Taizhou University

Microbial mineralization self-repair can effectively solve the problems of pores and cracks inside recycled concrete, thereby improving its mechanical properties. In order to reasonably solve the problem of bacteria’s long-term viability in the high alkaline environment of concrete, Bacillus licheniformis was selected as the mineralizing bacteria in this study, and its alkaline resistance was domesticated; at the same time, steel slag was used as the carrier material to protect the bacteria, and the addition of alumina was used to reduce the pH of the recycled concrete. In order to explore the optimal content of different additives, orthogonal tests were carried out on four factors: steel slag content, alumina content, calcium ion concentration, and urea concentration. The significance of the variables was assessed by analysis of variance (ANOVA) and analysis of range, and the optimal combination in the orthogonal test was determined using the Tukey method. The test results showed that the optimal mix design was at 10% steel slag dosing, Ca2+ concentration of 0.6 mol/L, Al2O3 dosing of 2%, and urea concentration of 0.9 mol/L, and the interactions between multiple factors were analyzed. On this basis, the repair effect and mechanical properties of recycled concrete under the optimal mix ratio are verified. Finally, the influence of Bacillus licheniformis particle-bound slag on the microstructure and micromechanical properties of recycled concrete was deeply analyzed through electron microscope scanning and nano-indentation testing, and its self-healing mechanism was revealed.

The arithmetic optimization algorithm (AOA) is a recently proposed swarm intelligence optimizer with a simple structure and few control parameters. However, the original AOA relies on a single update mechanism, which often leads to premature convergence and limited adaptability in complex optimization problems. To address these limitations, this paper proposes a multi-strategy improved arithmetic optimization algorithm (IAOA). The proposed algorithm constructs a heterogeneous strategy pool composed of six search strategies, including arithmetic update, differential evolution operators, competitive elite learning, interpolation-based acceleration, and curriculum education learning. Furthermore, an adaptive strategy regulation mechanism based on fitness improvement contribution is introduced to dynamically adjust the selection probability of each strategy. Extensive experiments conducted on the CEC2017 and CEC2022 benchmark suites demonstrate that IAOA achieves a superior optimization accuracy, convergence speed, and stability compared with several classical algorithms, recent metaheuristics, and AOA variants. Statistical tests including the Wilcoxon rank-sum test and Friedman mean rank test confirm the significance of the performance improvements. In addition, the algorithm is successfully applied to a three-dimensional path planning problem for amphibious unmanned aerial vehicles, demonstrating its effectiveness in solving complex engineering optimization problems.

GABAergic medial septal neurons play a key role in regulating hippocampus-dependent spatial memory, but the underlying mechanisms are not yet fully understood. In male mice, we establish an object-place recognition impairment model using an acute sleep deprivation protocol. Here we show that parvalbumin-positive neurons in the medial septum regulate object-location memory specificity during encoding by modulating hippocampal place cell population activity. Using in vivo electrophysiology combined with optogenetics, we characterize the role of medial septal parvalbumin-positive neurons in object-place recognition during memory encoding. Preference for objects relocated to novel positions parallels directional shifts in place fields of remapping neuronal populations, as well as decreased co-activity among place cells in dorsal CA1 during the encoding phase. Activating medial septal parvalbumin-positive neurons during memory encoding rescues object-place recognition impairments. These findings suggest that parvalbumin-positive neurons in the medial septum play a causal role in object-place recognition memory.