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Thermal inertia as an integrative parameter for building performance
No full textTraditionally, the energy efficiency properties of building envelope components are prescribed world-wide using the steady-state “U-value” where the insulation capabilities rely on the thermal conductivity of construction materials only. However, the heat flow through the building envelope is also restricted by the effect of other material properties combined in the form of the thermal inertia, a widely used parameter that can be controlled in the building environment through transient-state parameters such as the cyclic transmittance “u-value”. By controlling the thermal inertia of the building envelope components key aspects of the building performance such as the building thermal, energy efficiency and fire performance can be evaluated in a holistic manner so that balanced design solutions are obtained without detriment affecting each other. Herein, it is proposed a holistic assessment method that uses a numerical model to obtain the thermal inertia of building components from their thermal insulating parameters to ultimately predict reaction-to-fire performance. The method includes a complementary thermal test to achieve reliable and realistic assessments that enable the analysis of aspects like the effect of construction imperfections. Two wall assemblies were built first to illustrate the method including the thermal test and finally to verify the method by conducting reaction-to-fire tests
Enhancing bird-mediated seed dispersal to increase rainforest regeneration in disused pasture – A restoration experiment
No full textFrugivorous birds are important seed dispersers but are infrequent visitors to pasture. Therefore, the recruitment of rainforest trees into disused pasture is often limited by dispersal. We studied potential seed sources, seed-dispersing birds, seed rain and seedling recruitment in an experimental management project that aimed to catalyse rainforest regeneration adjacent to old-growth forest in north-eastern Australia. To attract birds, nine semi-natural perches and water basins were installed in each of three 0.64 ha experimental plots, concurrent with herbicide control of pasture grasses. Despite a diverse avian seed-disperser community in the adjacent forest, only three species visited the plots. However, the presence of water increased seed deposition. Water basins collected twelve times as many native tree seeds as mesh seed traps (a 24-fold increase in seed deposition per unit area), including more large seeds (≥10 mm), and more species, especially of bird-dispersed forest trees. This was due to the large-gaped Pied Currawong (Strepera graculina) that deposited large seeds beneath the perches, when using water to regurgitate seeds. Deposition of large native forest tree seeds was also enhanced under perches positioned close to an already established tree or large shrub, highlighting an important indirect effect of pasture trees. Such pasture trees can themselves be effective regeneration nuclei, and their function improved by actions to suppress pasture growth and encourage dispersers. However, in this study, these interventions were not sufficient to fully mitigate barriers to rainforest regeneration. Although seed deposition was enhanced by the presence of water, semi-natural perches and pasture trees, recruited seedlings in the plots were not representative of the seed deposited. Instead they were dominated by a subset of small-diaspore, pioneer species. To further test the potential for semi-natural perches, water and pasture suppression to increase rainforest regeneration in disused pasture, requires testing of water source designs and carefully designed experimental restoration to examine dispersal and other regeneration barriers
Cyclic gomesin, a stable redesigned spider peptide able to enter cancer cells
No full textAnticancer chemo- and targeted therapies are limited in some cases due to strong side effects and/or drug resistance. Peptides have received renascent interest as anticancer therapeutics and are currently being considered as alternatives and/or as complementary to biologics and small-molecule drugs. Gomesin, a disulfide-rich host defense peptide expressed in the Brazilian spider Acanthoscurria gomesiana selectively targets and disrupts cancer cell membranes. In the current study, we employed a range of biophysical methodologies with model membranes and bioassays to investigate the use of a cyclic analogue of gomesin as a drug scaffold to internalize cancer cells. We found that cyclic gomesin can internalize cancer cells via endocytosis and direct membrane permeation. In addition, we designed an improved non-disruptive and non-toxic cyclic gomesin analogue by incorporating D-amino acids within the scaffold. This improved analogue retained the ability to enter cancer cells and can be used as a scaffold to deliver drugs. Efforts to investigate the internalization mechanism used by host defense peptides, and to improve their stability, potency, selectivity and ability to permeate cancer cell membranes will increase the opportunities to repurpose peptides as templates for designing alternative anticancer therapeutic leads
Hydrophobic behavior of fluorite surface in strongly alkaline solution and its application in flotation
No full textNormally fluorite was collected by fatty acid collectors at pH 5–11, rendering the surface to be hydrophobic. In this study, we found that fluorite surfaces are naturally hydrophobic at high pH without any surfactant, which is beneficial for the selective flotation separation of fluorite from calcite. In a flotation test, fluorite recovery showed a decreasing trend at alkalescent pH but increased at high pH. Sum-frequency generation spectroscopy spectrum confirmed that the orientation and hydrogen bonding structure of the water molecules are dramatically changed at fluorite/water interface. Moreover, a new signal peak, wavenumber of 3657 cm, appeared under strongly alkaline conditions; this peak is normally attributed to free OH stretching region and indicates a hydrophobic surface. Meanwhile, the results of contact angle and atomic force microscopy measurements show that the hydrophobicity obviously increases at pH 13. Therefore, the surface structure of fluorite must undergo some significant changes, which will play an important role in the flotation of fluorite
Performance evaluation of a shallow prototype versus a standard depth traditional design drifting fish-aggregating device in the equatorial eastern Pacific tuna purse-seine fishery
No full textAn at-sea experiment was undertaken to evaluate the performance of 150 shallow depth (5 m) prototype drifting fish-aggregating devices (DFADs) with rope appendages, compared to 150 standard depth (∼ 40 m) traditional design DFADs with purse-seine net appendages, in the equatorial eastern Pacific Ocean tuna purse-seine fishery, seeking a solution to reduce purse-seine fishing mortality on undesirable sizes of bigeye tuna. Following concurrent deployments of the two DFAD types along transects, the average daily drift speeds were significantly different but similar as were the drift trajectories among the two DFAD types. Based on evaluations of the time-series of acoustic data from the echo-sounder buoys attached to the shallow and standard depth DFADs, the average time before aggregation by non-tuna species was 15.3 d (range: 3.2–65.5) and 18.2 d (range: 1.1–101.2), respectively, and the average time before aggregation by tuna species was 62.2 d (range: 3.3–248.3) and 70.2 d (range: 1.5–270.5), respectively. Analyses of the catch per set data for tunas and non-tuna species, using generalized additive mixed models with Bayesian inference, indicated no significant differences in catch rates from sets on shallow and standard depth DFADs. There was a similar proportion of bigeye tuna in the catch for purse-seine sets on the shallow and standard depth DFADs
Creating a safe haven during the crisis: How organizations can achieve deep compliance with COVID-19 safety measures in the hospitality industry
No full textThe COVID-19 health crisis has engendered a set of additional health and safety regulations and procedures (e.g. social distancing) to the hospitality industry. The purpose of this paper is to explore in-depth how organizations can facilitate employees’ deep compliance with these procedures. Employing an instrumental case-study approach, we collected multi-level interview data and archival data in a small-medium sized restaurant in China. The findings reveal that employees’ deep compliance with safety procedures includes a four-stage psychological process, and this process is underpinned by both management safety practices and organizational crisis strategies. As the hospitality industry starts to exit lockdown and ramp up operations, this study offers theoretical and practical insights on how organizations in hospitality can protect the health and safety of their employees and the broader community
Modelling phenology to probe for trade-offs between frost and heat risk in lentil and faba bean
No full textExtreme temperatures at critical developmental phases reduce grain yield. Combinations of sowing date and cultivar that favour faster development reduce the likelihood of heat stress but increase the risk of frost at critical phases. Current models are unable to predict pulse yield in response to frost and heat, hence our focus on phenology. Our aim was to model phenological variation with sowing date and cultivar for lentil and faba bean against the climatic patterns of frost and heat in 45 Australian locations that spanned 29 °S-41 °S, 11−340 m.a.s.l., and 1−423 km to the coast. For both crops, modelled mean and standard deviation of time to flowering were close to actuals and mean prediction error was below 5%. Comparison of actual and modelled time to flowering returned: r = 0.89 (n = 121, P 34 °C) probabilities between 1957 and 2018 were used to estimate the date of 10 % frost probability and the date of 30 % heat probability as the boundaries of a frost-heat risk window for the critical period. Out of the 45 locations, 12 were frost-free but with risk of heat, 7 were heat-free but with risk of frost, 3 were frost- and heat-free, and 23 featured a window defined by both frost and heat boundaries. Frost variables discriminated locations more strongly than heat variables. Geographical patterns in thermal regimes emerged that were associated with latitude, altitude and continentality. Realised warming between 1957 and 2018 advanced the time to 200 °Cd after flowering and shortened the critical period in most locations, particularly in early-sown crops. Comparisons of the probability curves of frost and heat between 1957–1985 and 1986–2018 showed, with few exceptions, an asymmetry between delayed late frost (up to 44 d) and earlier heat onset (up to 11 d), with a narrowing of the frost-heat risk window from 46 to 90 d for the period 1957–1985 to 34–64 d for 1986–2018. We identified a dominant role of frost as (i) the main discriminating factor among geographically distinct locations, (ii) the main source of variation of the frost-heat window, and (iii) a putatively increased risk factor with climate change. Adaptation to frost in the critical period for yield is important for pulses despite warming trends. Increased frost tolerance can directly improve yield and indirectly contribute to reduce risk of heat and drought later in the season
Convergence of 3D printed biomimetic wound dressings and adult stem cell therapy
No full textBiomimetically designed medical-grade polycaprolactone (mPCL) dressings are 3D-printed with pore architecture and anisotropic mechanical characteristics that favor skin wound healing with reduced scarring. Melt electrowritten mPCL dressings are seeded with human gingival tissue multipotent mesenchymal stem/stromal cells and cryopreserved using a clinically approved method. The regenerative potential of fresh or frozen cell-seeded mPCL dressing is compared in a splinted full-thickness excisional wound in a rat model over six weeks. The application of 3D-printed mPCL dressings decreased wound contracture and significantly improved skin regeneration through granulation and re-epithelialization compared to control groups. Combining 3D-printed biomimetic wound dressings and precursor cell delivery enhances physiological wound closure with reduced scar tissue formation
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