Laser Melting of Prefabrication AlOOH-Activated Film on the Surface of Nodular Cast Iron and Its Associated Properties.

This study aimed to improve the absorption rate of laser energy on the surface of nodular cast iron and further improve its thermal stability and wear resistance. After a 0.3 mm thick AlOOH activation film was pre-sprayed onto the polished surface of the nodular cast iron, a GWLASER 6 kw fiber laser cladding system was used to prepare a mixed dense oxide layer mainly composed of Al2O3, Fe3O4, and SiO2 using the optimal laser melting parameters of 470 W (laser power) and 5.5 mm/s (scanning speed). By comparing and characterizing the prefabricated laser-melted surface, the laser-remelted surface with the same parameters, and the substrate surface, it was found that there was little difference in the structure, composition, and performance between the laser-remelted surface and the substrate surface except for the morphology. The morphology, structure, and performance of the laser-melted surface underwent significant changes, with a stable surface line roughness of 0.9 µm and a 300-400 µm deep heat-affected zone. It could undergo two 1100 °C thermal shock cycles; its average microhardness increased by more than one compared to the remelted and substrate surfaces of 300 HV, with a maximum hardness of 900 HV; and the average friction coefficient and wear quantity decreased to 0.4370 and 0.001 g, respectively. The prefabricated activated film layer greatly improved the thermal stability and wear resistance of the nodular cast iron surface while reducing the laser melting power.

Expression of CPEB1 gene affects the cycle of ovarian granulosa cells from adult and young goats

Background: CPEB is considered as an RNA-binding protein first identified in Xenopus oocytes. Although CPEB1 was involved in the growth of oocyte, its role in goat follicular granulosa cell has not been fully elucidated. To clarify the functions of this gene in goat follicular granulosa cells, CPEB1-overexpressing vector and interference vector were structured and transfected into follicular granulosa cells from Jiangsu native white goats of Nantong city, Jiangsu Province, China. The expression levels of differentiation-related genes including CDK1, Cyclin B1, and C-mos were determined 24 h after administration of CPEB1 by quantitative real-time polymerase chain reaction and Western blotting methods. Results: The expression levels of CDK1, Cyclin B1, and C-mos were significantly upregulated after overexpression and significantly downregulated after interference with CPEB1. Conclusions: The CPEB1 gene expression could affect the transcription of genes related to early cleavage divisions, which provided a reference for further research on its role in the growth and maturation of oocytes.

Overexpression of CDC25C affects the cell cycle of ovarian granulosa cells from adult and young goats

Background: CDC25 is a dual-specificity phosphatase that was first identified in the yeast Schizosaccharomyces pombe as a cell cycle-defective mutant. Although CDC25 is involved in the cell cycle of ovarian granulosa cells, the CDC25 signaling pathway has not been clarified fully. To explore the role of CDC25C in the cell cycle of goat ovarian granulosa cells, a CDC25C-overexpressing vector, pCMV-HA-CDC25C, was constructed and transfected into granulosa cells from adult and young white goats from Jiangsu Nantong. RT-PCR was used to measure CDC25C, CDK1, and WEE1 gene expression levels, and flow cytometry was used to distinguish ovarian granulosa cells in different phases of the cell cycle. Progesterone and estradiol levels in transfected ovarian granulosa cells were also measured. Results: In adult goat follicular granulosa cells transfected with pCMV-HA-CDC25C, CDC25C expression increased significantly, which greatly increased the relative gene expression levels of both CDK1 and WEE1. Additionally, progesterone and estradiol levels were increased in goat follicular granulosa cells overexpressing CDC25C. And the cell cycle results showed that transfection of pCMV-HA-CDC25C leads to a higher proportion of cells in S phase compared to the no vector-transfected groups. Conclusions: The results of this study indicated that the overexpression of CDC25C may increase the gene expression levels of both WEE1 and CDK1 in S phase and accelerate the transition of cells from G1 phase to S phase.