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Wearable lower body robotic exoskeletons are an emerging technology used in gait rehabilitation to facilitate task-specific overground walking. Despite their proposed utility as a rehabilitation intervention, exoskeletons have not been widely implemented into clinical practice by physiotherapists. This study aims to inform future development of exoskeleton technology through the exploration of physiotherapy student perspectives on the use of the H2 robotic exoskeleton and the implementation of exoskeletons as a therapeutic technology in neurological gait rehabilitation.A qualitative descriptive study, including fifteen physiotherapy students, was conducted using three equally sized focus groups. A collaborative data analysis process was employed using the DEPICT model.Five themes were identified during data analysis: developing evidence-informed practice, clinical considerations for exoskeleton use, resource demands, device-specific challenges for implementation, and future development. The results suggest there are several barriers limiting novel clinicians' future use of exoskeletons.This study highlights current challenges surrounding exoskeleton implementation into clinical practice and provides direction for future exoskeleton development.Implications for rehabilitationPhysiotherapy students view exoskeletons as a potentially valuable rehabilitation tool once perceived limitations are addressed.This study encourages collaboration between physiotherapists and biomedical engineers for future exoskeleton development.More research is needed to inform treatment parameters and appropriate client criteria to guide exoskeleton use for gait rehabilitation.

Drug cues play an important role in relapse to drug use. Naltrexone is an opioid antagonist that is used to prevent relapse in opioid dependence. Central opioidergic pathways may be implicated in the heightened drug cue-reactivity, but the effects of the opioid receptors' blockade on the brain responses to drug cues in opioid dependence are unknown. To pursue this question, we studied 17 abstinent i.v. heroin users with brain functional magnetic resonance imaging (fMRI) during exposure to visual heroin-related cues and matched neutral images before and 10-14 days after an injection of extended-release naltrexone (XRNTX). Whole brain analysis of variance of fMRI data showed main effect of XRNTX in the medial frontal gyrus, precentral gyrus, cuneus, precuneus, caudate and the amygdala. fMRI response was decreased in the amygdala, cuneus, caudate and the precentral gyrus and increased in the medial frontal gyrus and the precuneus. Higher plasma levels of naltrexone's major metabolite, 6-beta-naltrexol, were associated with larger reduction in the fMRI response to drug cues after XRNTX in the precentral, caudate and amygdala clusters. The present data suggest that XRNTX pharmacotherapy of opioid-dependent patients may, respectively, decrease and potentiate prefrontal and limbic cortical responses to drug cues and that this effect might be related to the XRNTX metabolism. Our findings call for further evaluation of the brain fMRI response to drug-related cues and of the 6-beta-naltrexol levels as potential biomarkers of XRNTX therapeutic effects in patients with opioid dependence.

We consider the “intrinsic” symmetry group of a two-component link L, defined to be the image ∑(L) of the natural homomorphism from the standard symmetry group MCG(S3, L) to the product MCG(S3) × MCG(L). This group, first defined by Whitten in 1969, records directly whether L is isotopic to a link L′ obtained from L by permuting components or reversing orientations, it is a subgroup of Γ2, the group of all such operations. For two-component links, we catalog the 27 possible intrinsic symmetry groups, which represent the subgroups of Γ2 up to conjugacy. We are able to provide prime, nonsplit examples for 21 of these groups, some are classically known, some are new. We catalog the frequency at which each group appears among all 77,036 of the hyperbolic two-component links of 14 or fewer crossings in Thistlethwaite’s table. We also provide some new information about symmetry groups of the 293 non-hyperbolic two-component links of 14 or fewer crossings in the table.

Three commercial hockey balls, two with mixed cork, wool and polymer cores and one which was hollow, were tested dynamically using ball rebound and ‘hardness’ tests. The load / deformation behaviour of selected ball types was determined at low deformation rates (0.02 − 2 mm s−1) using a Zwick Z100 universal tester and at high deformation rates (16 − 24 m s−1) using a gas cannon and steel target. In addition, cylindrical samples taken from the core were compression tested (using the same slow deformation rates, also on the Zwick Z100) to determine their tangential modulus variation with strain and deformation rate as well as their viscoelastic energy losses. The trends shown during impact tests were consistent with those in the low strain rate compression tests and these correlated with the materials properties and dimensions. Lower impact speed behaviour was associated with deformation being dominated by the cover, whilst higher deformation rates gave significant differences in ball behaviour due to the composition and dimensions of their cores. These differences were, however, demonstrated in the core compression testing indicating that the core materials play a greater role as the speed of the shots increases and deformation spreads beyond the cover. The qualitative relationships between ball construction at deformation behaviour at varying speeds is also summarised.

The performance of golf balls during various shots occurs under a range of strains and strain rates, which results in varying ball stiffness and energy loss responses due to the viscoelastic nature of the polymers used in ball construction. Modelling of ball performance is often based on fitting FE models to ball rebound data, although some groups have started to successfully use the material properties of the various components to account for normal impact. The latter approach is more predictive as it allows the potential effects of varying material properties and ball constructions to be estimated before balls are actually fabricated. The normal impact is often represented through a normal coefficient of restitution (CoR), which is strain and strain rate dependent. In oblique impacts the situation is complicated as both normal and tangential forces act with the bending moment of the tangential force causing backspin generation. Modelling of oblique impact will need to be able to predict contact time of the ball on the club face as this is the time during which the tangential force is generating backspin. One route to this contact time could come from the normal part of the impact as the ball centre of mass velocity normal to the face is decelerated and then accelerated. This paper will report results of impacts of a number of commercial ball types with a series of angled plateds at a number of impact speeds. These tests have been analysed in terms of normal and tangential CoR values and show that the normal part of the oblique impact can be treated independently of the tangential. In addition the relationship between backspin rate and loft angle, determined by the tangential component can be characterised using an effective friction coefficient, which has been related to the material properties and dimensions of the cover and sub-surface regions of the golf ball.

Impact studies under dry conditions have been carried out for a range of golf balls (multi-piece solid construction balls representing a variety of compression ratings with both polyurethane (PU) and ionomer covers) using a gas cannon. The balls have been fired, at a speed of 30 m/s, at grooved and un-grooved plates at effective lofts between 20 and 70° with surface roughness, Ra=1 μm. The ball speed, launch angle and backspin magnitude post-mpact were measured using a stereoscopic launch monitor system. Analysis of backspin was successfully carried out using effective coefficient of friction and spin ratio measures. Within the range of lofts investigated the backspin rate for each of the balls showed a maximum, which was dependent on the ball type and presence of grooves. This behaviour has been rationalised as the deformation of the cover into surface features (particularly grooves at higher loft angles) leading to a higher effective friction coefficient and greater rolling. The behaviour of two-piece balls is largely characterised by the cover hardness, but the mantle needs to be incorporated for three-piece balls.

Canadian Federal and Ontario Provincial statutes are reviewed as they relate to suicide and attempted suicide. Issues addressed include involuntary committal to psychiatric facilities, death by suicide as a legal cause of action, insurance exclusionary clauses and coroner's inquests.

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