In this study, Cu/Ni and Cu/Al multilayer thin films with individual layer thickness varying from 25 nm to 200 nm were deposited at room temperature and further annealed up to 300 ℃. The mechanical and microstructural properties of the multilayers were characterized by nanoindentation, x-ray diffraction, and scanning electron microscopy. Both systems exhibited an increase in hardness with increasing annealing temperature. However, the Cu/Ni system showed a gradual and moderate (up to 30%) hardness increase from room temperature to 300 ℃, while the Cu/Al system showed a sharp increase (~150%) between 125℃ and 200℃. This distinct strengthening behavior is attributed to solid solution formation in Cu/Ni and diffusion-activated intermetallic formation in Cu/Al.

The development of the ovarian antral follicle is a complex, highly regulated process. Oocytes orchestrate and coordinate the development of mammalian ovarian follicles, and the rate of follicular development is governed by a developmental program intrinsic to the oocyte. Characterizing oocyte signatures during this dynamic process is critical for understanding oocyte maturation and follicular development. Although the transcriptional signature of sheep oocytes matured in vitro and preovulatory oocytes have been previously described, the transcriptional changes of oocytes in antral follicles have not. Here, we used single-cell transcriptomics (SmartSeq2) to characterize sheep oocytes from small, medium, and large antral follicles. We characterized the transcriptomic landscape of sheep oocytes during antral follicle development, identifying unique features in the transcriptional atlas, stage-specific molecular signatures, oocyte-secreted factors, and transcription factor networks. Notably, we identified specific gene and signaling pathways in each antral follicle stage that may reflect oocyte quality and in vitro maturation competency. Additionally, we discovered key biological processes that drive the transition from small to large antral follicles, revealing hub genes involved in follicle recruitment and selection. Thus, our work provides a comprehensive characterization of the single-oocyte transcriptome, filling a gap in the mapping of the molecular landscape of sheep oogenesis. We also provide key insights into the transcriptional regulation of the critical stages of antral follicular development, which is essential for understanding how the oocyte orchestrates follicular development.