Diagnostic techniques in deflagration and detonation studies

Advances in experimental, high-speed techniques can be used to explore the processes occurring within energetic materials. This review describes techniques used to study a wide range of processes: hot-spot formation, ignition thresholds, deflagration, sensitivity and finally the detonation process. As this is a wide field the focus will be on small-scale experiments and quantitative studies. It is important that such studies are linked to predictive models, which inform the experimental design process. The stimuli range includes, thermal ignition, drop-weight, Hopkinson Bar and Plate Impact studies. Studies made with inert simulants are also included as these are important in differentiating between reactive response and purely mechanical behaviour

Temperature and strain rate effects on the mechanical properties of a polymer-bonded explosive

© 2018, The Author(s). The aim of the research reported here was to investigate the strain rate and temperature sensitivity of Rowanex 1100 Type 1A, a polymer-bonded explosive (PBX). The stress supported by this PBX at high rates of deformation (1750 ± 225 s−1) was found to be about an order of magnitude greater than that supported at low rates (0.015 s−1). Temperature was also found to have a large effect, with the strength of the material decreasing exponentially with temperature over the range studied (–60 to +60 °C). The exponents for the decay of the PBX’s strength with temperature at both low and high strain rates were the same within experimental error. So a temperature/strain rate shift factor could be determined and was found to be 31.2 ± 2.4 K/decade of strain rate.BAe Systems, Glascoed, U

The effect of sertraline, haloperidol and apomorphine on the behavioural manipulation of slugs (Deroceras invadens) by the nematode Phasmarhabditis hermaphrodita

The nematode Phasmarhabditis hermaphrodita can infect and kill many species of slugs and has been formulated into a biological control agent for farmers and gardeners. P. hermaphrodita can manipulate the behaviour of slugs, making those infected move to areas where the nematode is present. Research suggests P. hermaphrodita uses manipulation of biogenic amines to achieve this, however the exact role of serotonin and dopamine needs further elucidation. Here we fed slugs Deroceras invadens (uninfected and infected with P. hermaphrodita) apomorphine, sertraline and haloperidol and observed their behaviour when given a choice between a P. hermaphrodita infested habitat, or a parasite free area of soil. In contrast to their usual P. hermaphrodita avoidance behaviour, uninfected D. invadens fed sertraline were attracted to the nematodes and conversely those fed haloperidol avoided the nematodes. D. invadens fed apomorphine were recorded equally on the control and nematode side. D. invadens pre-infected with P. hermaphrodita fed sertraline and apomorphine were found significantly more on the side with the nematodes. However, suppressing dopaminergic signalling through feeding with haloperidol abrogated this attraction and slugs were found on both sides. These results demonstrate that serotonin and dopamine are important potential regulators of behavioural manipulation by P. hermaphrodita

Prospects for resolving the Hubble constant tension with standard sirens

The Hubble constant ($H_0$) estimated from the local Cepheid-supernova (SN) distance ladder is in 3-$\sigma$ tension with the value extrapolated from cosmic microwave background (CMB) data assuming the standard cosmological model. Whether this tension represents new physics or systematic effects is the subject of intense debate. Here, we investigate how new, independent $H_0$ estimates can arbitrate this tension, assessing whether the measurements are consistent with being derived from the same model using the posterior predictive distribution (PPD). We show that, with existing data, the inverse distance ladder formed from BOSS baryon acoustic oscillation measurements and the Pantheon SN sample yields an $H_0$ posterior near-identical to the Planck CMB measurement. The observed local distance ladder value is a very unlikely draw from the resulting PPD. Turning to the future, we find that a sample of $\sim50$ binary neutron star "standard sirens" (detectable within the next decade) will be able to adjudicate between the local and CMB estimates

Characterisation of the impact response of energetic materials: Observation of a low-level reaction in 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105)

Time resolved and integrated diagnostics including high speed photography, mass and optical spectroscopy, and optical-radiometry used to study impact response of high explosives in far more detail than possible with conventional sensitiveness tests.The authors wish to acknowledge the funding and provision of samples for this research by AWE plc.This is the author accepted manuscript. The final version is available from the Royal Society of Chemistry via http://dx.doi.org/10.1039/C6RA03096

A single-source precursor approach to solution processed indium arsenide thin films

This paper reports the synthesis of the novel single-source precursor, [{(MeInAstBu)3}2(Me2InAs(tBu)H)2] and the subsequent first report of aerosol-assisted chemical vapour deposition of InAs thin films. Owing to the use of the single-source precursor, highly crystalline and stoichiometric films were grown at a relatively low deposition temperature of 450 °C. Core level XPS depth profiling studies showed some partial oxidation of the film surface, however this was self-limiting and disappeared on etch profiles. Valence band XPS analysis matched well with the simulated density of state spectrum. Hall effect measurements performed on the films showed that the films were n-type with promising resistivity (3.6 × 10−3 Ω cm) and carrier mobility (410 cm2 V−1 s−1) values despite growth on amorphous glass substrates

Spontaneous honeybee behaviour is altered by persistent organic pollutants

The effect of environmental pollutants on honeybee behaviour has focused mainly on currently used pesticides. However, honeybees are also exposed to persistent organic pollutants (POPs). The aim of this laboratory based study was to determine if exposure to sublethal field-relevant concentrations of POPs altered the spontaneous behaviour of foraging-age worker honeybees. Honeybees (Apis mellifera) were orally exposed to either a sublethal concentration of the polychlorinated biphenyl (PCB) mixture Aroclor 1254 (100 ng/ml), the organochlorine insecticide lindane (2.91 ng/ml) or vehicle (0.01% DMSO, 0.00015% ethanol in 1M sucrose) for 1–4 days. The frequency of single event behaviours and the time engaged in one of four behavioural states (walking, flying, upside down and stationary) were monitored for 15 min after 1, 2, 3 and 4 days exposure. Exposure to Aroclor 1254 but not lindane increased the frequency and time engaged in honeybee motor activity behaviours in comparison to vehicle. The Aroclor 1254—induced hyperactivity was evident after 1 day of exposure and persisted with repeated daily exposure. In contrast, 1 day of exposure to lindane elicited abdominal spasms and increased the frequency of grooming behaviours in comparison to vehicle exposure. After 4 days of exposure, abdominal spasms and increased grooming behaviours were also evident in honeybees exposed to Aroclor 1254. These data demonstrate that POPs can induce distinct behavioural patterns, indicating different toxicokinetic and toxicodynamic properties. The changes in spontaneous behaviour, particularly the PCB-induced chronic hyperactivity and the associated energy demands, may have implications for colony health

Managing Injuries of the Neck Trial (MINT) : design of a randomised controlled trial of treatments for whiplash associated disorders

Background: A substantial proportion of patients with whiplash injuries develop chronic symptoms. However, the best treatment of acute injuries to prevent long-term problems is uncertain. A stepped care treatment pathway has been proposed, in which patients are given advice and education at their initial visit to the emergency department (ED), followed by review at three weeks and physiotherapy for those with persisting symptoms. MINT is a two-stage randomised controlled trial to evaluate two components of such a pathway: 1. use of The Whiplash Book versus usual advice when patients first attend the emergency department; 2. referral to physiotherapy versus reinforcement of advice for patients with continuing symptoms at three weeks. Methods: Evaluation of the Whiplash Book versus usual advice uses a cluster randomised design in emergency departments of eight NHS Trusts. Eligible patients are identified by clinicians in participating emergency departments and are sent a study questionnaire within a week of their ED attendance. Three thousand participants will be included. Patients with persisting symptoms three weeks after their ED attendance are eligible to join an individually randomised study of physiotherapy versus reinforcement of the advice given in ED. Six hundred participants will be randomised. Follow-up is at 4, 8 and 12 months after their ED attendance. Primary outcome is the Neck Disability Index (NDI), and secondary outcomes include quality of life and time to return to work and normal activities. An economic evaluation is being carried out. Conclusion: This paper describes the protocol and operational aspects of a complex intervention trial based in NHS emergency and physiotherapy departments, evaluating two components of a stepped-care approach to the treatment of whiplash injuries. The trial uses two randomisations, with the first stage being cluster randomised and the second individually randomised

Individual patient data meta-analysis : Cervical stitch (cerclage) for preventing pregnancy loss in women

BACKGROUND: Cervical cerclage is a surgical procedure involving suturing the cervix with a purse type stitch to keep it closed during pregnancy. This procedure has been used widely in the management of pregnancies considered at high risk of preterm delivery. Several observational studies into the efficacy of cervical cerclage have claimed high rates of successful pregnancy outcome in women with a poor obstetric history attributed to cervical incompetence. However, a recent aggregate data Cochrane review found no such conclusive evidence from seven included randomised studies. Current data suggests that cervical cerclage is likely to benefit women considered to be 'at very high risk' of a second trimester miscarriage due to a cervical factor, however identifying such women remains elusive and many women may be treated unnecessarily. Undertaking an individual patient data (IPD) meta-analysis of the studies will allow us to investigate whether treatment is more effective in particular subgroups. Such an analysis will also provide a more powerful analysis of the predictors of preterm delivery and pregnancy loss, including ultrasound measurement of cervical length, and will allow a more complete analysis of 'time to event' outcomes. METHODS/DESIGN: The analysis will include data from randomised trials comparing the intervention of elective cerclage versus no cerclage or bedrest to prevent miscarriage or pre-term labour. A specific list of data will be requested for each trial, including demographic and obstetric history data. The primary outcomes of interest will be neonatal mortality/morbidity. Attention will also be given to secondary outcomes such as time from randomisation to delivery, preterm delivery before 32 weeks and maternal morbidity. An intention to treat analysis will be performed, with attention paid to assessing clinical and statistical heterogeneity. Multilevel models with patients and trials as the two levels will be explored to investigate treatment effect on various outcomes. Patient-level covariates will be incorporated into the models in an attempt to account for statistical heterogeneity as well as to investigate interactions with treatment effect. DISCUSSION: Predictive models generated from our analysis should lead to more effective counselling of women at risk and a more cost effective use of cerclage

Increased risk of A(H1N1)pdm09 influenza infection in UK pig industry workers compared to a general population cohort.

BACKGROUND: Pigs are mixing vessels for influenza viral reassortment but the extent of influenza transmission between swine and humans is not well understood. OBJECTIVES: To assess whether occupational exposure to pigs is a risk factor for human infection with human and swine-adapted influenza viruses. METHODS: UK pig industry workers were frequency-matched on age, region, sampling month, and gender with a community-based comparison group from the Flu Watch study. HI assays quantified antibodies for swine and human A(H1) and A(H3) influenza viruses (titres≥40 considered seropositive and indicative of infection). Virus-specific associations between seropositivity and occupational pig exposure were examined using multivariable regression models adjusted for vaccination. Pigs on the same farms were also tested for seropositivity. RESULTS: 42% of pigs were seropositive to A(H1N1)pdm09. Pig industry workers showed evidence of increased odds of A(H1N1)pdm09 seropositivity compared to the comparison group, albeit with wide confidence intervals (CI), Adjusted Odds Ratio after accounting for possible cross reactivity with other swine A(H1) viruses (aOR) 25.3, 95% CI [1.4-536.3], p=0.028. CONCLUSION: The results indicate that A(H1N1)pdm09 virus was common in UK pigs during the pandemic and subsequent period of human A(H1N1)pdm09 circulation, and occupational exposure to pigs was a risk factor for human infection. Influenza immunization of pig industry workers may reduce transmission and the potential for virus reassortment. This article is protected by copyright. All rights reserved