To elucidate the regulatory effects of titanium surface modification on the immune function of immature dendritic cells (imDCs), different crystalline nanomorphologies were constructed on titanium surface to investigate the mechanobiological response of imDCs to nanomorphologies with different crystalline phases.

Nanomorphologies with different crystalline phases were constructed on the titanium surface by anodic oxidation and calcination. The changes of the cytoskeleton F-actin, cell adhesion and morphology of imDCs cultured on nanomorphologies with different crystalline phases were observed by fluorescence staining. The relative gene expression of adhesion molecules was detected by quantitative real-time PCR. The migration behaviors of imDCs were observed using real-time live-cell imaging, and the membrane fluidity was detected by fluorescence polarization.

Nanomorphologies with different crystalline phases, namely amorphous phase, anatase and rutile, were obtained on the titanium surface by anodic oxidation and calcination. The cytoskeleton of imDCs on nanomorphologies with different crystalline phases was remodeled. The spreading area of cells on anatase crystalline phase was relatively small, which was (353.3±148.5) μm². The number of adherent cells was the largest, which was 587±132. The expression of adhesion molecules such as CD11a, integrin β2, ICAM1, and VCAM1 were also increased in cells which cultured on anatase crystalline phase. The imDCs cultured on anatase crystalline phase were equipped with strong migration ability. The accumulative migration distance was (383.6±177.7) μm, and the Euclidean migration distance was (51.82±50.13) μm. The membrane fluidity was relatively weak, and the fluorescence polarization was 0.348 5±0.041 8.

imDCs can respond to nanomorphologies with different crystalline phases on the titanium surface and exhibit different biomechanical behaviors. The results might provide a theoretical basis for the design of titanium biomaterials with immunomodulatory functions.

To explore the impact of vision impairment (VI) on the gait of hemiplegic patients, assess their walking ability and fall risks, and provide a basis for developing effective rehabilitation strategies.

Thirty hemiplegic patients were enrolled and stratified by the severity of visual acuity impairment into three groups (unimpaired, mildly impaired, and severely impaired). The gait data of patients under uncorrected vision were collected using the Qualisys motion capture system and the Kistler three-dimensional force platform, and the balance ability of patients was assessed simultaneously. Subsequently, the gait and assessment data were statistically analyzed to compare inter-group differences.

Compared with the visually unimpaired group, significant differences in step length, symmetry, and walking speed were observed in hemiplegic patients of the mild visual impairment group and severe visual impairment group. As VI increased, gait abnormalities became more pronounced, with a longer double-limb support phase, a longer swing phase of the affected limb, and a shorter single-limb support phase of the affected limb in the gait cycle. Compared with the visually unimpaired group, significant differences in center of pressure (COP) and COP symmetry were found between the mild visual impairment group and severe visual impairment group, with gait abnormalities intensifying. The Berg balance scale (BBS) scores showed that there was a significant difference between the visually unimpaired group and severe visual impairment group, indicating that the group with visual impairment had poorer balance ability.

VI has a significant negative impact on the gait and walking ability of hemiplegic patients. This study emphasizes the importance of focusing on the impact of VI in the rehabilitation of hemiplegic patients, with regular vision assessments and personalized interventions being conducted, which are of great significance in enhancing patients' walking quality.

To investigate the dynamic balance ability of healthy young adults under different obstacle-crossing strategies, thereby providing a theoretical basis for fall prevention training and public facility design.

Twenty healthy young adults participated in the experiment using F-scan plantar pressure analysis insoles. The subjects were required to cross three obstacles with different combinations of height and width. With their dominant foot serving as the leading foot and the non-dominant foot as the trailing foot, the subjects performed both lateral and forward crossing maneuvers, and their plantar pressure data were collected.

Different crossing strategies significantly affected the adjustment speed of the leading foot's center of pressure in the medial-lateral direction (COP_ML), the area of the 95% confidence circle, ML amplitude, and anterior-posterior (AP) amplitude (P<0.05). These strategies also significantly impacted the trailing foot's COP_ML adjustment speed, the area of the 95% confidence circle, and the range between the maximum and minimum swings (P<0.05). For the leading foot, during lateral and forward crossing, the balance parameter values under different heights and widths were statistically significant (P<0.05), increasing as the height and width increased. For the trailing foot, during forward crossing, the balance parameter values under different heights were statistically significant (P<0.05), increasing with height, while during lateral crossing, the differences in balance parameter values were not statistically significant (P>0.05).

Healthy young adults demonstrate better balance ability with the leading foot during forward obstacle crossing, which aligns with the movement habits of the dominant foot and daily activity patterns. The trailing foot exhibits a more stable plantar pressure distribution during lateral obstacle crossing, likely due to a larger contact area and more even center of gravity distribution.

To study how lipid bilayer fluidity modulates the interaction between β1 integrin and CD40L, as well as the formation of CD40L-mediated tumor cell contact interfaces.

Supported lipid bilayers (SLB) with different fluidities were prepared through adjusting the 1, 2-dioleoyl-sn-glycero-3-[N-(5-amino-1-carboxypentyl) iminodiacetic acid] succinyl nickel salt (DGS-NTA) content. The functionalization of lipid bilayers was achieved by anchoring fluorescently labeled CD40L molecules onto the membrane surface. The contact interface formation of PC9 cells on the functionalized lipid bilayers was observed through confocal fluorescence imaging and fluorescence recovery after photobleaching (FRAP) experiments, and data of two dimensional (2D) reaction kinetics of β1 integrin and CD40L were extracted from Zhu-Golan plots.

The diffusion coefficient of molecules in lipid bilayer was negatively correlated with DGS-NTA content. High fluidity of lipid bilayer promoted CD40L accumulation at cell contact interface and expanded the cell contact area. The 2D dissociation constants (2D K_d) of β1 integrin-CD40L complexes were approximately 13, 31 and 65 molecules/μm² for the three lipid bilayers with high, moderate and low fluidities, respectively.

High fluidity of lipid bilayers significantly facilitates diffusion and aggregation of CD40L to the cell contact interface, thus enhancing β1 integrin-CD40L interaction and the stability of cell contact interfaces.

To address the limitations of conventional physics-informed neural network (PINN) in handling hemodynamic boundary constraints, an improved hard boundary-constrained PINN (HBC-PINN) framework was proposed to achieve precise prediction of blood flow fields within stenotic arteries.

An idealized stenosed vessel geometry model was established and computational fluid dynamic simulation was performed to obtain a validation dataset. Appropriate boundary dependent trial functions were designed according to the hard constraint method to embed the flow boundary conditions into the network output. Thus, an HBC-PINN model with the hard boundary constraint method was constructed to predict the velocity field and pressure field of stenosed blood flow. Meanwhile, an original PINN model with the soft constraint method was also built for comparison. By evaluating the accuracy of the two models on the validation dataset, the capability of the HBC-PINN model to simulate hemodynamics without using any labeled data for training was verified.

The effectiveness of the HBC-PINN method in predicting hemodynamic parameters in stenosed blood flow tasks was validated. The relative L₂ errors of the flow velocity and pressure predicted by the HBC-PINN in two different stenosis scenarios were both lower than 0.5%, representing an improvement of over 48.8% in accuracy compared to the original PINN model. Additionally, the prediction accuracy of the transverse velocity also increased by more than 35.4%.

Implementing hard constraints on boundary conditions in the PINN modeling process can effectively improve the prediction accuracy of hemodynamic parameters and the efficiency of model solving.

To study the effect of medial collateral ligament (MCL) release on the squatting motion followling total knee arthroplasty (TKA) and provide reference data for ligament release during knee replacement surgery.

Based on CT and MRI images of a volunteer, a three-dimensional (3D) geometric anatomical model of the natural knee joint including bone tissues and major soft tissues was established. A finite element model of the artificial knee joint was established by simulating TKA surgery. The squatting motion after 30% release of the upper end, lower end, and both ends of the MCL was simulated, and motion characteristic data of the knee joint at flexion/extension angles from 0° to 135° were obtained.

The effects of ligament release at different locations on knee squatting motion varied. After releasing the lower end, the medial translation, posterior translation, superior translation, and adduction of the femur relative to the tibia increased by 13.74%, 3.83%, 9.74%, and 2.37%, respectively, while the external rotation decreased by 36.8%. After releasing the upper end, the medial translation and posterior translation increased by 10.65% and 10%, respectively, while the superior translation, adduction, and external rotation decreased by 4.52%, 33.89%, and 67.1%, respectively. After releasing both ends, the medial translation, posterior translation, and superior translation increased by 14.77%, 9.39%, and 22.56%, respectively, while the adduction and external rotation decreased by 15.62% and 47.3%, respectively.

After MCL released, the medial translation, anterior translation, superior translation, and abduction of the femur relative to the tibia increased, while the external rotation decreased. Releasing the lower end had the least effect on these femoral movements, showing an obvious advantage.

To analyze the fluid resistance characteristics of different drafting formations in marathon swimming using computational fluid dynamics (CFD) method, and provide theoretical guidance for selecting optimal drafting strategies in competitions and training.

Multi-swimmer models were established via three-dimensional body scanning technology, and various formation models (I-, A-, V-, L-, H-type) were created by adjusting lateral and longitudinal distances between swimmers. The ANSYS Discovery Live software was used to simulate the overall resistance of different models and the resistance of individual swimmers within formations.

The I3-type formation exhibited an overall drag reduction effect, reducing total resistance by 55.21%, whereas other formations increased overall resistance. The V-type formation showed the most significant resistance increase (31.88%). During drafting, the lowest resistance position was the rear position in the I3-type formation, while the highest resistance position was the middle position in the L-type formation. When leading, the fluid resistance of the leading swimmer in the A-type formation was significantly greater than that of an individual swimmer (P<0.05).

Longitudinal drafting formations demonstrated superior drag reduction effects, with the rear position in a three-person longitudinal arrangement showing the optimal drag reduction. Considering both tactical considerations and drag reduction effects, swimmers are advised to avoid the middle position in lateral formations.

The biological characteristics and action mechanisms underlying the excellent performance of skeletal muscles were studied through experiments to provide a scientific basis for the development of flexible actuators with performance comparable to that of skeletal muscles.

A frog skeletal muscle sample was contracted by applying electrical stimulation, and then tensile load was applied to it to analyze the relationship between the driving properties (such as contraction length and output force) of skeletal muscle and its structure from three aspects: skeletal muscle dimensions, tendon, and epimysium.

The contraction lengths of these skeletal muscle samples were approximately 28.92% and 20% under unloaded conditions and under 50% of their maximum output force, respectively. When the load on the skeletal muscles did not exceed 20% of their maximum output force, they also exhibited the property of rapid reduction (approximately 1.25 s). The active tendon increased contraction by approximately 19.68% compared with the inactive tendon, and the integrity of the epimysium protected the force transfer efficiency of skeletal muscles.

By simulating the structural and biomechanical properties of skeletal muscles, flexible actuators can achieve better driving performance, thus greatly promoting the development of bionic robots.