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The osteochondral defects (OCDs) resulting from the treatment of giant cell tumors of bone (GCTB) often present two challenges for clinicians: tumor residue leading to local recurrence and non-healing of OCDs. Therefore, this study focuses on developing a double-layer PGPC-PGPH scaffold using shell-core structure nanofibers to achieve “spatiotemporal control” for treating OCDs caused by GCTB. It addresses two key challenges: eliminating tumor residue after local excision and stimulating osteochondral regeneration in non-healing OCD cases. With a shell layer of protoporphyrin IX (PpIX)/gelatin (GT) and inner cores containing chondroitin sulfate (CS)/poly(lactic-co-glycolic acid) (PLGA) or hydroxyapatite (HA)/PLGA, coaxial electrospinning technology was used to create shell-core structured PpIX/GT-CS/PLGA and PpIX/GT-HA/PLGA nanofibers. These nanofibers were shattered into nano-scaled short fibers, and then combined with polyethylene oxide and hyaluronan to formulate distinct 3D printing inks. The upper layer consists of PpIX/GT-CS/PLGA ink, and the lower layer is made from PpIX/GT-HA/PLGA ink, allowing for the creation of a double-layer PGPC-PGPH scaffold using 3D printing technique. After GCTB lesion removal, the PGPC-PGPH scaffold is surgically implanted into the OCDs. The sonosensitizer PpIX in the shell layer undergoes sonodynamic therapy to selectively damage GCTB tissue, effectively eradicating residual tumors. Subsequently, the thermal effect of sonodynamic therapy accelerates the shell degradation and release of CS and HA within the core layer, promoting stem cell differentiation into cartilage and bone tissues at the OCD site in the correct anatomical position. This innovative scaffold provides temporal control for anti-tumor treatment followed by tissue repair and spatial control for precise osteochondral regeneration. [Display omitted] •Utilizing coaxial electrospinning, we generated shell-core structured nanofibers comprising a PpIX/GT shell layer and inner cores containing CS/PLGA or HA/PLGA.•By converting these nanofibers into short fibers, we developed distinct 3D printing inks, facilitating the creation of a double-layer PGPC-PGPH scaffold via advanced 3D printing methods.•The sonosensitizer PpIX embedded in the shell layer demonstrates targeted sonodynamic therapy, effectively damaging GCTB cells.•The specific inducing factors within the inner core precisely direct chondrogenesis in the PGPC layer and osteogenesis in the PGPH layer.•The PGPC-PGPH scaffold offers temporal control by eradicating GCTB cells followed by facilitating osteochondral regeneration, while also ensuring precise regeneration of upper cartilage and underlying bone through spatial control.

On the Chongqing’s straddle-type monorail train in China, serious abnormal wear of running wheel tires occurs in its routine use, leading to a series of safety, environmental, and economic concerns. To analyze the causes of abnormal wear, a dynamic model of straddle-type monorail vehicle with full consideration to the lateral behavior of running wheel tire was established using Lagrange equations and verified by Zhong’s model created using SIMPACK. Based on the boundary conditions provided in the dynamic model and the friction characteristics of tire and pavement, a finite element model of the running wheel tire was built and validated with vertical, lateral, and longitudinal stiffness tests of corresponding tires. The wear situations of each running wheel tire under extreme turning condition were described in detail with the contact behavior and an assessment was done based on the friction work and the friction work skewness value. Besides, the influence of slip angle, roll angle, and their combined effect on the abnormal wear of running wheel tire was analyzed. This research proposes that, reasonable matching of the slip angle and the roll angle is of engineering significance and it can reduce uneven wear of the running wheel tire.

The tire grounding parameters are a crucial component of the vehicle dynamics control system; accurate acquisition of grounding parameters is important for improving traction, braking force, and handling stability during vehicle operation. This paper studies strain-based intelligent tire contact patch length and vertical force estimation; first, a 205/55R16 radial tire was established, and static grounding experiments were carried out to verify the validity of the finite element model. Second, the sensitivity of the circumferential strain signal of the inner liner in the contact area of a tire with complex tread patterns was discussed. Methods for estimating the contact angle and contact patch length of rolling tires were established, and the estimation accuracy under different tire parameters and operating conditions were analyzed. Finally, the vertical force-sensitive response characteristics were analyzed and extracted, and the vertical force prediction model of a radial tire based on particle swarm optimization BP neural network was established.

The tire building process is a key part of tire manufacturing, serving as a bridge between the construction design and the finished tire, and the bladder is the core component to complete the shaping process. With the help of finite element method, the tire building process can be effectively reproduced, which help to carry out targeted problem solving and solution design. In this paper, the numerical simulation method is used to study the 205/55R16 radial tire building process, and the reliability of the simulation method is verified by comparing simulated green tire and its test section; then the shaping simulation model incorporating the bladder is established and compared with the finished tire parts to illustrate the reliability; On this basis, the influence of bladder parameters was analyzed by orthogonal design of experiment and simulated annealing optimization algorithm, the sensitivity of different parameters was obtained, the bladder parameters were optimized; compared with the bladder with original parameters, the optimized bladder effectively reduced the stress by 44.67 % and 55.54 %, while significantly improving the contact force between the bladders and the green tire. The results of the study provide a good methodological basis and theoretical guidance for tire design, manufacturing and bladder optimization.

As vehicle speed increases, the aerodynamic drag reduction becomes increasingly significant. The aim of this paper is to find out the effects of the wheelhouse shapes on the aerodynamics of an Ahmed body with a 35 slant angle. In this paper, based on the detached-eddy simulation method, the effects of the three classic different wheelhouse on the aerodynamic performance and near wake of the Ahmed body are presented. The mesh resolution and methodology are validated against the published test results. The results show that the front wheelhouse has a significant impact on the aerodynamic performance of the Ahmed body, leading to different aerodynamic drag forces and flow fields. Enlarging the wheelhouse cavity volume could result in a gradual increase in aerodynamic drag coefficients, the ratio of the wheelhouse cavity volume increased by 2.9% and 9.8%, the drag coefficients increased by 2.5% and 4.5% respectively. The increase in aerodynamic drag was primarily caused by flow separation in the large cavity volume wheelhouse.

Electric vehicles, with their distinct power systems, weight distribution, and power control strategies compared to traditional vehicles, influence the pressure distribution in the tire contact area, thereby affecting the estimation of road adhesion coefficient. In electric vehicle research, tire adhesion coefficient serves as a measure of the frictional force between the vehicle and the road surface, directly impacting the vehicle’s handling performance. The accurate estimation of the adhesion coefficient aids drivers in better understanding the vehicle’s driving state. However, the existing brush models neglect differences in ground pressure distribution along the width direction of tires during tire camber, potentially leading to inaccuracies in adhesion coefficient estimation. This study proposes a camber brush tire model that considers the width-direction pressure distribution characteristics, aiming to enhance the accuracy of adhesion coefficient estimation under camber conditions. Experimental comparisons between the improved and original models reveal a significant enhancement in estimation precision. Consequently, the findings of this study provide valuable insights for deepening our understanding of tire camber dynamics and for designing control systems for electric vehicles, thereby improving vehicle stability and safety.

Electric vehicles can lead to accelerated tire wear, an inevitable phenomenon during tire usage that can affect the cornering characteristics determining handling stability. In order to simulate tire wear, a finite element model for tire wear was established using the UMESHMOTION subroutine and Arbitrary Lagrangian–Eulerian (ALE) adaptive meshing in ABAQUS, which is based on the Archard theory. The tire’s cornering characteristics were analyzed based on the obtained worn tire. The research results demonstrate that as the wear amount increases, the cornering stiffness and aligning stiffness of the tire also increase. When there are differences in wear on both tire shoulders with the same global wear, the change in cornering stiffness is not significant, while the aligning stiffness exhibits noticeable differences. To explain the above phenomenon, grounding characteristics were incorporated as mediator variables. The analysis results indicate that wear has an impact on the grounding characteristics. Additionally, statistically significant correlations exist between grounding parameters and cornering characteristics. In conclusion, wear affects the tire’s cornering characteristics by changing the grounding characteristics.

Tire force is a critical state parameter for vehicle dynamics control systems during vehicle operation. Compared with tire force estimation methods relying on vehicle dynamics or tire models, intelligent tire technology can provide real-time feedback regarding tire–road interactions to the vehicle control system. To address the demand for accurate tire force prediction in active safety control systems under various operating conditions, this paper proposes an intelligent tire force estimation method, integrating sensor-measured dynamic response parameters and machine learning techniques. A 205/55 R16 radial tire was selected as the research object, and a finite element model was established using the parameterized modeling approach with the ABAQUS finite element simulation software. The validity of the finite element model was verified through indoor static contact and stiffness tests. To investigate the sensitive response areas and variables associated with tire force, the ground deformation area of the inner liner was refined along the transverse and circumferential directions. Variance-based global sensitivity analysis combined with dimensional reduction methods was used to evaluate the sensitivity of acceleration, strain, and displacement responses to variations in longitudinal and lateral forces. Based on the results of the global sensitivity analysis, the influence of longitudinal and lateral forces on sensitive response variables in their respective sensitive response areas was examined, and characteristic values of the corresponding response signal curves were analyzed and extracted. Three intelligent tire force estimation models with different sensor-targeting configurations were established using radial basis function (RBF) neural networks. The mean relative error (MRE) of intelligent tire force estimation for these models remained within 10%, with Model 3 demonstrating an MRE of less than 2% and estimation errors of 1.42% and 1.10% for longitudinal and lateral forces, respectively, indicating strong generalization performance. The results show that tire forces exhibit high sensitivity to acceleration and displacement responses in the crown and sidewall areas, providing methodological guidance for the targeted sensor configuration in intelligent tires. The intelligent tire force estimation method based on the RBF neural network effectively achieves accurate estimation, laying a theoretical foundation for the advancement of vehicle intelligence and technological innovation.

Tendinopathy poses a formidable challenge due to the inherent limitations of tendon regenerative capabilities post‐injury. At present, effective curative approaches for tendinopathy are still lacking. Collagen triple helix repeat‐containing 1 (CTHRC1) is an extracellular matrix protein with significant roles in both physiological and pathological processes. The present study aims to investigate the function and underlying mechanism of CTHRC1 in tendinopathy. In this study, CTHRC1 is identified as a potential effector in promoting tendon regeneration through multi‐proteomic analysis of Achilles tendon tissues in mice. In vitro, CTHRC1 enhances the proliferation, migration, and tenogenic differentiation of tendon stem/progenitor cell (TSPC). In vivo, CTHRC1 deletion impairs tendon healing, while its overexpression reverses the detrimental effects caused by CTHRC1 deficiency. Mechanistically, proteomics on TSPC stimulated with recombinant CTHRC1 reveal that CTHRC1 activates the mitogen‐activated protein kinase (MAPK) signaling pathway via binding to epidermal growth factor receptor (EGFR), which in turn promotes the proliferative, migrative, and tenogenic capacities of TSPC to attenuate Achilles tendinopathy. Conversely, inhibiting EGFR reverses the tendon‐healing effect of CRHRC1. The study demonstrates that CTHRC1 can promote the proliferative, migrative, and tenogenic capacities of TSPC, ultimately facilitating tendon healing through activating the EGFR/MAPK signaling pathway. CTHRC1 holds promise as a potential intervention for tendinopathy. Tendinopathy poses a formidable challenge due to the inherent limitations of tendon regenerative capabilities post‐injury. In this study, CTHRC1 is identified as a potential effector in promoting tendon regeneration through multi‐proteomic analysis of Achilles tendon tissues in mice. The study demonstrates that CTHRC1 can promote the proliferative, migrative, and tenogenic capacities of TSPC, ultimately facilitating tendon healing through activating the EGFR/MAPK signaling pathway.

Background Tibiotalocalcaneal (TTC) arthrodesis with a retrograde intramedullary nail for severe tibiotalar and talocalcaneal arthritis has a high fusion rate; however, no studies have focused on how to handle the fibula intraoperatively to achieve better results. This study aimed to compare the efficacies of various fibular procedures. Methods We retrospectively reviewed the cases of severe tibiotalar and talocalcaneal arthritis in adults treated with TTC arthrodesis using a retrograde intramedullary nail between January 2012 and July 2017. The patients were divided into three groups according to different fibular procedures: Fibular osteotomy (FO), fibular strut (FS), and fibular preservation (FP). Functional outcomes and pain were assessed using the American Orthopedic Foot and Ankle Society (AOFAS) ankle and hindfoot score and visual analog scales (VAS), respectively. The operation time, fusion time, radiographic evaluation, and complications were also recorded. Results Fifty-eight patients with an average age of 53.2 (range, 32–69) years were enrolled in the final analysis. The numbers of patients enrolled in the three groups were 21, 19, and 18 in the FO, FS, and FP groups, respectively. The mean postoperative follow-up time was 66.0 (range, 60–78) months. All groups showed a high fusion rate (90.5% for FO, 94.7% for FS, and 94.4% for FP) and significant improvement in AOFAS ankle and hindfoot scores and VAS scores at the latest follow-up. There were no significant differences in these parameters among the three groups. The mean operation time of FS (131.3 ± 17.1 min) was longer than that of FO (119.3 ± 11.7 min) and FS (112.2 ± 12.6 min), but the fusion time was shorter (15.1 ± 2.8 weeks for FS, 17.2 ± 1.9 weeks for FO, and 16.8 ± 1.9 weeks for FP). Statistically significant differences were observed in these parameters. Conclusions TTC arthrodesis using a retrograde intramedullary nail is an effective procedure with a high rate of fusion to treat severe tibiotalar and talocalcaneal arthritis in adults; however, FSs can shorten fusion time when compared with FO and FP. Level of clinical evidence Level 3.