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During prophase I of meiosis, chromosomes become organized as loop arrays around the proteinaceous chromosome axis. As homologous chromosomes physically pair and recombine, the chromosome axis is integrated into the tripartite synaptonemal complex (SC) as this structure's lateral elements (LEs). While the components of the mammalian chromosome axis/LE-including meiosis-specific cohesin complexes, the axial element proteins SYCP3 and SYCP2, and the HORMA domain proteins HORMAD1 and HORMAD2-are known, the molecular organization of these components within the axis is poorly understood. Here, using expansion microscopy coupled with 2-color stochastic optical reconstruction microscopy (STORM) imaging (ExSTORM), we address these issues in mouse spermatocytes at a resolution of 10 to 20 nm. Our data show that SYCP3 and the SYCP2 C terminus, which are known to form filaments in vitro, form a compact core around which cohesin complexes, HORMADs, and the N terminus of SYCP2 are arrayed. Overall, our study provides a detailed structural view of the meiotic chromosome axis, a key organizational and regulatory component of meiotic chromosomes.

Binary transition metal sulfides have garnered widespread concentration result from their superior electrical conductivity and outstanding capacitance. However, their poor cycling stability hinders their applications in energy storage devices. The objective of this study is to devise and prepare graphene and NiCo2S4 composite (NiCo2S4@graphene) using a simple one-step hydrothermal modality. Graphene is used as a conductive substrate, and NiCo2S4 nanoparticles are formed in situ and homogeneously anchored on graphene nanosheets through C-S-C covalent bonds. For example, the NiCo2S4@graphene composite has a high specific capacitance of 918.0 C g−1 at a current density of 1 A g−1 and enhanced cycling stability (90.1% after 6000 cycles). In addition, the asymmetric supercapacitor was fabricated with NiCo2S4@graphene as the positive electrode and graphene (GR) as the negative electrode, and the device provided a maximum energy density of 49.8 Wh kg−1 at a power density of 845.3 Wh kg−1. Besides, the capacitance retention rate was as high as 92.0% after 1000 cycles. The superior electrochemical properties of the NiCo2S4@graphene material verified its huge potential for realistic applications. [ABSTRACT FROM AUTHOR]

Molybdenum dioxide (MoO2) demonstrates a big potential toward lithium‐ion storage due to its high theoretical capacity. The sluggish reaction kinetics and large volume change during cycling process, however, unavoidably lead to inferior electrochemical performance, thus failing to satisfy the requirements of practical applications. Herein, we developed a molybdenum‐based oxyacid salt confined pyrolysis strategy to achieve a novel hierarchical porous MoO2@Mo2N@C composite. A two‐step successive annealing process was proposed to obtain a hybrid phase of MoO2 and Mo2N, which was used to further improve the electrochemical performance of MoO2‐based anode. We demonstrate that the well‐dispersed MoO2 nanoparticles can ensure ample active sites exposure to the electrolyte, while conductive Mo2N quantum dots afford pseudo‐capacitive response, which conduces to the migration of ions and electrons. Additionally, the interior voids could provide buffer spaces to surmount the effect of volume change, thereby avoiding the fracture of MoO2 nanoparticles. Benefiting from the aforesaid synergies, the as‐obtained MoO2@Mo2N@C electrode demonstrates a striking initial discharge capacity (1760.0 mAh g−1 at 0.1 A g−1) and decent long‐term cycling stability (652.5 mAh g−1 at 1.0 A g−1). This work provides a new way for the construction of advanced anode materials for lithium‐ion batteries. [ABSTRACT FROM AUTHOR]