Measurements of reflected overpressure in the extreme near field

Blast protection design requires a detailed knowledge of the loading imparted on a structure by a particular blast threat. This includes an understanding of the mechanisms involved in the rapid energy release that leads to fireball expansion and air shock development. In the far field (Z > 2 m/kg1/3) reliable semi-empirical methods exist for both the positive and negative phases of the blast wave. In the far field the explosion is sufficiently far away that only the propagating air shock interacts with the structure, while in the near field the fireball is still driving the air shock and can itself interact with the structure. There is currently a lack of reliable experimental data in this near field region, as the incredibly high pressures and temperatures pose particular experimental challenges. This is particularly the case in the extreme near field (Z < 0.5 m/kg1/3), where semi-empirical and physics-based predictions can vary by an order of magnitude. This paper presents the design of an experimental facility capable of recording spatially resolved reflected pressures in the extreme near field. The Mechanisms and Characterisation of Explosions (MaCE) facility is an evolution of the Characterisation of Blast Loading (CoBL) facility used for buried blasts, but with key near fieldspecific adaptations. An array of Hopkinson pressure bars embedded in a stiff target plate is used to make pressure measurements over a 100 mm radius instrumented area. Maraging steel pressure bars and specially designed strain gauges are used to increase the measurement capacity from 600 MPa to 1800 MPa, and 33 pressure bars in a radial grid are used to improve the spatial resolution from 25 mm to 12.5 mm. In addition, the pressure bar diameter is reduced from 10 mm to 4 mm, which greatly reduces stress wave dispersion, increasing the effective bandwidth. This enables the observation of high-frequency features in the pressure measurements, which is vital for validating the near-field transient effects predicted by numerical modelling and developing effective blast mitigation methods

Temporally and spatially resolved reflected overpressure measurements in the extreme near field

The design of blast-resistant structures and protective systems requires a firm understanding of the loadings imparted to structures by blast waves. While empirical methods can reliably predict these loadings in the far field, there is currently a lack of understanding on the pressures experienced in the very near field, where physics-based numerical modelling and semi-empirical fast-running engineering model predictions can vary by an order of magnitude. In this paper, we present the design of an experimental facility capable of providing definitive spatially and temporally resolved reflected pressure data in the extreme near field (Z<0.5 m/kg1/3 ). The Mechanisms and Characterisation of Explosions (MaCE) facility is a specific near-field evolution of the existing Characterisation of Blast Loading (CoBL) facility, which uses an array of Hopkinson pressure bars embedded in a stiff target plate. Maraging steel pressure bars and specially designed strain gauges are used to increase the measurement capacity from 600 MPa to 1800 MPa, and 33 pressure bars in a radial grid are used to improve the spatial resolution from 25 mm to 12.5 mm over the 100 mm radius measurement area. In addition, the pressure bar diameter is reduced from 10 mm to 4 mm, which greatly reduces stress wave dispersion, increasing the effective bandwidth. This enables the observation of high-frequency features in the pressure measurements, which is vital for validating the near-field transient effects predicted by numerical modelling and developing effective blast mitigation methods

MicroBlast - a benchmarking study of gramme-scale explosive trials

Explosions are a pressing and pervading threat in the modern world. The extensive damage caused by recent large scale urban explosions such as Tianjin (2015) and Beirut (2020) has highlighted a key gap in our knowledge. That is, we still do not yet understand, nor can we reliably and rapidly predict, blast loading in complex cityscape environments. Accordingly, determination of consequences related to risk, structural damage, and casualty numbers, is severely limited. Current experimental approaches do not have the sophistication nor fidelity required to accurately measure blast loading in urban environments, and there is a significant and growing disparity in the complexity with which numerical models and experimental work can operate. Because of this, key insights gained from detailed modelling studies have not been validated, and we do not yet fully understand how blast waves propagate and interact with multiple obstacles. This paper presents the development of a series of experimental studies aimed at addressing this shortfall. The ultimate objective of this work is to develop the MicroBlast facility: an ultra small-scale testing apparatus for rapid, high-rate, high-resolution, multi-parameter measurements of blast loading in complex environments. Here, we present results from preliminary trials aimed at establishing the reliability and repeatability of small-scale explosive testing, in increasingly complex layouts. The results are directly compared to commensurate larger-scale test data to confirm scalability of gramme-scale detonations

Recent development and research at the University of Sheffield blast lab in Buxton, UK

The Blast and Impact Dynamics Lab in Buxton, UK has recently undergone a significant refurbishment due to investment by the University of Sheffield and funding from the Engineering & Physical Sciences Research Council (EPSRC) through a Strategic Equipment Grant. This has complimented development in measurement techniques funded through standard EPSRC grants and commercial blast testing undertaken by Blastech Ltd. a spin out company of the University of Sheffield

A Q-methodological study of 'smoking identities'

publication-status: Publishedtypes: ArticleIn contrast to the psychological literature on adolescent smoking, little research has investigated the social identities of adult smokers. This study aimed to identify shared ‘smoking identities’ amongst a sample of 64 British smokers from different socio-economic groups using Q-methodology. Participants were asked to sort 70 items concerning smoking and smokers according to their agreement/disagreement with them. The 64 Q-sorts were then subjected to a by-person factor analysis yielding six factors, with the first four interpretable factors being presented here. Each factor is understood to represent a distinct ‘identity position’. The first two, the ‘addicted’ smoker, and the ‘in control’ smoker, oriented around a biomedical model of smoking as an addictive health risk. The final two, the ‘no big deal’ smoker and the ‘proud’ smoker reflected alternative understandings and values. The identity positions also differed in the extent to which smoking was considered a core part of self-identity. Unpacking the ‘smoking identities’ of current smokers offers the opportunity to devise targeted health promotion.Economic and Social Research Counci

Neuromotor tolerability and behavioural characterisation of cannabidiolic acid, a phytocannabinoid with therapeutic potential for anticipatory nausea

Rationale: Anticipatory nausea (AN) is a poorly controlled side-effect experienced by chemotherapy patients. Currently, pharmacotherapy is restricted to benzodiazepine anxiolytics, which have limited efficacy, significant sedative effects, and induce dependency. The non-psychoactive phytocannabinoid, cannabidiolic acid (CBDA), has shown considerable efficacy in pre-clinical AN models, however determination of its neuromotor tolerability profile is crucial to justify clinical investigation. Provisional evidence for appetite-stimulating properties also requires detailed investigation. Objectives: To assess the tolerability of CBDA in locomotor activity, motor coordination and muscular strength tests, and additionally for ability to modulate feeding behaviours. Methods: Male Lister hooded rats administered CBDA (0.05-5 mg/kg; p.o.) were assessed in habituated open field (for locomotor activity), static beam and grip strength tests. A further study investigated whether these CBDA doses modulated normal feeding behaviour. Finally, evidence of anxiolytic-like effects in the habituated open field prompted testing of 5 mg/kg CBDA for anxiolytic-like activity in unhabituated open field, light/dark box and novelty-supressed feeding (NSF) tests. Results: CBDA had no adverse effects upon performance in any neuromotor tolerability test, however anxiolytic-like behaviour was observed in the habituated open field. Normal feeding behaviours were unaffected by any dose. CBDA (5 mg/kg) abolished the increased feeding latency in the NSF test induced by the 5-HT1AR antagonist, WAY-100,635, indicative of anxiolytic-like effects, but had no effect on anxiety-like behaviour in the novel open field or light/dark box. Conclusions: CBDA is very well tolerated and devoid of the sedative side-effect profile of benzodiazepines, justifying its clinical investigation as a novel AN treatment

Making sense of being at 'high risk' of coronary heart disease within primary prevention

types: Journal ArticleCurrent National Health Service policy advocates screening to identify individuals at 'high risk' of cardio-vascular disease (CHD) in primary care. This article utilizes the work of Radley to explore how 'high risk' of CHD patients make sense of their new risk status. Results are presented here from a nested qualitative study within a quantitative randomized trial of a CHD risk intervention in primary care. 'Discovery' interviews were conducted with 'high risk' participants (n = 38, mean age = 55) two weeks after intervention and thematically analysed. In response to perceived threat, many participants sought to both 'minimize' and 'normalize' their risk status. They also reported intentions to act, particularly concerning dietary change and exercise, although less so for smoking amongst the lower socio-economic status participants. Such perceptions and intentions were contextualized within the life-course of later middle-age, so that both being at risk, and being treated for risk, were normalized as part of growing older. Social position, such as gender and SES, was also implicated. CHD risk interventions should be context-sensitive to the life-course and social position of those who find themselves at 'high risk' of CHD in later middle-age

Multicentre appraisal of amyotrophic lateral sclerosis biofluid biomarkers shows primacy of blood neurofilament light chain.

The routine clinical integration of individualized objective markers of disease activity in those diagnosed with the neurodegenerative disorder amyotrophic lateral sclerosis is a key requirement for therapeutic development. A large, multicentre, clinic-based, longitudinal cohort was used to systematically appraise the leading candidate biofluid biomarkers in the stratification and potential therapeutic assessment of those with amyotrophic lateral sclerosis. Incident patients diagnosed with amyotrophic lateral sclerosis (n = 258), other neurological diseases (n = 80) and healthy control participants (n = 101), were recruited and followed at intervals of 3-6 months for up to 30 months. Cerebrospinal fluid neurofilament light chain and chitotriosidase 1 and blood neurofilament light chain, creatine kinase, ferritin, complement C3 and C4 and C-reactive protein were measured. Blood neurofilament light chain, creatine kinase, serum ferritin, C3 and cerebrospinal fluid neurofilament light chain and chitotriosidase 1 were all significantly elevated in amyotrophic lateral sclerosis patients. First-visit plasma neurofilament light chain level was additionally strongly associated with survival (hazard ratio for one standard deviation increase in log10 plasma neurofilament light chain 2.99, 95% confidence interval 1.65-5.41, P = 0.016) and rate of disability progression, independent of other prognostic factors. A small increase in level was noted within the first 12 months after reported symptom onset (slope 0.031 log10 units per month, 95% confidence interval 0.012-0.049, P = 0.006). Modelling the inclusion of plasma neurofilament light chain as a therapeutic trial outcome measure demonstrated that a significant reduction in sample size and earlier detection of disease-slowing is possible, compared with using the revised Amyotrophic Lateral Sclerosis Functional Rating Scale. This study provides strong evidence that blood neurofilament light chain levels outperform conventional measures of disease activity at the group level. The application of blood neurofilament light chain has the potential to radically reduce the duration and cost of therapeutic trials. It might also offer a first step towards the goal of more personalized objective disease activity monitoring for those living with amyotrophic lateral sclerosis

Performing masculinity, influencing health: A qualitative mixed-methods study of young Spanish men

Background: The literature shows how gender mandates contribute to differences in exposure and vulnerability to certain health risk factors. This paper presents the results of a study developed in the south of Spain, where research aimed at understanding men from a gender perspective is still limited.Objective: The aim of this paper is to explore the lay perceptions and meanings ascribed to the idea of masculinity, identifying ways in which gender displays are related to health.Design: The study is based on a mixed-methods data collection strategy typical of qualitative research. We performed a qualitative content analysis focused on manifest and latent content.Results: Our analysis showed that the relationship between masculinity and health was mainly defined with regard to behavioural explanations with an evident performative meaning. With regard to issues such as driving, the use of recreational drugs, aggressive behaviour, sexuality, and body image, important connections were established between manhood acts and health outcomes. Different ways of understanding and performing the male identity also emerged from the results. The findings revealed the implications of these aspects in the processes of change in the identity codes of men and women.Conclusions: The study provides insights into how the category ‘man’ is highly dependent on collective practices and performative acts. Consideration of how males perform manhood acts might be required in guidance on the development of programmes and policies aimed at addressing gender inequalities in health in a particular local context.This research received no specific grant from any funding agency in the public, commercial, or not- for-profit sectors. However, we had the opportunity to write this paper with the financial support from the European Regional Development Fund (FEDER) and the Andalusian Government’s Economy, Innovation and Science Department (Exp P08-CTS-4321)