Fungal specificity bottlenecks during orchid germination and development.

Published versio

Open windrow composting of polymers: An investigation into the rate of degradation of polyethylene

The compostability of degradable polymers under open windrow composting conditions is explored within this paper. Areas for consideration were the use of, and impacts of, degradable polyethylene (PE) sacks on the composting process and the quality of the finished compost product. These factors were investigated through polymer weight loss over the composting process, the amount of polymer residue and chemical contaminants in the finished compost product, the windrow temperature profiles and a bioassay to establish plant growth and germination levels using the final compost product. This trial also included a comparative study of the weight loss under composting conditions of two different types of ‘degradable’ polymer sacks currently on the European market: PE and a starch based product. Statistical analysis of the windrow temperature profiles has led to the development of a model, which can help to predict the expected trends in the temperature profiles of open compost windrows where the organic waste is kerbside collected using a degradable PE sack

A Stochastic Finite Element Model for the Dynamics of Globular Macromolecules

We describe a novel coarse grained simulation method for modelling the dynamics of globular macromolecules, such as proteins. The macromolecule is treated as a viscoelastic continuum that is subject to thermal fluctuations. The model includes a non-linear treatment of elasticity and viscosity with thermal noise that is solved using finite element analysis. We have validated the method by demonstrating that the model provides average kinetic and potential energies that are in agreement with the classical equipartition theorem. In addition, we have performed Fourier analysis on the simulation trajectories obtained for a series of linear beams to confirm that the correct average energies are present in the first two Fourier bending modes. We have then used the new modelling method to simulate the thermal fluctuations of a representative protein over 500ns timescales. Using reasonable parameters for the material properties, we have demonstrated that the overall deformation of the biomolecule is consistent with the results obtained for proteins in general from atomistic molecular dynamics simulations

REPTATE rheology software: Toolkit for the analysis of theories and experiments

We present a new, free, and open source reptate (rheology of entangled polymers: toolkit for analysis of theory and experiment) software package for viewing, exchanging, and analyzing rheological and associated data. The main idea of reptate is to propose a powerful and user-friendly platform, which can be installed on the same computer as, e.g., the rheometer and which makes comparing experiments with classical, or latest, theories easy—without the need for a theoretician. The new reptate software offers full compatibility with different operating systems (Windows, Mac, and Linux). We demonstrate the use of reptate by reproducing predictions of recently published articles, from entangled, monodisperse, and polydisperse linear chains to branch-on-branch polymer systems in linear and nonlinear rheology regimes

The relationship between perfectionistic self-presentation and reactions to impairment and disability following spinal cord injury

Univariate and multivariate relationships between perfectionistic self-presentation and reactions to impairment and disability following spinal cord injury were examined. One hundred and forty-four adults with spinal cord injury (M = 48.18 years, SD = 15.96) completed self-report measures. Analyses revealed that, after controlling for time since injury and gender, perfectionistic self-presentation predicted six of eight reactions, shock, depression, and internalised anger particularly strongly. In addition, at multivariate level, perfectionistic self-presentation was positively related to non-adaptive reactions and negatively related to adaptive reactions. The findings suggest that perfectionistic self-presentation may contribute to poorer psychosocial adaptation to spinal cord injury

Modifying the pom-pom model for extensional viscosity overshoots

We have developed a variant of the pom-pom model that qualitatively describes two surprising features recently observed in filament stretching rheometer experiments of uniaxial extensional flow of industrial branched polymer resins: (i) Overshoots of the transient stress during steady flow and (ii) strongly accelerated stress relaxation upon cessation of the flow beyond the overshoot. Within the context of our model, these overshoots originate from entanglement stripping (ES) during the processes of normal chain retraction and branch point withdrawal. We demonstrate that, for a single mode, the predictions of our overshoot model are qualitatively consistent with experimental data. To provide a quantitative fit, we represent an industrial melt by a superposition of several individual modes. We show that a minimal version of our model, in which ES due to normal chain retraction is omitted, can provide a reasonable, but not perfect, fit to the data. With regard the stress relaxation after (kinematically) steady flow, we demonstrate that the differential version of tube orientation dynamics in the original pom-pom model performs anomalously. We discuss the reasons for this and suggest a suitable alternative

A is for Anthropocene:An A–Z of Design Ecology

This paper lists in A to Z format the changing ecology of design in the Anthropocene. From twenty-six points of view the paper contrasts design’s search for a coherent ecology – how it looks like it looks – with its search for a familiar ecology – how it is understood today. Taking each letter of the alphabet to create individual reviews of the vicissitudes of design, the paper critiques how design has historically explained to itself, and anyone who has been listening, what it has been doing, and contrasts that with what needs to be done

Metastable room-temperature twist-bend nematic phases via photopolymerization

The heliconical twist-bend nematic (NTB) phase is a promising candidate for novel electro-optic and photonic applications. However, the phase generally exists at elevated temperatures and across a narrow temperature interval, limiting its implementation in device fabrication, which would ideally require the liquid crystal phase to be stable at room temperature. Here we report the formation of room-temperature NTB phases by in situ photopolymerization. A complete phase diagram of the liquid crystal and monomer mixtures is presented and the nature of the polymerized samples is discussed in detail. In contrast to samples before polymerization–where the NTB phases exist at elevated temperatures and across temperature intervals of width <10 °C–all photopolymerized NTB samples are found to be stable at room temperature and exist over a temperature interval of up to 80 °C. Scanning electron microscopy of the polymerized NTB phase shows that the polymer strands assemble at an angle with respect to the direction of the helical axis. This suggests that photopolymerized NTB phases could be used to facilitate the tilt angle measurements in the twist-bend nematic phase

Fluctuating viscoelasticity based on a finite number of dumbbells

Two alternative routes are taken to derive, on the basis of the dynamics of a finite number of dumbbells, viscoelasticity in terms of a conformation tensor with fluctuations. The first route is a direct approach using stochastic calculus only, and it serves as a benchmark for the second route, which is guided by thermodynamic principles. In the latter, the Helmholtz free energy and a generalized relaxation tensor play a key role. It is shown that the results of the two routes agree only if a finite-size contribution to the Helmholtz free energy of the conformation tensor is taken into account. Using statistical mechanics, this finite-size contribution is derived explicitly in this paper for a large class of models; this contribution is non-zero whenever the number of dumbbells in the volume of observation is finite. It is noted that the generalized relaxation tensor for the conformation tensor does not need any finite-size correction

Magnetically responsive layer-by-layer microcapsules can be retained in cells and under flow conditions to promote local drug release without triggering ROS production.

Nanoengineered vehicles have the potential to deliver cargo drugs directly to disease sites, but can potentially be cleared by immune system cells or lymphatic drainage. In this study we explore the use of magnetism to hold responsive particles at a delivery site, by incorporation of superparamagnetic iron oxide nanoparticles (SPIONs) into layer-by-layer (LbL) microcapsules. Microcapsules with SPIONs were rapidly phagocytosed by cells but did not trigger cellular ROS synthesis within 24 hours of delivery nor affect cell viability. In a non-directional cell migration assay, SPION containing microcapsules significantly inhibited movement of phagocytosing cells when placed in a magnetic field. Similarly, under flow conditions, a magnetic field retained SPION containing microcapsules at a physiologic wall shear stress of 0.751 dyne cm-2. Even when the SPION content was reduced to 20%, the majority of microcapsules were still retained. Dexamethasone microcrystals were synthesised by solvent evaporation and underwent LbL encapsulation with inclusion of a SPION layer. Despite a lower iron to volume content of these structures compared to microcapsules, they were also retained under shear stress conditions and displayed prolonged release of active drug, beyond 30 hours, measured using a glucocorticoid sensitive reporter cell line generated in this study. Our observations suggest use of SPIONs for magnetic retention of LbL structures is both feasible and biocompatible and has potential application for improved local drug delivery