Studies of Mass and Size Effects in Three-Dimensional Vibrofluidized Granular Mixtures

We examine the steady state properties of binary systems of driven inelastic hard spheres. The spheres, which move under the influence of gravity, are contained in a vertical cylinder with a vibrating base. We computed the trajectories of the spheres using an event-driven molecular dynamics algorithm. In the first part of the study, we chose simulation parameters that match those of experiments performed by Wildman and Parker. Various properties computed from the simulation including the density profile, granular temperature and circulation pattern are in good qualitative agreement with the experiments. We then studied the effect of varying the mass ratio and the size ratio independently while holding the other parameters constant. The mass and size ratio are shown to affect the distribution of the energy. The changes in the energy distributions affect the packing fraction and temperature of each component. The temperature of the heavier component has a non-linear dependence on the mass of the lighter component, while the temperature of the lighter component is approximately proportional to its mass. The temperature of both components is inversely dependent on the size of the smaller component.Comment: 14 Pages, 12 Figures, RevTeX

Rigidity analysis of HIV-1 protease

We present a rigidity analysis on a large number of X-ray crystal structures of the enzyme HIV-1 protease using the 'pebble game' algorithm of the software FIRST. We find that although the rigidity profile remains similar across a comprehensive set of high resolution structures, the profile changes significantly in the presence of an inhibitor. Our study shows that the action of the inhibitors is to restrict the flexibility of the beta-hairpin flaps which allow access to the active site. The results are discussed in the context of full molecular dynamics simulations as well as data from NMR experiments.Comment: 4 pages, 3 figures. Conference proceedings for CMMP conference 2010 which was held at the University of Warwic

Variable temperature study of the crystal and magnetic structures of the giant magnetoresistant materials LMnAsO (L=La, Nd)

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A 3D printed drug delivery implant formed from a dynamic supramolecular polyurethane formulation

Using a novel molecular design approach, we have prepared a thermo-responsive supramolecular polyurethane as a matrix material for use in drug eluting implants. The dynamic supramolecular polyurethane (SPU) is able to self-assemble through hydrogen bonding and π-π stacking interactions, resulting in an addressable polymer network with a relatively low processing temperature. The mechanical properties of the SPU demonstrated the material was self-supporting, stiff, yet flexible thus making it suitable for hot-melt extrusion processing, inclusive of related 3D printing approaches. Cell-based toxicity assays revealed the SPU to be non-toxic and therefore a viable candidate as a biocompatible polymer for implant applications. To this end, the SPU was formulated with paracetamol (16 %w/w) and 4 wt% or 8 wt% poly(ethylene glycol) (PEG) as an excipient and hot melt extruded at 100 °C to afford a 3D printed prototype implant to explore the extended drug release required for an implant and the potential manipulation of the release profile. Furthermore, rheological, infra-red spectroscopy, powder X-ray diffraction and scanning electron microscopy studies revealed the chemical and physical properties and compatibility of the formulation components. Successful release of paracetamol was achieved from in vitro dissolution studies and it was predicted that the drug would be released over a period of up to 8.5 months with hydrophilic PEG being able to influence the release rate. This extended release time is consistent with applications of this novel dynamic polymer as a drug eluting implant matrix

226 A work load study to determine the proportion of time spent on delivering rescue vs. prevention clinical care in adults with cystic fibrosis

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Urinary ATP and visualization of intracellular bacteria: a superior diagnostic marker for recurrent UTI in renal transplant recipients?

Renal transplant recipients (RTR) are highly susceptible to urinary tract infections (UTIs) with over 50% of patients having at least one UTI within the first year. Yet it is generally acknowledged that there is considerable insensitivity and inaccuracy in routine urinalysis when screening for UTIs. Thus a large number of transplant patients with genuine urine infections may go undiagnosed and develop chronic recalcitrant infections, which can be associated with graft loss and morbidity. Given a recent study demonstrating ATP is released by urothelial cells in response to bacteria exposure, possibly acting at metabotropic P2Y receptors mediating a proinflammatory response, we have investigated alternative, and possibly more appropriate, urinalysis techniques in a cohort of RTRs.Mid-stream urine (MSU) samples were collected from 53 outpatient RTRs. Conventional leukocyte esterase and nitrite dipstick tests, and microscopic pyuria counts (in 1 ?l), ATP concentration measurements, and identification of intracellular bacteria in shed urothelial cells, were performed on fresh unspun samples and compared to ‘gold-standard’ bacterial culture results.Of the 53 RTRs, 22% were deemed to have a UTI by ‘gold-standard’ conventional bacteria culture, whereas 87%, 8% and 4% showed evidence of UTIs according to leukocyte esterase dipstick, nitrite dipstick, and a combination of both dipsticks, respectively. Intracellular bacteria were visualized in shed urothelial cells of 44% of RTRs, however only 1 of the 23 RTRs (44%) was deemed to have a UTI by conventional bacteria culture. A significant association of the ‘gold-standard’ test with urinary ATP concentration combined with visualization of intracellular bacteria in shed urothelial cells was determined using the Fisher’s exact test.It is apparent that standard bedside tests for UTIs give variable results and that seemingly quiescent bacteria in urothelial cells are very common in RTRs and may represent a focus of subclinical infection. Furthermore, our results suggest urinary ATP concentration combined with detection of intracellular bacteria in shed urinary epithelial cells may be a sensitive means by which to detect ‘occult’ infection in RTRs

The suppression of CMR in Nd(Mn1−xCox)AsO0.95F0.05

This research is supported by the EPSRC (research grant EP/L002493/1). We also acknowledge the UK Science and Technology Facilities Council (STFC) for provision of beam time at ISIS.Peer reviewedPostprin

Breakdown of Energy Equipartition in a 2D Binary Vibrated Granular Gas

We report experiments on the equipartition of kinetic energy between grains made of two different materials in a mixture of grains vibrated in 2 dimensions. In general, the two types of grains do not attain the same granular temperature, Tg = 1/2m v^2. However, the ratio of the two temperatures is constant in the bulk of the system and independent of the vibration velocity. The ratio depends strongly on the ratio of mass densities of the grains, but is not sensitive to the inelasticity of grains. Also, this ratio is insensitive to compositional variables of the mixture such as the number fraction of each component and the total number density. We conclude that a single granular temperature, as traditionally defined, does not characterize a multi-component mixture.Comment: 4 pages, 5 figures, submitted to Physical Review Letters, updated reference

Socioeconomic inequalities in vaccine uptake: A global umbrella review

This global umbrella review aimed to synthesise evidence of socioeconomic inequalities in the uptake of routine vaccinations and identify the mechanisms that may contribute to the association. To our knowledge, no attempt has been made to synthesise the global body of systematic reviews across a variety of vaccines, geographical locations, and measures of SES. The inclusion criteria were as follows: studies assessing vaccination uptake according to education, income, occupation/employment, and/or area-level deprivation; any country or universally recommended routine vaccination (according to the WHO); qualitative or quantitative reviews, published 2011-present. The searches were performed in eight databases. The screening process followed PRISMA-E guidelines, each stage was performed by one reviewer, and a 10% sample checked by a second for consistency. Included reviews underwent data extraction, quality appraisal (AMSTAR-2), and narrative synthesis according to country-context. After deduplication, 9,163 reports underwent title and abstract screening, leaving 119 full texts to be assessed for eligibility. Overall, 26 studies were included in the umbrella review. Evidence for lower uptake amongst disadvantaged SES individuals was found in all 26 reviews. However, 17 reviews showed mixed results, as inverse associations were also identified (lower uptake for advantaged SES, and/or higher uptake for disadvantaged SES). Those that explored high-income countries had a greater prevalence of mixed findings than those focusing on low/middle-income countries. The two most frequently cited mechanisms were vaccination knowledge, and confidence in vaccination or vaccination providers. These mechanisms were often understood by review authors as varying by level of education. We find socioeconomic differences in routine vaccination uptake, but the association did not always follow a gradient. Whilst education may be associated with uptake globally, our study indicates that its role varies by country-context. A limitation is the overlap of some primary studies across the included systematic reviews.10.1371/journal.pone.029468

The crystal structure and electrical properties of the oxide ion conductor Ba3WNbO8.5

This research was supported by the Northern Research Partnership and the University of Aberdeen. We also acknowledge Science and Technology Facilities Council (STFC) for provision of beamtime at ISIS.Peer reviewedPostprin