Thermoregulation during intermittent exercise in athletes with a spinal-cord injury

Purpose: Individuals with a spinal-cord injury have impaired thermoregulatory control due to a loss of sudomotor and vasomotor effectors below the lesion level. Thus, individuals with high-level lesions (tetraplegia) possess greater thermoregulatory impairment than individuals with lower-level lesions (paraplegia). Previous research has not reflected the intermittent nature and modality of wheelchair court sports or replicated typical environmental temperatures. Hence, the purpose of this study was to investigate the thermoregulatory responses of athletes with tetraplegia and paraplegia during an intermittent-sprint protocol (ISP) and recovery in cool conditions. Methods: Sixteen wheelchair athletes, 8 with tetraplegia (TP, body mass 65.2 ± 4.4 kg) and 8 with paraplegia (body mass 68.1 ± 12.3 kg), completed a 60-min ISP in 20.6°C ± 0.1°C, 39.6% ± 0.8% relative humidity on a wheelchair ergometer, followed by 15 min of passive recovery. Core temperature (Tcore) and mean (Tsk) and individual skin temperatures were measured throughout. Results: Similar external work (P = .70, ES = 0.20) yet a greater Tcore (P < .05, ES = 2.27) and Tsk (P < .05, ES = 1.50) response was demonstrated by TP during the ISP. Conclusions: Despite similar external work, a marked increase in Tcore in TP during exercise and recovery signifies that thermoregulatory differences between the groups were predominantly due to differences in heat loss. Further increases in thermal strain were not prevented by the active and passive recovery between maximal-effort bouts of the ISP, as Tcore continually increased throughout the protocol in TP

Thermoregulatory responses during competitive wheelchair rugby match play

The purpose of this study was to determine whether a player’s physical impairment or activity profile was related to the amount of thermal strain experienced during wheelchair rugby match play. 17 elite wheelchair rugby players played a competitive match, whilst activity profiles, measures of core and skin temperature, heart rate and perceptual responses were taken. Players were divided into 2 groups depending on their physical impairment: players with a cervical spinal cord injury, (n=10) or non-spinal related physical impairment (n=7). Total distance was lower (4 842±324 vs. 5 541±316 m, p<0.01, ES=2.2) and mean speed slower (1.13±0.11 vs. 1.27±0.11 m∙s−1, p<0.03, ES=1.3) in players with a spinal cord injury. Yet, the change in core temperature (1.6±0.4 vs. 0.7±0.3°C, p<0.01, ES=2.5) was significantly greater in players with a spinal cord injury. In conclusion, players with a spinal cord injury were under greater thermal strain during wheelchair rugby match play, as a result of their reduced heat loss capacity, due to their physical impairment and not because of their activity profile

Effects of cooling before and during simulated match play on thermoregulatory responses of athletes with tetraplegia

Objectives: Athletes with high level spinal cord injuries (tetraplegia) are under greater thermal strain during exercise than the able-bodied. The purpose of this study was to investigate the effectiveness of pre-cooling using an ice vest and the combination of pre-cooling and cooling during play using water sprays in athletes with tetraplegia. Design: Counter-balanced, cross-over design. Methods: Eight wheelchair rugby players with tetraplegia completed a 60 min intermittent sprint protocol (ISP) on a wheelchair ergometer in 20.2 °C ± 0.2 °C and 33.0% ± 3.1% relative humidity. The ISP was conducted on three occasions; no cooling (NC), pre-cooling with an ice vest (P) and pre-cooling with an ice vest and water sprays between quarters (PW). Gastrointestinal (Tgi) temperature, mean skin temperature (Tsk) and perceptual responses were measured throughout. Results: At the end of pre-cooling, the change in Tgi was not significantly different between conditions (P > 0.05) but the change in Tsk was significantly greater in P and PW compared to NC (P 0.05). Conclusions: Water spraying between quarters combined with pre-cooling using an ice vest lowers thermal strain to a greater degree than pre-cooling only in athletes with tetraplegia, but has no effect on simulated wheelchair rugby performance or perceptual responses

Assessing the Risk of Metals and Their Mixtures in the Antarctic Nearshore Marine Environment with Diffusive Gradients in Thin-Films

© 2019 American Chemical Society. Robust environmental assessments and contaminant monitoring in Antarctic near-shore marine environments need new techniques to overcome challenges presented by a highly dynamic environment. This study outlines an approach for contaminant monitoring and risk assessment in Antarctic marine conditions using diffusive gradients in thin-films (DGT) coupled to regionally specific ecotoxicology data and environmental quality standards. This is demonstrated in a field study where DGT samplers were deployed in the near-shore marine environment of East Antarctica around the operational Casey station and the abandoned Wilkes station to measure the time-averaged biologically available fraction of metal contaminants. The incorporation of DGT-labile concentrations to reference toxicity mixture models for three Antarctic organisms predicted low toxic effects (<5% effect to the growth or development of each organism). The comparison of metal concentrations to the Australian and New Zealand default water quality guideline values (WQGVs) showed no marine site exceeding the WQGVs for 95% species protection. However, all sites exceeded the 99% WQGVs due to copper concentrations that are likely of geogenic origin (i.e., not from anthropogenic sources). This study provides evidence supporting the use of the DGT technique to monitor contaminants and assess their environmental risk in the near-shore marine environment of Antarctica

Age dependence of serum beta-N-acetylhexosaminidase (NAG) activity

Serum Nacetyl-beta-Dglucosaminidase (NAG; EC 3.2.1.30) is a hexosaminidase and may be a predictor of vascular injury, e.g., in infant respiratory distress syndrome, pneumonia, bronchopulmonary dysplasia and necrotizing enterocolitis. To estimate the new diagnostic prospects we have modified our urinary NAG assay. In this sensitive colorimetric microassay, VRAGlcNAc was used as a substrate. In the present study the age dependence of serum NAG activity was investigated in newborn babies, infants (124 months), children (218 years) and adults (1980 years). Serum NAG activity was found to be agedependent; it is higher in early childhood (1159 U/l) but decreases to a constant value at the age of 12 years. After the age of 2 years it is similar to adults NAG (1030 U/l). In pediatrics agematched reference ranges must be taken into consideration

Evaporative heat loss insufficient to attain heat balance at rest in individuals with a spinal cord injury at high ambient temperature

The aim of the study was to determine whether climatic limits for achieving heat balance at rest are affected by spinal cord injury (SCI). Twenty-three males (8 able-bodied (AB), 8 with paraplegia (PP) and 7 with tetraplegia (TP)) rested in 37°C and 20% relative humidity (RH) for 20 mins. With the ambient temperature held constant, RH was increased by 5% every 7 mins, until gastrointestinal temperature (Tgi) showed a clear inflection or increased by >1°C. Tgi, skin temperatures, perceptual responses and metabolic energy expenditure were measured throughout. Metabolic heat production (AB: 123 (21) W, PP: 111 (15) W, TP: 103 (29) W) and required rate of evaporative cooling for heat balance (Ereq, AB: 113 (20) W, PP: 107 (17) W, TP: 106 (29) W) were similar between groups (p = 0.22 and p = 0.79). Compared to AB, greater increases in Tgi were observed in TP (p = 0.01), with notable increases in mean skin temperature (Tsk) for TP and PP (p = 0.01). A Tgi inflection point was demonstrated by 7 AB, only 3 out of 8 PP and none of TP. Despite metabolic heat production (and Ereq) being similar between groups evaporative heat loss was not large enough to obtain heat balance in TP, linked to a shortfall in evaporative cooling potential. Although PP possess a greater sweating capacity, the continual increase in Tgi and Tsk, in most PP, while lower than for TP, implies that latent heat loss for PP is also insufficient to attain heat balance

Infographic. Thermoregulatory impairment in athletes with a spinal cord injury

Presented in this infographic is a summary of studies investigating the thermoregulatory impairment of athletes with a spinal cord injury during real-world sporting scenarios. The infographic depicts the heightened thermal strain experienced by athletes with tetraplegia (high level lesions), both compared to athletes with paraplegia (low level lesions) and within the sport of wheelchair rugby. In addition to the cooling interventions presented, the infographic highlights the significant need for appropriate interventions to reduce the risk of overheating and potential performance decrements. This infographic was field tested with those who work within a wheelchair sports environment, ranging from practitioners, researchers, athletes with an SCI and sports clinicians. The experimental studies were also designed in consultation with the wheelchair rugby coaches and players

Energy-Efficiency and Greenhouse Gas Mitigation Policy Options: Assisting Chinese Cities in Prioritizing and Choosing Strategies

Myriad energy-efficiency and greenhouse gas mitigation policy options are available for urban communities to reduce energy use and emissions from buildings, transportation systems, industries, utilities, public lighting, water and wastewater, and solid waste disposal. This paper describes a methodology to assist urban community planners and policymakers in China to prioritize and choose strategies to implement for their particular situation. The methodology was developed for use in a dynamic decision-making tool, the Benchmarking and Energy-Saving Tool for Low Carbon Cities (BEST-Cities), which was specifically designed for urban communities in China but which could be used internationally. The methodology builds on concepts from other urban low-carbon planning tools, but augments them to address specific Chinese conditions and needs. The methodology starts by conducting a simple inventory of energy use by end-use sector, which is then converted by the tool into units of carbon dioxide and methane emissions. Next, Key Performance Indicators are calculated and the tool benchmarks the city to other cities, providing an indication of the energy saving and emissions reduction potential for each end-use sector as a first step for policy prioritization. Then the level of authority and capacity of the city in terms of financial and human resources and enforcement is self-assessed since these are also important inputs for policy prioritization. The tool then provides Chinese planners and policy-makers with a menu of policies and measures prioritized by sector based on the identified energy and emissions reduction potential and distinguished by speed of implementation, carbon savings potential, and first cost to the government. Planners and policymakers then prioritize the policy options based on their specific criteria and needs

(Micro)evolutionary changes and the evolutionary potential of bird migration

Seasonal migration is the yearly long-distance movement of individuals between their breeding and wintering grounds. Individuals from nearly every animal group exhibit this behavior, but probably the most iconic migration is carried out by birds, from the classic V-shape formation of geese on migration to the amazing nonstop long-distance flights undertaken by Arctic Terns Sterna paradisaea. In this chapter, we discuss how seasonal migration has shaped the field of evolution. First, this behavior is known to turn on and off quite rapidly, but controversy remains concerning where this behavior first evolved geographically and whether the ancestral state was sedentary or migratory (Fig. 7.1d, e). We review recent work using new analytical techniques to provide insight into this topic. Second, it is widely accepted that there is a large genetic basis to this trait, especially in groups like songbirds that migrate alone and at night precluding any opportunity for learning. Key hypotheses on this topic include shared genetic variation used by different populations to migrate and only few genes being involved in its control. We summarize recent work using new techniques for both phenotype and genotype characterization to evaluate and challenge these hypotheses. Finally, one topic that has received less attention is the role these differences in migratory phenotype could play in the process of speciation. Specifically, many populations breed next to one another but take drastically different routes on migration (Fig. 7.2). This difference could play an important role in reducing gene flow between populations, but our inability to track most birds on migration has so far precluded evaluations of this hypothesis. The advent of new tracking techniques means we can track many more birds with increasing accuracy on migration, and this work has provided important insight into migration's role in speciation that we will review here