Joint Stress Research Articles

Investigation of customized total knee implant with articular cartilage under loading conditions using finite element analysis.

Knee osteoarthritis (KOA) is a degenerative joint disease predominantly affecting the elderly and is often managed through knee replacement surgeries. West Asians, who frequently engage in activities involving bending and kneeling during their prayers, tend to exhibit distinct bone anatomy compared to the Caucasian population. This research posits that patient-specific, customized knee implants with articular cartilages may lead to reduced post-surgical discomfort and a better implant fit compared to conventional standard implants. This study presents a novel concept and approach for the development of a customized total knee implant with articular cartilages, specifically tailored to simulate loading conditions using finite element analysis (FEA) for the Saudi Arabian population. The research analyses patient-specific customized knee implants with articular cartilages under both pre- and post-implant conditions using a finite element model (FEM). Computed tomography (CT) images of patients were utilized to create a solid model, which was then analysed under various constraints and conditions. The meshing process employed tetrahedral elements, converging with 76,197 nodes and 43,009 elements. The analysis was conducted under different body weights, specifically 75-80 kg and 100-105 kg. Two sets of force and moment were applied: the first with a force of 1000 N and a moment of 1.5 N-m, and the second with a force of 750 N and a moment of 0.8 N-m. The results indicated a 5% reduction in stress with implants designed for a 100 kg body weight, along with a significant reduction in ligament strain when compared to conventional knee joint stresses. This study offers a promising pathway toward reducing post-surgical discomfort. The proposed innovative solution has the potential to revolutionize total knee implant technology, offering enhanced functionality and improved patient outcomes for the Saudi Arabian population.

RELATIONSHIP BETWEEN STRESS AND TEMPOROMANDIBULAR JOINT DISORDERS IN MEDICAL AND DENTISTRY STUDENT OF UNIVERSITAS JENDERAL ACHMAD YANI

Temporomandibular joint disorder is a condition that is often unrecognized by patients. One of the etiologies of temporomandibular joint disorder is stress. Medical and dental students may experience stress associated with symptoms of temporomandibular joint disorders. The aim of this study was to determine the relationship between stress and temporomandibular joint disorders in dental and medical faculty students. The research design is analytic with a cross-sectional method on 196 students of Medicine and Dentistry at The University Jenderal Achmad Yani, class of 2020. Chi-square analysis was utilized to investigate the relationship between temporomandibular joint disorders and stress. The results indicate a significant association between symptoms of temporomandibular joint disorders and stress (p = 0.002). Stress is one of the etiological factors in the occurrence of temporomandibularjoint disorders.

Dynamic Responses and Crack Propagation of Rock with Crossed Viscoelastic Joints Under Blasting Loads

To investigate the propagation of stress waves in viscoelastic joints under blasting loads, and their impact on crack propagation and dynamic response in rock masses, a numerical model incorporating intersecting viscoelastic joints was developed using LS-DYNA. This study focuses on the influence of various joint geometric parameters, including thickness and angle, on stress wave propagation and damage patterns in rock. The Riedel–Hiermaier–Thoma (RHT) model was employed to simulate the dynamic behavior of rock, while the Poynting–Thomson model was used to describe the viscoelastic properties of the joint fillings. The simulation results provide detailed insights into the principal stress, displacement, and particle vibration velocity around the joints. Based on the stress wave propagation theory, the velocity transmission coefficients were calculated to quantify the attenuation of stress waves across the joints. The findings demonstrate that viscoelastic joint properties significantly affect the damage patterns in the rock mass. Specifically, the area of the crushed zone and the width of cracks on the blasting side are proportional to joint thickness, while crack propagation at the joint tips is governed by differences in principal stress. Moreover, the propagation of vibration velocity is notably weakened at the second joint, highlighting the critical role played by joint characteristics in stress wave dynamics. These results underscore the complex interaction between joint properties and stress wave behavior in rock masses, providing valuable insights for optimizing blasting designs and improving the safety of underground engineering projects.

Experimental and Numerical Investigation of Welding Residual Stress of U-Rib Joints in Orthotropic Steel Bridge Decks

The residual stresses at U-rib joints have a significant adverse impact on the structure. Therefore, it is necessary to conduct research and analysis on their residual stresses. Based on experimental testing and thermal elastic-plastic finite element analysis (FEA), this study investigates the residual stress (RS) of a U-rib joint using gas metal arc welding in an orthotropic steel bridge deck (OSBD). X-ray diffraction (XRD) was adopted to measure the RS of the U-rib welds, and the measurement results were utilized to verify the FEA. The effects of the weld root gap, weld penetration, and weld groove angle on the RS of U-rib welds were investigated by using FEA. The weld root gap had minor effect on the RS of the U-rib welds. With an increase in weld penetration, the peak values of the transverse tensile RS at both the deck plate and the U-rib weld toes increased. Additionally, an enlargement of the groove angle also resulted in a notable increase in the transverse tensile RS peak at the deck plate weld toe.

Comparison of the Reliability of SAC305 and Innolot-Based Solder Alloy in a Board-Level BGA Package Considering Harmonic and Random Vibration Environment

This paper presents a comparative study of the fatigue life of solder joints in a board-level Ball Grid Array (BGA) assembly. It specifically contrasts the commonly used SAC305 alloy with the advanced Innolot-based solder alloy, recognized for its superior tensile strength. Through Finite Element Analysis (FEA), we simulate and predict the reliability of these solder joints under harmonic and random vibration conditions. Following the JEDEC (Joint Electronic Device Engineering Council) standards, two different board-level BGA assemblies are used for the analysis. In both assemblies, the dimensions of the substrate, molding compound, and solder balls remain identical; only the board dimensions are changed to observe how they affect stress in the solder joints. The results indicate that using Innolot raises the volume-averaged stress levels by more than 25% on larger boards and about 5% on smaller boards compared to SAC305. This increase in stress levels is due to the Innolot alloy having a less significant stiffening effect than SAC305, which results in higher stress levels under the same excitation conditions. While the stress in the Innolot-based solder joint is greater than that in the SAC305 joint under identical excitation conditions, the fatigue life of the Innolot joint is significantly higher than that of the SAC305 joint. The results show that the Innolot-based alloy exceeds the performance of SAC305, and that it is suitable for use as a solder alloy in extreme vibration conditions.

The influence of pain exacerbation on rear foot eversion and plantar pressure symmetry in women with patellofemoral pain: a cross sectional study

BackgroundThe patellofemoral joint (PFJ) stress as a primary mechanical stimulus in the patellofemoral pain (PFP) etiology is affected by plantar pressure symmetry. This study evaluated how pain exacerbation affects rear foot eversion and plantar pressure distribution symmetry.MethodSixty women with PFP participated in this study. Pain intensity, rear foot eversion, and plantar pressure were evaluated in the two conditions with and without pain exacerbation during double-leg squats. The MANOVA test was used to compare pain intensity, rear foot eversion, and plantar pressure symmetry between the two conditions. The Pearson correlation was used to evaluate the relationship between the pain intensity with the rear foot eversion and the plantar pressure symmetry.ResultsThe comparison between the two conditions showed a significant difference in pain intensity (P < 0.001, η2 = 0.623), rear foot eversion (P < 0.001, η2 = 0.485), plantar pressure distribution symmetry of the right-left foot (P < 0.001, η2 = 0.438), forefoot and rear-foot of the right foot (P < 0.001, η2 = 0.607), and forefoot and rear-foot of the left foot (P < 0.001, η2 = 0.548). An excellent correlation was observed between the pain intensity with rear foot eversion (P < 0.001, r = 0.835) and plantar pressure distribution symmetry of the right-left foot (P < 0.001, r = 0.812), forefoot and rear-foot of the right foot (P < 0.001, r = 0.834), and forefoot and rear-foot of the left foot (P < 0.001, r = 0.811).ConclusionsAfter the pain exacerbation, the rear foot eversion was greater, and plantar pressure asymmetrical was observed, which can help in the development of PFP severity.

Polyvinyl acetate–glycidyl methacrylate co-polymer emulsion-based heat-resistant wood adhesive

In this research work, vinyl acetate (VAc) and glycidyl methacrylate (GMA) emulsion copolymers have been developed and tested as wood adhesives. Further, the emulsion samples are formulated with polyvinyl alcohol (PVA) solution, plasticizer, and preservatives, and compared the polyvinyl acetate (PVAc) homo-polymer based adhesive against PVAc-GMA based adhesive sample. Utilizing differential scanning calorimetry (DSC), the glass transition temperatures (Tg) of the polymer films were found. To assess the effectiveness of the adhesives, the tensile shear strength of wood joints under dry and wet conditions was evaluated in compliance with the EN 204 and EN 205 standard. The heat resistance of the wood adhesives was assessed using the EN 14257 standard, which measures the shear stress of wood joints at 80 °C. According to the experimental findings, the amount of GMA in the emulsion caused significant increases in Tg and hardness. The results of DSC, which were confirmed by tests on the hardness of films, showed that the Tg in the GMA-based adhesive was significantly higher than in the PVAc homo-polymer-based adhesive. According to EN 204, the tensile shear strength of a GMA-based adhesive increased by 43.62% after 6 h of bonding in a dry environment and by 75% in a wet environment when compared to a PVAc homopolymer-based adhesive. Comparing the GMA adhesive to a PVAc homopolymer-based glue, the GMA adhesive demonstrated better heat resistance. The technique developed provides a straightforward and useful path to adhesives with better heat, water, and bonding strength resistance.

PROPERTIES OF JOINTS WELDED USING THE MAG METHOD S355J2+N STEEL AFTER PEENING PROCESS

The aim of the research was to determine the impact of peening of each weld on the properties of a butt joint made of S355J2+N steel welded using a ceramic washer. The welding process was carried out using the MAG method on a robotic station. The analysis was based on a comparison of three butt joints: after welded, with peening of each bead and with post weld heat treatment – stress relief annealing. High frequency peening (90Hz) of each bead made was intended to reduce stress in the weld joint by introducing compressive stress into it. A Weld Line 10 pneumatic hammer was used. Tests such as visual, penetration, radiographic and destructive tests (macroscopic, transverse tensile test, transverse bending test, impact strength test, hardness) are conducted on the test samples prepared in the MAG process. The test results are compared to the acceptance values from the ISO standard. Additionally, stress measurements were made using the Barkhausen effect based on the research procedure of the technology supplier. The research performed showed that use of high – frequency peening after each bead did not affect the negative results of all the required tests during the qualification of the welding technology of S355J2+N steel compared to the test plates (after welded and after post weld heat treatment – stress relief annealing).

Anand Model Constants of Sn–Ag–Cu Solders: What Do They Actually Mean?

Abstract Finite element simulations are broadly utilized to calculate the thermally induced mechanical deformations of interconnecting solder materials in electronics. The Anand unified viscoplasticity model is a prevalent choice for simulating the mechanical responses of solder joints, comprising nine parameters whose individual effects are not fully addressed in the literature. For this reason, this study examines the influence of each Anand parameter on the mechanical response of leadless tin–silver–copper (SAC) solder alloys with varying silver content through comprehensive nonlinear finite element simulations. Anand model coefficients for different SAC alloys, including SAC105, SAC205, SAC305, and SAC405, were sourced from existing literature and used to establish a systematic study matrix for each parameter. These coefficients were then integrated into thermomechanical simulations to induce inelastic deformations in the solder interconnections. The response of the solder interconnects is analyzed in terms of equivalent inelastic strains and inelastic strain energy density. Results indicated that specific Anand parameters could skew the solder joint stress–strain response toward brittle behavior, while other parameters could lead to a more ductile response. Through statistical factorial analysis, the significance of each parameter is found to vary considerably, ranging from negligible to highly significant. The findings of this study are crucial for understanding the behavior of different SAC solder configurations and their expected thermal fatigue performance based on Anand creep constants. Furthermore, this paper provides foundational insights into the interpretation of Anand coefficients and their influence on the mechanical response of solder materials, a topic not yet explored in the existing literature.

Enhanced Foot Proprioception Through 3-Minute Walking Bouts with Ultra-Minimalist Shoes on Surfaces That Mimic Highly Rugged Natural Terrains.

The use of minimalist shoes can lead to enhanced foot somatosensory activation and postural stability but can also increase the incidence of overuse injuries during high-impact or prolonged activities. Therefore, it appears useful to explore new strategies that employ minimalist shoes to effectively facilitate the somatosensory activation of the foot while minimizing acute and cumulative joint stress and risk of injury. To this purpose, this study introduces a novel exercise paradigm: walking for three minutes in ultra-minimalist shoes on artificial flat surfaces designed to mimic highly rugged natural terrains. The activity of foot muscles and lumbar multifidus, pain perception level, and stabilometric parameters were recorded and analyzed to characterize the novel exercise, comparing it to walking barefoot or in conventional shoes on the same rugged surface. Compared to being barefoot, ultra-minimalist shoes effectively filter nociceptive stimuli from the rugged surface, while compared to conventional shoes, they enhance the somatosensory input supporting static stability. Walking with ultra-minimalist and conventional shoes yielded higher gastrocnemius activity and lower tibialis anterior and multifidus activity compared to barefoot walking. This study highlights a practical and safe framework for enhancing foot somatosensory activation and postural stability. The new intervention is suitable for people of all ages, requires minimal time commitment, and can be performed in controlled environments such as homes, gyms, and healthcare facilities.

Exploring the Relationship Between Foot Position and Reduced Risk of Knee-Related Injuries in Side-Cutting Movements

Background: Knee-related injuries often result from poor movement patterns that destabilize the joint and increase stress on knee structures. Understanding the influence of foot positioning on knee biomechanics is critical for identifying high-risk movement patterns and preventing injuries. Methods: Twenty healthy male participants performed side-cutting movements at three different foot progression angles. One participant’s data were used to develop and validate a knee finite element model with high-speed dual fluoroscopic imaging (DFIS). Combined with a musculoskeletal analysis, the model simulated internal knee loads under various foot-positioning conditions. Results: The analysis revealed that, as the external foot progression angle increased, the ankle plantarflexion decreased, while the ankle internal rotation and knee valgus moments increased. Higher stress concentrations were observed on the ACL, lateral meniscus, lateral tibial cartilage, and medial collateral ligament, particularly at the femoral–tibial ACL attachments. Conclusion: The findings suggest that a toe-out foot position elevates the risk of knee injuries by increasing stress on key structures, whereas a toe-in position may enhance joint stability, reduce the ACL injury risk, and promote favorable muscle activation patterns.

Rehabilitation Technologies by Integrating Exoskeletons, Aquatic Therapy, and Quantum Computing for Enhanced Patient Outcomes.

Recent advancements in patient rehabilitation integrate both traditional and modern techniques to enhance treatment efficacy and accessibility. Hydrotherapy, leveraging water's physical properties, is crucial for reducing joint stress, alleviating pain, and improving circulation. The rehabilitation of upper limbs benefits from technologies like virtual reality and robotics which, when combined with hydrotherapy, can accelerate recovery. Exoskeletons, which support and enhance movement, have shown promise for patients with neurological conditions or injuries. This study focused on implementing and comparing proportional-integral-derivative (PID) and fuzzy logic controllers (FLCs) in a lower limb exoskeleton. Initial PID control tests revealed instability, leading to a switch to a PI controller for better stability and the development of a fuzzy control system. A hybrid strategy was then applied, using FLC for smooth initial movements and PID for precise tracking, with optimized weighting to improve performance. The combination of PID and fuzzy controllers, with tailored weighting (70% for moderate angles and 100% for extensive movements), enhanced the exoskeleton's stability and precision. This study also explored quantum computing techniques, such as the quantum approximate optimization algorithm (QAOA) and the quantum Fourier transform (QFT), to optimize controller tuning and improve real-time control, highlighting the potential of these advanced tools in refining rehabilitation devices.

Single/joint effects of pyrene and heavy metals in contaminated soils on the growth and physiological response of maize (Zea mays L.).

The widespread presence of polycyclic aromatic hydrocarbons (PAHs) and toxic heavy metals in soils is having harmful effects on food crops and the environment. However, the defense mechanisms and capacity of plants to counteract these substances have not been comprehensively explored, necessitating a systematic categorization of their inhibitory effects. Accordingly, an experimental investigation was conducted to examine the growth and physiological response of maize (Zea mays L.) to different concentrations and combinations of pyrene, copper (Cu), and cadmium (Cd), with an indicator developed to assess the joint stress. The results showed that 57-day culture with contaminations significantly inhibited the plant biomass via causing root cell necrosis, inducing lipid peroxidation, and damaging photosynthesis. Cd (50-100 mg/kg) induced stronger inhibition than Cu (800-1000 mg/kg) under both single and joint stress, and their co-existence further aggravated the adverse effects and generated synergetic inhibition. Although the presence of pyrene at a low concentration (5-50 mg/kg) can somewhat diminish the metal stress, the elevated pollutant concentrations (400-750 mg/kg pyrene, 50-100 mg/kg Cd, and 800-1000 mg/kg Cu) switched the antagonistic effect to additive inhibition on maize growth. A satisfactory tolerance of a low-level pyrene and/or metal stress was determined, associated with a relative stability of chlorophyll-a (Chl-a) content and antioxidant enzymes activity. Nevertheless, the photosynthesis and antioxidant system were significantly damaged with increasing contaminant concentrations, resulting in chlorosis and biomass reduction. These findings could provide valuable knowledge for ensuring crop yield and food quality as well as implementing soil phytoremediation.

Overlap Removal by Stochastic Gradient Descent With(out) Shape Awareness.

In many 2D visualizations, data points are projected without considering their surface area, although they are often represented as shapes in visualization tools. These shapes support the display of information such as labels or encode data with size or color. However, inappropriate shape and size selections can lead to overlaps that obscure information and hinder the visualization's exploration. Overlap Removal (OR) algorithms have been developed as a layout post-processing solution to ensure that the visible graphical elements accurately represent the underlying data. As the original data layout contains vital information about its topology, it is essential for OR algorithms to preserve it as much as possible. This article presents an extension of the previously published FORBID algorithm by introducing a new approach that models OR as a joint stress and scaling optimization problem, utilizing efficient stochastic gradient descent. The goal is to produce an overlap-free layout that proposes a compromise between compactness (to ensure the encoded data is still readable) and preservation of the original layout (to preserve the structures that convey information about the data). Additionally, this article proposes SORDID, a shape-aware adaptation of FORBID that can handle the OR task on data points having any polygonal shape. Our approaches are compared against state-of-the-art algorithms, and several quality metrics demonstrate their effectiveness in removing overlaps while retaining the compactness and structures of the input layouts.

Enhancement effect of Ni on the mechanical and thermodynamic properties of Au-xNi (x = 0.5,1.0,1.5,2.0,2.5,3.0) alloy: a first-principles study

Abstract Au-17.5Ni is a high-performance solder extensively utilized in the assembly of satellites, aircraft engines, and ceramic components, owing to its exceptional high-temperature properties. However, its inherent brittleness renders it susceptible to defects such as fractures, cracking, and delamination during the manufacturing of welding wires and foils. To mitigate these challenges, this study employs first-principles calculations to investigate the structural stability, mechanical properties, and thermal behavior of the primary phase in the Au-17.5Ni alloy, with a particular focus on the Au-rich phase, a solid solution of Ni in Au. The results indicate that the Au-2.0Ni composition exhibits the highest plasticity, characterized by a Pugh’s ratio (B/G) of 7.671 and a hardness value of 0.643 GPa, representing a 31.76% increase compared to pure Au. These improvements significantly enhance the processing performance of the Au-17.5Ni alloy. Moreover, the constant pressure specific heat capacity (Cp) of Au-xNi alloys exceeds that of pure Au and increases with higher Ni content. At 800 K, the Au-3.0Ni alloy exhibits the highest Cp at 31.179 J mol−1·K−1, indicating improved high-temperature stability. Additionally, the thermal expansion coefficients for Au-1.0Ni, Au-2.0Ni, and Au-3.0Ni increase by 13.037%, 22.858%, and 38.097%, respectively, which may lead to elevated thermal stresses in welded joints. Consequently, maintaining the Ni content in the Au-rich phase of the Au-17.5Ni solder below 2.0 wt% can significantly enhance solder processability, ultimately improving the yield of welding wires and foils.

An Exponential Drucker‐Prager Constitutive Model of Polyurethane Adhesive for Finite Element Model Simulation

ABSTRACTThe elasto‐plastic model‐based finite element method (FEM) simulation can graphically describe the nonlinearly mechanical response of adhesives to various loadings. Its prediction accuracy significantly hinges on the constitutive models of the adhesives. In this study, the plasticity property of the polyurethane adhesive is characterized by the Exponential Drucker‐Prager model (EDPM), and the model parameters are identified through tensile and shear tests. The FEM simulations and validation experiments reveal that there exists a monotonically increasing nonlinear relationship between the bonding thickness and the maximum stress of the adhesive joint as well as the stress peaked in the end of the single‐lap‐joint (SLJ), while the joint strength shows a monotonically decreasing tendency with the increment of the bonding length, and the stress at the joint end is distributed uniformly. The EDPM‐based constitutive model of polyurethane adhesive can accurately delineate the elastic–plastic deformation process of the bonding joints, which lays a theoretical foundation for optimizing the material properties of the adhesive and the bonding process.

Optimization research on biomechanical characteristics and motion detection technology of lower limbs in basketball sports

In basketball, the biomechanics of the lower limbs play a significant role in executing specific movements like sprints, jumps, and directional changes. Optimizing the performance of these movements is necessary for enhancing overall athletic performance and reducing injury risks. The objective of the research is to generate and execute a motion detection algorithm focusing on lower limbs in basketball utilizing a deep learning (DL) based approach. The study proposes the Refined Harries Hawks optimized Intelligent Long-Short Term Memory (RHH-ILSTM) method to improve the accuracy of detecting and analyzing biomechanical characteristics of lower limb movements. Data collection involved basketball players equipped with wearable sensors on their lower limbs to gather on-time data throughout dynamic movements to train the method. The data is pre-processed to remove noise, normalize values, and segment movements into discrete time intervals. Principal Component Analysis (PCA) is utilized to extract characteristics by reducing the dimensionality of the data while maintaining significant biomechanical aspects. The RHH-ILSTM system combines the exploration capabilities of the RHH optimization algorithm with ILSTM’s capacity to handle time-series data, leading to improved detection accuracy of lower limb biomechanics. The model efficiently captures crucial lower limb biomechanics, achieving a higher accuracy (94.58%) and recall (95.62%) in detecting movement phases and joint stresses. The proposed RHH-ILSTM method provides a robust solution for monitoring and analyzing lower limb movements in basketball.

Passive shoulder occupational exoskeleton reduces shoulder muscle coactivation in repetitive arm movements

Humans naturally employ muscle coactivation to facilitate a broad range of movements, enhancing joint stability and movement accuracy. However, excessive muscle coactivation can become unfavorable or even detrimental. This phenomenon is often observed in industrial workers who endure repetitive or prolonged joint stress, particularly in areas such as the shoulders. Prolonged stress can result in soft tissue damage and the onset of work-related musculoskeletal disorders (MSDs). In recent years, there have been efforts to mitigate the emergence of work-related MSDs among industrial workers through the implementation of upper-limb occupational exoskeletons (OEs). While previous research has demonstrated their effectiveness in reducing shoulder muscle activation, particularly in static and overhead work activities, there has been a lack of studies examining the impact of upper-limb OEs on muscle coactivation during repetitive arm movements. To bridge this gap in knowledge, our study systematically assesses the influence of a passive exoskeleton’s anti-gravitational support on shoulder muscle coactivation during repetitive arm movements. Results show that peak and mean coactivation levels linearly decrease with the increase of the amount of anti-gravitational support provided by the upper-limb OE, reaching approximately 51% and 54%, respectively. Conversely, the percentage of the movement cycle corresponding to the coactivation peak appears unaffected by the level of assistance. This study marks the first instance in which a passive upper-limb OE has been shown to reduce shoulder muscle coactivations, potentially paving the way for a novel methodology in their evaluation.

Small heterodimer partner-interacting leucine zipper protein suppresses pain and cartilage destruction in an osteoarthritis model by modulating the AMPK/STAT3 signaling pathway

ObjectiveOsteoarthritis (OA) is a degenerative joint disease caused by the breakdown of joint cartilage and adjacent bone. Joint injury, being overweight, differences in leg length, high levels of joint stress, abnormal joint or limb development, and inherited factors have been implicated in the etiology of OA. In addition to physical damage to the joint, a role for inflammatory processes has been identified as well. Small heterodimer partner-interacting leucine zipper protein (SMILE) regulates transcription and many cellular functions. Among the proteins activated by SMILE is the peroxisome proliferator-activated receptor (PPAR) γ, which mediates the activities of CD4 + T helper cells, including Th1, Th2, and Th17, as well as Treg cells. PPAR-γ binds to STAT3 to inhibit its transcription, thereby suppressing the expression of the NF-κB pathway, and in turn, the expression of the inflammatory cytokines interferon (IFN), interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α, which are sub-signals of STAT3 and NF-κB.MethodsOA was induced in control C57BL/6 mice and in C57BL/6-derived SMILE-overexpressing transgenic (SMILE Tg) mice. The protein expression levels in the joint and spleen tissues were analyzed by immunohistochemistry and immunofluorescence images. In addition, flow cytometry was performed for detecting changes of the changes of immune cells.ResultsLess cartilage damage and significantly reduced levels of OA biomarkers (MMP13, TIMP3 and MCP-1) were observed in SMILE Tg mice. Immunohistochemistry performed to identify the signaling pathway involved in the link between SMILE expression and OA revealed decreased levels of IL-1β, IL-6, TNF-α, and phosphorylated AMPK in synovial tissues as well as a significant decrease in phosphorylated STAT3 in both cartilage and synovium. Changes in systemic immune cells were investigated via flow cytometry to analyze splenocytes isolated from control and SMILE Tg mice. SMILE Tg mice had elevated proportions of CD4 + IL-4 + cells (Th2) and CD4 + CD25 + Foxp3 + cells (Treg) and a notable decrease in CD4 + IL-17 + cells (Th17).ConclusionOur results show that overexpressed SMILE attenuates the symptoms of OA, by increasing AMPK signaling and decreasing STAT3, thus reducing the levels of inflammatory immune cells.

Statistical evaluation of mechanical load on technicians during electric vehicle battery replacement using Python simulation

Electric vehicle (EV) battery replacement poses significant mechanical strain on technicians, increasing the risk of musculoskeletal disorders (MSDs). This study uses Python-based simulations and biomechanical modeling to evaluate the mechanical load distribution during the battery replacement process, focusing on joint stress and technician posture. The analysis covers different task phases, including battery removal, transport, and installation, with statistical methods used to assess forces and torques applied to critical joints. The results indicate that the removal and installation phases exert the highest mechanical loads on the lower back and shoulders. The study suggests ergonomic interventions such as workstation redesign, lifting tools, and improved posture techniques to reduce the risk of injury and enhance the safety and efficiency of EV maintenance tasks.