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Fabricating efficient oxygen evolution reaction (OER) electrocatalysts is crucial for water electrocatalysis. Herein, the spinel-type high-entropy oxides of (Co, Fe, Mn, Ni, Cr)3O4 were synthesized through the high-temperature calcination approach. The influences of calcination temperatures on structures and electrochemical properties were investigated. The optimized catalyst of HEO-900 contains the hybrid structure of regular polyhedrons and irregular nanoparticles, which is beneficial for the exposure of electrochemically active sites. It was identified that the abundant high-valence metal species of Ni3+, Co3+, Fe3+, Mn4+, and Cr3+ are formed during the OER process, which is generally regarded as the electrochemically active sites for OER. Because of the synergistic effect of multi-metal active sites, the optimized HEO-900 catalyst indicates excellent OER activity, which needs the overpotential of 366 mV to reach the current density of 10 mA cm−2. Moreover, HEO-900 reveals the prominent durability of running for 24 h at the current density of 10 mA cm−2 without clear delay. Therefore, this work supplies a promising route for preparing high-performance multi-metal OER electrocatalysts for water electrocatalysis application. [ABSTRACT FROM AUTHOR]

The dynamic characteristics of the filler are intricately linked to the stability of the subgrade. In this investigation, relying on Haoji (Haolebaoji-Ji'an, China) heavy-haul railway engineering, cyclic triaxial tests were executed to scrutinize the dynamic attributes exhibited by the 3%–5% cement-stabilized expansive soil (CSES) across a series of diverse cyclic stress, confining pressures, and frequencies. Concurrently, in situ vibration trials were undertaken to dissect the dynamic characteristics inherent to the CSES subgrade. The outcomes of cyclic triaxial tests indicate that the augmentation in both the dynamic shear strength and modulus of CSES by a factor of 2–3, coupled with an escalation of the critical dynamic stress threshold by five tosix times, is attributed to the heightened internal structural density within the CSES compared to virgin expansive soil. In identical settings, it is noteworthy that the mean critical dynamic stress threshold observed for CSES surpasses that of Group A filling by a factor of 1.5–1.7. Furthermore, the maximum critical dynamic stress exhibited by CSES achieves a 1.2-fold superiority over its lime-stabilized expansive soil (LSES). The outcomes gleaned from the in situ vibration tests elucidate that, when subjected to the passage of a high-velocity train traveling at 120 km/hr, bearing the load of 25–30 tons per axle, the subgrade surface exhibits dynamic stress ranging from 98.57 to 116.07 kPa. Meanwhile, the dynamic stress undergoes a notable escalation due to rainfall infiltration, intensifying by a factor of 1.02–1.28 times its original magnitude. The influence depth of dynamic stress extends 1.4–1.6 times beyond the designed subgrade bed thickness of 2.5 m. Notably, the critical dynamic stress of the filler surpasses the dynamic stress at the same position, underscoreing the capacity of 3%–5% CSES filling for heavy-haul railways to ensure long-term dynamic stability. [ABSTRACT FROM AUTHOR]

Background/Purpose: Delayed gastric emptying (DGE) is one of the most common complications after pancreaticoduodenectomy (PD). The aim of the present meta‐analysis was to evaluate the effect of Billroth‐II(B‐II) versus Roux‐en‐Y (R‐Y) reconstruction for gastrojejunostomy on DGE after PD. Methods: A systematic literature search was performed using the electronic database MEDLINE (via PubMed and OVID), EMBASE and Cochrane Central Register of Controlled Trials (CENTRAL) of the Cochrane Library to select pertinent randomized controlled trials (RCTs) on this topic from January 1990 to January 2020. The primary outcome was identified as postoperative DGE. Subgroup analysis was established to compare the incidence of grade B and C DGE. Software Revman 5.3 was used for the statistical analysis, summary statistics were calculated using fixed effect model or random effect model. Results: Five RCTs including a total of 612 patients were eligible for this meta‐analysis. The incidence of grade B and C DGE was significantly lower with the B‐II reconstruction than with the R‐Y reconstruction (8.0% vs. 14.8%, OR = 0.49, 95% CI: 0.26‐0.95, P = 0.03) and the B‐II reconstruction took a shorter operation time (WMD=−7.18, 95% CI: [−13.09, −1.27], P = 0,02). No statistically significant difference was found between the two reconstruction methods in terms of the incidence of postoperative pancreatic fistula (POPF), bile leak, intra‐abdominal abscess, postoperative pneumonia and the length of postoperative hospital stay. Conclusions: B‐II reconstruction after PD has a lower incidence of grade B and C DGE and shorter operation time compared with R‐Y reconstruction. [ABSTRACT FROM AUTHOR]