Single step additive manufacturing (3D printing) of electrocatalytic anodes and cathodes for efficient water splitting

We enhance the current capability of additive manufacturing (AM)/(3D printing) to produce electronic devices by presenting a facile methodology for the production of electroconductive/electrocatalytic AM polylactic acid (PLA) filaments containing electrocatalytic materials; 2D-MoSe2 (M), electro-conductive carbon (C) and 20% Pt on carbon (Pt/C). The AM printed structures/electrodes (AMEs) produced using these filaments display bespoke electrochemical signals, in this case, efficient catalysis towards the major reactions that occur within a water electrolyser, namely the hydrogen evolution reaction (HER) on the cathode and the oxygen evolution reaction (OER) on the anode without the need for any postproduction treatments. Various percentage mass incorporations, of the additives, into the PLA filaments were explored, with a 25% mass incorporation representing an ideal compromise between electroactivity and printability. Utilizing the optimized M10%–C15%-AME and Pt/C25%-AME as the cathode and anode, respectively, whilst a commercially available alkaline battery applied a potential of 1.5 V, water-splitting was achieved with obvious effervescence occurring at each electrode. This AM technique could mitigate the need for complex fabrication procedures, allowing researchers, industry and any interested individuals to rapidly go from ‘desktop designs’ to workable electrochemical prototype devices

Modulating calcium phosphate formation using CO2 laser engineering of a polymeric material

The use of simulated body fluid (SBF) is widely used as a screening technique to assess the ability of materials to promote calcium phosphate formation. This paper details the use of CO2 laser surface treatment of nylon® 6,6 to modulate calcium phosphate formation following immersion in SBF for 14 days. Through white light interferometry (WLI) it was determined that the laser surface processing gave rise to maximum Ra and Sa parameters of 1.3 and 4.4 µm, respectively. The use of X-ray photoelectron spectroscopy (XPS) enabled a maximum increase in surface oxygen content of 5.6 %at. to be identified. The laser-induced surface modifications gave rise to a modulation in the wettability characteristics such that the contact angle, θ, decreased for the whole area processed samples, as expected, and increased for the patterned samples. The increase in θ can be attributed to a transition in wetting nature to a mixed-state wetting regime. It was seen for all samples that calcium phosphate formed on each surface following 14 days. The largest increase in mass, Δg, owed to calcium phosphate formation, was brought about by the whole area processed sample irradiated with a fluence of 51 Jcm-2. No correlation between the calcium phosphate formation and the laser patterned surface properties was determined due to the likely affect of the mixed-state wetting regime. Strong correlations between θ, the surface energy parameters and the calcium phosphate formation for the whole area processed samples allow one to realize the potential for this surface treatment technique in predicting the bone forming ability of laser processed materials

Pre-hybridisation: an efficient way of suppressing endogenous biotin-binding activity inherent to biotin–streptavidin detection system

Endogenous biotin or biotinylated protein binding activity is a major drawback to biotin-avidin/streptavidin detection system. The avidin/streptavidin conjugate used to detect the complex of the biotinylated secondary antibody and the primary antibody binds to endogenous biotin or biotinylated proteins leading to non-specific signals. In Western blot, the endogenous biotin or biotinylated protein binding activity is usually manifested in the form of ~72kDa, ~75kDa and ~150kDa protein bands, which often mask the signals of interest. To overcome this problem, a method based on prior hybridisation of the biotinylated secondary antibody and the streptavidin conjugate was developed. The method was tested alongside the conventional biotin-streptavidin method on proteins extracted from zebrafish (Danio rerio) embryos. Results showed that the newly developed method efficiently suppresses the endogenous biotin or biotinylated protein binding activity inherent to the biotin-streptavidin detection system

Formic acid synthesis using CO₂ as raw material: Techno-economic and environmental evaluation and market potential

The future of carbon dioxide utilisation (CDU) processes, depend on (i) the future demand of synthesised products with CO₂, (ii) the availability of captured and anthropogenic CO₂, (iii) the overall CO₂ not emitted because of the use of the CDU process, and (iv) the economics of the plant. The current work analyses the mentioned statements through different technological, economic and environmental key performance indicators to produce formic acid from CO₂, along with their potential use and penetration in the European context. Formic acid is a well-known chemical that has potential as hydrogen carrier and as fuel for fuel cells. This work utilises process flow modelling, with simulations developed in CHEMCAD, to obtain the energy and mass balances, and the purchase equipment cost of the formic acid plant. Through a financial analysis, with the net present value as selected metric, the price of the tonne of formic acid and of CO₂ are varied to make the CDU project financially feasible. According to our research, the process saves CO₂ emissions when compared to its corresponding conventional process, under specific conditions. The success or effectiveness of the CDU process will also depend on other technologies and/or developments, like the availability of renewable electricity and steam

The effect of octopaminergic compounds on the behaviour and transmission of Gyrodactylus

Background: The high transmission potential of species belonging to the monogenean parasite genus Gyrodactylus, coupled with their high fecundity, allows them to rapidly colonise new hosts and to increase in number. One gyrodactylid, Gyrodactylus salaris Malmberg, 1957, has been responsible for devastation of Altantic salmon (Salmo salar L.) populations in a number of Norwegian rivers. Current methods of eradicating G. salaris from river systems centre around the use of non-specific biocides, such as rotenone and aluminium sulphate. Although transmission routes in gyrodactylids have been studied extensively, the behaviour of individual parasites has received little attention. Specimens of Gyrodactylus gasterostei Gläser, 1974 and G. arcuatus Bychowsky, 1933, were collected from the skin of their host, the three-spined stickleback (Gasterosteus aculeatus L.), and permitted to attach to the substrate. The movements of individual parasites were recorded and analysed. Results: The behaviour patterns of the two species were similar and parasites were more active in red light and darkness than in white light. Four octopaminergic compounds were tested and all four inhibited the movements of parasites. Treatment ultimately led to death at low concentrations (0.2 μM), although prolonged exposure was necessary in some instances. Conclusions: Octopaminergic compounds may affect the parasite's ability to locate and remain on its host and these or related compounds might provide alternative or supplementary treatments for the control of G. salaris infections. With more research there is potential for use of octopaminergic compounds, which have minimal effects on the host or its environment, as parasite-specific treatments against G. salaris infections

Cosmic-ray strangelets in the Earth's atmosphere

If strange quark matter is stable in small lumps, we expect to find such lumps, called ``strangelets'', on Earth due to a steady flux in cosmic rays. Following recent astrophysical models, we predict the strangelet flux at the top of the atmosphere, and trace the strangelets' behavior in atmospheric chemistry and circulation. We show that several strangelet species may have large abundances in the atmosphere; that they should respond favorably to laboratory-scale preconcentration techniques; and that they present promising targets for mass spectroscopy experiments.Comment: 28 pages, 4 figures, revtex

Digital signaling decouples activation probability and population heterogeneity

Digital signaling enhances robustness of cellular decisions in noisy environments, but it is unclear how digital systems transmit temporal information about a stimulus. To understand how temporal input information is encoded and decoded by the NF-κB system, we studied transcription factor dynamics and gene regulation under dose- and duration-modulated inflammatory inputs. Mathematical modeling predicted and microfluidic single-cell experiments confirmed that integral of the stimulus (or area, concentration × duration) controls the fraction of cells that activate NF-κB in the population. However, stimulus temporal profile determined NF-κB dynamics, cell-to-cell variability, and gene expression phenotype. A sustained, weak stimulation lead to heterogeneous activation and delayed timing that is transmitted to gene expression. In contrast, a transient, strong stimulus with the same area caused rapid and uniform dynamics. These results show that digital NF-κB signaling enables multidimensional control of cellular phenotype via input profile, allowing parallel and independent control of single-cell activation probability and population heterogeneity.ISSN:2050-084