Prolonging disuse in aged mice amplifies cortical but not trabecular bones’ response to mechanical loading

Objective: Short-term neurectomy-induced disuse (SN) has been shown to restore load responses in aged mice. We examined whether this restoration was further enhanced in both cortical and trabecular bone by simply extending the SN. Methods: Following load: strain calibration, tibiae in female C57BL/J6 mice at 8, 14 and 20 weeks and 18 months (n=8/group) were loaded and bone changes measured. Effects of long-term SN examined in twenty-six 18 months-old mice, neurectomised for 5 or 100 days with/without subsequent loading. Cortical and trabecular responses were measured histomorphometrically or by micro-computed tomography. Results: Loading increased new cortical bone formation, elevating cross-sectional area in 8, 14 and 20 week-old (p <0.05), but not 18 month-old aged mice. Histomorphometry showed that short-term SN reinstated load-responses in aged mice, with significant 33% and 117% increases in bone accrual at 47% and 37%, but not 27% of tibia length. Cortical responses to loading was heightened and widespread, now evident at all locations, following prolonged SN (108, 167 and 98% at 47, 37 and 27% of tibial length, respectively). In contrast, loading failed to modify trabecular bone mass or architecture. Conclusions: Mechanoadaptation become deficient with ageing and prolonging disuse amplifies this response in cortical but not trabecular bone

Pressure ulcer related pain in community populations: a prevalence survey.

BACKGROUND: Pressure ulcers are costly to the healthcare provider and can have a major impact on patient's quality of life. One of the most distressing symptoms reported is pain. There is very little published data on the prevalence and details of pain experienced by patients with pressure ulcers, particularly in community populations. The study was conducted in two community NHS sites in the North of England. METHODS: The aim was to estimate the prevalence of pressure area related pain within a community population. We also explored the type and severity of the pain and its association with pressure ulcer classification. A cross-sectional survey was performed of community nurses caseloads to identify adult patients with pressure ulcers and associated pain. Consenting patients then had a full pain assessment and verification of pressure ulcer grade. RESULTS: A total of 287 patients were identified with pressure ulcers (0.51 per 1000 adult population). Of the 176 patients who were asked, 133 (75.6%) reported pain. 37 patients consented to a detailed pain assessment. Painful pressure ulcers of all grades and on nearly all body sites were identified. Pain intensity was not related to number or severity of pressure ulcer. Both inflammatory and neuropathic pain were reported at all body sites however the proportion of neuropathic pain was greater in pressure ulcers on lower limbs. CONCLUSIONS: This study has identified the extent and type of pain suffered by community patients with pressure ulcers and indicates the need for systematic and regular pain assessment and treatment

Proterozoic - basal Cambrian stratigraphy across Nares Strait: correlation between Inglefield Land and Bache Peninsula

In the Kane Basin region of Nares Strait (78° to 79°N) unmetamorphosed Proterozoic and basal Cambrian platform strata overlie the Precambrian Shield both in Inglefield Land in Greenland, and on Bache Peninsula in Ellesmere Island. The platform succession is composed of two shallow-water elastic sequences separated by an erosional disconformity. The lower formation, of multicoloured sandstone and siltstone with minor shale and stromatolitic dolomite, is assigned to the redefined Rensselaer Bay Formation; the upper, composed of red and overlying white sandstone with dolomitic sandstone and siltstone at the top, is assigned to the Dallas Bugt Formation. Basic sills from the Rensselaer Bay Formation have yielded isotopic ages as old as 1200 m.y., while the trace fossils Rusophycus and Skolithos suggest a basal Cambrian age for the Dallas Bugt Formation. The platform sequences of Inglefield Land and Bache Peninsula show striking similarity in lithology and thickness and the detail correlation is supported by the evidence from isotopic ages of basic sills and from trace fossils. In both areas the bipartite succession is overlain with apparent conformity by dolomites that pass upwards into limestones containing Early Cambrian macrofauna. The Rensselaer Bay Formation thickens southwards and passes into the much thicker sedimentary sequence of the Thule Basin, while the Dallas Bugt Formation and the overlying dolomites thicken northwards, indicating that the two formations were laid down in separate sedimentary basins. The close correlation of the platform successions and the corresponding configuration of the depositional slopes on both sides of the Kane Basin clearly indicate that the Proterozoic - Early Cambrian sedimentary pattern has not been radically disturbed by tectonism or by any appreciable transcurrent movement along Nares Strait

Petrov types of slowly rotating fluid balls

Circularly rotating axisymmetric perfect fluid space-times are investigated to second order in the small angular velocity. The conditions of various special Petrov types are solved in a comoving tetrad formalism. A number of theorems are stated on the possible Petrov types of various fluid models. It is shown that Petrov type II solutions must reduce to the de Sitter spacetime in the static limit. Two space-times with a physically satisfactory energy-momentum tensor are investigated in detail. For the rotating incompressible fluid, it is proven that the Petrov type cannot be D. The equation of the rotation function $\omega$ can be solved for the Tolman type IV fluid in terms of quadratures. It is also shown that the rotating version of the Tolman IV space-time cannot be Petrov type D.Comment: 14 pages, version to appear in Gen. Rel. Gra

Particle dynamics of a cartoon dune

The spatio-temporal evolution of a downsized model for a desert dune is observed experimentally in a narrow water flow channel. A particle tracking method reveals that the migration speed of the model dune is one order of magnitude smaller than that of individual grains. In particular, the erosion rate consists of comparable contributions from creeping (low energy) and saltating (high energy) particles. The saltation flow rate is slightly larger, whereas the number of saltating particles is one order of magnitude lower than that of the creeping ones. The velocity field of the saltating particles is comparable to the velocity field of the driving fluid. It can be observed that the spatial profile of the shear stress reaches its maximum value upstream of the crest, while its minimum lies at the downstream foot of the dune. The particle tracking method reveals that the deposition of entrained particles occurs primarily in the region between these two extrema of the shear stress. Moreover, it is demonstrated that the initial triangular heap evolves to a steady state with constant mass, shape, velocity, and packing fraction after one turnover time has elapsed. Within that time the mean distance between particles initially in contact reaches a value of approximately one quarter of the dune basis length

'Working out’ identity: distance runners and the management of disrupted identity

This article contributes fresh perspectives to the empirical literature on the sociology of the body, and of leisure and identity, by analysing the impact of long-term injury on the identities of two amateur but serious middle/long-distance runners. Employing a symbolic interactionist framework,and utilising data derived from a collaborative autoethnographic project, it explores the role of ‘identity work’ in providing continuity of identity during the liminality of long-term injury and rehabilitation, which poses a fundamental challenge to athletic identity. Specifically, the analysis applies Snow and Anderson’s (1995) and Perinbanayagam’s (2000) theoretical conceptualisations in order to examine the various forms of identity work undertaken by the injured participants, along the dimensions of materialistic, associative and vocabularic identifications. Such identity work was found to be crucial in sustaining a credible sporting identity in the face of disruption to the running self, and in generating momentum towards the goal of restitution to full running fitness and reengagement with a cherished form of leisure. KEYWORDS: identity work, symbolic interactionism, distance running, disrupted identit

Using causal loop diagrams to explore behavioural and socio-technical safety challenges

In 2021, the EI published a Research report: Achieving greater resilience to major events – Organisational learning for safety risk management in complex environments, which identified common contributory organisational and cultural deficiencies that led to 12 major process safety events. From that, a set of expectations of good practice was created that organisations can use to help identify weaknesses and make interventions to potentially avoid future organisational incidents.Following this, the EI Research report: Question-set to understand and evaluate socio-technical organisational resilience (QUESTOR) was published, in which a methodology was developed to help organisations identify potential shortfalls in meeting these expectations. Question sets were created, designed to assess the extent to which the expectations are being met in ‘operational reality’. This practical tool is aimed to be utilised by leaders, managers, ‘specialists’ and a sample of the workforce.The EI Research report: Using causal loop diagrams to explore behavioural and socio-technical safety challenges is a further continuation of the two previous reports, and builds upon the use of causal loop diagrams (CLDs) as a tool for organisations to identify, and understand, vulnerabilities that lead to failures within complex work systems, as well as model interventions that aim to prevent these vulnerabilities being introduced.The purpose of the report is to demonstrate how CLDs might be used by teams to model the causes of incidents (perhaps even before incidents have occurred if vulnerabilities are found proactively, such as by using the QUESTOR tool) so that interventions might be designed that can effectively tackle these, without introducing unexpected and undesirable consequences.The intended audience of this report includes health, safety and environment (HS&amp;E) managers, senior leaders, and others who may have responsibility for auditing and measuring safety performance within organisations