Stevens, CJ, Bennett, KJM, Sculley, DV, Callister, R, Taylor, L, and Dascombe, BJ. A comparison of mixed-method cooling interventions on preloaded running performance in the heat. J Strength Cond Res ...31(3): 620-629, 2017-The purpose of this investigation was to assess the effect of combining practical methods to cool the body on endurance running performance and physiology in the heat. Eleven trained male runners completed 4 randomized, preloaded running time trials (20 minutes at 70% VCombining Dot AboveO2max and a 3 km time trial) on a nonmotorized treadmill in the heat (33° C). Trials consisted of precooling by combined cold-water immersion and ice slurry ingestion (PRE), midcooling by combined facial water spray and menthol mouth rinse (MID), a combination of all methods (ALL), and control (CON). Performance time was significantly faster in MID (13.7 ± 1.2 minutes; p < 0.01) and ALL (13.7 ± 1.4 minutes; p = 0.04) but not PRE (13.9 ± 1.4 minutes; p = 0.24) when compared with CON (14.2 ± 1.2 minutes). Precooling significantly reduced rectal temperature (initially by 0.5 ± 0.2° C), mean skin temperature, heart rate and sweat rate, and increased iEMG activity, whereas midcooling significantly increased expired air volume and respiratory exchange ratio compared with control. Significant decreases in forehead temperature, thermal sensation, and postexercise blood prolactin concentration were observed in all conditions compared with control. Performance was improved with midcooling, whereas precooling had little or no influence. Midcooling may have improved performance through an attenuated inhibitory psychophysiological and endocrine response to the heat.
The current study explored the association between talent pool size and relative age effects in Football Australia's talent pathway. It also compared relative age effects between male and female ...players. Participants were 54,207 youth football players (females: n = 12,527, age-range = 14.0-15.9; males: n = 41,680, age-range = 13.0-14.9) eligible for the National Youth Championships. We developed linear regression models to examine the association between the member federation size and the probability of a player being born earlier in the year. We also analysed selection probabilities based on birth quartile and year half across three layers. Overall, talent pool size was associated with a higher probability of selecting a player born in the first half of the year over the second. More specifically, an increase of 760 players led to a 1% higher selection probability for those born in the first six months of a chronological age group. In addition, there were more occurrences of relative age effects in the male than the female sample. Future studies should focus on the impact of the talent pool size on relative age effects at each major talent identification/selection stage of a talent pathway.
To investigate the construct and discriminant validity of a video-based decision-making assessment for talent identification in youth soccer.
Observational study.
A total of 328 academy youth soccer ...players (tier one, tier two, and tier three) from three developmental stages (late childhood, early adolescence, and mid-adolescence) participated in this study. The control group consisted of 59 youth athletes with no soccer experience in the last five years. Players completed a video-based decision-making assessment on an iPad, with response accuracy and response time recorded for various attacking situations (2 vs. 1, 3 vs. 1, 3 vs. 2, 4 vs. 3, and 5 vs. 3).
The video-based decision-making assessment showed some construct validity. Response times were significantly faster in early and mid-adolescent players when compared to those in the late childhood group. Furthermore, an overall decline in decision-making performance (i.e. decrease in response accuracy and increase in response time) was observed from the 2 vs. 1 to the 4 vs. 3 situations. The video-based decision-making assessment lacked discriminant validity as minimal differences between academies were evident for response accuracy and response time. Only response accuracy was able to discriminate youth academy soccer players from the control group to some extent.
Coaches and sporting professionals should apply caution when interpreting data from practical, video-based decision-making assessments. There is currently limited conclusive evidence supporting the effectiveness of these assessments for talent identification.
Talent identification in youth soccer is a complex decision-making process that requires selectors to judge an individual's future potential. While there has been considerable research into the ...performance characteristics of talented players, investigators have limited consensus on the best approach to assess soccer skills. Most of the research explains why we should measure skill instead of how we go about assessing skill. Therefore, the current scoping review aimed to synthesize and analyse skill assessments in youth soccer. Four electronic databases (EBSCO, ProQuest, PubMed, and Scopus) were searched for relevant studies. Information regarding the sample characteristics and methodological design of the skill assessments were extracted, synthesised, and presented in a qualitative analysis. Overall, 226 skill assessments were used across the 93 included studies. Male players from different ages (U/7-U/23) and playing levels comprised most (89%) of the collective sample. The majority of assessments were performed in settings not representative of football match-play (68%), focused on offensive skills (99%), and included skill outcome measures (95%). The variability of assessments highlights some confusion about the best way to assess soccer skill, potentially limiting selectors ability to identify skilful players. Ultimately, this will impact the number of quality players within the talent pool.
Abundant natural gas reserves, along with increased biogas production, have prompted recent interest in harnessing methane as an industrial feedstock for the production of liquid fuels and chemicals. ...Methane can either be used directly for fermentation or first oxidized to methanol via biological or chemical means. Methanol is advantageous due to its liquid state under normal conditions. Methylotrophy, defined as the ability of microorganisms to utilize reduced one-carbon compounds like methane and methanol as sole carbon and energy sources for growth, is widespread in bacterial communities. However, native methylotrophs lack the extensive and well-characterized synthetic biology toolbox of platform microorganisms like Escherichia coli, which results in slow and inefficient design-build-test cycles. If a heterologous production pathway can be engineered, the slow growth and uptake rates of native methylotrophs generally limit their industrial potential. Therefore, much focus has been placed on engineering synthetic methylotrophs, or non-methylotrophic platform microorganisms, like E. coli, that have been engineered with synthetic methanol utilization pathways. These platform hosts allow for rapid design-build-test cycles and are well-suited for industrial application at the current time. In this review, recent progress made toward synthetic methylotrophy (including methanotrophy) is discussed. Specifically, the importance of amino acid metabolism and alternative one-carbon assimilation pathways are detailed. A recent study that has achieved methane bioconversion to liquid chemicals in a synthetic E. coli methanotroph is also briefly discussed. We also discuss strategies for the way forward in order to realize the industrial potential of synthetic methanotrophs and methylotrophs.
•Recent progress toward synthetic methylotrophy and methane bioconversion.•Importance of amino acid metabolism and alternative one-carbon assimilation pathways.•Functional expression of sMMO allows methane bioconversion in E. coli.•Importance of adaptive laboratory evolution in achieving true methylotrophy.
Our objective was to undertake a systematic review ascertaining the accuracy of using administrative healthcare data to identify epilepsy cases. We searched MEDLINE and Embase from 01/01/1975 to ...03/07/2018 for studies evaluating the diagnostic accuracy of routinely collected healthcare data in identifying epilepsy cases. Any disease coding system in use since the International Classification of Diseases, Ninth Revision (ICD‐9) was permissible. Two authors independently screened studies, extracted data, and quality‐assessed studies. We assessed positive predictive value (PPV), sensitivity, negative predictive value (NPV), and specificity. The primary analysis was a narrative synthesis of review findings. Thirty studies were included, published between 1989 and 2018. Risks of bias were low, high, and unclear in 4, 14, and 12 studies, respectively. Coding systems included ICD‐9, ICD‐10, and Read Codes, with or without antiepileptic drugs (AEDs). PPVs included ranges of 5.2%–100% (Canada), 32.7%–96.0% (USA), 47.0%–100% (UK), and 37.0%–88.0% (Norway). Sensitivities included ranges of 22.2%–99.7% (Canada), 12.2%–97.3% (USA), and 79.0%–94.0% (UK). Nineteen studies contained at least one algorithm with a PPV >80%. Sixteen studies contained at least one algorithm with a sensitivity >80%. PPV was highest in algorithms consisting of disease codes (ICD‐10 G40‐41, ICD‐9 345) in combination with one or more AEDs. The addition of symptom codes to this (ICD‐10 R56; ICD‐9 780.3, 780.39) lowered PPV. Sensitivity was highest in algorithms consisting of symptom codes with one or more AEDs. Although using AEDs alone achieved high sensitivities, the associated PPVs were low. Most NPVs and specificities were >90%. We conclude that it is reasonable to use administrative data to identify people with epilepsy (PWE) in epidemiological research. Studies prioritizing high PPVs should focus on combining disease codes with AEDs. Studies prioritizing high sensitivities should focus on combining symptom codes with AEDs. We caution against the use of AEDs alone to identify PWE.
Due to the lack of research in real-world sports competitions, the International Olympic Committee, in 2012, called for data characterising athletes' sport and event-specific thermal profiles. ...Studies clearly demonstrate that elite athletes often attain a core body temperature (Tc) ≥ 40°C without heat-related medical issues during competition. However, practitioners, researchers and ethical review boards continue to cite a Tc ≥ 40°C (and lower) as a threshold where athlete health is impacted (an assumption from laboratory studies). Therefore, this narrative review aims to: (i) summarise and review published data on Tc responses during competitive sport and identify key considerations for practitioners; (ii) establish the incidence of athletes experiencing a Tc ≥ 40°C in competitive sport alongside the incidence of heat illness/heat stroke (EHI/EHS) symptoms; and (iii) discuss the evolution of Tc measurement during competition. The Tc response is primarily based on the physical demands of the sport, environmental conditions, competitive level, and athlete disability. In the reviewed research, 11.9% of athletes presented a Tc ≥ 40°C, with only 2.8% of these experiencing EHI/EHS symptoms, whilst a high Tc ≥ 40°C (n = 172; Tc range 40-41.5°C) occurred across a range of sports and environmental conditions (including some temperate environments). Endurance athletes experienced a Tc ≥ 40°C more than intermittent athletes, but EHI/EHS was similar. This review demonstrates that a Tc ≥ 40°C is not a consistently meaningful risk factor of EHI/EHS symptomology in this sample; therefore, Tc monitoring alongside secondary measures (i.e. general cognitive disturbance and gait disruption) should be incorporated to reduce heat-related injuries during competition.
There is limited research in talent identification in youth Australian Football (AF), especially the factors that underpin selection into higher-level development programs. Therefore, this study ...explored age-related differences in high-level youth AF players and investigated characteristics influencing selection into a high-level development program. Anthropometry (stature, sitting height, body mass), maturity (estimated age at peak height velocity), motor competence (Körperkoordinationstest für Kinder), fitness (change of direction speed, lower body power and upper body muscular endurance) and coach skill ratings (kicking, marking and handballing) of 277 state academy players (U13-U15) were assessed. MANOVAs identified significant age-related differences for anthropometry, fitness, and coach skill ratings. Furthermore, 90.9 and 90.0% of U15 selected and deselected players were classified correctly. Selected players were more mature, taller, heavier, more explosive, faster at changing directions, and had superior kick technique and marking results. These results demonstrate considerable age-group performance outcome differences, highlighting that high-level academies should aim to select or deselect after 15 years of age. Additionally, it appears earlier maturing players are favoured for selection into a high-level academy. While practitioners must consider the confounding effect of maturation, early maturing players may be favoured for their ability to withstand increasing demands in higher-level youth AF.
Recent attempts to create synthetic
Escherichia coli
methylotrophs identified that de novo biosynthesis of amino acids, in the presence of methanol, presents significant challenges in achieving ...autonomous methylotrophic growth. Previously engineered methanol-dependent strains required co-utilization of stoichiometric amounts of co-substrates and methanol. As such, these strains could not be evolved to grow on methanol alone. In this work, we have explored an alternative approach to enable biosynthesis of all amino acids from methanol-derived carbon in minimal media without stoichiometric coupling. First, we identified that biosynthesis of threonine was limiting the growth of our methylotrophic
E. coli
. To address this, we performed adaptive laboratory evolution to generate a strain that grew efficiently in minimal medium with methanol and threonine. Methanol assimilation and growth of the evolved strain were analyzed, and, interestingly, we found that the evolved strain synthesized all amino acids, including threonine, from methanol-derived carbon. The evolved strain was then further engineered through overexpression of an optimized threonine biosynthetic pathway. We show that the resulting methylotrophic
E. coli
strain has a methanol-dependent growth phenotype with homoserine as co-substrate. In contrast to previous methanol-dependent strains, co-utilization of homoserine is not stoichiometrically linked to methanol assimilation. As such, future engineering of this strain and successive adaptive evolution could enable autonomous growth on methanol as the sole carbon source.
Key points
• Adaptive evolution of E. coli enables biosynthesis of all amino acids from methanol.
• Overexpression of threonine biosynthesis pathway improves methanol assimilation.
• Methanol-dependent growth is seen in minimal media with homoserine as co-substrate.
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