Voluntary activation of human knee extensors measured using transcranial magnetic stimulation

The aim of this study was to determine the applicability and reliability of a transcranial magnetic stimulation twitch interpolation technique for measuring voluntary activation of a lower limb muscle group. Cortical voluntary activation of the knee extensors was determined in nine healthy men on two separate visits by measuring superimposed twitch torques evoked by transcranial magnetic stimulation during isometric knee extensions of varying intensity. Superimposed twitch amplitude decreased linearly with increasing voluntary torque between 50 and 100% of mean maximal torque, allowing estimation of resting twitch amplitude and subsequent calculation of voluntary activation. There were no systematic differences for maximal voluntary activation within day (mean ± S.D. 90.9 ± 6.2 versus 90.7 ± 5.9%; P = 0.98) or between days (90.8 ± 6.0 versus 91.2 ± 5.7%; P = 0.92). Systematic bias and random error components of the 95% limits of agreement were 0.23 and 9.3% within day versus −0.38 and 7.5% between days. Voluntary activation was also determined immediately after a 2 min maximal voluntary isometric contraction; in four of these subjects, voluntary activation was determined 30 min after the sustained contraction. Immediately after the sustained isometric contraction, maximal voluntary activation was reduced from 91.2 ± 5.7 to 74.2 ± 12.0% (P < 0.001), indicating supraspinal fatigue. After 30 min, voluntary activation had recovered to 85.4 ± 8.8% (P = 0.39 versus baseline). These results demonstrate that transcranial magnetic stimulation enables reliable measurement of maximal voluntary activation and assessment of supraspinal fatigue of the knee extensors

Infanticide, a mother’s crime : expert evidence and infanticide cases, 1688-1955

“Infanticide: A Mother’s Crime” explores expert evidence in cases of infanticide with a view to determining the extent of certainty, created by medical men who founded their evidence on anatomical exploration and science. As the thesis progresses, it becomes clear that medical men were unable to scientifically establish cause of death, and in doing so convey certainty; instead medical men conveyed uncertainty. However, rather than being seen as a professional failing, this thesis will argue, that the uncertainty created by medical men made a positive contribution to infanticide cases. The combination of uncertainty created by medical experts and the changing perceptions of infanticidal women by the court, allowed the jury to find infanticidal women not guilty of a capital offence. A number of cases demonstrate that the jury found the women guilty of the lesser offence of concealment of birth; a favourable outcome for both the women and the collective conscience of the jury.This research begins in the year 1688 with an examination of evidence given by the midwife. In the absence of medical reasoning or discourse, she gave evidence based purely on her experience and knowledge, until the eighteenth century when the courts seemed to demand greater certainty from expert evidence. As the midwife was replaced in the courtroom by medical men, during the eighteenth century, this research will continue by drawing on the testimony of medical men, mental state experts and pathologists until its conclusion in 1955. The longevity of this research has been divided into forty or fifty year periods, allowing the testimony to be examined within each period, and timeframes to be compared over a substantial period of time. Cases have been examined both within and outside the London area, by drawing on examplesfrom the Old Bailey and Hull and the surrounding area

Facilitating interoceptive awareness as a self-management and self-regulation tool to increase engagement in learning and education

Interoceptive awareness is the conscious perception or active noticing of one’s internal body signals, such as muscle tension, bladder state, heart rate, etc. This mixed methods thesis examined whether teaching students to actively notice their internal body signals would increase self-management and self-regulation within the school context, the consequence of which would be a reduction in behaviours that were affecting teaching and learning. In addition, this thesis examined if there was any impact on engagement in learning and education as students developed their interoceptive awareness. Data were drawn from a one-year pilot with one school, and then a one-year trial with 11 schools in regional South Australia. The findings demonstrated a reduction in reported behavioural consequences across the schools, with qualitative findings detailing the impacts of learning interoceptive techniques for individuals and their own perceptions of their behaviours. This thesis utilised Siegel’s (2010) hand model of the brain, in combination with a novel way of presenting the two branches of the autonomic nervous system, as a potential explanation for the findings that teaching interoceptive awareness increased engagement in learning and education, self-management, and self-regulation in the school context. The resultant model that was developed by the researcher is a clear visual that can support education staff to understand and respond to challenging behaviour more effectively and proactively across both high school and primary school contexts

Acute Resveratrol Administration Increases Neural Effort but Not Whole Body Metabolism or Cognitive Performance in Healthy, Young Participants

Research into the cognitive enhancing effects of polyphenols is small but growing. Single doses of the stilbene polyphenol resveratrol can increase cerebral blood flow (CBF) but have failed to improve cognitive performance in young, healthy cohorts. As both CBF and overall energy expenditure are closely related to neural activity, this randomised, double-blind, placebo-controlled, crossover investigation, assessed the metabolic consequences of resveratrol during high cognitive demand via indirect calorimetry (ICa). Twenty-seven, self-reported healthy participants (15 male, 12 female; mean age = 22) who reported themselves free of any food intolerances and any herbal supplementation or prescription medications were recruited for the current study. Participants arrived at the testing facility at 8 a.m. on three separate occasions to complete a serial subtraction demand battery 45 min and 2 and 3 h following administration with 500 mg, 250 mg trans-resveratrol or inert placebo, while connected to an online gas analysis system. A series of within-subjects ANOVAs (with planned comparisons) revealed a significant shift towards higher carbohydrate oxidisation during cognitive demand, as indexed by a significant increase in respiratory exchange ratio (RER) at 45-min and 3-h time points, following administration of 500 mg resveratrol. Despite this, no subsequent resveratrol-related benefits to cognitive performance were observed. These results show that acute supplementation with resveratrol in young, healthy adults can modulate fuel utilization during cognitive demand, yet this does not translate into clear improvements in cognitive performance. This study adds further understanding behind the lack of cognitive effects of resveratrol in young and or healthy individuals. Future research should direct efforts towards assessing the cognitive impact of resveratrol, and other vasoactive polyphenols, in populations with age-related or dietary-induced metabolic deficits

A review of the state of the art in tools and techniques used to evaluate remanufacturing feasibility

Remanufacturing often seems a sensible approach for companies looking to adopt sustainable business plans to achieve long term success. However, remanufacturing must not be treated as a panacea for achieving a sustainable business, as issues such as market demand, product design, end of life condition and information uncertainty can affect the success of a remanufacturing endeavour. Businesses therefore need to carefully assess the feasibility of adopting remanufacturing before committing to a particular activity or strategy. To aid this decision process, a number of tools and techniques have been published by academics. However, there is currently not a formal review and comparison of these tools and how they relate to the decision process. The main research objective of this study has therefore been to identify tools and methods which have been developed within academia to support the decision process of assessing and evaluating the viability of conducting remanufacturing, and evaluate how they have met the requirements of the decision stage. This has been achieved by conducting a content analysis. Three bibliographic databases were searched (Compendex, Web of Science and Scopus) using a structured keyword search to identify relevant literature. The identified tools were then split into 6 categories based upon the specific decision stages and applications, then evaluated against a set of key criteria which are, the decision factors (economic, environmental, social) and the inclusion of uncertainty. The key finding of this study has been that although decision factors are generally well covered, operational tools and the use of uncertainty are often neglected

Supraspinal fatigue after normoxic and hypoxic exercise in humans.

Inadequate cerebral O₂ availability has been proposed to be an important contributing factor to the development of central fatigue during strenuous exercise. Here we tested the hypothesis that supraspinal processes of fatigue would be increased after locomotor exercise in acute hypoxia compared to normoxia, and that such change would be related to reductions in cerebral O₂ delivery and tissue oxygenation. Nine endurance-trained cyclists completed three constant-load cycling exercise trials at ∼80% of maximal work rate: (1) to the limit of tolerance in acute hypoxia; (2) for the same duration but in normoxia (control); and (3) to the limit of tolerance in normoxia. Throughout each trial, prefrontal cortex tissue oxygenation and middle cerebral artery blood velocity (MCAV) were assessed using near-infrared spectroscopy and trans-cranial Doppler sonography, respectively. Cerebral O₂ delivery was calculated as the product of arterial O₂ content and MCAV. Before and immediately after each trial, twitch responses to supramaximal femoral nerve stimulation and transcranial magnetic stimulation were obtained to assess neuromuscular and cortical function, respectively. Exercise time was reduced by 54%in hypoxia compared to normoxia (3.6 ± 1.3 vs. 8.1 ± 2.9 min; P0.05). Cortical voluntary activation was also decreased after exercise in all trials, but the decline in hypoxia (Δ18%) was greater than in the normoxic trials (Δ5-9%)(P <0.05). The reductions in cortical voluntary activation were paralleled by reductions in cerebral O₂ delivery. The results suggest that curtailment of exercise performance in acute severe hypoxia is due, in part, to failure of drive from the motor cortex, possibly as a consequence of diminished O₂ availability in the brain

Extending maintenance intervals of track switches utilising multi-channel redundancy of actuation and sensing

A concept for a novel track switch arrangement has been developed at Loughborough University, which, through a novel locking arrangement, allows parallel, multi-channel actuation and locking functions for the first time. This switch has been developed as part of the REPOINT project, and is referred to as the REPOINT switch. Existing track switches generally use a single-channel actuator and lock, and undergo an intensive maintenance and inspection regime to ensure an acceptable level of reliability/availability. This paper demonstrates, through mathematical modelling with very conservative assumptions, that an increase in switch availability is possible alongside a corresponding decrease in ongoing maintenance intensity using the REPOINT multi-channel approach. The paper firstly introduces the theory behind the design of the REPOINT switch, using a switch with 2-out-of-3 redundant actuation and sensing channels as an example. An existing switch is analysed using real-world data as a benchmark. Availability is determined by the target time in which Maintenance Teams must have replaced any failed components, expressed herein as τ. Availability measures are obtained as functions of τ which show the range of possible switch availability against maintenance response times, for the given set of assumptions. The results show that for a REPOINT installation, gains in system availability are possible even when response times are set many times longer than current standards, indicating a significant reduction in ongoing maintenance cost

Rethinking rail track switches for fault tolerance and enhanced performance

© 2016, © IMechE 2016. Railway track switches, commonly referred to as ‘turnouts’ or ‘points,’ are a necessary element of any rail network. However, they often prove to be performance-limiting elements of networks. A novel concept for rail track switching has been developed as part of a UK research project with substantial industrial input. The concept is currently at the demonstrator phase, with a scale (384 mm) gauge unit operational in a laboratory. Details of the novel arrangement and concept are provided herein. This concept is considered as an advance on the state of the art. This paper also presents the work that took place to develop the concept. Novel contributions include the establishment of a formal set of functional requirements for railway track switching solutions, and a demonstration that the current solutions do not fully meet these requirements. The novel design meets the set of functional requirements for track switching solutions, in addition to offering several features that the current designs are unable to offer, in particular to enable multi-channel actuation and rail locking, and provide a degree of fault tolerance. This paper describes the design and operation of this switching concept, from requirements capture and solution generation through to the construction of the laboratory demonstrator. The novel concept is contrasted with the design and operation of the ‘traditional’ switch design. Conclusions to the work show that the novel concept meets all the functional requirements whilst exceeding the capabilities of the existing designs in most non-functional requirement areas

Rethinking rail track switches for fault tolerance and enhanced performance

Railway track switches, commonly referred to as ‘turnouts’ or ‘points,’ are a necessary element of any rail network. However, they often prove to be performance-limiting elements of networks. A novel concept for rail track switching has been developed as part of a UK research project with substantial industrial input. The concept is currently at the demonstrator phase, with a scale (384 mm) gauge unit currently operational in a laboratory. Details of the novel arrangement and concept are provided herein. This concept is considered as an advance on the state of the art. This paper also presents the work that took place to develop the concept. Novel contributions include the establishment of a formal set of functional requirements for railway track switching solutions, and a demonstration that the current solutions do not fully meet these requirements. The novel design meets the set of functional requirements for track switching solutions, in addition to offering several features that the current designs are unable to offer, in particular to enable multi-channel actuation and rail locking, and provide a degree of fault tolerance. This paper describes the design and operation of this switching concept, from requirements capture and solution generation through to the construction of the laboratory demonstrator. The novel concept is contrasted with the design and operation of the ‘traditional’ switch design. Conclusions to the work show that the novel concept meets all the functional requirements whilst exceeding the capabilities of the existing designs in most non-functional requirement areas