To achieve non-invasive and precise prediction of mean arterial pressure (MAP) based on a fully convolutional neural network (FCNN).

A high-precision blood pressure data acquisition system compliant with international metrological standards was used in conjunction with the ‘gold standard’ auscultation method to collect blood pressure and pulse waveform data from patients. True MAP values were derived via Gaussian fitting of pulse waveform data, constructing a traceable dataset. The FCNN was applied to this dataset to develop a novel MAP prediction method. Additionally, the predictive accuracy of the FCNN was compared with linear regression and conventional empirical formulas.

The mean squared errors (MSE) for MAP prediction using the FCNN, linear regression, and empirical formulas were 19.76, 21.40, and 30.97, respectively. The coefficients of determination (R²) were 0.90, 0.89, and 0.84, and the prediction accuracies were 0.90, 0.89, and 0.85, respectively.

By using systolic blood pressure, diastolic blood pressure, age, and arm circumference as input parameters, the FCNN-based MAP prediction method significantly reduces the bias of empirical formulas. This approach not only improves the accuracy of hemodynamic boundary condition acquisition but also contributes to refining the metrological traceability system of non-invasive blood pressure measurement.

To study the hemodynamic characteristics of autologous arteriovenous fistula (AVF) and provide a theoretical basis for reducing its stenosis rate.

Bidirectional fluid-structure interaction (FSI) simulations were conducted on a modified AVF model. Flow field and wall shear stress (WSS) distributions in the internal fistula at different periods and angles in a cardiac cycle were analyzed for retrograde flow (confluence) and anterograde flow (shunt) modes in models with varying anastomosis angles.

Under confluence modes, the WSS<1 Pa area in the 60° anastomosis angle model was the smallest (7.027 mm²), while the 45°, 60°, and 90° models showed no significant differences in eddy current size and intensity. Under shunt modes, the 45° anastomosis angle model had the smallest WSS<1 Pa area (9.079 mm²), but the 60° model exhibited the lowest eddy current intensity and distribution area. In addition, the difference in the WSS<1 Pa area between the 60° and 45° models was only 2.661 mm².

Under both confluence and shunt flow modes, establishing an AVF with 60° anastomosis angle is conducive to reducing the risk of vascular stenosis in arteriovenous fistula.

To investigate the feasibility of parallel capillary bundle arrays for physiomimetic impedance modeling and establish a parametric quantification framework, thereby providing a customizable impedance characterization methodology for diverse in-vitro mock circulation researches.

Based on the parallel flow resistance and Poiseuille equation, a tube resistance element with multiple parallel-aligned capillary glass tubes was designed and fabricated. The resistance values of the capillary-bundle and a ball valve were measured through constant flow experiments analogous to electrical resistance measurement method. Moreover, a simple lumped-parameter mock circulation loop was constructed and the pressure and flow rate for each node of the loop were measured under different input flow waveforms. An 0D-Windkessel model corresponding to the experiment was developed. The impedance and compliance were adjusted to match the simulated and experimental pressure and flow waveforms. The accuracy of the capillary bundle impedance in pulsatile experiments was verified by using the computational resistance values.

The constant-flow impedance calibration experiments revealed that the capillary bundle impedance remained unaffected by flow rate variations over a wide flow range. When the capillary bundle impedance was integrated into the pulsatile circulatory system and the same impedance value obtained from the constant-flow calibration was applied in the computational model, the resulting pressure and flow waveforms showed good agreement with those measured in the pulsatile experiments. However, when the ball valves with nominally identical impedance values were inserted in the pulsatile system, the calculated impedance exhibited a two-fold difference, and significant discrepancies were observed between the simulated and experimental terminal flow waveforms.

The capillary bundle impedance maintains a constant value regardless of flow rate variations. Once the calibrated resistance value is determined through constant flow experiments, it can be directly applied to pulsatile systems. This approach can provide quantitative pulsatile flow conditions for testing various medical devices.

To design and verify an implantable dialysis port that enables the central venous catheter to no longer be placed on the body surface, and to study the effect of the central venous catheter's structural design on its performance.

The feasibility of the dialysis port was verified by flow and pressure experiments. Four representative catheter structures were analyzed by finite element method. The recirculation rate, flow rate-pressure ratio and proportion of indwelling particles were recorded, and performance differences were analyzed. An experimental platform was built to verify the simulation conclusion, and the fluid flow direction of the arteriovenous cavity was quantified by the salinity measurement method.

The dialysis port could reach the flow requirement of 300 mL/min under the 45 kPa pressure. The recirculation rate of the measured central venous catheter was between 10.7% and 23.5%, and the residual value of heparin was between 2.3% and 2.8%. The performance of the catheter with bundle mouth, positive position and side hole structure was better.

The implantable dialysis port can potentially cooperate with central venous catheters to establish a new vascular access approach. The structure of the central venous catheter should adopt the design of bundle mouth, positive position and side hole, which has better recirculation rate and heparin locking performance with low flow rate-pressure ratio. This study provides a theoretical and experimental basis for structural design and clinical selection of the central venous catheter.

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 investigate the therapeutic effects of copper-doped barium titanate (BaCuTiO₄) piezoelectric materials combined with low-intensity pulsed ultrasound (LIPUS) to activate their piezoelectric-catalytic synergistic effect for treating implant-associated infections.

BaCuTiO₄ coatings were synthesized on the surface of Ti-6Al-4V substrates using a hydrothermal method, and their surface morphology was characterized by scanning electron microscopy. The piezoelectric characteristics of the coatings were analyzed using a piezoresponse force microscope. An in vitro biofilm model of methicillin-resistant staphylococcus aureus (MRSA) was used, with barium titanate (BaTiO₃) coatings serving as the control group. Under LIPUS intervention (1.0 W/cm², 1 MHz, 10 min), the bacterial viability was assessed using colony counting to evaluate the antibacterial performance of the BaCuTiO₄ coatings. Confocal microscopy was used to observe biofilm viability in different groups, assessing the biofilm removal capability of the coatings. Reactive oxygen species (ROS) generation in each group was detected using Rhodamine b as a probe to evaluate the catalytic efficiency of the coatings in generating ROS.

Copper doping significantly reduced the piezoelectric coefficient of the coating (from 17.7 pm/V to 7.8 pm/V), bringing its piezoelectric performance closer to the requirements of natural bone tissues. Under LIPUS activation, the BaCuTiO₄ coatings increased the generation efficiency of reactive oxygen species by 67.5% and effectively disrupted and removed biofilms formed by MRSA, achieving an antibacterial rate of 90.5%.

The BaCuTiO₄ coatings achieve efficient antibacterial and biofilmclearing functions through a piezoelectric-catalytic synergistic mechanism. Their piezoelectric properties are well-matched with natural bone tissues, promoting implant osseointegration.

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.

By applying the long short-term memory (LSTM) neural network model and using lower body landmark coordinates obtained from a markerless motion capture system as inputs, to estimate ground reaction force (GRF) curves during running.

The video images and GRF data of 59 amateur runners during running were collected by the markerless motion capture system and three-dimensional (3D) force plates. The LSTM model was established, and the 3D coordinates of 11 lower body landmarks, obtained via the Theia3D markerless system, were used as inputs to estimate the 3D GRF curves during the stance of running. The estimation performance was evaluated using correlation coefficients r, root mean square error (RMSE), and normalized root mean square error (nRMSE) by comparing LSTM model estimation and force plate measurement. Statistical parametric mapping was used to analyze differences in GRF curves estimated by the LSTM model and measured by the force plate, while paired t-tests were used to assess differences in GRF characteristics between model estimation and actual measurement.

A strong correlation (r>0.85, P<0.001) and lower error (RMSE<0.3 body weight, nRMSE<15%) was found between the LSTM model estimation and actual measurements. No significant difference was found in GRF curve intervals between LSTM model estimation and actual measurements. There was no significant difference in GRF characteristics between LSTM model estimation and actual measurements (P>0.05).

Based on the LSTM model, the 3D GRF curves can be effectively estimated by lower body landmark coordinates obtained from the makerless motion capture system, thereby acquiring the highly accurate GRF characteristics. The LSTM model developed in this study can be used to monitor injury risks during running in outdoor environments.

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 investigate the risk of thoracoabdominal injuries in six-year-old child occupants in a reclined seating posture during frontal collisions, and provide a reference for developing child restraint systems (CRS).

Three validated biomechanical models of six-year-old child occupants in different seating postures with detailed anatomical structures were used. The acceleration curve from a sport utility vehicle crash test was applied to analyze the effects of seating posture on thoracic motion trajectory, chest acceleration, thoracoabdominal compression, viscous criterion (VC) of the chest and abdomen, internal organ strain, and spinal stress.

Thoracic motion trajectories varied in the Z-direction under three seating postures. As the upper torso angle increased, thoracoabdominal kinematic injury parameters showed an upward trend. The thoracic and abdominal VC under 120° and 135° posture increased by 67% and 113%, 10.7% and 25% compared with that under 105° standard sitting posture. The risk of thoracic internal organ injury was inversely related to the seating angle, while the risk of abdominal internal organ injury was positively related to the seating angle. The primary spinal injury mechanism was compression-flexion.

CRS protection evaluation should comprehensively consider thoracoabdominal kinematic parameters, internal organ biomechanics, and spinal injury risk. These findings have important implications for CRS development in intelligent driving systems and occupant protection strategy formulation.