Lateral Contact Research Articles

Fast and Efficient Mitigation of Coupled Axial-Torsional Drillstring Vibrations through State-Feedback Linear-Quadratic-Integral (LQI) Control

Summary In the exploitation of subsurface hydrocarbon and geothermal energy, more than 50% of total expenses are typically attributed to drilling and well completion. Coupled triaxial vibrations in the drilling system, excited by various mechanical, hydraulic, and geological sources, are major causes of premature downhole tool failures, excessive bit damage, compromised hole quality, reduced rate of penetration (ROP), and increased nonproductive time. Drillstring dynamic models, shock absorption tools, and controllers have been developed since the 1960s to understand and mitigate detrimental vibrations in the drilling system, aiming for smoother and more efficient operations. With advancements in measurement/logging while drilling technologies, rig equipment, mud pulse/wired pipe telemetry, and the digitalization of drilling engineering, a foundation has been established for proactive drilling vibration detection, analysis, and control to achieve efficient and safe drilling. In this study, a reduced-order axial-torsional drillstring dynamic model with soft string lateral contacts is first developed. Nonlinear drilling boundary conditions and inputs, such as bit-rock interactions (BRIs) with torque-on-bit (TOB) velocity-weakening effects, wellbore-drillstring contacts/friction, drillstring gravity, mud buoyancy, and more, are defined within the modeling framework. Equilibrium states and linearization of the model are derived for any given weight-on-bit (WOB) and rotational speed (RPM) setpoints, 3D well trajectories, and drillstring dimensions. A linear-quadratic-integral (LQI) controller is developed and tested for drillstring vibration suppression using a 6,562 ft (2000 m) drillstring model. In comparison to commercially available controllers for stick/slip mitigation, which are designed based on impedance matching and only address the decoupled drillstring torsional dynamics, the proposed state-feedback LQI controller emphasizes the coupling between the axial and torsional drillstring dynamics by simultaneously controlling WOB and RPM. Simulation results demonstrate that the LQI controller can suppress stick/slip and stabilize downhole WOB within 7 seconds, while a commercial drilling controller takes more than 35 seconds to achieve the same. Additionally, valuable insights and potential future directions for nonlinear drillstring vibration mitigation and drilling controller design are provided. With its fast drilling dysfunction stabilization time, small downhole RPM/WOB overshoots, minimal rig control inputs, robustness against drilling nonlinearities, and high efficiency, the proposed multi-input-multi-output state-feedback drilling controller holds great potential for application in proactive drilling vibration control, drilling automation, and real-time drilling optimization.

Validation of full-length radiograph based musculoskeletal modeling method to estimate medial and lateral knee contact forces

BackgroundAnatomical parameters of the pelvis, femur, and tibia derived from the full-length radiograph can be used to create a more accurate musculoskeletal model compared to marker-based linear scaling method. However, whether this model leads to more accurate estimations of medial knee contact force (MCF) and lateral knee contact force (LCF) than marker-based linear scaling method is still unknown. Research questionThis main purpose of this study was to determine whether musculoskeletal model generated from full-length radiograph improves the estimations of MCF and LCF. MethodsAn open-source dataset including marker trajectories, ground reaction forces, in vivo knee contact forces, and full-length radiograph was used to evaluate the accuracy of full-length radiograph musculoskeletal modeling method. Subject-specific musculoskeletal models were created using anatomical parameters derived from the full-length radiograph or marker-based linear scaling methods. MCF and LCF were estimated using musculoskeletal simulations of normal walking trails. The accuracy of modeling methods was determined by comparing the estimated and in vivo measured MCF and LCF. ResultsCompared to the marker-based linear scaling approach, the full-length radiograph musculoskeletal modeling method exhibited decreases of 38.3 % and 41.3 % in root mean square error for MCF and LCF respectively, as well as reductions of 50.0 % and 49.3 % in mean peak errors for MCF and LCF respectively. SignificanceThe full-length radiograph musculoskeletal modeling method provides a more accurate way to estimate MCF and LCF compared to the traditional maker-based linear scaling approach, which may contribute to understand the initiation, progression, and treatment of OA.

Sickle Cell Hemoglobin "Drugged" with Cyclic Peptides Is Aggregation Incompetent.

Sickle cell disease (SCD) is a monogenic blood disorder associated with a mutation in the hemoglobin subunit β gene encoding for the β-globin of normal adult hemoglobin (HbA). This mutation transcribes into a Glu-β6 → Val-β6 substitution in the β-globins, inducing the polymerization of this hemoglobin form (HbS) when in the T-state. Despite advances in stem cell and gene therapy, and the recent approval of a new antisickling drug, therapeutic limitations persist. Herein, we demonstrate through molecular dynamics and umbrella sampling, that (unrestrained) blockage of the hydrophobic pocket involved in the lateral contact of the HbS fibers by 5-mer cyclic peptides, recently proposed as SCD aggregation inhibitors (Neto, V.; J. Med. Chem. 2023, 66, 16062-16074), is enough to turn the dimerization of HbS thermodynamically unfavorable. Among these potential drugs, some exhibit an estimated pocket abandonment probability of around 15-20% within the simulations' time frame, and an impressive specificity toward the mutated Val-β6. Additionally, we show that the dimerization can be thermodynamically unfavored by blocking a nearby region while the pocket remains vacant. These results are compared with curcumin, an antisickling molecule and a pan-assay interference compound, with a good binding affinity for different proteins and protein domains. Our results confirm the potential of some of these cyclic peptides as antisickling drug candidates to reduce the concentration of aggregation-competent HbS.

Numerical characterisation of reaction forces’ contribution to initial stiffness in speed-lock beam-to-upright connections

This article presents a detailed numerical model of speed-lock (boltless) beam-to-upright connections in steel storage pallet rack systems. The model is capable of predicting initial stiffness and characterising the reaction forces of connector-to-upright interactions. The study examines nine configurations, combining three types of uprights and three types of beams with a common connector. Initially, experimental tests were conducted using the monotonic cantilever test method according to EN 15512 standard, with initial stiffness calculated using a standardised version of the initial stiffness method. Subsequently, a numerical analysis was developed through a finite element model based on the experimental setup. The model introduces new geometric details, evaluating each impact on behaviour, particularly on initial stiffness. Results show that numerical accuracy improves with detailed components such as inclined tabs, more detailed perforations, and 3D weld modelling. The contribution of reaction forces of connector-to-upright interactions to initial stiffness was analysed, considering the impact of the rotation centre’s position. It was found that a lower rotation centre position reduces the connector-to-upright lateral contact contribution while increasing tab-to-slot interaction contributions. The impact of beam height and beam weld position on initial stiffness was also analysed, with results showing that increasing these variables consistently led to increased initial stiffness. Finally, the rotation centre’s position was shown to evolve throughout the test, redefining the contribution of interactions. It clarified that connector-to-upright lateral interaction and tab1-to-slot1 and tab2-to-slot2 interactions have the highest contributions. This information is valuable for rack manufacturers to improve, optimise, and ensure the safety of their designs.

Evaluation of Tibiofemoral Contact Mechanics After a Novel Hybrid Procedure for Femoral Osteochondral Defect Repairs With a Subchondral Implant and Dermal Matrix.

There is a lack of procedures that adequately address the subchondral bone structure and function for reconstructing osteochondral defects in the femoral condyles. To biomechanically evaluate the tibiofemoral joint contact characteristics before and after reconstruction of femoral condylar osteochondral defects using a novel hybrid reconstructive procedure, which was hypothesized to restore the contact characteristics to the intact condition. Controlled laboratory study. Tibiofemoral contact areas, contact forces, and mean contact pressures were measured in 8 cadaveric knees (mean age 52 ± 11 years; 6 women, 2 men) using a custom testing system and pressure mapping sensors. Five conditions were tested for each condyle: intact, 8-mm defect, 8-mm repair, 10-mm defect, and 10-mm repair. Medial femoral condylar defects were evaluated at 30° of knee flexion and lateral condylar defects were evaluated at 60° of knee flexion, with compressive loads of 50, 100, and 150 N. The defects were reconstructed with a titanium fenestrated threaded implant countersunk in the subchondral bone and an acellular dermal matrix allograft. Repeated-measures analysis of variance with Bonferroni correction for multiple comparisons was used to compare the results between the 5 testing conditions at each load. Medial condylar defects significantly increased mean contact pressure on the lateral side (P < .042), which was restored to the intact levels with repair. The lateral condylar defect decreased the mean contact pressure laterally while increasing the mean pressure medially. The lateral and medial mean contact pressures were restored to intact levels with the 8-mm lateral condylar defect repair. The medial mean contact pressure was restored to intact levels with the 10-mm lateral condylar defect repair. The lateral mean contact pressure decreased compared with the intact state with the lateral condylar 10-mm defect repair. Tibiofemoral joint contact pressure was restored to the intact condition after reconstruction of osteochondral defects with dermal allograft matrix and subchondral implants for the repair of both 8- and 10-mm lateral condylar defects as well as 8-mm medial condylar defects but not completely for 10-mm medial condylar defects. The novel hybrid procedure for osteochondral defect repair restored tibiofemoral joint contact characteristics to normal in a cadaveric model.

Numerical study on the influence of cemented components on the mechanical properties of Xiyu Conglomerate

Xiyu Conglomerate is a common type of weakly cemented gravel stone formation found in northwestern China. This material is mainly composed of mud, mud–calcium, and calcium cement, possessing mechanical properties that are superior to those of soils but significantly weaker than those of rocks. Assessing these properties is crucial in ensuring the successful implementation of hydraulic engineering projects involving this material. This work establishes a microscale contact bonding model with a mud–calcium transition by surveying Xiyu Conglomerate’s material composition in a typical engineering area. The particle flow code method is used to investigate the influence of cemented materials on the mechanical properties of the conglomerate. After appropriate model calibration, numerical results show that the difference between the vertical and lateral contact forces becomes increasingly significant as the proportion of mud cement decreases and the content of calcium cement increases. The bond breakage process within the cemented material can be divided into three stages: no bond breakage, rapid bond breakage, and differential bond breakage development. When the mud cement content exceeds 50 %, the characteristics tend toward a soil-like behavior, while it resembles a soft rock behavior if the calcium cement content exceeds 50 %. Mud cement connects particles internally, whereas calcium cement strengthens the structure, both contributing to the randomness, heterogeneity, and discontinuity of Xiyu Conglomerate. The results can serve as a reference for future construction and engineering practices in the region.

Prevalence of different types of interproximal contacts in the permanent dentition – a study cast evaluation

Background A new classification called OXIS was proposed for categorizing the interproximal contacts of primary molars, modified for the primary canines and its prevalence was established. No such information is available for the permanent dentition. Hence, the aim was to establish the variations in interproximal contacts of the permanent dentition and thereby modify the OXIS classification of primary molars and primary canines to the permanent dentition. Methods We propose a study-cast-based classification of interproximal contacts of the permanent dentition. Three hundred and forty-three pretreatment casts of patients based on an inclusion and exclusion criteria were selected. Contacts of posterior teeth were classified based on OXIS classification of interproximal contacts, and its modification was used for anterior teeth. Results Among the posterior contacts, the ‘O’ type of contact was least prevalent, while most prevalent was the ‘S’ type for second molar-first molar contact, ‘I’ type for the first molar-second premolar contact, and ‘X’ type for the second premolar-first premolar contact. Among the anterior contacts, least prevalent was ‘S1’ type for the first premolar-canine contact, and I type for the canine-lateral incisor and the lateral incisor-central incisor contacts. There was no statistical significance between right- and left-side contacts (P &gt; 0.05) while significance was seen between maxillary and mandibular contacts (P &lt; 0.05). Similarity of contacts ranged from 5.17% to 10.05%. Conclusion The OXIS classification is applicable to posterior permanent teeth, and its modification is representative of anterior permanent teeth.

Dual Dirac Nodal Line in Nearly Freestanding Electronic Structure of β-Sn Monolayer.

Two-dimensional topological insulators (2D TIs) have distinct electronic properties that make them attractive for various applications, especially in spintronics. The conductive edge states in 2D TIs are protected from disorder and perturbations and are spin-polarized, which restrict current flow to a single spin orientation. In contrast, topological nodal line semimetals (TNLSM) are distinct from TIs because of the presence of a 1D ring of degeneracy formed from two bands that cross each other along a line in the Brillouin zone. These nodal lines are protected by topology and can be destroyed only by breaking certain symmetry conditions, making them highly resilient to disorder and defects. However, 2D TNLSMs do not possess protected boundary modes, which makes their investigation challenging. There have been several theoretical predictions of 2D TNLSMs, however, experimental realizations are rare. β-Sn, a metallic allotrope of tin with a superconducting temperature of 3.72 K, may be a candidate for a topological superconductor that can host Majorana Fermions for quantum computing. In this work, single layers of α-Sn and β-Sn on a Cu(111) substrate are successfully prepared and studied using scanning tunneling microscopy, angle-resolved photoemission spectroscopy, and density functional theory calculations. The lattice and electronic structure undergo a topological transition from 2D topological insulator α-Sn to 2D TNLSM β-Sn, with two types of nodal lines coexisting in monolayer β-Sn. Such a realization of two types of nodal lines in one 2D material has not been reported to date. Moreover, we also observed an unexpected phenomenon of freestanding-like electronic structures of β-Sn/Cu(111), highlighting the potential of ultrathin β-Sn films as a platform for exploring the electronic properties of 2D TNLSM and topological superconductors, such as few-layer superconducting β-Sn in lateral contact with topological nodal line single-layer β-Sn.

Automatic Detection of Fatigued Gait Patterns in Older Adults: An Intelligent Portable Device Integrating Force and Inertial Measurements with Machine Learning.

This study aimed to assess the feasibility of early detection of fatigued gait patterns for older adults through the development of a smart portable device. The smart device incorporated seven force sensors and a single inertial measurement unit (IMU) to measure regional plantar forces and foot kinematics. Data were collected from 18 older adults walking briskly on a treadmill for 60min. The optimal feature set for each recognition model was determined using forward sequential feature selection in a wrapper fashion through fivefold cross-validation. The recognition model was selected from four machine learning models through leave-one-subject-out cross-validation. Five selected characteristics that best represented the state of fatigue included impulse at the medial and lateral arches (increased, p = 0.002 and p < 0.001), contact angle and rotation range of angle in the sagittal plane (increased, p < 0.001), and the variability of the resultant swing angular acceleration (decreased, p < 0.001). The detection accuracy based on the dual signal source of IMU and plantar force was 99%, higher than the 95% accuracy based on the single source. The intelligent portable device demonstrated excellent generalization (ranging from 93 to 100%), real-time performance (2.79ms), and portability (32g). The proposed smart device can detect fatigue patterns with high precision and in real time. The application of this device possesses the potential to reduce the injury risk for older adults related to fatigue during gait.

Efficient and stable perovskite mini-module via high-quality homogeneous perovskite crystallization and improved interconnect

The efficiency and stability of perovskite module devices are mainly limited by the quality of scalable perovskite films and sub-cells’ lateral contact. Here, firstly, we report constant low temperature substrate to regulate the growth of perovskite intermediate films to slow down the crystallization for obtaining high-quality homogeneous perovskite films in large scale size, which avoid the effect of the ambient temperature on the film quality. Secondly, a scribing step named P1.5 was added before the top function layers deposition, the diffusion barrier layer can be formed “naturally” at the interconnection interface without introducing any additional materials, which well alleviates the diffusion degradation process. As a result, our inverted perovskite devices exhibit a very small efficiency loss with area expansion comparable to other photovoltaic devices (for example, Cadmium Telluride), the perovskite module (aperture area 14.61 cm2) shows a certified quasi-steady-state power conversion efficiency of 22.73%, and the module maintaining over 90% of its initial efficiency after 1000 hours of continuous operation under illumination.

A novel gate over source-channel overlap dual-gate TFET with insulator pocket and lateral source contact for optimizing subthreshold characteristic

In this work, we propose a novel hetero-junction hetero-gate-dielectric gate over source-channel overlap dual-gate TFET with an insulator pocket and a lateral source contact (IP-LSC-HJ-HGD-GoSo-DGTFET). In the IP-LSC-HJ-HGD-GoSo-DGTFET, an insulator pocket placed between channel and the right side of source is adopted to suppress the source corner effect which can cause SS to deteriorate. Therefore, an ultra-steep SSAVER of 5.5 mV/dec is obtained within 10 orders of magnitude of IDS. Moreover, IOFF is improved by one order of magnitude when the vertical source contact is replaced by a lateral source contact. Finally, the ION, ION/IOFF, VONSET, and gm of IP-LSC-HJ-HGD-GoSo-DGTFET are 97 μA/μm, 2.8 × 1013, 0 V and 510 μS/μm through the optimization of DC performance, respectively. As for the analog/RF performance, IP-LSC-HJ-HGD-GoSo-DGTFET achieves ƒT of 39 GHz and GBP of 17.3 GHz, respectively. Compared with other GoSo-DGTFETs, the proposed IP-LSC-HJ-HGD-GoSo-DGTFET is a better potential candidate in the application field of ultra-low power integrated circuit.

Research on the traction characteristic evaluation of urban rail vehicles based on entropy weight TOPSIS

This paper aims to investigate the influence of different speed at the end of the constant power section of the traction characteristic curve (TCC) on the vehicle dynamic performance and evaluate the TCC. A dynamics co-simulation model is developed in SIMPACK and MATLAB for dynamic analysis of the urban rail vehicle (URV) under different traction characteristics. Then it is used to investigate how acceleration distance and vehicle dynamic performance varies with the speed at the end of the constant power section of the TCC under different starting torques. Moreover, the entropy weight TOPSIS method which is widely used to solve the multi-objective decision-making problem is chosen to evaluate the traction characteristics based on various dynamic performance indexes over 25 test sections and acceleration distance. The results show that under traction conditions, the starting torque has effects on the lateral and vertical accelerations of car body, lateral and vertical wheel-rail contact forces, derailment coefficient and wheel unloading factor. The higher the torque, the greater the value of each index, that means the poorer the vehicle ride characteristics and running safety. For a given starting torque, the dynamic performance indexes increase with the increase of the speed at the end of the constant power section from 50 km/h to 80 km/h during the vehicle speed-up process. The maximum growth rate of the lateral and vertical accelerations of car body, lateral and vertical wheel-rail contact forces are 17%, 8%, 8% and 2%, respectively, when the speed at the end of the constant power section increases from 50 km/h to 80 km/h. Last, the comprehensive evaluation of traction characteristics using entropy-weight TOPSIS method reveals when the starting torque is 800 [Formula: see text], 1000 [Formula: see text], 1200 [Formula: see text] and 1400 [Formula: see text], the corresponding optimal speed at the end of the constant power section is 80 km/h, 80 km/h, 70 km/h and 50 km/h, respectively. The result of the study can provide theoretical support for traction characteristic design and traction control for URVs.

Constrained patterning of orientated metal chalcogenide nanowires and their growth mechanism

One-dimensional metallic transition-metal chalcogenide nanowires (TMC-NWs) hold promise for interconnecting devices built on two-dimensional (2D) transition-metal dichalcogenides, but only isotropic growth has so far been demonstrated. Here we show the direct patterning of highly oriented Mo6Te6 NWs in 2D molybdenum ditelluride (MoTe2) using graphite as confined encapsulation layers under external stimuli. The atomic structural transition is studied through in-situ electrical biasing the fabricated heterostructure in a scanning transmission electron microscope. Atomic resolution high-angle annular dark-field STEM images reveal that the conversion of Mo6Te6 NWs from MoTe2 occurs only along specific directions. Combined with first-principles calculations, we attribute the oriented growth to the local Joule-heating induced by electrical bias near the interface of the graphite-MoTe2 heterostructure and the confinement effect generated by graphite. Using the same strategy, we fabricate oriented NWs confined in graphite as lateral contact electrodes in the 2H-MoTe2 FET, achieving a low Schottky barrier of 11.5 meV, and low contact resistance of 43.7 Ω µm at the metal-NW interface. Our work introduces possible approaches to fabricate oriented NWs for interconnections in flexible 2D nanoelectronics through direct metal phase patterning.

Running safety assessment method of trains under seismic conditions based on the derailment risk domain

The accurate assessment of running safety during earthquakes is of significant importance for ensuring the safety of railway lines. Currently, assessment methods based on a single index suffer from issues such as misjudgment of operational safety and difficulty in evaluating operational margin, making them unsuitable for assessing train safety during earthquakes. Therefore, in order to propose an effective evaluation method for the running safety of trains during earthquakes, this study employs three indexes, namely lateral displacement of the wheel–rail contact point, wheel unloading rate, and wheel lift, to describe the lateral and vertical contact states between the wheel and rail. The corresponding evolution characteristics of the wheel–rail contact states are determined, and the derailment forms under different frequency components of seismic motion are identified through dynamic numerical simulations of the train–track coupled system under sine excitation. The variations in the wheel–rail contact states during the transition from a safe state to the critical state of derailment are analyzed, thereby constructing the evolutionary path of train derailment and seismic derailment risk domain. Lastly, the wheel–rail contact and derailment states under seismic conditions are analyzed, thus verifying the effectiveness of the evaluation method for assessing running safety under earthquakes proposed in this study. The results indicate that the assessment method based on the derailment risk domain accurately and comprehensively reflects the wheel–rail contact states under seismic conditions. It successfully determines the forms of train derailment, the risk levels of derailment, and the evolutionary paths of derailment risk.

Relevance of instrumented gait analysis in the prediction of the rebound phenomenon after guided growth intervention

Predictors of rebound after correction of coronal plane deformities using temporary hemiepiphysiodesis (TH) are not well defined. The following research questions were tested: (1) Is the dynamic knee joint load useful to improve rebound prediction accuracy? (2) Does a large initial deformity play a critical role in rebound development? (3) Are BMI and a young age risk factors for rebound? Fifty children and adolescents with idiopathic knee valgus malalignment were included. A deviation of the mechanical femorotibial angle (MFA) of ≥ 3° into valgus between explantation and the one-year follow-up period was chosen to classify a rebound. A rebound was detected in 22 of the 50 patients (44%). Two predictors of rebound were identified: 1. reduced peak lateral knee joint contact force in the first half of the stance phase at the time of explantation (72.7% prediction); 2. minor initial deformity according to the MFA (70.5% prediction). The best prediction (75%) was obtained by including both parameters in the binary logistic regression method. A TH should not be advised in patients with a minor initial deformity of the leg axis. Dynamic knee joint loading using gait analysis and musculoskeletal modeling can be used to determine the optimum time to remove the plates.

Palaeozoic Amotape Group in the Colán District:

The Amotape Gr. Consists of metasedimentites with varying degrees of metamorphism and Paleozoic intrusions, exposed as isolated blocks that form an NNE-SSW belt, separating the Meso-Cenozoic depocenters of the Talara (west) and Sechura and Tumbes basins (east) along the Pacific margin of NW Perú. We describe three metamorphic/tectonic episodes that produced sub-planar structures (cleavages, fractures) affecting the rocks of the Amotape Gr, allowing this unit to be classified as a fractured reservoir. Field survey and multi-scale subsurface data from the Colán region, evidence a secondary porosity system associated with fracture networks that affect both the basin fill and the basement units. This configures a complementary unconventional exploration target. Sandstone levels in lateral contact with leptometamorphic rocks of the Amotape Gr. define good reservoir potential due to the preferentially brittle mechanical behavior of the basement, which develops abundant fractures. The porosity values of the Amotape Gr range between 4.62% and 1.23%, while permeabilities are on the order of 0.519-0.016 mD. Elevated trapping positions seem to be successfully sealed by Cretaceous units. The reservoir properties define a complementary play concept that could be extended to other positions of the technical basement in the Talara Basin and analogous regions.

Epidemiology of lateral ankle sprain focusing on indirect contact mechanism in male and female soccer players: An 18.5-month cohort study

BackgroundEpidemiological research highlights the need to understand sports injuries for effective prevention. Yet, detailed knowledge about lateral ankle sprain (LAS) in soccer, especially related to indirect contact mechanisms and specific sports movements, remains scarce. This study aimed to determine the prevalence of LAS by examining injury mechanisms, focusing on indirect contact, and analyzing sports-related movements. Study designProspective study. MethodsIn this prospective study, 304 high-school and college soccer players (age: 19.0 ± 2.2 years, height: 168.3 ± 10.6 cm, weight: 64.2 ± 11.1 kg) were monitored for 18.5 months. Attendance and LAS incidents were recorded daily. Injury details, including movement at the time of injury, contact presence, and direction, were collected through interviews conducted on the injury day. LAS were categorized into direct contact, indirect contact, and non-contact mechanisms. Direct contact injuries were due to external forces on the lower leg or foot. Indirect contact injuries resulted from impacts on areas other than the lower leg or foot, and non-contact injuries involved no interaction with the ball or opponent. Incidence rates per 1,000 athlete exposures and 95 % confidence intervals (CIs) were calculated, along with rate ratios (RR) to assess sex differences. ResultsThe study recorded 59 LAS injuries. Indirect injuries were predominant, accounting for 47.5 % (n = 28) of the cases. Men experienced a higher incidence of indirect injuries, with an RR of 2.29 (95 % CI: 1.06–4.96). Outward contact was the most common (77.8 %; n = 21), while inward contact occurred in 22.2 % of the cases (n = 6). ConclusionHigh school and college soccer players primarily sustained injuries through indirect contact mechanisms, with a significant number of injuries occurring during lateral contact. Men were more prone to indirect contact injuries. Furthermore, 47.5 % of LAS incidents involved reactive movements, and injuries frequently occurred during specific sports actions, such as ball interception.

Effect of Medial Patellofemoral Complex Reconstruction Technique on Patellofemoral Contact Pressure, Contact Area, and Kinematics.

Medial patellofemoral ligament (MPFL) reconstruction is considered by many to be the gold standard to treat lateral patellar instability; however, some investigators have reported good clinical results after isolated medial quadriceps tendon-femoral ligament (MQTFL) reconstruction or a combined MPFL/MQTFL reconstruction. A handful of studies have preliminarily investigated the biomechanical consequences of these various medial patellar stabilizing procedures. Despite this, no existing study has included multiple medial patellofemoral complex (MPFC) reconstructions and assessment of lateral patellar translation at distinct flexion angles. Combined MPFL/MQTFL reconstruction would restore patellofemoral contact areas, forces, and kinematics closest to the native state compared with isolated reconstruction of the MPFL or MQTFL alone. Controlled laboratory study. Ten adult cadaveric knee specimens were prepared and analyzed under 5 different conditions: (1) intact state, (2) transected MPFC, (3) isolated MPFL reconstruction, (4) isolated MQTFL reconstruction, and (5) combined MPFL/MQTFL reconstruction. Patellar tilt, lateral patellar translation, patellofemoral contact forces, and patellofemoral contact areas were measured in each condition from 0° to 80° through simulated knee flexion using a custom servohydraulic load frame with pressure sensor technology and a motion capture system for kinematic data acquisition. The isolated MPFL, isolated MQTFL, and combined MPFL/MQTFL reconstruction conditions produced significantly less lateral patellar tilt compared with the transected MPFC state (P < .05). No statistically significant differences were found when each reconstruction technique was compared with the intact state in patellar tilt, lateral patellar translation, contact forces, and contact areas. All 3 reconstruction techniques (isolated MPFL reconstruction, isolated MQTFL reconstruction, and combined MPFL/MQTFL reconstruction) restored native knee kinematics, contact forces, and contact areas without overconstraint. Isolated MPFL reconstruction, isolated MQTFL reconstruction, and combined MPFL/MQTFL reconstruction all restore patellofemoral stability comparable with the intact MPFC state without the overconstraint that could be concerning for increasing risk of patellofemoral arthritis.

Induced fatigue impact on plantar pressure in females with mild hallux valgus

Fatigue has been established to change plantar pressure distribution, yet its impact on hallux valgus (HV) patients, who exhibit morphological and biomechanical changes in the foot, remains insufficiently studied. Twenty-eight female participants, comprising 16 with mild HV and 12 healthy controls, were recruited. Plantar pressures were recorded pre- and post-fatigue using the Footscan platform during self-selected-speed walking trials, fatigue protocol was performed on a treadmill. Foot was segmented into 10 anatomical regions for calculating parameters including maximal force, peak pressure, impulse, contact duration, contact area, and force time-series, alongside assessing the distribution of medial and lateral contact forces (Foot balance) across the groups. During post-fatigue, patients with mild HV demonstrated adaptive changes in plantar pressure distinct from healthy controls, with significant reductions in maximal force, peak pressure, and impulse in the M1 and M2 regions and increases in the M3–M5 regions. In contrast, the control group exhibited an opposite pattern, concentrating pressure in the M1 and M2 regions post-fatigue. The force time-series analysis revealed significant disparities between HV patients and controls, particularly in the M4 and M5 regions, where HV patients showed a less pronounced and lower passive peak in forces. Results show that women with mild HV demonstrate adaptive changes in plantar pressure post-fatigue, distinctly different from healthy individuals, aiding in preventive strategies for fatigue-induced foot injuries for HV patients.

Injection of anomalous-Hall current into a load circuit

The anomalous-Hall current injection is studied in a Hall device contacted to a lateral load circuit. This anomalous-Hall current is generated inside a Co75Gd25 ferrimagnetic Hall bar and injected into a lateral load circuit contacted at the edges. The current, the voltage, and the power are measured as a function of the magnetization states, the load resistance Rl, and the temperature. It is shown that (1) the resistance associated with the anomalous-Hall current flowing inside the Hall bar is that of the portion of the ferrimagnet located between the lateral contacts, (2) the role of the non-uniformity of the current due to the lateral contacts is small, (3) the maximum power efficiency of the current injection into the load circuit corresponds to the condition of the resistance matching of the two sub-circuits, and (4) this maximum power efficiency is of the order of the square of the anomalous-Hall angle. These observations are in agreement with recent predictions based on a non-equilibrium variational approach.