1,839 research outputs found
Proposal to disregard athletics world records prior to 2005: a radical and misjudged initiative
The recent announcement that the European Athletics Council has proposed to disregard all athletics world records set prior to 20051 has caused considerable controversy and debate among the athletics community. It is a radical initiative with commendable aims to redress the consequences of past undetected doping violations that may have led to some of the least attainable world records. This proposal has now been put to the world governing body, the International Amateur Athletics Federation (IAAF), and its merits require discussion
Rapid antimicrobial sensitivity testing by single cell nanoscale optical interference
Growing antimicrobial resistance (AMR) is a serious global threat to human health, with estimates of AMR leading to 10 million deaths per year and costing the global economy $100tn by 20501,2. Current methods to detect resistance include phenotypic antibiotic sensitivity testing (AST) which measures bacterial growth and is therefore hampered by slow time to result (~12-24 hours). Therefore new rapid phenotypic methods for AST are urgently needed3. Here we describe a novel method for detecting phenotypic antibiotic resistance in ~45 minutes, capable of detecting single bacteria. The method uses a sensitive laser and detector system to measure nanoscale optical interference of single bacterial cells present in media, with simple sample preparation. This provides a read out of bacterial antibiotic resistance by detecting growth (resistant) or death (sensitive), much faster than current methods. We demonstrate the potential of this technique by determining resistance in both lab and clinical strains of E. coli, a key species for clinically burdensome urinary tract infections. This work provides the basis for a simple and fast diagnostic tool to detect antibiotic resistance in bacteria, reducing the health and economic burdens of AMR
Short-term reliability of inflammatory mediators and response to exercise in the heat.
Prospective application of serum cytokines, lipopolysaccharide (LPS), and heat shock proteins (eHSPs) requires reliable measurement of these biomarkers that can signify exercise-induced heat stress in hot conditions. To accomplish this, both short-term (7 day) reliability (at rest, n = 12) and the acute responsiveness of each biomarker to exercise in the heat (pre and post 60-min cycling, 34.5°C and 70% RH, n = 20) were evaluated. Serum was analysed for the concentration of C-reactive protein (CRP), interleukin-6 (IL-6), heat shock protein 72 (eHSP72), immunoglobulin M (IgM) and LPS. Test–retest reliability was determined as the coefficient of variation (CV). Biomarkers with the least short-term within-participant variation were IL-6 (19%, ±20%; CV, ±95% confidence limits (CL)) and LPS (23%, ±13%). Greater variability was observed for IgM, eHSP72 and CRP (CV range 28–38%). IL-6 exhibited the largest increase in response to acute exercise (95%, ±11%, P = < 0.001) and although CRP had a modest CV (12%, ±7%), it increased substantially post-exercise (P = 0.02, ES; 0.78). In contrast, eHSP72 and LPS exhibited trivial changes post-exercise. It appears variation of common inflammatory markers after exercise in the heat is not always discernible from short-term (weekly) variation
Second Order Perturbations of Flat Dust FLRW Universes with a Cosmological Constant
We summarize recent results concerning the evolution of second order
perturbations in flat dust irrotational FLRW models with . We
show that asymptotically these perturbations tend to constants in time, in
agreement with the cosmic no-hair conjecture. We solve numerically the second
order scalar perturbation equation, and very briefly discuss its all time
behaviour and some possible implications for the structure formation.Comment: 6 pages, 1 figure. to be published in "Proceedings of the 5th
Alexander Friedmann Seminar on Gravitation and Cosmology", Int. Journ. Mod.
Phys. A (2002). Macros: ws-ijmpa.cls, ws-p9-75x6-50.cl
Lactobacillus fermentum (PCC®) supplementation and gastrointestinal and respiratory-tract illness symptoms: a randomised control trial in athletes
BACKGROUND Probiotics purportedly reduce symptoms of gastrointestinal and upper respiratory-tract illness by modulating commensal microflora. Preventing and reducing symptoms of respiratory and gastrointestinal illness are the primary reason that dietary supplementation with probiotics are becoming increasingly popular with healthy active individuals. There is a paucity of data regarding the effectiveness of probiotics in this cohort. The aim of this study was to evaluate the effectiveness of a probiotic on faecal microbiology, self-reported illness symptoms and immunity in healthy well trained individuals. METHODS Competitive cyclists (64 males and 35 females; age 35 ± 9 and 36 ± 9 y, VO2max 56 ± 6 and 52 ± 6 ml.kg-1.min-1, mean ± SD) were randomised to either probiotic (minimum 1 × 109 Lactobacillus fermentum (PCC®) per day) or placebo treatment for 11 weeks in a double-blind, randomised, controlled trial. The outcome measures were faecal L. fermentum counts, self-reported symptoms of illness and serum cytokines. RESULTS Lactobacillus numbers increased 7.7-fold (90% confidence limits 2.1- to 28-fold) more in males on the probiotic, while there was an unclear 2.2-fold (0.2- to 18-fold) increase in females taking the probiotic. The number and duration of mild gastrointestinal symptoms were ~2-fold greater in the probiotic group. However, there was a substantial 0.7 (0.2 to 1.2) of a scale step reduction in the severity of gastrointestinal illness at the mean training load in males, which became more pronounced as training load increased. The load (duration×severity) of lower respiratory illness symptoms was less by a factor of 0.31 (99%CI; 0.07 to 0.96) in males taking the probiotic compared with placebo but increased by a factor of 2.2 (0.41 to 27) in females. Differences in use of cold and flu medication mirrored these symptoms. The observed effects on URTI had too much uncertainty for a decisive outcome. There were clear reductions in the magnitude of acute exercise-induced changes in some cytokines. CONCLUSION L. fermentum may be a useful nutritional adjunct for healthy exercising males. However, uncertainty in the effects of supplementation on URTI and on symptoms in females needs to be resolved. TRIAL REGISTRATION The trial was registered in the Australia and New Zealand Clinical Trials Registry (ACTRN12611000006943).The study was funded by Christian Hansen A/S, Probiomics and the Australian Institute of Sport
Therapeutic potential of targeting sphingosine kinases and sphingosine 1-phosphate in hematological malignancies
Sphingolipids, such as ceramide, sphingosine and sphingosine 1-phosphate (S1P) are bioactive molecules that have important functions in a variety of cellular processes, which include proliferation, survival, differentiation and cellular responses to stress. Sphingolipids have a major impact on the determination of cell fate by contributing to either cell survival or death. Although ceramide and sphingosine are usually considered to induce cell death, S1P promotes survival of cells. Sphingosine kinases (SPHKs) are the enzymes that catalyze the conversion of sphingosine to S1P. There are two isoforms, SPHK1 and SPHK2, which are encoded by different genes. SPHK1 has recently been implicated in contributing to cell transformation, tumor angiogenesis and metastatic spread, as well as cancer cell multidrug-resistance. More recent findings suggest that SPHK2 also has a role in cancer progression. This review is an overview of our understanding of the role of SPHKs and S1P in hematopoietic malignancies and provides information on the current status of SPHK inhibitors with respect to their therapeutic potential in the treatment of haematological cancers
Manipulating graded exercise test variables affects the validity of the lactate threshold and VO2peak
Background To determine the validity of the lactate threshold (LT) and maximal oxygen uptake (V_ O2max) determined during graded exercise test (GXT) of different durations and using different LT calculations. Trained male cyclists (n = 17) completed five GXTs of varying stage length (1, 3, 4, 7 and 10 min) to establish the LT, and a series of 30-min constant power bouts to establish the maximal lactate steady state (MLSS). V_ O2 was assessed during each GXT and a subsequent verification exhaustive bout (VEB), and 14 different LTs were calculated from four of the GXTs (3, 4, 7 and 10 min)—yielding a total 56 LTs. Agreement was assessed between the highest V_ O2 measured during each GXT (V_ O2peak) as well as between each LT and MLSS. V_ O2peak and LT data were analysed using mean difference (MD) and intraclass correlation (ICC). Results The V_ O2peak value from GXT1 was 61.0 ± 5.3 mL.kg-1.min-1 and the peak power 420 ± 55 W (mean ± SD). The power at the MLSS was 264 ± 39 W. V_ O2peak from GXT3, 4, 7,10 underestimated V_ O2peak by ~1–5 mL.kg-1.min-1. Many of the traditional LT methods were not valid and a newly developed Modified Dmax method derived from GXT4 provided the most valid estimate of the MLSS (MD = 1.1 W; ICC = 0.96). Conclusion The data highlight how GXT protocol design and data analysis influence the determination of both V_ O2peak and LT. It is also apparent that V_ O2max and LT cannot be determined in a single GXT, even with the inclusion of a VEB
A self-reported questionnaire for quantifying illness symptoms in elite athletes
PURPOSE: To develop and evaluate a questionnaire that quantifies the self-reported frequency, duration and severity of illness symptoms in highly-trained athletes. We examined whether runners had more symptoms than recreationally-active individuals, and whether runners more prone to illness were undertaking more strenuous training programs. METHODS: A daily illness questionnaire was administered for three months during the summer to quantify the type, frequency, duration, and severity of illness symptoms as well as the functional impact on the ability to undertake exercise performance. A total of 35 participants (12 highly-trained runners living in a community setting and 23 recreationally-active medical students) completed the questionnaire. RESULTS: Runners had a similar frequency of illness (2.1 ± 1.2 vs. 1.8 ± 2.3 episodes, mean ± SD, P = 0.58), but substantially longer duration (5.5 ± 9.9 vs 2.8 ± 3.1 days, P < 0.01) and illness load (7.7 ± 16.2 vs 4.5 ± 4.8 units, P = 0.001) than age- and sex-matched recreationally-active individuals respectively. Runners more prone to illness symptoms had marginally higher training loads. CONCLUSIONS: The athlete illness questionnaire is useful for quantifying the pattern of self-reported symptoms of illness in field settings. Highly-trained runners experience longer episodes of illness with a greater impact on daily activity than recreationally-active individuals
Fullerene van der waals Oligomers as electron traps
Density functional theory calculations indicate that van der Waals fullerene dimers and larger oligomers can form interstitial electron traps in which the electrons are even more strongly bound than in isolated fullerene radical anions. The fullerenes behave like super atoms , and the interstitial electron traps represent one-electron intermolecular σ-bonds. Spectroelectrochemical measurements on a bis-fullerene-substituted peptide provide experimental support. The proposed deep electron traps are relevant for all organic electronics applications in which non-covalently linked fullerenes in van der Waals contact with one another serve as n-type semiconductors
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