8,330 research outputs found

    Pre-Participation Cardiac Screening: consideration for Young Athletes

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    This article is the first of two focusing on the utility and evidence base for pre-participation cardiac screening in competitive athletic populations. The second article will focus on the diagnostic value of different screening modalities used in the large-scale screening of athletic populations. The current article, however, focuses on the incidence of sudden cardiac death (SCD) in young athletic populations and goes on to consider the effectiveness of cardiac screening programmes for reducing the risk of SCD. Cardiac screening in athletic populations is problematic as it may be difficult to distinguish between physiological adaptations resulting from a specific exercise training stimulus and pathological conditions. Different types of chronic exercise training can induce eccentric or concentric myocardial hypertrophy, which may mimic pathological conditions. The final section discusses some of the practical issues that a clinician may face when needing to advise a young athlete to either stop or modify his/her habitual patterns of physical activity including future exercise considerations

    Quartz ball valve

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    A ball valve particularly suited for use in the handling of highly corrosive fluids is described. It is characterized by a valve housing formed of communicating segments of quartz tubing, a pair of communicating sockets disposed in coaxial alignment with selected segments of tubing for establishing a pair of inlet ports communicating with a common outlet port, a ball formed of quartz material supported for displacement between the sockets and configured to be received alternately thereby, and a valve actuator including a rod attached to the ball for selectively displacing the ball relative to each of the sockets for controlling fluid flow through the inlet ports

    Cycling and Health Innovative Pilot Projects (Executive summary)

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    The Cycling and Health Innovative Pilot Project (CHIPPS) provided cycle training for adults in Nottingham and Northamptonshire from 2007 to 2010. The Primary Care Trusts in each area have delivered these projects in collaboration with partners. In Nottingham collaboration with Ridewise delivered the Cycling for Health Project that aimed to involve people from deprived communities and employees of the Primary Care Trust; in Northamptonshire the Easy Rider project delivered via Age UK was also aimed at those living in deprived areas and middle-aged people. Throughout the three years the initiative was evaluated by the Carnegie Research Institute of Leeds Metropolitan University. Those taking part completed questionnaires at the outset, at the end of their training, three months later and finally after a year. In addition, a mix of one-to-one interviews and focus groups were conducted with policy makers, those delivering the projects and participants (including those who dropped out)

    Variability in heart rate recovery measurements over 1 year in healthy, middle-aged adults.

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    This study assessed the longer-term (12-month) variability in post-exercise heart rate recovery following a submaximal exercise test. Longitudinal data was analysed for 97 healthy middle-aged adults (74 male, 23 female) from 2 occasions, 12 months apart. Participants were retrospectively selected if they had stable physical activity habits, submaximal treadmill fitness and anthropometric measurements between the 2 assessment visits. A submaximal Bruce treadmill test was performed to at least 85% age-predicted maximum heart rate. Absolute heart rate and Δ heart rate recovery (change from peak exercise heart rate) were recorded for 1 and 2 min post-exercise in an immediate supine position. Heart rate recovery at both time-points was shown to be reliable with intra-class correlation coefficient values ≥ 0.714. Absolute heart rate 1-min post-exercise showed the strongest agreement between repeat tests (r = 0.867, P < 0.001). Lower coefficient of variation (≤ 10.2%) and narrower limits of agreement were found for actual heart rate values rather than Δ heart rate recovery, and for 1-min rather than 2-min post-exercise recovery time points. Log-transformed values generated better variability with acceptable coefficient of variation for all measures (2.2-10%). Overall, 1 min post-exercise heart rate recovery data had least variability over the 12-month period in apparently healthy middle-aged adults

    Deuterated nucleotides as chemical probes of RNA structure: a detailed protocol for the enzymatic synthesis of a complete set of nucleotides specifically deuterated at ribose carbons

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    We describe here a detailed protocol for the synthesis of ribonucleotides specifically deuterated at each ribose carbon atom. We synthesized 20 specifically deuterated ribonucleotides: ATP, CTP, GTP, and UTP, each of which contained one of five deuterated riboses (either 1′-D, 2″-D, 3′-D, 4′-D, or 5′,5″-D2). Our synthetic approach is inspired by the pioneering work of Tolbert and Williamson, who developed a method for the convenient one-pot enzymatic synthesis of nucleotides (Tolbert, T. J. and Williamson, J. R. (1996) J. Am. Chem. Soc. 118, 7929–7940). Our protocol consists of a comprehensive list of required chemical and enzymatic reagents and equipment, detailed procedures for enzymatic assays and nucleotide synthesis, and chromatographic procedures for purification of deuterated nucleotides. As an example of the utility of specifically deuterated nucleotides, we used them to synthesize specifically deuterated sarcin/ricin loop (SRL) RNA and measured the deuterium kinetic isotope effect on hydroxyl radical cleavage of the SRL.https://www.scienceopen.com/document/read?vid=eb44f1b0-c408-4336-a2c0-aed203250898Published versio

    Validity of telemetric-derived measures of heart rate variability: a systematic review

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    Heart rate variability (HRV) is a widely accepted indirect measure of autonomic function with widespread application across many settings. Although traditionally measured from the 'gold standard' criterion electrocardiography (ECG), the development of wireless telemetric heart rate monitors (HRMs) extends the scope of the HRV measurement. However, the validity of telemetric-derived data against the criterion ECG data is unclear. Thus, the purpose of this study was twofold: (a) to systematically review the validity of telemetric HRM devices to detect inter-beat intervals and aberrant beats; and (b) to determine the accuracy of HRV parameters computed from HRM-derived inter-beat interval time series data against criterion ECG-derived data in healthy adults aged 19 to 62 yrs. A systematic review of research evidence was conducted. Four electronic databases were accessed to obtain relevant articles (PubMed, EMBASE, MEDLINE and SPORTDiscus. Articles published in English between 1996 and 2016 were eligible for inclusion. Outcome measures included temporal and power spectral indices (Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology (1996). The review confirmed that modern HRMs (Polar® V800™ and Polar® RS800CX™) accurately detected inter-beat interval time-series data. The HRV parameters computed from the HRM-derived time series data were interchangeable with the ECG-derived data. The accuracy of the automatic in-built manufacturer error detection and the HRV algorithms were not established. Notwithstanding acknowledged limitations (a single reviewer, language bias, and the restricted selection of HRV parameters), we conclude that the modern Polar® HRMs offer a valid useful alternative to the ECG for the acquisition of inter-beat interval time series data, and the HRV parameters computed from Polar® HRM-derived inter-beat interval time series data accurately reflect ECG-derived HRV metrics, when inter-beat interval data are processed and analyzed using identical protocols, validated algorithms and software, particularly under controlled and stable conditions

    The interplay between viral-derived miRNAs and host immunity during infection

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    MicroRNAs are short non-coding RNAs that play a crucial role in the regulation of gene expression during cellular processes. The host-encoded miRNAs are known to modulate the antiviral defense during viral infection. In the last decade, multiple DNA and RNA viruses have been shown to produce miRNAs known as viral miRNAs (v-miRNAs) so as to evade the host immune response. In this review, we highlight the origin and biogenesis of viral miRNAs during the viral lifecycle. We also explore the role of viral miRNAs in immune evasion and hence in maintaining chronic infection and disease. Finally, we offer insights into the underexplored role of viral miRNAs as potential targets for developing therapeutics for treating complex viral diseases

    Influence of intervals of radiant heat on performance and pacing dynamics during rowing exercise

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    Abstract: The purpose of this study was to investigate whether intervals of radiant heat during thermoneutral exercise altered either the performance outcome or the dynamics of pacing within the exercise bout. Eleven male participants ( ; 56 ± 12 ml∙kg-1∙min-1) performed three 5000m exercise trials on a rowing ergometer in three different conditions, in a random order. The participants were either: non-warmed (NW), warmed (W), or periodically warmed in intervals throughout each trial (IW). Warming was achieved using radiant heat lamps to raise the localised environmental temperature from 18 ˚C to 35 ˚C. Intervals of warming were applied over fixed periods of the 5000m bouts between 1000-2000m (W1) and 3000-4000m (W2). The results of the experiment demonstrated that performance time and average power output of the 5000m matched intensity trials were not significantly different between conditions (p=0.10 ; p=0.189). However, the application of warming significantly reduced intra-trial power output during the first (W1) interval in the IW condition (p=0.03) but not during the second (W2) warming interval (p=0.10). Tsk increased by 0.51˚C (p=0.05) in response to the application of warming during W1 in the IW condition and by 0.15 ˚C in W2 (p=0.28). No significant between-condition differences were observed in Tc throughout the trials. These findings suggest that an abrupt change to environmental conditions brought about through intervals of radiant warming can affect the transient pacing dynamics of an exercise bout, but not necessarily impact overall performance time. Performance time appears unaffected by intervals of radiant heat during an exercise bout, although further work is required in more challenging dynamic environmental conditions
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