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Experimental evidence shows that natural bone is piezoelectric, and bioelectric phenomena in natural bone play an essential role in bone development and bone defect repair. Piezoelectric ceramics can deform with physiological movements and consequently deliver electrical stimulation to cells or damaged tissue without the need for an external power source. They exhibit piezoelectricity and good biological properties similar to those of natural bone and have shown great potential in bone tissue engineering. This study aims to present an overview of the relationship between electrical stimulation and bone repair as well as the principle of the piezoelectric effect, emphasizing the material characteristics, research progress and application of piezoelectric ceramics in bone tissue regeneration. The limitations of piezoelectric ceramics in promoting osteogenesis by electrical stimulation were also analysed. Overall, this review comprehensively emphasized the essential characteristics of piezoelectric ceramics and pointed out the new direction for the future development of piezoelectric ceramics.

Bacterial wilt caused by Ralstonia solanacearum is one of the most important diseases in solanaceous plants, including peppers. It generally tends to be more serious under warm−temperature and moist (WM) conditions than at moist room−temperature (RM) conditions. Although immunity mechanisms at room temperature have been intensively studied, the mechanisms underlying WM conditions remain poorly understood. Herein, the pepper cysteine protease CaZingipain2 was expressed and functionally characterized in pepper immunity against R. solanacearum at WM conditions and at room temperature. The results showed that CaZingipain2 localized to the nucleus and was upregulated at the transcript level in pepper plants upon R. solanacearum infection under WM conditions (RSWM). Virus−induced gene silencing of CaZingipain2 significantly increased the susceptibility of pepper plants to RSWM, and was coupled with the downregulation of CaPRP1 and CaMgst3, which are specifically related to pepper immunity against RSWM, according to our previous studies, while its overexpression significantly reduced the susceptibility of N. benethamiana plants to RSWM compared to that of wild−type plants. In addition, our data showed that CaZingipain2 also acts positively in pepper immunity against R. solanacearum infection at room temperature by upregulating the SA− and JA−responsive PR genes, including CaNPR1 and CaDEF1. All these results indicate that CaZingipain2 improves pepper immunity against R. solanacearum under WM conditions and at room temperature by regulating different PR genes. [ABSTRACT FROM AUTHOR]

AbstractThe effective reconstruction of osteochondral biomimetic structures is a key factor in guiding the regeneration of full-thickness osteochondral defects. Due to the avascular nature of hyaline cartilage, the greatest challenge in constructing this scaffold lies in both utilizing the biomimetic structure to promote vascular differentiation for nutrient delivery to hyaline cartilage, thereby enhancing the efficiency of osteochondral reconstruction, and effectively blocking vascular ingrowth into the cartilage layer to prevent cartilage mineralization. However, the intrinsic relationship between the planning of the microporous pipe network and the flow resistance in the biomimetic structure, and the mechanism of promoting cell adhesion to achieve vascular differentiation and inhibiting cell adhesion to block the growth of blood vessels are still unclear. Inspired by the structure of tree trunks, this study designed a biomimetic tree-like tubular network structure for osteochondral scaffolds based on Murray’s law. Utilizing computational fluid dynamics, the study investigated the influence of the branching angle of micro-pores on the flow velocity, pressure distribution, and scaffold permeability within the scaffold. The results indicate that when the differentiation angle exceeds 50 degrees, the highest flow velocity occurs at the confluence of tributaries at the ninth fractal position, forming a barrier layer. This structure effectively guides vascular growth, enhances nutrient transport capacity, increases flow velocity to promote cell adhesion, and inhibits cell infiltration into the cartilage layer. [ABSTRACT FROM AUTHOR]

Numerical well testing is used mostly in oil/gas, geothermal, and coalbed methane injection/falloff well-testing interpretations while few published studies have been presented on how to adjust the models and numerical experiments parameters. Meanwhile, there is no simple and highly applicable evaluation standard on the approximation degree between the simulated and field-measured pressure response. In this paper, seven groups of numerical experiments were conducted to obtain the simulated pressure response. The Pearson correlation coefficients and the grey correlation between the simulated and field-measured pressure response were calculated to evaluate the approximation degree. In homogeneous, stress-independent, multi-layered, heterogeneous and integrated models, the simulated pressure response curves all fit to the field data well at the early and late time of the falloff period. However, the highest approximation degree was only found in the integrated model. Finally, the permeability, initial pressure, skin factor and investigation radius of the tested CBM reservoir were determined. The results show that, to obtain a reliable interpretation result, it is best to give an approximation degree evaluation standard on the approximation degree between the simulated and field-measured pressure response, build an integrated numerical model, and input the correct parameters, such as the effective thickness and the testing fluid viscosity. Otherwise, it will also drop into a pitfall of multi-results. The method we used is very relevant to CBM exploration and safe mining in Hedong coalfield. [ABSTRACT FROM AUTHOR]

The deposit morphology, microstructure, and mechanical properties of wire and arc additive manufacturing (WAAM) of ER2319 aluminium alloy with and without assisted longitudinal magnetic field (ALMF) were investigated comprehensively and comparatively in this study. The results showed that the ALMF improved the surface forming accuracy slightly, and effectively promoted the equiaxed transformation of grains. Simultaneously, the introduction of ALMF is beneficial to improving the morphology and distribution of the strengthening phase and reducing the tendency of intergranular corrosion caused by the segregation of Cu elements along the grain boundaries. Moreover, ALMF can remarkably reduce the generation rate of large pores, thereby effectively improving the tensile strength of the deposits and reducing the anisotropy of mechanical properties. [ABSTRACT FROM AUTHOR]