RESUMO
Platinum group metal (PGM)-free catalysts represented by nitrogen and iron co-doped carbon (Fe-N-C) catalysts are desirable and critical for metal-air batteries, but challenges still exist in performance and stability. Here, cerium oxides (CeOx) are incorporated into a two-dimensional Fe-N-C catalyst (FeNC-Ce-950) via a host-guest strategy. The Ce4+/Ce3+ redox system creates a large number of oxygen vacancies for rapid O2 adsorption to accelerate the kinetics of oxygen reduction reaction (ORR). Consequently, the as-synthesized FeNC-Ce-950 catalyst exhibits a half-wave potential (E1/2) of 0.921 V and negligible decay (<2 mV for ΔE1/2) after 5,000 accelerated durability cycles, significantly outperforming most of ORR catalysts reported in recent years and precious metal counterparts. When applied in a zinc-air battery, it demonstrates a peak power density of 175 mW cm-2 and a specific capacity of 757 mAh gZn-1. This study also provides a reference for the exploration of Fe-N-C catalysts decorated with variable valence metal oxides.
RESUMO
OBJECTIVE: To evaluate the effects and safety of transperitoneal laparoscopic radical prostatectomy (TLRP) and extraperitoneal laparoscopic radical prostatectomy (ELRP) in the treatment of localized prostate cancer. METHODS: We searched the Cochrane Library, Medline, Chinese Journal Full-text Database, Wanfang and CBM for clinical controlled trials addressing TLRP and ELRP in the treatment of localized prostate cancer. Two independent reviewers extracted comparable data from eligible studies and performed meta-analysis with the Statal 2.0 software on the relevant indexes of operation time, intraoperative blood loss, postoperative catheterization, postoperative intestinal function recovery, and postoperative hospital stay. RESULTS: Nine clinical controlled trials with 942 cases were included in this analysis, 492 treated by TLRP and the other 450 by ELRP. Meta-analysis showed no statistically significant differences between the TLRP and ELRP groups in operation time (SMD = 0.60, 95% CI: -0.06,1.26), intraoperative blood loss (SMD = 0.01, 95% CI: -0.35, 0.36) , postoperative catheterization time (SMD = 0.10, 95% CI: -0.21, 0.40) and postoperative hospital stay (SMD = 0.45, 95% CI: -0.01, 0.91), except in the time of postoperative intestinal function recovery, which was significantly shorter in the ELRP than in the TLRP group (SMD = 1.18, 95% CI: 0.26, 2.10). CONCLUSION: For the treatment of localized prostate cancer, ELRP is similar to TLRP with respect to operation time, intraoperative blood loss, postoperative catheterization and postoperative hospital stay, but superior to the latter in postoperative intestinal function recovery.
