RESUMEN
Nanocrystalline (nc) metals are generally strong yet thermally unstable, rendering them difficult to process and unsuitable for use, particularly at elevated temperatures. Nc multicomponent and high-entropy alloys (HEAs) are found to offer enhanced thermal stability but only in a few empirically discovered systems out of a vast compositional space. In response, this work develops a combinatorial strategy to accelerate the discovery of nc-(TiZrHf)x(NbTa)1- x alloy library with distinct thermal stability, in terms of phases and grain sizes. Based on synchrotron X-ray diffraction and electron microscopy characterizations, a phase transition is observed from amorphous-crystalline nanocomposites to a body-centered cubic (bcc) phase upon annealing. With increased NbTa content (decreased x value), the system tends to achieve thermally stable dual bcc phases upon annealing; in contrast, alloys with increased TiZrHf content (x > 0.6) maintain a single-composition nanocomposite state, impeding crystallization and grain growth. This investigation not only broadens the understanding of thermal stability but also delves into the onset of crystallization in HEA systems.
RESUMEN
BACKGROUND: Growing evidence suggests that immunotherapy has a positive effect on non-small cell lung cancer (NSCLC) patients with brain metastases (BMs). However, it remains unclear which type of immunotherapy is more efficient. The aim of this network meta-analysis (NMA) was to compare the efficacy and safety of different immunotherapy types and determine the optimal option. METHOD: Four databases (PubMed, Cochrane Library databases, Embase, and Web of Science) and ClinicalTrial.gov were searched from inception until January 26, 2023. Randomized controlled trials (RCTs), prospective nonrandomized trials, or observational studies investigating NSCLC patients with BMs treated by immunotherapy were included. The quality of the included studies was evaluated using the Cochrane risk of bias (ROB) tool and the Newcastle-Ottawa Scale (NOS). The efficacy of immunotherapy on NSCLC patients with BMs was evaluated using frequentist random-effects NMA. RESULT: Eleven studies from 1560 citations, encompassing 1437 participants, were included in this NMA. Statistical analysis showed that pembrolizumab (SMD = 4.35, 95% CI [2.21, 6.60]) and nivolumab+ipilimumab (SMD = 3.81, 95% CI [1.21, 6.40]) could improve overall survival (OS). Pembrolizumab (SMD = 3.32, 95% CI [2.75, 3.90]) demonstrated better effects in improving the overall response rate (ORR). No significant difference in adverse event (AE) was observed between immunotherapy and chemotherapy. CONCLUSION: Our findings indicated that pembrolizumab was the most promising immunotherapy for NSCLC patients with BMs. Nivolumab+ipilimumab might be an alternative choice to improve OS. LIMITATION: Inconsistency tests were not performed because of the scarcity of direct comparison. Besides, high heterogeneity was observed in our NMA.