Xinhua Yao

Biomanufacturing is a key technology in bioengineering, driving the transformation and upgrading of the manufacturing industry. Although it can efficiently produce biomaterials, its broader application potential in modern medicine remains constrained by the lack of control in material shaping. Herein, we propose a “print-and-mineralize” strategy that integrates biofabrication and biomanufacturing to address this technical limitation. Projection-based 3D bioprinting is employed to construct precise polymer networks with bioinks encapsulating Sporosarcina pasteurii , followed by in situ microbial mineralization to endow scaffolds with bone-mimetic mechanical and biological properties. This method enables the fabrication of scaffolds with 54.06 wt% inorganic content and increases the compressive modulus from 84.80 kPa to 12.05 MPa within 5 days. The mineralized scaffolds significantly promote osteogenic differentiation of mesenchymal stem cells. Furthermore, in vivo experiments on critical-sized rat cranial defects further demonstrate improved bone regeneration. This versatile platform provides a proof-of-concept strategy for fabricating structurally complex and bioactive constructs, showing potential for advanced tissue engineering and sustainable material development.

Articular cartilage, which plays a vital role in joint structure, is susceptible to damage from trauma and degenerative joint diseases. Traditional methods

Common complications following endotracheal intubation or tracheostomy include tracheal stenosis and infection, which often exacerbate one another, complicating treatment. In this context, airway stents with stable antimicrobial properties and excellent biocompatibility emerge as an ideal therapeutic option. Silver nanoparticles (AgNPs) are renowned for their remarkable antibacterial and anti-inflammatory activities, making their incorporation into airway stent coatings a promising strategy for addressing stent-associated infections and granulation tissue proliferation. In preliminary research, a silicone airway stent coated with a Silver nanoparticles/Carbon nanotubes (AgNPs/CNTs) layer was successfully fabricated, and the present study was conducted to further evaluate its antimicrobial properties and tissue compatibility through systematic in vitro and in vivo experiments. In vitro experiments assessed its antimicrobial properties using the paper disc agar diffusion method and bacterial co-cultivation assay, with the bacteriostatic effect quantified through bacterial counting. For in vivo experiments, a New Zealand rabbit model was employed, wherein AgNPs/CNTs-coated airway stents were implanted alongside standard silicone stents. Tracheal lavage was performed at two and four weeks post-surgery, followed by colony counting. Additionally, histological evaluations were conducted to assess inflammation, granulation tissue proliferation, and collagen deposition, while confocal microscopy was used to observe and measure biofilm formation on the surface of the airway stents. The in vitro antimicrobial zone tests demonstrated that the AgNPs/CNTs coating effectively inhibited the growth of Staphylococcus aureus and Pseudomonas aeruginosa, with inhibition zones measuring 17.13 ± 1.21 mm and 13.55 ± 0.81 mm, respectively. In the bacterial co-cultivation assay, the AgNPs/CNTs group exhibited significantly fewer colony counts compared to the standard silicone group (P < 0.05). In vivo antimicrobial experiments revealed that the colony count in the AgNPs/CNTs-coated group was significantly lower than that of the standard silicone group at both the 2-week and 4-week time points (P < 0.05). Histological analysis under microscopy indicated that the AgNPs/CNTs group had significantly reduced granulation tissue thickness, inflammatory cell infiltration, and collagen deposition compared to the standard silicone group (P < 0.05). Furthermore, confocal microscopy measurements of biofilm formation revealed that the biofilm thickness on the surface of the AgNPs/CNTs-coated stents was 25.75 ± 5.93 μm, significantly lower than the 45.27 ± 12.84 μm observed on the standard silicone stents (P < 0.05). The AgNPs/CNTs-coated airway stent exhibited exceptional antimicrobial properties both in vitro and in vivo, effectively inhibiting bacterial growth, reducing bacterial colonization and biofilm formation within the airway, and significantly alleviating granulation tissue proliferation and collagen deposition. This, in turn, improved the airway microenvironment. This study provides a theoretical foundation for the clinical application of AgNPs/CNTs-coated airway stents.

The thermal characteristics of the spindle system for CNC machine tools are influenced by multiple factors which are nonlinear and time-varying. In this paper, a nonlinear time-varying thermal characteristics solving model for the spindle system was established based on the numerical solution method. Through theoretical deduction and data fitting, mathematical models of nonlinear time-varying factors including the friction torque generated by lubricants, convective heat transfer coefficient, and coolant and ambient temperature are constructed. The temperature and displacement of the spindle system at each time step are solved by considering the comprehensive effect of multiple nonlinear time-varying factors. And the actual temperature and axial deformation data of the spindle system are obtained through thermal characteristics detection experiments. By comparing solution results affected by multiple nonlinear time-varying factors and by non time-varying factors with experimental data, it can be concluded that the nonlinear time-varying thermal characteristics model has advantages in reflecting the trend of numerical changes and the accuracy of result solving over a method considering non time-varying factors and the solution values of temperature affected by multiple nonlinear time-varying factors are almost consistent with detection values and the relative errors are all within ±3%. The relative error of axial deformation between the value solved by the model and the detection value is close to −1%. This conclusion demonstrates the rationality and accuracy of the thermal characteristics solving model and the construction of nonlinear time-varying factors. This study is of great significance for exploring the thermal characteristics of the spindle system and improving CNC machine tool performance in depth.

CNC machine tools play an important role in manufacturing and are characterized by high total energy consumption and low energy efficiency. The energy consumption characteristics of the machine tool itself determine the total energy consumption and pollutant emission during its service life. Therefore, it is particularly important to design machine tools with energy consumption as the optimization target to analyze the composition of energy consumption and related characteristics, build a corresponding model based on reliability verification, guide the structural design and optimization according to the model, and ultimately use the evaluation system to evaluate and judge the overall energy consumption. In this paper, from four perspectives—the composition of the energy consumption of machine tools, modeling methods, design and optimization methods, and evaluation methods—with energy consumption optimization as the entry point, we analyze the research on CNC machine tools based on energy consumption around the world. The research results indicate that we should look forward to the role of energy consumption in the design of machine tools.

Acoustic metamaterials possess fire-new capacities to manipulate the reflected, refracted and diffracted wave wavefronts effectively and flexibly through designing special artificial structures. In this paper, a transmission-type phase gradient metamaterials with high efficiency transmission and variations phase shift covering a full range of 2 π was reported. Capacities of manipulating transmission angle using the designed acoustic metamaterials were expected to be realized under the guidance of the generalized Snell’s law. An acoustic filtering strategy occupying the selective permeability for the desired transmitted frequency were theoretically and numerically presented. Furthermore, a multi-channel filtering strategy was also designed and demonstrated. The results verified that the devices were highly sensitive to the incidence frequency and the transmission coefficients over 0.7 can be obtained at the working frequencies. The provided devices show an overwhelming promise of applications in various situations, such as architectural acoustics, acoustic logical manipulation, noise control, ultrasound imaging and multifunctional materials.