Face stability of shallow shield tunnels in inclined sand-clay strata: effects of dip angle and interface elevation

Accurate quantification of punch force is essential for performance assessment and training optimization in combat sports. This study introduces a Custom-Built Punch Force Dynamometer using two S-type load cells and evaluates its reliability, sensitivity, and partial ecological validity under sport-specific conditions. The device was mounted vertically on a wall and tested under both controlled and sport-specific conditions. Mechanical trials were assessed using a standardized drop-weight protocol with repeated trials. Partial ecological validity involved 11 experienced athletes from striking-based combat sports performing standardized straight punches across two lab visits. Reliability metrics included intraclass correlation coefficients (ICC), standard error of measurement (SEM), and smallest worthwhile change (SWC). The dynamometer demonstrated excellent reliability during mechanical trials (ICC > 0.90) and good to excellent reliability during partial ecological validity (ICC = 0.75-0.90). SEM values were consistently lower than SWC, indicating strong measurement sensitivity. These findings support the reliability and practical utility of this device for assessing punch force in both laboratory-based research and sport-specific applications.

Intravenous (IV) fluid therapy is one of the basic procedures applied for the infusion of fluid, medicine and nutrients to patients. Continuous measurement of IV fluid level is necessary for avoiding risks like dehydration, blood reflux, air embolism and discontinuation of therapy. The current practice for measurement mainly involves manual observation of healthcare staff at regular intervals, which might delay the response in case of emergency due to workload in clinical settings. Hence, in order to resolve this problem, this paper proposes an Internet of Things (IoT) based Intra Venous (IV) Fluid Monitoring System with Real Time Alert and remote supervision of IV fluid therapy. The proposed design involves 5 kg load cell, HX711 amplifier, ESP32 microcontroller, LCD screen, buzzer and Blynk platform to monitor IV bag weight, measure the remaining amount of fluid in the bag and communicate the information wirelessly to the healthcare personnel. Alerts are set based on threshold values and generated both locally and remotely if the level reaches the critical value. The experimental testing proved that the system has an accuracy rate of 98.7%. The system exhibited reliable synchronization in the cloud, quick notifications, and consistent real-time operation, thus proving to be a cost-efficient, scalable, and effective approach towards enhancing patient safety.

This study proposes and evaluates a novel, proxy method for assessing the performance of back support exoskeletons (BSEs), to address some limitations of electromyography (EMG) and metabolic cost (MC) measurements in workplace and field environments. We introduce the use of interface force between the user and exoskeleton as an alternative evaluation metric. To enable this, a compact load cell was integrated into the exoskeleton's thigh cuff, providing reliable force measurements without noticeably altering the system's kinematics or inertia. While interface force measurements can be affected by sweat and other human-related factors like EMG and MC, interface force can still represent the assistive force, allowing for real-time assessment of exoskeleton assistance in both laboratory and real-world settings. Experimental results demonstrated a statistically significant, strong correlation between mean interface force and lower-back muscle EMG activity during the upright phase of a squat lifting task with load. Whereas for MC, though not statistically significant, there was a strong correlation between mean interface force and MC reduction during a repetitive squat lifting task. These findings indicate that interface force sensing offers a promising proxy alternative to traditional EMG and MC evaluations, enabling more feasible, field-ready assessment of BSE performance in real-world workplace environments.

AimsReliable assessment of joint stiffness is essential for studying arthrofibrosis in preclinical animal models. This study presents a new dedicated biomechanics device for measuring knee stiffness in mouse, rat, and rabbit models of arthrofibrosis, with the aim of validating its performance and comparing it to a previously validated device.MethodsThe new system integrates a torque load cell, stepper motor, and absolute encoder in a through-hole, unified configuration for precise continuous torque-angle measurement, with custom limb brackets ensuring species-specific alignment at the joint’s centre of rotation. To validate this device and compare it to a previously validated device, arthrofibrosis was induced using established models of extra-articular immobilization in mice and intra-articular violation with immobilization in rats and rabbits, followed by defined remobilization periods. Torque-angle curves were recorded ex vivo across species-specific torque ranges, and measurement variability between the new and a previous validated device was statistically compared using Brown-Forsythe’s test.ResultsThe onset of hyperextension in contralateral limbs occurred at mean angles of 152.4° (mice), 154.4° (rats), and 152.8° (rabbits), and at maximum torque, mean flexion angles were 79.2°, 87.3°, and 140.5°, respectively. No significant differences in measurement variability were observed between devices across all species.ConclusionThese findings demonstrate that our new device provides reproducible torque-angle data while maintaining the statistical robustness of the previous device and offering improved mechanical design and operational standardization. By enabling standardized, cross-species joint stiffness quantification, this platform improves cross-study comparability and strengthens the translational reliability of preclinical arthrofibrosis research.Cite this article: Bone Joint Res 2026;15(6):716–725.

Cranial cruciate ligament (CCL) rupture is uncommon in cats but may cause persistent stifle instability. Previous ex vivo assessments of tibial plateau levelling osteotomy and tibial tuberosity advancement have failed to restore stability in the feline stifle. This study evaluated whether centre-of-rotation-of-angulation-based levelling osteotomy (CBLO) improves ex vivo stability in a refined feline limb-press model that preserves hip flexion-extension. Ten feline hindlimbs were tested intact, after CCL transection, and after CBLO under 30% bodyweight axial loading. Radiographic measurements included proxy CCL distance, joint angles, tibial plateau angle (TPA), anatomical-mechanical axis (AMA) angle, and gastrocnemius lever-arm characteristics. Muscle forces were recorded using calibrated load cells. CBLO reduced mean TPA from 23.8° (SD 2.2°) to 9.4° (SD 2.5°). AMA angle after CBLO (0.5°, SD 0.9°) did not differ significantly from zero (95% CI -0.1° to 1.1°, P = 0.1). Joint condition significantly affected proxy CCL distance (P < 0.001). Compared to intact limbs, distances increased by 7.1mm (95% CI 6.0 to 8.2, P < 0.001) after CCL transection and by 6.1mm (95% CI 4.9 to 7.3, P < 0.001) after CBLO, with no significant difference between CCL-deficient and CBLO limbs (-1.0mm; 95% CI -2.6 to 0.5, P = 0.3). Joint angles and simulated muscle forces were unaffected by joint condition. Gastrocnemius lever-arm length using the calcaneal tunnel was 86% (SD 2.0%) of the anatomical length. CBLO, as performed in this model, corrected tibial slope but did not restore ex vivo stability of the feline stifle following CCL transection.

BackgroundEndodontically Treated Teeth (ETT) have challenges in resisting fracture against occlusal forces. This study aimed to assess the fracture resistance (FR) of endodontically treated premolar teeth restored with an innovative self-adhesive bulk-fill resin-based composite (RBC) (Stela , SDI Limited, Australia), a short-fiber-reinforced composite (SFRC) (EverX flow, GC., Tokyo, Japan), a conventional nanohybrid (RBC) (Filtek Z250 XT, 3M ESPE, St. Paul, MN, USA) , and a Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) Lithium Disilicate (Emax, Dentsply Sirona, Bensheim, Germany) Endocrown. MethodsFor the FR test, 44 human extracted maxillary premolars were included in the study. Endodontic treatment was done, and a single operator prepared standardized mesio‑occlusal‑distal (MOD) cavities in the teeth and divided into four groups (n=11) according to the restorative material used. Group (F1): ETT restored with Stela resin-based composite, which was inserted into the cavity as a single 5 mm increment. Group (F2): ETT restored with (EverX Flow) composite,which was packed and light-cured for 20 seconds, leaving a 2 mm occlusal layer to be restored with nanohybrid composite (Filtek Z250 XT). Group (F3): ETT restored with Filtek Z250 XT resin-based composite only. Group (F4): ETT restored with (CAD/CAM Cerec MCXL) Lithium Disilicate endocrown, preparations were scanned with the Omnicam, and restorations were designed using CEREC Premium Software (version 4.4). For direct restoration groups the proximal walls were reconstructed by using a tofflemire matrix retainer and band. All restored teeth were subjected to FR testing using a universal testing machine ( Bluehill Lite Software on an Instron® / Each specimen’s failure load was recorded in Newton). Each specimen was individually mounted on the computer-controlled machine equipped with a 5 kN load cell, with the acrylic block secured to the lower fixed head. ResultsStatistical analyses were conducted using SPSS 27®, GraphPad Prism®, and Microsoft Excel 2016. Data normality was assessed with the Shapiro-Wilk and Kolmogorov-Smirnov tests, which indicated a nonparametric distribution. Comparison between groups revealed a significant difference (P<0.0001), with Group F4 (Endocrown) demonstrating the highest performance (1427.73 ± 156.96), compared to all direct restoration materials. In contrast, there were no significant differences among the three direct restoration groups despite slight differences in their means. Group F2 (EverX+Z250, mean: 619.87 ± 186.41) was higher than Group F1 (Stella, mean: 561.75 ± 173.74) with P = 1.000, and higher than Group F3 (Z250, mean: 452.22 ± 202.72) with P = 0.471. Group F1 (Stella) exceeded Group F3 (Z250), but this difference was not statistically significant (P = 0.838). ConclusionsWhile lithium disilicate endocrowns exhibit superior fracture resistance, direct restorative materials may serve as a clinically acceptable alternative for routine applications. Nevertheless, these findings should be interpreted with caution, given the inherent limitations of the in vitro study design.

A novel methodological framework for the assessment of the neural control of the shoulder using high-density surface electromyography.

Biomechanical comparison of sustained dynamic compression and static screw fixation in subtalar arthrodesis: A benchtop synthetic bone study.

Accurate characterization of the out-of-plane shear properties of laminated composites is essential for understanding their structural integrity under complex loading. While in-plane shear moduli are well-studied, out-of-plane properties are often challenging to measure, especially in natural fiber-based laminates. This study proposes an experimental method, based on the Mindlin-Reissner plate theory, to determine out-of-plane shear moduli of woven kenaf laminates using a torsional test setup enhanced by three-dimensional digital image correlation (3D-DIC). Rectangular specimens of two lengths (50 mm and 90 mm) were clamped and subjected to quasi-static torsion. The torque was recorded using a load cell, and full-field strain was captured via 3D-DIC. The average in-plane shear modulus (G 1 2) was found to be 1589.5 MPa, while the out-of-plane shear modulus (G 1 3) was 693.85 MPa. A specimen geometry sensitivity analysis revealed that a width-to-thickness ratio below 3 leads to significant overestimation or underestimation of the respective shear moduli. The proposed method is non-destructive, adaptable to relatively thin laminates, and well-suited for characterizing sustainable composites, making it a promising tool for design and performance assessment in bio-based structural applications.

Mechanical testing in a controlled laboratory setting is a vital part of orthopaedic research for investigating the structural-level performance or material-level properties of bones, joints, cartilage, soft tissues, and implants. The results can help researchers stay up to date on new findings, medical companies to develop more effective products, and university educators to instruct students on the practical relevance of classroom learning, so that there is a better understanding of orthopaedic conditions and injuries to optimize treatment. This article provides a brief and practical introduction to commonly used state-of-the-art methods, as well as some classic methods which are accurate, easy to use, and inexpensive, to measure different outcomes during in vitro mechanical testing. Planning a mechanical testing study, however, must be done before any experimentation by goal formation, timeline creation, literature review, and so on. Force or torque methods use mechanical testing machines and individual load cells. Displacement or rotation methods include electromagnetic tracking, extensometers or inclinometers, ultrasonic tracking, and videography. Surface strain or stress methods consist of acoustic emission, digital image correlation, fibre optic sensors, strain gauges, and thermography. Interface area or pressure methods encompass Fujifilm, piezoelectric sensors, staining dye, and Tekscan. Interface tribology methods involve the analysis of fretting corrosion friction and wear.Cite this article: Bone Joint Res 2026;15(6):610–616.

To assess how resin cement viscosity and thickness influence the static shear bond strength (s-SBS) of adhesively bonded lithium disilicate ceramic. Cylindrical lithium disilicate samples were prepared and randomly assigned to four experimental groups (n = 10), based on two factors: resin cement thickness (thin ≈50 µm or thick ≈150 µm) and viscosity (high or low). A tri-layer configuration (ceramic-resin cement-ceramic) was used, with standardized ceramic discs obtained from CAD/CAM blocks. The bonding ceramic surfaces were etched with hydrofluoric acid, silanized, and a defined bonding area (≈6 mm2) was delimited using adhesive tape. The resin cement thickness was controlled by applying either one (thin) or three (thick) overlapping layers of adhesive tape. Resin cement was applied, and assemblies were seated under a 100 g static load. After light-curing, specimens were subjected to static shear bond strength testing (s-SBS) using a universal testing machine (crosshead speed: 1 mm/min; load cell: 1 kN). Failure mode was classified under stereomicroscopy, and representative samples were analysed under SEM. Additional specimens were used to confirm cement layer thickness using a profilometer. For the thick resin cement layer (≈150 µm), viscosity significantly influenced bond strength, with high-viscosity cement showing higher mean values (27.36 MPa) compared to the low-viscosity cement (19.65 MPa). In contrast, resin cement viscosity did not affect the bond strength in the thin layer condition (≈50 µm). Most specimens exhibited adhesive failure at the ceramic-cement interface. Resin cement selection based on viscosity is particularly relevant when a thick cement layer is anticipated, whereas for ideal, thin cement films, viscosity is a less consequential factor for interfacial bond strength.

This work investigates the influence of the chord Reynolds number Rec and the dimensionless freestream shear rate K on a NACA 0012 airfoil in the ranges of Rec=(1.0–3.0)×104 and K=0.21–0.56. Loads on the airfoil and the streamwise velocity over the suction surface are measured using a load cell and molecular tagging velocimetry. For the range of parameters examined, the dominant effects are attributed to Rec, whereas shear has a weak influence, except at angles α near stall. A key finding is the change in behavior from trailing-edge to leading-edge (LE) stall with a small Rec increment in the range of Rec=(1.0–1.5)×104. The lift coefficient characteristics CL−α for both uniform and shear flows exhibit a nonlinear behavior where the slope CL,α initially increases beyond α=0. The increase, which occurs abruptly for LE stall cases, is unambiguously connected to closure of the separation bubble on the suction surface. CL,α at α=0 is found to generally increase with K but decrease with Rec. Shear creates asymmetry by enhancing the magnitude of the maximum lift-to-drag ratio L/D for α<0 and all Rec as compared to uniform flow. For α>0, there is little change except in the narrow range of Rec=(1.0–1.5)×104, where L/D decreases when shear is present.

Sloped Walking Surface Characteristics Modulate Unconstrained Slip Mechanics and Subsequent Fall Risk.

Solid-medium deformation apparatuses of the Griggs type have been widely used for experimental studies of rock and mineral rheology at high pressure and temperature, but precise determination of differential stress has long been limited by friction within solid confining media. In the 1960s, Kumazawa independently developed a double piston-cylinder type deformation apparatus, which enables independent and simultaneous measurements of axial and confining forces using two pairs of load cells. However, the potential of this design for accurate stress measurements has not been fully explored. Here, we present a newly developed Kumazawa-type deformation apparatus designed for high-pressure (up to 2GPa confining pressure) and high-temperature experiments. The apparatus allows simultaneous, real-time monitoring of axial stress and confining pressure, making it possible to quantitatively evaluate frictional stresses acting within solid sample assemblies. We review the design principles of the original Kumazawa apparatus, describe the methodology for stress measurement and correction, and report results from preparatory calibration tests and deformation experiments at room temperature using a newly developed system. The results demonstrate that frictional stress variations during pressurization, heating, and axial deformation can be resolved in real time, providing a basis for improving the reliability of differential stress measurements in solid-medium deformation experiments.

A fiber-optic monitoring approach for safety assurance of anchor bolt support with application to deep mining roadways

An open-source BLDC motor test bed utilizing ESC telemetry for cost-effective educational laboratories

This study proposes a digital twin-based CPR compression measurement system (DTCMS) architecture for real-time monitoring of CPR compression. The system combines a load cell, an inertial measurement unit (IMU), a LabVIEW acquisition platform, and a CNN module to capture multi-modal motion characteristics during CPR repetitive compression training. A calibration-aware sensor fusion framework synchronizes heterogeneous signals, reduces drift, and enhances robustness under high-frequency operation. Real-time data acquisition, latency-controlled transmission, and digital twin visualization enable synchronized physical–virtual interaction. Experimental results demonstrate high accuracy (R2 > 0.99), stable repeatability (coefficient of variation: CV < 3.5%), and reliable dynamic tracking. The compression depth error was maintained within ±1.5 mm, and synchronization latency remained below 0.2 s. Results confirm the proposed DTCMS architecture as a robust solution for real-time biomechanical monitoring and digital twin-based interactive systems. Compared with conventional single-sensor CPR monitoring systems, the proposed framework improves synchronization stability and sensing robustness through calibration-aware multi-sensor fusion.

PurposeThe analysis of knee joint biomechanics under intraoperative‐like conditions is fundamental to support surgical decisions and improve clinical outcomes. Many experimental systems developed in recent years are characterized by high complexity and limited portability, which may restrict the reproduction of surgical intraoperative workflows. Therefore, this study describes the design and experimentally validates a compact and portable testing platform capable of accurately analysing knee tibio‐femoral and patello‐femoral kinematics and laxity under intraoperative‐like conditions.MethodsThe system integrates motion capture, mechanical fixation, motor‐driven actuation, force measurement and dedicated software into a unique platform. It enables passive and active open‐chain knee motions, as well as standardized ligament laxity testing. Tibio‐femoral and patello‐femoral kinematics are simultaneously recorded while quadriceps and external forces are measured respectively through mono‐axial and tri‐axial load cells. System accuracy and repeatability were assessed through load cell calibration and dynamic testing on a synthetic knee model. Transportability, setup time and overall performance were evaluated under realistic ex vivo experimental conditions.ResultsValidation demonstrated close agreement between set and measured loads, with measurement accuracies of approximately 1% for quadriceps forces and 0.75% for externally applied knee forces. Motor‐driven motion showed high repeatability, with mean standard deviations of 0.51° for flexion–extension cycles and 1.62° for multiple dynamic flexion tests. Motion capture calibration achieved a pointer tip positional error of approximately 0.20 mm. Ex vivo testing confirmed reliable reproduction of knee motion and highly reproducible measurement, with rapid set‐up and workflow smoothness.ConclusionThe system represents a portable, accurate, repeatable and validated experimental platform for biomechanical assessment of knee joint kinematics and laxity under intraoperative‐like conditions. Its modular design, rapid setup and capability to combine kinematic and kinetic measurements make it a valuable tool for investigating the biomechanical impact of surgical techniques or implants, and patient‐specific joint behaviour in ex vivo settings.Level of EvidenceN/A.

Long-acting injectable antiretroviral therapy (LAI-ART) has the potential to transform HIV treatment for adolescents with perinatal HIV infection (APHI). Given the existing knowledge gaps surrounding this recent strategy, we aimed to assess interest in LAI-ART among ART-experienced APHI in Cameroon. We conducted a cross-sectional study among ART-experienced APHI aged 10–19 years, across four paediatric HIV clinics in the Centre region of Cameroon. Data were collected from 4 to 30 November 2024 using structured questionnaires to assess sociodemographic characteristics, awareness of, and interest in LAI-ART. HIV-1 viral load (VL) and CD4 cell counts were measured during the same period. Logistic regression analysis was used to identify factors associated with interest in switching to LAI-ART. Of 248 participants (48.8% female; median [IQR] age 15 [13–17]), 40.0% lived with a guardian and 75.8% had partial/full HIV-disclosure; 3.2% reported stigma. Clinically, 77.5% were in multi-month ARV-dispensation (MDSD) and 28.2% had poor ART-adherence; fear of injection was none/moderate/high in 73.4%, 15.7% and 10.9%, respectively. Viral undetectability (VL < 50 copies/mL) and CD4 ≥ 500 cells/mm³ were 71.6% and 72.5%, respectively. Overall, 92.3% expressed interest in LAI-ART, motivated by reduced pill burden/fatigue (63.7%) and expected better adherence (74.2%); 30.2% reported prior LAI-ART awareness. In multivariable analysis, no prior awareness had 81% lower odds of interest (p = 0.036). Compared with no-fear, moderate-fear was associated with 46% lower odds (p = 0.393), while high-fear was associated with 78% lower odds (p = 0.017). Disparities in sex, education, residence, adherence, virological response, or treatment history did not influence interest in LAI-ART. Among all respondents, 77.1% said they would choose LAI-ART if available, whereas 20.2% preferred MDSD. In this Cameroonian APHI cohort, awareness of LAI-ART was low despite high-interest once adolescents were informed. Rollout in low/middle-income countries should prioritise targeted education, youth-friendly counselling to close knowledge gaps, reduce fear and ensure equitable uptake.