ABSTRACT
PURPOSE: Stress response is a common complication during extubation, mainly manifested by dramatic hemodynamic fluctuations. Transcutaneous electrical acupoint stimulation (TEAS) is widely applied in the perioperative period. We performed this meta-analysis to evaluate whether the TEAS could relieve the stress response during extubation in noncardiac surgery patients. DESIGN: A systematic review and meta-analysis of randomized controlled trials. METHODS: We searched six databases (PubMed, Web of Science, Embase, Cochrane Library, China National Knowledge Infrastructure, CNKI, and Wan Fang) for relevant literature. A risk of bias assessment was executed based on the Cochrane Criteria. We applied RevMan5.4.1 software to analyze data. When the χ2 test did not show heterogeneity, we adopted the fixed-effect model. Otherwise, the random-effect model was used. FINDINGS: ln total, 12 randomized controlled trials with 1,347 participants were enrolled in this meta-analysis. Meta-analysis showed the heart rate and mean arterial pressure of the intervention group were significantly lower than the control group at immediately, 5 minutes, and 10 minutes after extubation. The occurrence rate of emergency agitation (RR 0.39, 95% CI [0.26,0.60]) and postoperative delirium (RR 0.40, 95% CI [0.22, 0.72] were also lower in the TEAS group. The consumption of propofol (standardized mean difference (SMD) 0.47, 95% CI [-0.77, -0.18]) and remifentanil (SMD 1.49, 95% CI [-2.01, -0.96]) of the intervention group were also significantly reduced compared with the control group. CONCLUSIONS: TEAS was beneficial for improving stress response during extubation, emergence agitation, postoperative delirium, and reduced the consumption of intraoperative propofol and remifentanil, but it was necessary to note the limitations of the current evidence.
ABSTRACT
In this paper, we present a novel cooperative scheme of joint optimal resource allocation, such that the overall performance of the coexisting radar-communications (CRC) system can be improved. In our proposed scheme, target detection and multiuser communication are performed by radar and communication subsystems at the same time, as well as a control center, which is responsible for joint resource management. We aim to minimize the ISLR for target detection and maximize the sum-rate for communications simultaneously by jointly optimizing the band assignment and transmit power allocation. Since the resulting optimization problem involving two performance metrics and a binary constraint is a multiobjective nonconvex problem, a two-tier iterative decomposition (TT-ID) approach is devised to obtain the globally optimal solution. However, compared with the conventional radar signals, the autocorrelation function of the devised radar signal may still have relatively high sidelobes. In particular, when the data transmission becomes the primary purpose of the CRC system, the sidelobe performance gets worse. As a consequence, some weak targets are most likely overshadowed by the adjacent strong targets through the matched filtering at the radar receiver. To address this, a spectral estimation algorithm based on the Bayes Cauchy-Gaussian (Bayes-CG) model is employed to further reduce the range sidelobes of the matched filter output at the radar receiver according to the prior distribution of the desired autocorrelation. Finally, several numerical results are provided to show the merits of the proposed method.
ABSTRACT
Tuning the chemical composition and surface structure of electrodes is demonstrated as a feasible and effective strategy to tailor advanced catalysts for energy electrocatalysis. In this work, hierarchical palladium-silver alloy nanosheets (PdAg NS) with the thickness ~7 atoms and rich atomic defects are successfully prepared, using the carbon monoxide (CO) confinement approach. The optimized Pd7Ag3 NS/C exhibits 8.8 times higher catalytic peak current density and much better stability toward ethanol electrooxidation than Pd NS/C catalyst. The catalytic enhancement mechanism could be attributed to the synergetic effects among optimized electronic structure of Pd, novel architecture, and rich atomic defects.
ABSTRACT
Perforated ultrathin Pd nanosheets with crystalline/amorphous heterostructures are rationally synthesized to offer a large electrochemically active surface area of 172.6 m2 g-1 and deliver a 5.6 times higher apparent reaction rate in comparison to commercial Pd/C, thus offering a facile confined growth method to generate superior catalysts.
