Optimizing skyrmionium movement and stability via stray magnetic fields in trilayer nanowire constructs.

Skyrmioniums, known for their unique transport and regulatory properties, are emerging as potential cornerstones for future data storage systems. However, the stability of skyrmionium movement faces considerable challenges due to the skyrmion Hall effect, which is induced by deformation. In response, our research introduces an innovative solution: we utilized micro-magnetic simulations to create a sandwiched trilayer nanowire structure augmented with a stray magnetic field. This combination effectively guides the skyrmionium within the ferromagnetic (FM) layer. Our empirical investigations reveal that the use of a stray magnetic field not only reduces the size of the skyrmionium but also amplifies its stability. This dual-effect proficiently mitigates the deformation of skyrmionium movement and boosts their thermal stability. We find these positive outcomes are most pronounced at a particular intensity of the stray magnetic field. Importantly, the required stray magnetic field can be generated using a heavy metal (HM1) layer of suitable thickness, rendering the practical application of this approach plausible in real-world experiments. Additionally, we analyze the functioning mechanism based on the Landau-Lifshitz-Gilbert (LLG) equation and energy variation. We also develop a deep spiking neural network (DSNN), which achieves a remarkable recognition accuracy of 97%. This achievement is realized through supervised learning via the spike timing dependent plasticity rule (STDP), considering the nanostructure as an artificial synapse device that corresponds to the electrical properties of the nanostructure. In conclusion, our study provides invaluable insights for the design of innovative information storage devices utilizing skyrmionium technology. By tackling the issues presented by the skyrmion Hall effect, we outline a feasible route for the practical application of this advanced technology. Our research, therefore, serves as a robust platform for continued investigations in this field.

Control and regulation of skyrmionic topological charge in a novel synthetic antiferromagnetic nanostructure.

Skyrmionium is a combination of a skyrmion with a topological charge (Q is +1 or -1), resulting in a magnetic configuration with a total topological charge of Q = 0. Skyrmionium has distinctive characteristics, including a slightly higher velocity, motion restricted to the middle of the track without the skyrmion Hall effect (SkHE), and absence of an acceleration phase. However, there is little stray field due to the zero net magnetization, the topological charge Q is zero due to the magnetic configuration, and detecting skyrmionium is still challenging. In the present work, we propose a novel nanostructure composed of triple nanowires with a narrow channel. It was found that the skyrmionium is converted into a DW pair or skyrmion by the concave channel. It was also found that the topological charge Q can be regulated by Ruderman-Kittel-Kasuya-Yosida (RKKY) antiferromagnetic (AFM) exchange coupling. Moreover, we analyzed the mechanism of the function based on the Landau-Lifshitz-Gilbert (LLG) equation and energy variation and constructed a deep spiking neural network (DSNN) with a recognition accuracy of 98.6% with supervised learning via the spike timing dependent plasticity rule (STDP) by considering the nanostructure as an artificial synapse device corresponding to the electrical properties of the nanostructure. These results provide the means for skyrmion-skyrmionium hybrid application and neuromorphic computing applications.

miR-5195-3p Suppresses Cell Proliferation and Induces Apoptosis by Directly Targeting NEDD9 in Osteosarcoma.

Objective: Aberrantly expressed microRNAs (miRs) have associated with the development and progression of osteosarcoma (OS). In this study, the authors aimed to investigate the biological function of miR-5195-3p and the underlying mechanisms. Methods: Quantitative real-time polymerase chain reaction analysis was performed to determine the expression of miR-5195-3p in OS tissues and cell lines. Then, two OS cell lines (MG-63 and U2OS) were transfected with miR-5195-3p mimics to obtain stably miR-5195-3p overexpression cell lines. A series of functional assays, including Cell Counting Kit-8 assay, colony formation assay, flow cytometry assay, and Hoechst staining were performed to analyze cell proliferation and apoptosis. Results: The authors first observed downregulation of miR-5195-3p in OS tissues and cell lines. A series of functional assays demonstrated that miR-5195-3p overexpression significantly attenuated OS cell proliferative activity and induced apoptosis. At a molecular level, the neural precursor cell which expressed developmentally downregulated protein 9 (NEDD9), was inversely correlated with the expression level of miR-5195-3p. Furthermore, ectopic expression of NEDD9 counteracted the antiproliferative and apoptotic effects of miR-5195-3p overexpression in OS cells. Conclusions: In summary, the miR-5195-3p/NEDD9 axis may be a promising antitumor agent for OS.