Search Results (24)

Background/Objectives: Vaccination is important for controlling foot-and-mouth disease (FMD) in endemic regions and to lessen the effects of outbreaks in FMD-free countries. The adaptation of FMD virus to BHK cells is a necessary but time-consuming and costly step in vaccine production and can prove problematic for some isolates. Adaptation is, in part, driven by receptor availability and selects variants with altered receptor specificity that result from amino acid substitutions in the capsid proteins. Methods: To bypass the need for cell culture adaptation, we generated chimeric viruses with field-strain capsids and introduced amino acid substitutions associated with cell culture adaptation. We targeted two sites on the capsid: the canonical heparan sulphate binding site and the icosahedral 5-fold symmetry axes. Results: Our results show that some viruses with unmodified wild-type (wt) capsids grew well in BHK cells (suspension and adherent), whereas others showed poor growth. For viruses that showed good growth, the introduction of amino acid changes associated with cell culture adaptation improved the rate of growth but not virus titres or yields of 146S particles, whereas growth and 146S yields for viruses that grew poorly in BHK cells were greatly enhanced by some of the amino acid changes. For the latter viruses, the introduced changes did not appear to adversely affect virion stability or antigenicity. Conclusions: For FMD viruses that grow poorly in BHK cells, this approach could be a viable alternative to protracted adaptation by serial passage and could expedite the production of a new vaccine strain from a field virus. Full article

The analysis of running gait has conventionally taken place within an expensive and restricted laboratory space, with wearable technology offering a practical, cost-effective, and unobtrusive way to examine running gait in more natural environments. This pilot study presents a wearable inertial measurement unit (IMU) setup for the continuous analysis of running gait during an outdoor parkrun (i.e., 5 km). The study aimed to (1) provide analytical validation of running gait measures compared to time- and age-graded performance and (2) explore performance validation. Ten healthy adults (7 females, 3 males, mean age 37.2 ± 11.7 years) participated. The participants wore Axivity AX6 IMUs on the talus joint of each foot, recording tri-axial accelerometer and gyroscope data at 200 Hz. Temporal gait characteristics—gait cycle, ground contact time, swing time, and duty factor—were extracted using zero-crossing algorithms. The data were analyzed for correlations between the running performance, foot strike type, and fatigue-induced changes in temporal gait characteristics. Strong correlations were found between the performance time and both the gait cycle and ground contact time, with weak correlations for foot strike types. The analysis of asymmetry and fatigue highlighted modest changes in gait as fatigue increased, but no significant gender differences were found. This setup demonstrates potential for in-field gait analysis for running, providing insights for performance and injury prevention strategies. Full article

Flexible pressure sensors are increasingly recognized for their potential use in wearable electronic devices, attributed to their sensitivity and broad pressure response range. Introducing surface microstructures can notably enhance sensitivity; however, the pressure response range remains constrained by the limited volume of the compressible structure. To overcome this limitation, this study implements an aligned airgap structure fabricated using 3D printing technology. This structure, designed with a precisely aligned triaxial airgap configuration, offers high deformability under pressure, substantially broadening the pressure response range and improving sensitivity. This study analyzes the key structural parameters—the number of axes and pore size—that influence the compressibility and stability of the dielectric material. The results indicate that the capacitive pressure sensor with an aligned airgap structure, manufactured via 3D printing, exhibits a wide operating pressure range (50 Pa to 500 kPa), rapid response time (100 ms), wide limit of detection (50 Pa), and approximately 21 times enhancement in sensitivity (~0.019 kPa⁻¹ within 100 kPa) compared with conventional bulk structures. Furthermore, foot pressure monitoring trials for wearable sensor applications demonstrated exceptional performance, indicating the sensor’s suitability as a wearable device for detecting plantar pressure. These findings advocate for the potential of 3D printing technology to supplant traditional sensor manufacturing processes. Full article

Background: Enthesitis is a common feature of spondyloarthritis and can severely impair the patient’s quality of life. International guidelines recommend multidisciplinary management of this condition, combining physical and pharmacological interventions. In this case report, we demonstrate clinical and ultrasonographic improvements by prescribing local cryotherapy and therapeutic exercise alone in an adult woman with non-radiographic axial SpA (nRX-AxSpA) complaining of heel enthesitis. Methodology: A personalized program was prescribed that focused on reducing pain, joint stiffness, and muscle tightness, improving strength and endurance. Pain, function, and degree of disability were assessed using the Numerical Rating Scale, the Victorian Institute of Sport Assessment-Achilles, the single-leg heel lift test, and the Foot Function Index. In addition, lower limb muscle strength was measured using a dynamometer and enthesitis was assessed ultrasonographically using the Glasgow Ultrasound Enthesitis Score System. Results: Benefits were evident as early as week 5 and persisted at 3 months on ultrasound assessment. No side effects were reported. Discussion: To the best of our knowledge, this is the first report of prescribing such a strategy in a patient with nRX-AxSpA. Given the good tolerability, this intervention could be considered in patients with contraindications to pharmacologic approaches. 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

This manuscript aims to present a novel model to find the optimal area of a rectangular isolated footing with an eccentric column, taking into account that the footing is partially supported; that is, one part of the contact surface is compressed and the other part has zero pressure. The methodology is developed by integration and can also be verified using the geometric properties of a triangular-based pyramid to determine the axial load, the moments in the X and Y axes in terms of the available allowable soil pressure, the footing sides, the greatest distance on one of its sides in the X-direction where it crosses the neutral axis, the greatest distance on one of its sides in the Y-direction where it crosses the neutral axis, and the coordinates at the base of the footing. Four types of numerical problems are shown to find the optimal area of a rectangular footing with an eccentric column subjected to biaxial bending: (1) the column in the center of the footing; (2) the column on the edge of the footing in the X-direction; (3) the column on the edge of the footing in the Y-direction; and (4) the column in the corner of the footing. A comparison is presented of the new model against a model proposed by another author. The new model presents a reduction of up to 42.37% for the column in the center of the footing and up to 40.32% for the column in the corner of the footing compared to the model by the other authors. Therefore, the new model will be of great help to professionals in foundation design. Full article

Background: Little evidence has been provided regarding the effects of carrying standardized load equipment and foot parameters during quiet standing. Therefore, the main purpose of the study was to examine whether a load carriage might impact static foot parameters in police recruits. Methods: Eight hundred and forty-five police recruits (27.9% women) were tested in ‘no load’ vs. standardized ‘3.5 kg load’ conditions. Foot characteristics during standing were assessed with the Zebris FDM pedobarographic pressure platform. Results: Carrying a 3.5 kg load significantly increased the 95% confidence ellipse area (∆ = 15.0%, p = 0.009), the center of pressure path length (∆ = 3.3%, p = 0.023) and average velocity (∆ = 11.1%, p = 0.014), the length of the minor axis (∆ = 8.2%, p < 0.009) and the deviation in the X (∆ = 12.4%, p = 0.005) and Y (∆ = 50.0%, p < 0.001) axes. For relative ground reaction forces, a significant increase in the left forefoot (∆ = 2.0%, p = 0.002) and a decrease in the left hindfoot (∆ = −2.0%, p = 0.002) were shown. No significant changes in relative ground reaction forces beneath the forefoot and hindfoot regions for the right foot were observed (p > 0.05). Conclusions: The findings suggest that spatial and temporal foot parameters may be more prone to change while carrying heavy loads, especially the center of pressure characteristics. Full article

There are many studies analyzing human motion. However, we do not yet fully understand the mechanisms of our own bodies. We believe that mimicking human motion and function using a robot will help us to deepen our understanding of humans. Therefore, we focus on the characteristics of the human gait, and the goal is to realize a human-like bipedal gait that lands on its heels and takes off from its toes. In this study, we focus on kinematic synergy (planar covariation) in the lower limbs as a characteristic gait seen in humans. Planar covariation is that elevation angles at the thigh, shank, and foot in the sagittal plane are plotted on one plane when the angular data are plotted on the three axes. We propose this feature as a reward for reinforcement learning. By introducing this reward, the bipedal robot achieved a human-like bipedal gait in which the robot lands on its heels and takes off from its toes. We also compared the learning results with those obtained when this feature was not used. The results suggest that planar covariation is one factor that characterizes a human-like gait. Full article

The overall aim of this study was to determine the effects of running kinematics on the peak upper trunk segmental accelerations captured with an accelerometer embedded in a commonly used GPS device. Thirteen male participants (age: 27 ± 3.7 years, height: 1.81 ± 0.06 m, mass: 82.7 ± 6.2 kg) with extensive running experience completed a single trial of treadmill running (1 degree inclination) for 40 s at nine different speeds ranging from 10 to 18 km/h at 1 km/h increments. Three-dimensional peak upper trunk acceleration values were captured via a GPS device containing a tri-axial accelerometer. Participants’ running kinematics were calculated from the coordinate data captured by an 18-camera motion capture system. A series of generalized linear mixed models were employed to determine the effects of the kinematic variables on the accelerometer acceleration peaks across the key gait phases of foot contact. Results showed that running kinematics had significant effects on peak accelerometer-measured accelerations in all axes (p < 0.05). Overall, peak segment velocities had a larger effect than joint/segment kinematics on resultant (F values = 720.9/54.2), vertical (F values = 149.8/48.1) and medial–lateral (F values = 55.4/33.4) peak accelerometer accelerations. The largest effect on peak accelerometer accelerations were observed during the impact subphase of foot contact at the adduction/abduction velocity of the shank (F value = 129.2, coefficient = −0.03) and anterior/posterior velocity of the pelvis (F value = 58.9, coefficient = 0.01). Axis-dependent effects of running kinematics were also observed, specifically at the trunk segment in the vertical and anterior–posterior peak accelerometer accelerations. This study showed the intersegmental relationship between joint/segment kinematics, segment velocities and the resulting peak accelerations of the upper trunk during running over several speeds. These findings provide insights into the lower body’s GRF attenuation capacity and its contribution to trunk stability whilst running. Full article

The ankle is a complex joint with a high injury incidence. Rehabilitation Robotics applied to the ankle is a very active research field. We present the kinematics and statics of a cable-driven reconfigurable ankle rehabilitation robot. First, we studied how the tendons pull mid-foot bones around the talocrural and subtalar axes. We proposed a hybrid serial-parallel mechanism analogous to the ankle. Then, using screw theory, we synthesized a cable-driven robot with the human ankle in the closed-loop kinematics. We incorporated a draw-wire sensor to measure the axes’ pose and compute the product of exponentials. We also reconfigured the cables to balance the tension and pressure forces using the axis projection on the base and platform planes. Furthermore, we computed the workspace to show that the reconfigurable design fits several sizes. The data used are from anthropometry and statistics. Finally, we validated the robot’s statics with MuJoCo for various cable length groups corresponding to the axes’ range of motion. We suggested a platform adjusting system and an alignment method. The design is lightweight, and the cable-driven robot has advantages over rigid parallel robots, such as Stewart platforms. We will use compliant actuators for enhancing human–robot interaction. Full article

Salinity is an important ecological factor affecting the osmolality of aquatic animals. Solenaia oleivora is an endemic and economically important freshwater shellfish in China. However, its osmotic response and osmoregulatory mechanisms under high salinity stress are still unclear. In this study, S. oleivora was exposed to saline water (salinity: 2.2‰) for 3 h, 6 h, 12 h, 24 h, and 48 h, and then the changes in osmolality, ion concentrations, free amino acid (FAA) content, Na⁺/K⁺-ATPase (NKA) activity, and gill histology were analyzed. The hemolymph osmolality increased from 3 h after salinity stress and stabilized between 24–48 h. Na⁺ in the hemolymph increased from 24 h after salinity stress, and Cl⁻ increased from 3 h. The content of total FAAs in the hemolymph increased after salinity stress. The content of alanine, glycine, glutamine, proline, and other FAAs increased after salinity stress. NKA activity in the gill, hepatopancreases, adductor muscle, and axe foot decreased during 3–48 h of salinity stress. The gill filament space increased and the number of gill cilia decreased after salinity stress. Principal component analysis (PCA) showed that the first two principal components (PC1 and PC2) cumulatively explained 77.6% of the total variation. The NKA activity was positively associated with PC1, while the ion concentration and most FAAs were negatively associated with PC1. Thus, these results indicated that S. oleivora is an osmoconformer, and inorganic ions, FAA, NKA, and gill structure changes play an important role in its osmoregulation. Full article

This study evaluates a method to accurately, repeatably, and reliably extract camel zoo-metric data (linear and tridimensional) from 2D digital images. Thirty zoometric measures, including linear and tridimensional (perimeters and girths) variables, were collected on-field with a non-elastic measuring tape. A scaled reference was used to extract measurement from images. For girths and perimeters, semimajor and semiminor axes were mathematically estimated with the function of the perimeter of an ellipse. On-field measurements’ direct translation was determined when Cronbach’s alpha (Cα) > 0.600 was met (first round). If not, Bayesian regression corrections were applied using live body weight and the particular digital zoometric measurement as regressors (except for foot perimeter) (second round). Last, if a certain zoometric trait still did not meet such a criterion, its natural logarithm was added (third round). Acceptable method translation consistency was reached for all the measurements after three correction rounds (Cα = 0.654 to 0.997, p < 0.0001). Afterwards, Bayesian regression corrected equations were issued. This research helps to evaluate individual conformation in a reliable contactless manner through the extraction of linear and tridimensional measures from images in dromedary camels. This is the first study to develop and correct the routinely ignored evaluation of tridimensional zoometrics from digital images in animals. Full article

The athletic performance and safety of racehorses is influenced by hoof–surface interactions. This intervention study assessed the effect of eight horseshoe–surface combinations on hoof acceleration patterns at impact and foot-off in 13 galloping Thoroughbred racehorses retired from racing. Aluminium, barefoot, GluShu (aluminium–rubber composite) and steel shoeing conditions were trialled on turf and artificial (Martin Collins Activ-Track) surfaces. Shod conditions were applied across all four hooves. Tri-axial accelerometers (SlamStickX, range ±500 g, sampling rate 5000 Hz) were attached to the dorsal hoof wall (x: medio-lateral, medial = positive; y: along dorsal hoof wall, proximal = positive; and z: perpendicular to hoof wall, dorsal = positive). Linear mixed models assessed whether surface, shoeing condition or stride time influenced maximum (most positive) or minimum (most negative) accelerations in x, y and z directions, using ≥40,691 strides (significance at p < 0.05). Day and horse–rider pair were included as random factors, and stride time was included as a covariate. Collective mean accelerations across x, y and z axes were 22–98 g at impact and 17–89 g at foot-off. The mean stride time was 0.48 ± 0.07 s (mean ±2 SD). Impact accelerations were larger on turf in all directions for forelimbs and hindlimbs (p ≤ 0.015), with the exception of the forelimb z-minimum, and in absolute terms, maximum values were typically double the minimum values. The surface type affected all foot-off accelerations (p ≤ 0.022), with the exception of the hindlimb x-maximum; for example, there was an average increase of 17% in z-maximum across limbs on the artificial track. The shoeing condition influenced all impact and foot-off accelerations in the forelimb and hindlimb datasets (p ≤ 0.024), with the exception of the hindlimb impact y-maximum. Barefoot hooves generally experienced the lowest accelerations. The stride time affected all impact and foot-off accelerations (p < 0.001). Identifying factors influencing hoof vibrations upon landing and hoof motion during propulsion bears implication for injury risk and racing outcomes. Full article

This paper presents a hybrid force/position control. We developed it for a hexapod walking robot that combines multiple bipedal robots to increase its load. The control method integrated Extenics theory with neutrosophic logic to obtain a two-stage decision-making algorithm. The first stage was an offline qualitative decision-applying Extenics theory, and the second was a real-time decision process using neutrosophic logic and DSmT theory. The two-stage algorithm separated the control phases into a kinematic control method that used a PID regulator and a dynamic control method developed with the help of sliding mode control (SMC). By integrating both control methods separated by a dynamic switching algorithm, we obtained a hybrid force/position control that took advantage of both kinematic and dynamic control properties to drive a mobile walking robot. The experimental and predicted results were in good agreement. They indicated that the proposed hybrid control is efficient in using the two-stage decision algorithm to drive the hexapod robot motors using kinematic and dynamic control methods. The experiment presents the robot’s foot positioning error while walking. The results show how the switching method alters the system precision during the pendulum phase compared to the weight support phase, which can better compensate for the robot’s dynamic parameters. The proposed switching algorithm directly influences the overall control precision, while we aimed to obtain a fast switch with a lower impact on the control parameters. The results show the error on all axes and break it down into walking stages to better understand the control behavior and precision. Full article

A Drift-Free 3D Orientation and Displacement estimation method (DFOD) based on a single inertial measurement unit (IMU) is proposed and validated. Typically, body segment orientation and displacement methods rely on a constant- or zero-velocity point to correct for drift. Therefore, they are not easily applicable to more proximal segments than the foot. DFOD uses an alternative single sensor drift reduction strategy based on the quasi-cyclical nature of many human movements. DFOD assumes that the quasi-cyclical movement occurs in a quasi-2D plane and with an approximately constant cycle average velocity. DFOD is independent of a constant- or zero-velocity point, a biomechanical model, Kalman filtering or a magnetometer. DFOD reduces orientation drift by assuming a cyclical movement, and by defining a functional coordinate system with two functional axes. These axes are based on the mean acceleration and rotation axes over multiple complete gait cycles. Using this drift-free orientation estimate, the displacement of the sensor is computed by again assuming a cyclical movement. Drift in displacement is reduced by subtracting the mean value over five gait cycle from the free acceleration, velocity, and displacement. Estimated 3D sensor orientation and displacement for an IMU on the lower leg were validated with an optical motion capture system (OMCS) in four runners during constant velocity treadmill running. Root mean square errors for sensor orientation differences between DFOD and OMCS were 3.1 ± 0.4° (sagittal plane), 5.3 ± 1.1° (frontal plane), and 5.0 ± 2.1° (transversal plane). Sensor displacement differences had a root mean square error of 1.6 ± 0.2 cm (forward axis), 1.7 ± 0.6 cm (mediolateral axis), and 1.6 ± 0.2 cm (vertical axis). Hence, DFOD is a promising 3D drift-free orientation and displacement estimation method based on a single IMU in quasi-cyclical movements with many advantages over current methods. Full article