Investigation into the effect of Si doping on the performance of SrFeO3-δ SOFC electrode materials

In this paper we report the successful incorporation of silicon into SrFeO3-δ perovskite materials for potential applications as electrode materials for solid oxide fuel cells. It is observed that Si doping leads to a change from a tetragonal cell (with partial ordering of oxygen vacancies) to a cubic one (with the oxygen vacancies disordered). Annealing experiments in 5% H2/95% N2 (up to 800 °C) also showed the stabilization of the cubic form for the Si-doped samples under reducing conditions, suggesting that they may be suitable for both cathode and anode applications. In contrast to the cubic cell of the reduced Si doped system, reduction of undoped SrFeO3-δ leads to the formation of a brownmillerite structure with ordered oxide ion vacancies. SrFe 0.90Si0.10O3-δ and SrFe 0.85Si0.15O3-δ were analysed by neutron powder diffraction, and the data confirmed the cubic cell, with no long range oxygen vacancy ordering. Mössbauer spectroscopy data were also recorded for SrFe0.90Si0.10O3-δ, and indicated the presence of only Fe3+ and Fe5+ (i.e. disproportionation of Fe4+ to Fe3+ and Fe5+) for such doped samples. Conductivity measurements showed an improvement in the conductivity on Si doping. Composite electrodes with 50% Ce0.9Gd0.1O 1.95 were therefore examined on dense Ce0.9Gd 0.1O1.95 pellets in two different atmospheres: air and 5% H2/95% N2. In both atmospheres an improvement in the area specific resistance (ASR) values is observed for the Si-doped samples. Thus the results show that silicon can be incorporated into SrFeO3-δ- based materials and can have a beneficial effect on the performance, making them potentially suitable for use as cathode and anode materials in symmetrical SOFCs. © 2013 The Royal Society of Chemistry.Peer Reviewe

BioCIDER: a Contextualisation InDEx for biological Resources discovery

Summary The vast, uncoordinated proliferation of bioinformatics resources (databases, software tools, training materials etc.) makes it difficult for users to find them. To facilitate their discovery, various services are being developed to collect such resources into registries. We have developed BioCIDER, which, rather like online shopping ‘recommendations’, provides a contextualization index to help identify biological resources relevant to the content of the sites in which it is embedded

A randomised controlled trial of prehabilitation in patients undergoing elective cardiac surgery

The feasibility, safety and efficacy of prehabilitation in adult patients awaiting elective cardiac surgery are unknown. A total of 180 participants undergoing elective cardiac surgery were allocated randomly to receive either standard pre-operative care or prehabilitation, consisting of pre-operative exercise and inspiratory muscle training. The primary outcome was change in six-minute walk test distance from baseline to pre-operative assessment. Secondary outcomes included change in inspiratory muscle strength (maximal inspiratory pressure); sarcopenia (handgrip strength); quality of life and compliance. Safety outcomes were pre-specified surgical and pulmonary complications and adverse events. All outcomes were assessed at baseline; at pre-operative assessment; and 6 and 12 weeks following surgery. Mean (SD) age was 64.7 (10.2) years; 33/180 (18%) were women. In total, 65/91 (71.4%) participants who were allocated to prehabilitation attended at least four of eight supervised in-hospital exercise classes; participants aged > 50 years were more likely than younger participants to attend (odds ratio (95%CI) of 4.6 (1.0–25.1)). Six-minute walk test was not significantly different between groups (mean difference (95%CI) -7.8 m (-30.6–15.0), p = 0.503) in the intention-to-treat analysis. Subgroup analyses based on tests for interaction indicated improvements in six-minute walk test distance were larger amongst sarcopenic patients in the prehabilitation group (p = 0.004). Change in maximal inspiratory pressure from baseline to all time-points was significantly greater in the prehabilitation group, with the greatest mean difference (95%CI) observed 12 weeks after surgery (10.6 cmH2O (4.6–16.6) cmH2O, p < 0.001). There were no differences in handgrip strength or quality of life up to 12 weeks after surgery. There was no significant difference in postoperative mortality (one death in each group), surgical or pulmonary complications. Of 71 pre-operative adverse events, six (8.5%) were related to prehabilitation. The combination of exercise and inspiratory muscle training in a prehabilitation intervention before cardiac surgery was not superior to standard care in improving functional exercise capacity measured by six-minute walk test distance pre-operatively. Future trials should target patients living with sarcopenia and include inspiratory muscle strength training

The Olive Ridley Project (ORP): A successful example of how to engage researchers, conservation practitioners and civil society

The Olive Ridley Project (ORP) was set up to protect sea turtles and their habitats. The project was formed in 2013, and it became a registered charity in the UK in 2016. From its inception, ORP took a multidisciplinary approach to achieve its goals. Part of its objectives, and the reason why the charity came to fruition, are related to the issue of olive ridley sea turtle (Lepidochelys olivacea) entanglement in abandoned, lost or discarded fishing gear (also known as ‘ghost gear’ or ‘ghost nets’), and the search for ghost gear and turtle entanglement ‘hot spots’ throughout the Indian Ocean. The initial ORP research questions were soon challenged by societal interests to develop inclusive educational programmes in local communities and tourist resorts that could raise awareness about the need for conservation of all sea turtle species. In February 2017, ORP opened the first veterinarian-run, fully equipped Marine Turtle Rescue Centre in the Maldives, bringing together the work of researchers, citizen scientists, volunteers, environmentalists, marine biologists and veterinarians. The present work of ORP sits on a strong and scientifically robust collaborative plan. Current ORP research projects range from sea turtle population analyses, spatial ecology, rehabilitation of injured and sick individuals, epibiont parasite analyses, precise turtle identification through photo-ID research, linking ghost gear to responsible fisheries, and analyses of ghost gear drift patterns. The programme enhances community education and outreach by engaging schoolchildren, organizing workshops, promoting sustainable use of ghost gear waste, and training citizen scientists and local fishing communities. The ORP programme encompasses many principles of research engagement, effectively combining scientific knowledge, education and action. This article explores all stages of the process (from research planning and design, to knowledge exchange and inter- and trans-disciplinary impact assessments), describing the active engagement originated by the ORP initiative. A reflective insight into the learning, enrichment and challenges of engaging researchers and community actors is also included, considering the current social and scientific framework

Carreau fluid in a wall driven corner flow

Taylor’s classical paint scraping problem provides a framework for analyzing wall-driven corner flow induced by the movement of an oblique plane with a fixed velocity U. A study of the dynamics of the inertialess limit of a Carreau fluid in such a system is presented. New perturbation results are obtained both close to, and far from, the corner. When the distance from the corner r is much larger than UΓ , where Γ is the relaxation time, a loss of uniformity arises in the solution near the region, where the shear rate becomes zero due to the presence of the two walls. We derive a new boundary layer equation and find two regions of widths r−nr−n and r−2,r−2, where r is the distance from the corner and n is the power-law index, where a change in behavior occurs. The shear rate is found to be proportional to the perpendicular distance from the line of zero shear. The point of zero shear moves in the layer of size r−2r−2. We also find that Carreau effects in the far-field are important for corner angles less than 2.2 rad

Ergonomics and sustainability: Towards and embrace of complexity and emergence

Technology offers a promising route to a sustainable future, and ergonomics can serve a vital role. The argument of this article is that the lasting success of sustainability initiatives in ergonomics hinges on an examination of ergonomics' own epistemology and ethics. The epistemology of ergonomics is fundamentally empiricist and positivist. This places practical constraints on its ability to address important issues such as sustainability, emergence and complexity. The implicit ethical position of ergonomics is one of neutrality, and its positivist epistemology generally puts value-laden questions outside the parameters of what it sees as scientific practice. We argue, by contrast, that a discipline that deals with both technology and human beings cannot avoid engaging with questions of complexity and emergence and seeking innovative ways of addressing these issues.No Full Tex

A Phenomenological Analysis of Gluon Mass Effects in Inclusive Radiative Decays of the J/ψ\rm{J/\psi} and $\Upsilon

The shapes of the inclusive photon spectra in the processes \Jp \to \gamma X and \Up \to \gamma X have been analysed using all available experimental data. Relativistic, higher order QCD and gluon mass corrections were taken into account in the fitted functions. Only on including the gluon mass corrections, were consistent and acceptable fits obtained. Values of $0.721^{+0.016}_{-0.068}$ GeV and $1.18^{+0.09}_{-0.29}$ GeV were found for the effective gluon masses (corresponding to Born level diagrams) for the \Jp and \Up respectively. The width ratios \Gamma(V \to {\rm hadrons})/\Gamma(V \to \gamma+ {\rm hadrons}) V=\Jp, \Up were used to determine $\alpha_s(1.5 {\rm GeV})$ and $\alpha_s(4.9 {\rm GeV})$. Values consistent with the current world average $\alpha_s$ were obtained only when gluon mass correction factors, calculated using the fitted values of the effective gluon mass, were applied. A gluon mass $\simeq 1$ GeV, as suggested with these results, is consistent with previous analytical theoretical calculations and independent phenomenological estimates, as well as with a recent, more accurate, lattice calculation of the gluon propagator in the infra-red region.Comment: 50 pages, 11 figures, 15 table

Discrete cilia modelling with singularity distributions

We discuss in detail techniques for modelling flows due to finite and infinite arrays of beating cilia. An efficient technique, based on concepts from previous ‘singularity models’ is described, that is accurate in both near and far-fields. Cilia are modelled as curved slender ellipsoidal bodies by distributing Stokeslet and potential source dipole singularities along their centrelines, leading to an integral equation that can be solved using a simple and efficient discretisation. The computed velocity on the cilium surface is found to compare favourably with the boundary condition. We then present results for two topics of current interest in biology. 1) We present the first theoretical results showing the mechanism by which rotating embryonic nodal cilia produce a leftward flow by a ‘posterior tilt,’ and track particle motion in an array of three simulated nodal cilia. We find that, contrary to recent suggestions, there is no continuous layer of negative fluid transport close to the ciliated boundary. The mean leftward particle transport is found to be just over 1 μm/s, within experimentally measured ranges. We also discuss the accuracy of models that represent the action of cilia by steady rotlet arrays, in particular, confirming the importance of image systems in the boundary in establishing the far-field fluid transport. Future modelling may lead to understanding of the mechanisms by which morphogen gradients or mechanosensing cilia convert a directional flow to asymmetric gene expression. 2) We develop a more complex and detailed model of flow patterns in the periciliary layer of the airway surface liquid. Our results confirm that shear flow of the mucous layer drives a significant volume of periciliary liquid in the direction of mucus transport even during the recovery stroke of the cilia. Finally, we discuss the advantages and disadvantages of the singularity technique and outline future theoretical and experimental developments required to apply this technique to various other biological problems, particularly in the reproductive system

Lack of clinical AIDS in SIV-infected sooty mangabeys with significant CD4+ T cell loss is associated with double-negative T cells

SIV infection of natural host species such as sooty mangabeys results in high viral replication without clinical signs of simian AIDS. Studying such infections is useful for identifying immunologic parameters that lead to AIDS in HIV-infected patients. Here we have demonstrated that acute, SIV-induced CD4+ T cell depletion in sooty mangabeys does not result in immune dysfunction and progression to simian AIDS and that a population of CD3 +CD4-CD8- T cells (double-negative T cells) partially compensates for CD4+ T cell function in these animals. Passaging plasma from an SIV-infected sooty mangabey with very few CD4 + T cells to SIV-negative animals resulted in rapid loss of CD4 + T cells. Nonetheless, all sooty mangabeys generated SIV-specific antibody and T cell responses and maintained normal levels of plasma lipopolysaccharide. Moreover, all CD4- low sooty mangabeys elicited a de novo immune response following influenza vaccination. Such preserved immune responses as well as the low levels of immune activation observed in these animals were associated with the presence of double-negative T cells capable of producing Th1, Th2, and Th17 cytokines. These studies indicate that SIV-infected sooty mangabeys do not appear to rely entirely on CD4+ T cells to maintain immunity and identify double-negative T cells as a potential subset of cells capable of performing CD4+ T cell-like helper functions upon SIV-induced CD4+ T cell depletion in this species