Heat accumulation during femtosecond laser treatment at high repetition rate – A morphological, chemical and crystallographic characterization of self-organized structures on Ti6Al4V

This study presents a detailed characterization of self-organized nano- and microstructures on Ti6Al4V evoked by different scanning strategies and fluences with a 300 fs laser operating at a laser wavelength of 1030 nm. The resulting surface morphology was visualized via field emission scanning electron microscopy (FEG-SEM) images of the surface and cross-sections. X-ray diffraction (XRD)-analysis was performed to analyse changes in crystal structures. The chemical surface composition of the near-surface layer was determined by X-ray photoelectron spectroscopy (XPS). Results show a significant influence of heat accumulation while processing with high laser repetition rates on the formation, crystallinity and chemical composition of self-organized structures depending on the scanning strategy. The ablation with different laser scanning strategies led to varying dynamics of growth-mechanisms of self-organized structures, formation of intermetallic phases (Ti3Al), sub-oxides and oxides (Ti6O, TiO) as well as ions (Ti3+, Ti4+) in surface layer reliant on applied fluence. Furthermore, investigations revealed a heat-affected zone up to several micrometers in non-ablated material. © 2021 The Author

Prepackaged central line kits reduce procedural mistakes during central line insertion: a randomized controlled prospective trial

BACKGROUND: Central line catheter insertion is a complex procedure with a high cognitive load for novices. Providing a prepackaged all-inclusive kit is a simple measure that may reduce the cognitive load. We assessed whether the use of prepackaged all-inclusive central line insertion kits reduces procedural mistakes during central line catheter insertion by novices. METHODS: Thirty final year medical students and recently qualified physicians were randomized into two equal groups. One group used a prepackaged all-inclusive kit and the other used a standard kit containing only the central vein catheter and all other separately packaged components provided in a materials cart. The procedure was videotaped and analyzed by two blinded raters using a checklist. Both groups performed central line catheter insertion on a manikin, assisted by nursing students. RESULTS: The prepackaged kit group outperformed the standard kit group in four of the five quality indicators: procedure duration (26:26 ± 3:50 min vs. 31:27 ± 5:57 min, p = .01); major technical mistakes (3.1 ± 1.4 vs. 4.8 ± 2.6, p = .03); minor technical mistakes (5.2 ± 1.7 vs. 8.0 ± 3.2, p = .01); and correct steps (83 ± 5% vs. 75 ± 11%, p = .02). The difference for breaches of aseptic technique (1.2 ± 0.8 vs. 3.0 ± 3.6, p = .06) was not statistically significant. CONCLUSIONS: Prepackaged all-inclusive kits for novices improved the procedure quality and saved staff time resources in a controlled simulation environment. Future studies are needed to address whether central line kits also improve patient safety in hospital settings

Plastics in aquaculture: A circular economy guidebook

This report presents 25 concepts for making plastics from aquaculture more circular. The concepts are based on industry initiatives, circular business models and management principles. Furthermore, the report describes the theory behind circular economy and relevant concepts, as well as the background for plastics in aquaculture, including regulatory context.publishedVersio

Development of Highly Stable Low Ni Content Catalyst for Dry Reforming of CH4-Rich Feedstocks

Highly active and coking-resistant Ni catalysts suited for the dry reforming of CH4-rich gases (70 vol %, e. g. biogas or sour natural gas) were prepared starting from a Mg-rich Mg−Al hydrotalcite support precursor. Calcination at 1000 °C yields two phases, MgO and MgAl2O4 spinel. Complexation-deposition of Ni with citric acid on the preformed support as well as lanthanum addition yields a catalyst with remarkably low carbon accumulation over 100 h on stream attributed to both high Ni dispersion and preferred interactions of Ni with MgO on MgAl2O4. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA