-parametric statistics (Mann–Whitney U test and ρ-Spearman test) applied for analysis. The average height was 179 cm for men and 165 cm for women, with average weights of 70 kg for men and 54 kg for women. BMI was 21.5 (SD = 1.43) for men and 20.4 (SD = 1.74) for women, with significantly lower BMI values in women (Z = 2.054, p = 0.04). Men’s BMI decreased with age (R = −0.534, p < 0.01). The BMI value of masters foot orienteers is typical for middle-distance runners. Women are closer to the somatotype of 1500 m athletes and men to 800 m athletes. Lack of earlier elite success does not preclude being on the podium at the WMOC (only 3 of the 50 medallists surveyed had won a medal in elite competition in the past). Full article

Crawling robots are the focus of intelligent inspection research, and the main feature of this type of robot is the flexibility of in-plane attitude adjustment. The crawling robot HIT_Spibot is a new type of steam generator heat transfer tube inspection robot with a unique mobility capability different from traditional quadrupedal robots. This paper introduces a hierarchical motion planning approach for HIT_Spibot, aiming to achieve efficient and agile maneuverability. The proposed method integrates three distinct planners to handle complex motion tasks: a nonlinear optimization-based base motion planner, a TOPSIS-based base orientation planner, and a Mask-D3QN (MD3QN) algorithm-based gait motion planner. Initially, the robot’s base and foot workspace were delineated through envelope analysis, followed by trajectory computation using Larangian methods. Subsequently, the TOPSIS algorithm was employed to establish an evaluation framework conducive to foundational turning planning. Finally, the MD3QN algorithm trained foot-points to facilitate robot movement along predefined paths. Experimental results demonstrated the method’s adaptability across diverse tube structures, showcasing robust performance even in environments with random obstacles. Compared to the D3QN algorithm, MD3QN achieved a 100% success rate, enhanced average overall scores by 6.27%, reduced average stride lengths by 39.04%, and attained a stability rate of 58.02%. These results not only validate the effectiveness and practicality of the method but also showcase the significant potential of HIT_Spibot in the field of industrial inspection. Full article

Severe adult-acquired flatfoot deformity is widely addressed surgically via the Grice–Green subtalar arthrodesis. Standard radiographic measurements have been reported, but these are limited to planar views. These complex deformities and the relevant corrections after surgery should be assessed in weight-bearing using 3D analyses now enabled by modern cone-beam CT scans. The present study is aimed at reporting these 3D radiographical foot bone alignments and the clinical results for this surgery. Ten patients were treated with the Grice–Green procedure. This implies inserting an autologous bone graft from the proximal tibial into the extra-articular sinus-tarsi to perform a subtalar arthrodesis. Before and after surgery, the patients were assessed based on the clinical range-of-motion and Foot-Function and Posture Indexes. Three-dimensional models of the tibia, calcaneus, talus, navicular, and 1st metatarsus were reconstructed from cone-beam CT scans in a single-leg up-right posture. Relevant longitudinal axes were defined to calculate ten spatial angles. Post-operatively, a significant realignment was observed for seven angles, including corrections lift-up of the talus (on average by 15°) and subtalar joint (13° in 3D), as well as the Meary’s angle (21°). Only few correlations were found between traditional clinical and novel 3D radiographical measurements, suggesting the former only limitedly represent the corresponding real skeletal status, and the latter thus offer the physician a more comprehensive evaluation. The present original analysis from modern cone-beam CT scans shows precisely the correction of foot and ankle bone alignments achieved using the Grice–Green surgical procedure, finally in 3D and in weight-bearing. For the first time, traditional clinical and score system evaluations are reported together with bone orientation and joint angles in the three anatomical planes. Full article

Background: Atypical Anorexia Nervosa (AAN) is a Feeding and Eating Disorder characterized by fear of gaining weight and body image disturbance, in the absence of significantly low body weight. AAN may present specific clinical and psychopathological features. Nonetheless, the literature lacks data concerning the nutritional characteristics and body composition of children and adolescents with AAN and their variation over time. Methods: Case series, including 17 children and adolescents with AAN. All the patients were assessed at the first evaluation (T0) with a standardized dietary assessment (24 h Dietary Recall, 24 hDR). Nutritional data were compared with European dietary reference values (DRVs). Body composition parameters (weight, fat mass, fat-free mass) and their changes over time at two (T1) and six (T2) months were collected as well, using a Bioelectrical impedance analysis (Wunder WBA300 with four poles and foot contact; impedance frequency 50 kHz 500 μA; impedance measurement range 200~1000 Ω/0.1 Ω). Results: The included individuals presented eating behaviors oriented towards significantly low daily energy intake (p < 0.001) compared with DRVs set by the European Food Safety Authority (EFSA) (with low carbohydrates and fats), and increased proteins (p < 0.001). A longer latency before observation (illness duration before observation) correlated with a negative change in weight. Body composition parameters were described, with no significant changes across the six-month outpatient assessment. Discussion: This is the first research to systematically assess the body composition and nutritional features of a group of individuals with AAN in the developmental age. Further research should assess the effect of targeted treatment interventions on body composition and nutritional features. Full article

Background: The reconstruction of plantar load-bearing foot defects faces many plastic surgeons with a major challenge. The optimal patient- and defect-oriented reconstructive strategy must be selected. Methods: To analyze the current trends and recommendations in reconstruction of plantar load-bearing foot defects, we conducted an international survey among plastic surgeons querying them about their recommendations and experiences. Results: The survey revealed that the most common strategies for reconstruction of the foot sole are locoregional and microvascular free flaps, emphasizing the relevance of plastic surgery. Among microvascular free flaps, muscle and fascio-cutaneous free flaps are by far the most frequently used. The target qualities of the reconstructed tissue to be considered are manifold, with adherence being the most frequently mentioned. We observed a noteworthy correlation between the utilization of muscle flaps and a preference for adherence. In addition, we identified a substantial correlation between the usage of fascio-cutaneous free flaps and further target qualities, such as good skin quality and sensitivity. Conclusions: Our findings provide insights into the clinical reality and highlight important aspects that must be considered in reconstruction of the weight-bearing areas of the foot providing support in the selection of the appropriate therapy. Full article

Plantar pressure distribution is a thoroughly recognized parameter for evaluating foot structure and biomechanical behavior, as it is utilized to determine musculoskeletal conditions and diagnose foot abnormalities. Experimental testing is currently being utilized to investigate static foot conditions using invasive and noninvasive techniques. These methods are usually expensive and laborious, and they lack valuable data since they only evaluate compressive forces, missing the complex stress combinations the foot undergoes while standing. The present investigation applied medical and engineering methods to predict pressure points in a healthy foot soft tissue during normal standing conditions. Thus, a well-defined three-dimensional foot biomodel was constructed to be numerically analyzed through medical imaging. Two study cases were developed through a structural finite element analysis. The first study was developed to evaluate barefoot behavior deformation and stresses occurring in the plantar region. The results from this analysis were validated through baropodometric testing. Subsequently, a customized 3D model total-contact foot orthosis was designed to redistribute peak pressures appropriately, relieving the plantar region from excessive stress. The results in the first study case successfully demonstrated the prediction of the foot sole regions more prone to suffer a pressure concentration since the values are in good agreement with experimental testing. Employing a customized insole proved to be highly advantageous in fulfilling its primary function, reducing peak pressure points substantially. The main aim of this paper was to provide more precise insights into the biomechanical behavior of foot pressure points through engineering methods oriented towards innovative assessment for absolute customization for orthotic devices. Full article

Background: The basic position on the starting block can influence the performance at the start, as it is the initial phase on which the other phases depend, as well as the swimming performance in sprint events in all swimming styles. The aim of our study is to analyze the effect of the foot in the base position on the block start on performance in the 5 m distance start. Material and Methods: Fifteen performance swimmers aged 17 ± 2 years were tested in their preferred wide and narrow starting positions, performing a total of six starts during which angular, temporal, and length changes were monitored in block, flight, and underwater phases. Fisher individual tests for differences of means were used to determine differences in kinematic parameters of the kick start to the 5 m distance. Differences in the position of the feet in kinematic parameters of the kick start to the 5 m distance were determined using the two-sample t-test with equal variance and effect size by Cohen’s d. Results: Swimmers were found to have significant differences (p < 0.05) between foot widths in block time (0.02 s), time to 2 m (0.05 s), flight and glide time and distance, maximal depth, and time to 5 m (0.08) in favor of the narrow baseline position. Conclusions: We recommend marking the center of the start block on the OSB or OSB platform for the competitors, as well as the center of the backrest, for better orientation and assuming the correct basic foot position on the start block. Full article

This paper presents a novel hybrid control method for position tracking of an underwater quadruped walking robot. The proposed approach combines an existing position-tracking control method with a deep-learning neural network. The neural network compensates for non-linear dynamic characteristics, such as the effect of fluid, without relying on mathematical modeling. To achieve this, a Multi-Layer Perceptron neural network is designed to analyze joint torque in relation to the joint angle and angular velocity of the robot, as well as the position and orientation of the foot tip and environmental data. The improvement in tracking control performance is evaluated using a 4-DOF underwater robot leg. For the neural network design, position tracking control data, including dynamic characteristics, were collected through position command-based position tracking control. Afterward, a learning model was constructed and trained to predict joint torque related to the robot’s motion and posture. This learning process incorporates non-linear dynamic characteristics, such as joint friction and the influence of fluid, in the joint torque prediction. The proposed method is then combined with conventional task-space PD control to perform position-tracking control with enhanced performance. Finally, the proposed method is evaluated using the underwater robot leg and compared to a single task-space PD controller. The proposed method demonstrates higher position accuracy with similar joint torque output, thereby increasing compliance and tracking performance simultaneously. Full article

Pilgrimage is undergoing a revival in western Europe, mainly as newly established or revitalised pilgrim routes, such as the Camino de Santiago in northern Spain. These trails have helped to foster the widespread idea that pilgrimage is essentially a journey: a spiritual or “meaningful” journey undertaken slowly, and preferably on foot, in the medieval tradition. The purpose of this article is to problematise this journey-oriented understanding of pilgrimage in Christian and post-Christian societies and to suggest that the importance given to the pilgrimage journey by many scholars, and by wider society, is more a product of modern Western values and post-Reformation culture than a reflection of historical and current-day religious practices. Drawing on evidence from a range of contemporary sources, it shows that many medieval pilgrims understood pilgrimage as a destination-based activity as is still the case at numerous Roman Catholic shrines today. Full article