Application of BP Artificial Neural Network in Preparation of Ni–W Graded Coatings

The internal stress difference between soft-ductile aluminum alloy substrate and hard-brittle Ni–W alloy coating will cause stress concentration, thus leading to the problem of poor bonding force. Herein, this work prepared the Ni–W graded coating on aluminum alloy matrix by the pulse electrodeposition method in order to solve the mechanical mismatch problem between substrate and coatings. More importantly, a backward propagation (BP) neural network was applied to efficiently optimize the pulse electrodeposition process of Ni–W graded coating. The SEM, EDS, XRD, Vickers hardness tester and Weighing scales are used to analyze the micromorphology, chemical element, phase composition, and micro hardness as well as oxidation weight increase, respectively. The results show that the optimal process conditions with BP neural network are as follows: the bath temperature is 30 °C, current density is 15 mA/cm2 and duty cycle is 0.3. The predicted value of the model agrees well with the experimental value curve, the relative error is minor. The maximum error is less than 3%, and the correlation coefficient is 0.9996. The Ni–W graded coating prepared by BP neural network shows good bonding with the substrate which has flat and smooth interface. The thickness of the coating is about 136 μm, which slows down the oxidation of the substrate and plays an effective role in protecting the substrate

Remote Ischemic Preconditioning Reduces Perioperative Cardiac and Renal Events in Patients Undergoing Elective Coronary Intervention: A Meta-Analysis of 11 Randomized Trials

<div><p>Background</p><p>Results from randomized controlled trials (RCT) concerning cardiac and renal effect of remote ischemic preconditioning(RIPC) in patients with stable coronary artery disease(CAD) are inconsistent. The aim of this study was to explore whether RIPC reduce cardiac and renal events after elective percutaneous coronary intervention (PCI).</p><p>Methods and Results</p><p>RCTs with data on cardiac or renal effect of RIPC in PCI were searched from <i>Pubmed</i>, <i>EMBase</i>, and <i>Cochrane library</i> (up to July 2014). Meta-regression and subgroup analysis were performed to identify the potential sources of significant heterogeneity(<i>I</i>²≥40%). Eleven RCTs enrolling a total of 1713 study subjects with stable CAD were selected. Compared with controls, RIPC significantly reduced perioperative incidence of myocardial infarction (MI) [odds ratio(OR)  = 0.68; 95% CI, 0.51 to 0.91; <i>P</i> = 0.01; <i>I²</i> = 41.0%] and contrast-induced acute kidney injury(AKI) (OR = 0.61; 95% CI, 0.38 to 0.98; <i>P</i> = 0.04; <i>I²</i> = 39.0%). Meta-regression and subgroup analyses confirmed that the major source of heterogeneity for the incidence of MI was male proportion (coefficient  = −0.049; <i>P</i> = 0.047; adjusted <i>R²</i> = 0.988; <i>P</i> = 0.02 for subgroup difference).</p><p>Conclusions</p><p>The present meta-analysis of RCTs suggests that RIPC may offer cardiorenal protection by reducing the incidence of MI and AKI in patients undergoing elective PCI. Moreover, this effect on MI is more pronounced in male subjects. Future high-quality, large-scale clinical trials should focus on the long-term clinical effect of RIPC.</p></div

Summarized patient characteristics of included randomized trials.

<p>Summarized patient characteristics of included randomized trials.</p

Searching process for the eligible studies.

<p>RCT, randomized controlled trial.</p

Forest plot for the incidence of myocardial infarction (MI).

<p>RIPC significantly decreased the risk of MI [odds ratio (OR)  = 0.68, <i>P</i> = 0.01].RIPC, remote ischemic preconditioning.</p

Potential source of heterogeneity for the incidence of MI in PCI.

<p>Note: MI, myocardial infarction; Coeff., coefficient; OR, odds ratio; CI, Confidence Interval.</p><p>Potential source of heterogeneity for the incidence of MI in PCI.</p

Summarized study design of included randomized trials.

<p>Note: I/R, ischemia/reperfusion; SBP, systolic blood pressure; DBP, diastolic blood pressure; N.R, not report; RIC, remote ischemic conditioning; Ctrl, control.</p><p>Summarized study design of included randomized trials.</p

Forest plot for incidence of acute kidney injury (AKI).

<p>RIPC significantly prevented post-PCI AKI (OR = 0.61, <i>P</i> = 0.04). RIPC, remote ischemic preconditioning.</p

Meta-regression plots on the incidence of MI in PCI[Male proportion (%); coefficient = −0.049; <i>P</i> = 0.047)].

<p>Meta-regression plots on the incidence of MI in PCI[Male proportion (%); coefficient  = −0.049; <i>P</i> = 0.047)].</p