RESUMO
Vacuum induction melting in a refractory crucible is an economical method to produce TiAl-based alloys, aiming to reduce the preparation cost. In this paper, a Sr2CeZrO6 refractory was synthesized by a solid-state reaction method using SrCO3, CeO2 and ZrO2 as raw materials, and its interaction with TiAl alloy melt was investigated. The results showed that a single-phase Sr2CeZrO6 refractory could be fabricated at 1400 °C for 12 h, and its space group was Pnma with a = 5.9742(3) Å, b = 8.3910(5) Å and c = 5.9069(5) Å. An interaction layer with a 40µm thickness and dense structure could be observed in Sr2CeZrO6 crucible after melting TiAl alloy. Additionally, the interaction mechanism showed that the Sr2CeZrO6 refractory dissolved in the alloy melt, resulting in the generation of Sr3Zr2O7, SrAl2O4 and CeO2-x, which attached to the surface of the crucible.
RESUMO
Insulin is essential for diverse biological processes in human pluripotent stem cells (hPSCs). However, the underlying mechanism of insulin's multitasking ability remains largely unknown. Here, we show that insulin controls hPSC survival and proliferation by modulating RNA translation via distinct pathways. It activates AKT signaling to inhibit RNA translation of pro-apoptotic proteins such as NOXA/PMAIP1, thereby promoting hPSC survival. At the same time, insulin acts via the mTOR pathway to enhance another set of RNA translation for cell proliferation. Consistently, mTOR inhibition by rapamycin results in eIF4E phosphorylation and translational repression. It leads to a dormant state with sustained pluripotency but reduced cell growth. Together, our study uncovered multifaceted regulation by insulin in hPSC survival and proliferation, and highlighted RNA translation as a key step to mediate mitogenic regulation in hPSCs.