Peeling fingers in an elastic Hele-Shaw channel

Using experiments and a depth-averaged numerical model, we study instabilities of two-phase flows in a Hele-Shaw channel with an elastic upper boundary and a non-uniform cross-section prescribed by initial collapse. Experimentally, we find increasingly complex and unsteady modes of air-finger propagation as the dimensionless bubble speed, Ca, and level of collapse are increased, including pointed fingers, indented fingers and the feathered modes first identified by Cuttle et al.(J. Fluid Mech., vol. 886, 2020, A20). By introducing a measure of the viscous contribution to finger propagation, we identify a Ca threshold beyond which viscous forces are superseded by elastic effects. Quantitative prediction of this transition between 'viscous' and 'elastic' reopening regimes across levels of collapse establishes the fidelity of the numerical model. In the viscous regime, we recover the non-monotonic dependence on Ca of the finger pressure, which is characteristic of benchtop models of airway reopening. To explore the elastic regime numerically, we extend the depth-averaged model introduced by Fontana et al. (J. Fluid Mech., vol. 916, 2021, A27) to include an artificial disjoining pressure which prevents the unphysical self-intersection of the interface. Using time simulations, we capture for the first time the majority of experimental finger dynamics, including feathered modes. We show that these disordered states continually evolve, with no evidence of convergence to steady or periodic states. We find that the steady bifurcation structure satisfactorily predicts the bubble pressure as a function of Ca, but that it does not provide sufficient information to predict the transition to unsteady dynamics which appears strongly nonlinear.Comment: 28 pages, 15 figure

Using legume-based mixtures to enhance the nitrogen use efficiency and economic viability of cropping systems - Final report (LK09106/HGCA3447)

As costs for mineral fertilisers rise, legume-based leys are recognised as a potential alternative nitrogen source for crops. Here we demonstrate that including species-rich legume-based leys in rotations helps to maximise synergies between agricultural productivity and other ecosystem services. By using functionally diverse plant species mixtures, these services can be optimised and fine-tuned to regional and farm-specific needs. Replicated field experiments were conducted over three years at multiple locations, testing the performance of 12 legume species and 4 grass species sown in monocultures, as well as in a mixture of 10 of the legumes and all 4 grasses (called the All Species Mix, ASM). In addition, we compared this complex mixture to farmer-chosen ley mixtures on 34 sites across the UK. The trials showed that there is a large degree of functional complementarity among the legume species. No single species scored high on all evaluation criteria. In particular, the currently most frequently used species, white clover, is outscored by other legume species on a number of parameters such as early development and resistance to decomposition. Further complementarity emerged from the different responses of legume species to environmental variables, with soil pH and grazing or cutting regime being among the more important factors. For example, while large birdsfoot trefoil showed better performance on more acidic soils, the opposite was true for sainfoin, lucerne and black medic. In comparison with the monocultures, the ASM showed increased ground cover, increased above-ground biomass and reduced weed biomass. Benefits of mixing species with regard to productivity increased over time. In addition, the stability of biomass production across sites was greater in the ASM than in the legume monocultures. Within the on-farm trials, we further found that on soils low in organic matter the biomass advantage of the ASM over the Control ley was more marked than on the soils with higher organic matter content. Ecological modelling revealed that the three best multifunctional mixtures all contained black medic, lucerne and red clover. Within the long term New Farming Systems (NFS) rotational study, the use of a clover bi-crop showed improvement to soil characteristics compared to current practice (e.g. bulk density and water infiltration rate). Improvements in wheat yield were also noted with respect to the inclusion of a clover bi-crop in 2010, but there was evidence of a decline in response as the N dose was increased. Cumulatively, over both the wheat crop and the spring oilseed rape crop, the clover bi-crop improved margin over N. The highest average yield response (~9%) was associated with the ASM legume species mix cover cropping approach

Systemic long-term metabolic effects of acute non-severe paediatric burn injury

A growing body of evidence supports the concept of a systemic response to non-severe thermal trauma. This provokes an immunosuppressed state that predisposes paediatric patients to poor recovery and increased risk of secondary morbidity. In this study, to understand the long-term systemic effects of non-severe burns in children, targeted mass spectrometry assays for biogenic amines and tryptophan metabolites were performed on plasma collected from child burn patients at least three years post injury and compared to age and sex matched non-burn (healthy) controls. A panel of 12 metabolites, including urea cycle intermediates, aromatic amino acids and quinolinic acid were present in significantly higher concentrations in children with previous burn injury. Correlation analysis of metabolite levels to previously measured cytokine levels indicated the presence of multiple cytokine-metabolite associations in the burn injury participants that were absent from the healthy controls. These data suggest that there is a sustained immunometabolic imprint of non-severe burn trauma, potentially linked to long-term immune changes that may contribute to the poor long-term health outcomes observed in children after burn injury

Exploring dynamic lighting, colour and form with smart textiles

This paper addresses an ongoing research, aiming at the development of smart textiles that transform the incident light that passes through them – light transmittance – to design dynamic light without acting upon the light source. A colour and shape change prototype was developed with the objective of studying textile changes in time; to explore temperature as a dynamic variable through electrical activation of the smart materials and conductive threads integrated in the textile substrate; and to analyse the relation between textile chromic and morphologic behaviour in interaction with light. Based on the experiments conducted, results have highlighted some considerations of the dynamic parameters involved in the behaviour of thermo-responsive textiles and demonstrated design possibilities to create interactive lighting scenarios.This work is supported by FEDER funds through the Operational Programme for Competitiveness Factors – COMPETE and National Funds through FCT – Foundation for Science and Technology within the scope of the projects SFRH/BD/87196/2012, POCI-01-0145-FEDER-007136 and UID/CTM/00264. The authors also like to acknowledge Smart Textiles Design Lab for the support on the prototype development.info:eu-repo/semantics/publishedVersio

Exploring perceptions of common practices immediately following burn injuries in rural communities of Bangladesh

© 2018 The Author(s). Background: Burns can be the most devastating injuries in the world, they constitute a global public health problem and cause widespread public health concern. Every year in Bangladesh more than 365,000 people are injured by electrical, thermal and other causes of burn injuries. Among them 27,000 need hospital admission and over 5600 people die. Immediate treatment and medication has been found to be significant in the success of recovering from a burn. However, common practices used in the treatment of burn injuries in the community is not well documented in Bangladesh. This study was designed to explore the perception of local communities in Bangladesh the common practices used and health-seeking behaviors sought immediately after a burn injury has occurred. Methods: A qualitative study was conducted using Focus Group Discussions (FGD) as the data collection method. Six unions of three districts in rural Bangladesh were randomly selected and FGDs were conducted in these districts with six burn survivors and their relatives and neighbours. Data were analyzed manually, codes were identified and the grouped into themes. Results: The participants stated that burn injuries are common during the winter in Bangladesh. Inhabitants in the rural areas said that it was common practice, and correct, to apply the following to the injured area immediately after a burn: egg albumin, salty water, toothpaste, kerosene, coconut oil, cow dung or soil. Some also believed that applying water is harmful to a burn injury. Most participants did not know about any referral system for burn patients. They expressed their dissatisfaction about the lack of available health service facilities at the recommended health care centers at both the district level and above. Conclusions: In rural Bangladesh, the current first-aid practices for burn injuries are incorrect; there is a widely held belief that using water on burns is harmful

Comparing oil based ointment versus standard practice for the treatment of moderate burns in Greece: a trial based cost effectiveness evaluation

<p>Abstract</p> <p>Background</p> <p>The local treatment of burn wounds has long been a subject of debate. The objective of this study was to compare the cost and the effectiveness of Moist Exposed Burn Ointment -MEBO versus a combination of <it>povidone iodine </it>plus <it>bepanthenol </it>cream for partial thickness burns.</p> <p>Methods</p> <p>The study was carried out in the Burn Center of a state hospital in Athens, Greece. 211 patients needing conservative therapy were prospectively selected according to the depth of the burn wound. The treatment was allocated according to the Stratified Randomization Design. The outcomes measured were mean cost of in-hospital stay, rate of complications, time of 50% wound healing, pain scores, in hospital stay diminution. We have adopted a societal perspective.</p> <p>Results</p> <p>In the total groups MEBO presented lower cost, (although not significantly different: p = 0.10) and better effectiveness. The data suggest that MEBO is the dominant therapy for superficial partial burn wound with significantly lower costs and significantly higher effectiveness due to a lesser time of recovery and consequently lower time of hospitalization and follow-up. MEBO presented similar percentages of complications with the comparator, lower pain levels and smaller time of no healthy appearance of the burn limits for superficial partial thickness burns.</p> <p>Conclusions</p> <p>The data suggested that topical application of MEBO may be considered for further investigation as a potential first-line treatment modality for superficial partial thickness burns.</p> <p>Trial registration</p> <p>The trial has been registered on the International Standard Randomised Controlled Trial Number Register (ISRCTN) and given the registration number <a href="http://www.controlled-trials.com/ISRCTN74058791">ISRCTN74058791</a>.</p

Visual Coding in Locust Photoreceptors

Information capture by photoreceptors ultimately limits the quality of visual processing in the brain. Using conventional sharp microelectrodes, we studied how locust photoreceptors encode random (white-noise, WN) and naturalistic (1/f stimuli, NS) light patterns in vivo and how this coding changes with mean illumination and ambient temperature. We also examined the role of their plasma membrane in shaping voltage responses. We found that brightening or warming increase and accelerate voltage responses, but reduce noise, enabling photoreceptors to encode more information. For WN stimuli, this was accompanied by broadening of the linear frequency range. On the contrary, with NS the signaling took place within a constant bandwidth, possibly revealing a ‘preference’ for inputs with 1/f statistics. The faster signaling was caused by acceleration of the elementary phototransduction current - leading to bumps - and their distribution. The membrane linearly translated phototransduction currents into voltage responses without limiting the throughput of these messages. As the bumps reflected fast changes in membrane resistance, the data suggest that their shape is predominantly driven by fast changes in the light-gated conductance. On the other hand, the slower bump latency distribution is likely to represent slower enzymatic intracellular reactions. Furthermore, the Q10s of bump duration and latency distribution depended on light intensity. Altogether, this study suggests that biochemical constraints imposed upon signaling change continuously as locust photoreceptors adapt to environmental light and temperature conditions