940 research outputs found

    The potential for regenerated protein fibres within a circular economy: lessons from the past can inform sustainable innovation in the textiles industry

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    Humanity is currently facing a crisis of excess, with a growing population and the trend towards disposable goods, and the world’s resources are under tremendous pressure. This is especially evident in the textiles industry, with increasing consumer numbers and the trend of ‘fast fashion’ causing demand to be at an all-time high, with non-renewable feedstocks depleting and production of natural fibres also under strain. Considering the future of textile production, it can be beneficial to investigate our past for inspiration towards more sustainable approaches. Much of the research into regenerated protein fibres was performed out of necessity during wartime, and while this demonstrates the potential for food waste to be exploited as a resource, the manufacturing methods used at the time now present issues for a circular economy due to the high amounts of toxic waste produced. Using a range of historical and modern literature sources, including journal articles, patents and conference papers, this review presents the historical precedent and research per-formed into azlons, regenerated fibres produced from waste protein-rich materials. Historical evidence shows that the success of these azlon fibres was short-lived, partly due to negative as-sociations with deprivation and hardship, alongside the emergence of alternative man-made fibres which were devoid of these connotations with never-before-seen physical properties. The social and political climate leading to the creation, and ultimate demise, of azlons is explored along with the influence of evolving technologies and the marketing of these textile products to consumers. Although the creation of products from waste is not a new concept, the literature has identified that the synergy between the challenges faced in a time of resource scarcity and the current trend of problematic excess reveals an exciting opportunity to learn from our past to create a greener future. Lessons that could help with the current crisis within the textile industry are extracted and pre-sented within the concept of a circular textiles economy. Our findings show that there is notable potential for one regenerated protein fibre, made from casein extracted from milk waste, to be manufactured within a localised, circular economy in conjunction with the principles of green chemistry and sustainable textiles technology

    Comparison of the effects of salmeterol/fluticasone propionate with fluticasone propionate on airway physiology in adults with mild persistent asthma

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    <p>Abstract</p> <p>Background</p> <p>This study compared the effect of inhaled fluticasone propionate (FP) with the combination of salmeterol/fluticasone propionate (SFC) on lung function parameters in patients with mild asthma.</p> <p>Methods</p> <p>Adult patients with mild persistent asthma (≥ 80% predicted FEV<sub>1</sub>) receiving 200–500 μg of BDP or equivalent were randomised to receive either FP 100 μg or SFC 50/100 μg twice daily from a Diskus<sup>® </sup>inhaler for four weeks. The primary outcome was the change from baseline in airway resistance (sRaw) at 12 hrs post dose measured by whole body plethysmography. Impulse oscillometry and spirometry were also performed.</p> <p>Results</p> <p>A comparison of the geometric mean sRaw at 12 hrs post dose in the SFC group to the FP group gave a ratio of 0.76 (0.66 – 0.89, p < 0.001) at week 2 and 0.81 (0.71 – 0.94, p = 0.006) at week 4. Similarly, significant results in favour of SFC for oscillometry measurements of resistance and reactance were observed. FEV<sub>1 </sub>was also significantly superior at week 2 in the SFC group (mean difference 0.16L, 95% CI; 0.03 – 0.28, p = 0.015), but not at week 4 (mean difference 0.17L, 95% CI -0.01 – 0.34, p = 0.060).</p> <p>Conclusion</p> <p>SFC is superior to FP in reducing airway resistance in mild asthmatics with near normal FEV<sub>1 </sub>values. This study provides evidence that changes in pulmonary function in patients with mild asthma are detected more sensitively by plethysmography compared to spirometry</p> <p>Trial registration number</p> <p>NCT00370591.</p

    Mapping and monitoring carbon stocks with satellite observations: a comparison of methods

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    Mapping and monitoring carbon stocks in forested regions of the world, particularly the tropics, has attracted a great deal of attention in recent years as deforestation and forest degradation account for up to 30% of anthropogenic carbon emissions, and are now included in climate change negotiations. We review the potential for satellites to measure carbon stocks, specifically aboveground biomass (AGB), and provide an overview of a range of approaches that have been developed and used to map AGB across a diverse set of conditions and geographic areas. We provide a summary of types of remote sensing measurements relevant to mapping AGB, and assess the relative merits and limitations of each. We then provide an overview of traditional techniques of mapping AGB based on ascribing field measurements to vegetation or land cover type classes, and describe the merits and limitations of those relative to recent data mining algorithms used in the context of an approach based on direct utilization of remote sensing measurements, whether optical or lidar reflectance, or radar backscatter. We conclude that while satellite remote sensing has often been discounted as inadequate for the task, attempts to map AGB without satellite imagery are insufficient. Moreover, the direct remote sensing approach provided more coherent maps of AGB relative to traditional approaches. We demonstrate this with a case study focused on continental Africa and discuss the work in the context of reducing uncertainty for carbon monitoring and markets

    Permeability during magma expansion and compaction

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    Plinian lapilli from the 1060 Common Era Glass Mountain rhyolitic eruption of Medicine Lake Volcano, California, were collected and analyzed for vesicularity and permeability. A subset of the samples were deformed at a temperature of 975°, under shear and normal stress, and postdeformation porosities and permeabilities were measured. Almost all undeformed samples fall within a narrow range of vesicularity (0.7–0.9), encompassing permeabilities between approximately 10−15 m2 and 10−10 m2. A percolation threshold of approximately 0.7 is required to fit the data by a power law, whereas a percolation threshold of approximately 0.5 is estimated by fitting connected and total vesicularity using percolation modeling. The Glass Mountain samples completely overlap with a range of explosively erupted silicic samples, and it remains unclear whether the erupting magmas became permeable at porosities of approximately 0.7 or at lower values. Sample deformation resulted in compaction and vesicle connectivity either increased or decreased. At small strains permeability of some samples increased, but at higher strains permeability decreased. Samples remain permeable down to vesicularities of less than 0.2, consistent with a potential hysteresis in permeability-porosity between expansion (vesiculation) and compaction (outgassing). We attribute this to retention of vesicle interconnectivity, albeit at reduced vesicle size, as well as bubble coalescence during shear deformation. We provide an equation that approximates the change in permeability during compaction. Based on a comparison with data from effusively erupted silicic samples, we propose that this equation can be used to model the change in permeability during compaction of effusively erupting magmas

    Impacts of large-scale climatic disturbances on the terrestrial carbon cycle

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    BACKGROUND: The amount of carbon dioxide in the atmosphere steadily increases as a consequence of anthropogenic emissions but with large interannual variability caused by the terrestrial biosphere. These variations in the CO(2 )growth rate are caused by large-scale climate anomalies but the relative contributions of vegetation growth and soil decomposition is uncertain. We use a biogeochemical model of the terrestrial biosphere to differentiate the effects of temperature and precipitation on net primary production (NPP) and heterotrophic respiration (Rh) during the two largest anomalies in atmospheric CO(2 )increase during the last 25 years. One of these, the smallest atmospheric year-to-year increase (largest land carbon uptake) in that period, was caused by global cooling in 1992/93 after the Pinatubo volcanic eruption. The other, the largest atmospheric increase on record (largest land carbon release), was caused by the strong El Niño event of 1997/98. RESULTS: We find that the LPJ model correctly simulates the magnitude of terrestrial modulation of atmospheric carbon anomalies for these two extreme disturbances. The response of soil respiration to changes in temperature and precipitation explains most of the modelled anomalous CO(2 )flux. CONCLUSION: Observed and modelled NEE anomalies are in good agreement, therefore we suggest that the temporal variability of heterotrophic respiration produced by our model is reasonably realistic. We therefore conclude that during the last 25 years the two largest disturbances of the global carbon cycle were strongly controlled by soil processes rather then the response of vegetation to these large-scale climatic events

    Performance deficits of NK1 receptor knockout mice in the 5 choice serial reaction time task: effects of d Amphetamine, stress and time of day.

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    Background The neurochemical status and hyperactivity of mice lacking functional substance P-preferring NK1 receptors (NK1R-/-) resemble abnormalities in Attention Deficit Hyperactivity Disorder (ADHD). Here we tested whether NK1R-/- mice express other core features of ADHD (impulsivity and inattentiveness) and, if so, whether they are diminished by d-amphetamine, as in ADHD. Prompted by evidence that circadian rhythms are disrupted in ADHD, we also compared the performance of mice that were trained and tested in the morning or afternoon. Methods and Results The 5-Choice Serial Reaction-Time Task (5-CSRTT) was used to evaluate the cognitive performance of NK1R-/- mice and their wildtypes. After training, animals were tested using a long (LITI) and a variable (VITI) inter-trial interval: these tests were carried out with, and without, d-amphetamine pretreatment (0.3 or 1 mg/kg i.p.). NK1R-/- mice expressed greater omissions (inattentiveness), perseveration and premature responses (impulsivity) in the 5-CSRTT. In NK1R-/- mice, perseveration in the LITI was increased by injection-stress but reduced by d-amphetamine. Omissions by NK1R-/- mice in the VITI were unaffected by d-amphetamine, but premature responses were exacerbated by this psychostimulant. Omissions in the VITI were higher, overall, in the morning than the afternoon but, in the LITI, premature responses of NK1R-/- mice were higher in the afternoon than the morning. Conclusion In addition to locomotor hyperactivity, NK1R-/- mice express inattentiveness, perseveration and impulsivity in the 5-CSRTT, thereby matching core criteria for a model of ADHD. Because d-amphetamine reduced perseveration in NK1R-/- mice, this action does not require functional NK1R. However, the lack of any improvement of omissions and premature responses in NK1R-/- mice given d-amphetamine suggests that beneficial effects of this psychostimulant in other rodent models, and ADHD patients, need functional NK1R. Finally, our results reveal experimental variables (stimulus parameters, stress and time of day) that could influence translational studies

    Complex circular subsidence structures in tephra deposited on large blocks of ice: Varða tuff cone, Öræfajökull, Iceland

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    Several broadly circular structures up to 16 m in diameter, into which higher strata have sagged and locally collapsed, are present in a tephra outcrop on southwest Öræfajökull, southern Iceland. The tephra was sourced in a nearby basaltic tuff cone at Varða. The structures have not previously been described in tuff cones, and they probably formed by the melting out of large buried blocks of ice emplaced during a preceding jökulhlaup that may have been triggered by a subglacial eruption within the Öræfajökull ice cap. They are named ice-melt subsidence structures, and they are analogous to kettle holes that are commonly found in proglacial sandurs and some lahars sourced in ice-clad volcanoes. The internal structure is better exposed in the Varða examples because of an absence of fluvial infilling and reworking, and erosion of the outcrop to reveal the deeper geometry. The ice-melt subsidence structures at Varða are a proxy for buried ice. They are the only known evidence for a subglacial eruption and associated jökulhlaup that created the ice blocks. The recognition of such structures elsewhere will be useful in reconstructing more complete regional volcanic histories as well as for identifying ice-proximal settings during palaeoenvironmental investigations

    Oxygen uptake and denitrification in soil aggregates

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    A mathematical model of oxygen uptake by bacteria in agricultural soils is presented with the goal of predicting anaerobic regions in which denitrification occurs. In an environment with a plentiful supply of oxygen, microorganisms consume oxygen through normal respiration. When the local oxygen concentration falls below a threshold level, denitrification may take place leading to the release of nitrous oxide, a potent agent for global warming. A two-dimensional model is presented in which one or more circular soil aggregates are located at a distance below the ground-level at which the prevailing oxygen concentration is prescribed. The level of denitrification is estimated by computing the area of any anaerobic cores which may develop in the interior of the aggregates. The oxygen distribution throughout the model soil is calculated first for an aggregated soil for which the ratio of the oxygen diffusivities between an aggregate and its surround is small via an asymptotic analysis. Second, the case of a non-aggregated soil featuring one or more microbial hotspots, for which the diffusion ratio is arbitrary, is examined numerically using the boundary-element method. Calculations with multiple aggregates demonstrate a sheltering effect whereby some aggregates receive less oxygen than their neighbours. In the case of an infinite regular triangular network representing an aggregated soil, it is shown that there is an optimal inter-aggregate spacing which minimises the total anaerobic core area

    The face of equipoise - delivering a structured education programme within a randomized controlled trial: qualitative study

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    Background: In trials of behavioural interventions, the individuals who deliver the intervention are in a position of key influence on the success of the trial. Their fidelity to the intervention is crucial. Yet little is understood about the experiences of this group of trial personnel. This study aimed to investigate the views and experiences of educators who delivered a structured education intervention to people with type 2 diabetes, which incorporated training in self-monitoring of either blood glucose (SMBG) or urine glucose (SMUG) as part of a randomized controlled trial (RCT). Methods: Educators’ views were explored through focus groups before and after training (N = 18) and approximately 1 year into the trial (N = 14), and semi-structured telephone interviews at approximately 2 years (N = 7). Analysis was based on the constant comparative method. Results: Educators held preferences regarding the intervention variants; thus, they were not in individual equipoise. Training raised awareness of preferences and their potential to impact on delivery. Educators were confident in their unbiased delivery, but acknowledged the challenges involved. Concealing their preferences was helped by a sense of professionalism, the patient-centred nature of the intervention, and concessions in the trial protocol (enabling participants to swap monitoring methods if needed). Commitment to unbiased delivery was explained through a desire for evidence-based knowledge in the contentious area of SMBG. Conclusions: The findings provide insight into a previously unexplored group of trial personnel - intervention deliverers in trials of behavioural interventions - which will be useful to those designing and running similar trials. Rather than individual equipoise, it is intervention deliverers’ awareness of personal preferences and their potential impact on the trial outcome that facilitates unbiased delivery. Further, awareness of community equipoise, the need for evidence, and relevance to the individual enhance commitment to the RCT
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