Formic Acid from Carbon Dioxide on Nanolayered Electrocatalyst

Formic acid is electrochemically generated from carbon dioxide (CO2) on nanolayered lead (Pb) electrode. Stepwise potential deposition method is applied to prepare nanostructured Pb, composed of particles and platelets with hexagonal and cubic crystallinities. Their electrocatalytic activities in an electroreduction of CO2 are compared. We observed higher faradaic efficiencies of 94.1% on a cubic Pb surface than that of polycrystalline Pb smooth films (52.3%) at 278 K. Analyzing the mass changes of the electrodes by electrochemical quartz crystal microbalance, the mechanistic origin of CO2 reduction is studied, and the indirect reduction of CO2 via Had atoms might be more reasonable than the direct electron transfer of CO2 molecules

Evidence based recommendations for reducing head-neck taper connection fretting corrosion in hip replacement prostheses

© 2017 Wichtig Publishing. Introduction: This systematic review seeks to summarise the published studies investigating prosthetic design, manufacture and surgical technique’s effect on fretting corrosion at the head-neck taper connection, and provide clinical recommendations to reduce its occurrence. Methods: PubMed, MEDLINE and EMBASE electronic databases were searched using the terms taper, trunnion, cone and head-neck junction. Articles investigating prosthetic design, manufacture and surgical technique’s effect on fretting corrosion were retrieved, reviewed and graded according to OCEBM levels of evidence and grades of recommendation. Results: The initial search yielded 1,224 unique articles, and 91 were included in the analysis. Conclusions: There is fair evidence to recommend against the use of high offset femoral heads, larger diameter femoral heads, and to pay particular consideration to fretting corrosion’s progression with time and risk with heavier or more active patients. Particular to metal-on-metal hip prostheses, there is fair evidence to recommend positioning the acetabular component to minimise edge loading. Particular to metal-on-polyethylene hip prostheses, there is fair evidence to recommend the use of ceramic femoral heads, against use of cast cobalt alloy femoral heads, and against use of low flexural rigidity femoral stems. Evidence related to taper connection design is largely conflicting or inconclusive. Head-neck taper connection fretting corrosion is a multifactorial problem. Strict adherence to the guidelines presented herein does not eliminate the risk. Prosthesis selection is critical, and well-controlled studies to identify each design parameter’s relative contribution to head-neck taper connection fretting corrosion are required