Programmed vs. Thirst-Driven Drinking during Prolonged Cycling in a Warm Environment

We compared the effect of programmed (PFI) and thirst-driven (TDFI) fluid intake on prolonged cycling performance and exercise associated muscle cramps (EAMC). Eight male endurance athletes (26 ± 6 years) completed two trials consisting of 5 h of cycling at 61% V˙O2peak followed by a 20 km time-trial (TT) in a randomized crossover sequence at 30 °C, 35% relative humidity. EAMC was assessed after the TT with maximal voluntary isometric contractions of the shortened right plantar flexors. Water intake was either programmed to limit body mass loss to 1% (PFI) or consumed based on perceived thirst (TDFI). Body mass loss reached 1.5 ± 1.0% for PFI and 2.5 ± 0.9% for TDFI (p = 0.10). Power output during the 20 km TT was higher (p < 0.05) for PFI (278 ± 41 W) than TDFI (263 ± 39 W), but the total performance time, including the breaks to urinate, was similar (p = 0.48) between conditions. The prevalence of EAMC of the plantar flexors was similar between the drinking conditions. Cyclists competing in the heat for over 5 h may benefit from PFI aiming to limit body mass loss to <2% when a high intensity effort is required in the later phase of the race and when time lost for urination is not a consideration.

The Effectiveness of the Blended Learning in Enhancing EFL Learning and Collaboration

This descriptive-analytical study investigates undergraduates' perceptions and reflections toward adopting the Blended-Learning system in the university instructions. For this goal, the study employed two tools to collect data. Firstly, a) (n=38) pre-service teachers wrote reflection essays, and b) Google forms closed-ended five scales' questionnaire investigated the academic and interaction indicators, each consisting of thirty items, distributed among (n=110) pre-service teachers. The participants were majoring in English as a Foreign language at multi-stages, Saudi Arabia, 2020/2021. The study employed the content and the SPSS analysis. The questionnaire's results showed the undergraduates' positive perceptions toward combining online and face-to-face learning and how this environment improved their learning outcomes, created a collaborative community, fostered openness for sharing, asking, expressing, and getting talk-worthy ideas. The essays' content analysis reflected the undergraduates' experiences and how they enjoyed transitioning between online and face-to-face learning; they were satisfied by the ability to track their scores. These results created a continuous feedback loop correlated with their academic progress through various activities. However, they encountered a few challenges in online classes like a) missed face-to-face warm environment, b) lost attention, and c) missed instructors' nonverbal cues. Generalized, blended learning facilitated learners' knowledge by reducing education costs, distance, efforts, and time without reducing the students' benefits. The study recommends that the BL instructors have to show some enthusiasm and inspiration. The study proposes future research.

Body mapping of sweating patterns of pre-pubertal children during intermittent exercise in a warm environment

Purpose To determine sweating responses of pre-pubertal children during intermittent exercise in a warm environment and create whole-body maps of regional sweat rate (RSRs) distribution across the body. Methods Thirteen pre-pubertal children; six girls and seven boys (8.1 ± 0.8 years) took part. Sweat was collected using the technical absorbent method in the last 5 min of a 30-min intermittent exercise protocol performed at 30 ℃, 40% relative humidity and 2 m·s−1 frontal wind. Results Mean gross sweat loss (GSL) was 126 ± 47 g·m−2·h−1 and metabolic heat production was 278 ± 50 W·m2. The lower anterior torso area had the lowest RSR with a median (IQR) sweat rate (SR) of 40 (32) g·m−2·h−1. The highest was the forehead with a median SR of 255 (163) g·m−2·h−1. Normalised sweat maps (the ratio of each region’s SR to the mean SR for all measured pad regions) showed girls displayed lower ratio values at the anterior and posterior torso, and higher ratios at the hands, feet and forehead compared to boys. Absolute SRs were similar at hands and feet, but girls sweated less in most other areas, even after correction for metabolic rate. Conclusion Pre-pubertal children have different RSRs across the body, also showing sex differences in sweat distribution. Distributions differ from adults. Hands and feet RSR remain stable, but SR across other body areas increase with maturation. These data can increase specificity of models of human thermoregulation, improve the measurement accuracy of child-sized thermal manikins, and aid companies during product design and communication.

A Basidiomycete Fungus Responsible for Fresh Mushroom Off-Flavour in Wines: Crustomyces subabruptus, (Bourdot & Galzin) Jülich 1978

Grape rot can cause organoleptic deviations in wines, including the aroma of fresh mushrooms; one of the molecules responsible for this is 1-octen-3-one. The bunches affected by this defect are often contaminated by Botrytis cinerea; however, they may also contain a whitish mycelium that cannot be attributed to B. cinerea. This additional fungal growth is the subject of this study. Several isolations of this fungus were carried out on grape bunches from different vineyards in the French Alsace and Champagne regions using a culture medium containing an anti-Botrytis fungicide (Boscalid). The sequencing of the ITS regions showed that most isolations corresponded to Crustomyces subabruptus (Bourdot & Galzin; Jülich 1978), an endophyte basidiomycete. Contamination tests carried out on bunches and grape juice with this fungus confirmed its responsibility for the appearance of fresh mushroom defects in wines, and showed that it has the capacity to produce large quantities of 1-octen-3-one in a wet and warm environment. The results of this study suggest that this basidiomycete is responsible for fresh mushroom aromas in wines.

Bacteriological Examination of Used Towels from Female and Male Hostel of Federal University of Lafia

Bath towels have the ability to retain microbes, moist and warm environment offers microbes a favorable place to grow and survive. These microbes can be transmitted through direct contact with our hands and other inanimate objects within the environment. This study aimed at examining bacterial contamination of used towels. Used towels from male and female hostels at Federal University of Lafia, were assessed to determine their bacterial concentration. A total of sixteen (16) used towels were sampled, eight towels each from female and male hostels were sampled between April and May 2021. Identification and characterization of bacterial isolates was carried out using standard cultural, morphological and biochemical methods. Pseudomonas spp, Staphylococcus aureus, Klebsiella spp, Escherichia coli, Streptococcus, Micrococcus spp, Serratia sp and Coagulase Negative Staphylococcus were identified as contaminants in the towel samples analyzed. The female towels assessed in this study had the highest number of colonies with 4.39 x 109, while the male towels had the least number of colonies 3.88 x 109. Male and female towels sampled were all contaminated, but with no significant difference in the contamination rates (p>0.05). Staphylococcus aureus and coagulase-negative Staphylococcus were the most prevalent organisms isolated from male (62.5%; 5/8) and female (100%; 8/8) towels respectively. The high prevalence of diverse bacterial species is worrisome considering the epidemiology and clinical importance of the isolates, compounded by antimicrobial resistance and high mortality rate. Hence, there is need to enforce and improve hygiene practice among students. Frequent washing of towels and use of medicated soaps and disinfectants in bathing and washing water is hereby canvassed.

Would the (too?) normal adaptation to exercise in sickle cell trait carrier be a reflection of preventive mechanisms against potential myocardial and muscle injury?

Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Commission, Region Guadeloupe Background. Sickle cell trait (SCT) is an inherited red blood cell condition without medical consequence in most cases. However, its strong association with increased risk of exercise-induced sudden death (independent of pre-existing disease) or exertional collapse has been demonstrated in athletes, military recruits and firefighters. The mechanisms potentially leading to cardiac arrest during or after exercise in SCT have not been fully elucidated although contributing factors have been identified (the main one being rhabdomyolysis) or suspected. Warm environment (even without dehydration) can contribute to the occurrence of fatal events. Purpose. The aims of this study were to 1) compare the biomarkers of myocardial and muscle injury response (and their determinants) to exercise in SCT carriers and controls performing a hard bout of exercise 2) identify the potential deleterious role of warmth during exercise and recovery in SCT and non-SCT. Methods. Nine otherwise healthy 21 ± 3yo male students with SCT and 11 non-SCT (comparable in physical fitness, regular exercise participation and body mass index) were included. The volunteers performed in a randomized order 3 sessions: cycling exercise in a control (21°C) and warm (31°C) environment followed by recovery in a room at 21°C, and both exercise and recovery in a warm environment. The exercise was as follows: 18-min rectangular moderate intensity period + maximal incremental test + 3 30-s supramaximal sprints spaced with 20-s resting intervals. Recovery and hydration were planned between each exercise part. The ECG was monitored throughout exercise. Blood was sampled before and at the end of the exercise but also during the recovery including a meal up to 130-min after the end of exercise. Results. No evidence of severe cardiac injury (ECG and biomarkers), rhabdomyolysis or occlusive events (clinical signs and biomarkers), infection (complete blood count), inflammation (biomarkers) or electrolyte imbalance (ionogram) was observed in the SCT carriers of this study: indices were comparable between SCT and non-SCT carriers, with normal exercise-related evolutions and normal recovery. Interestingly, some indices however converge towards a profile with lower complication risk in SCT. The lactate concentrations tended to be lower in SCT than non-SCT during exercise (p = 0.062) and were significantly lower during the recovery in particular after exercising at 31°C but not at 21°C. The leukocytes count was lower in SCT than non-SCT (p = 0.043) and increased in a greater extent with exercise in the later (p = 0.041). The exercise-induced increase in cortisol and glucose concentrations observed in non-SCT did not occur in SCT carriers (interactions p and p = 0.040 and p = 0.033). Conclusions. Although these results do not evidence pathophysiological mechanisms, they feed the hypothesis of "storm" against which protective mechanisms could have developed and that may fail under particular conditions.

A Mathematical Study of Effect of Humidity on Human Skin Temperature at Warm Environment

The ability of the human body to regulate its heat exchange depends on various environmental factors together with its ability to exchange heat in in-vivo tissue. The environmental factor humidity plays a crucial role in heat regulation within the human body. The heat regulation within in-vivo tissue constitutes temperature regulation in the layers of the dermal part to maintain body core temperature constant. The purpose of this article is to develop a mathematical model to study the effect of humidity on temperature regulation within the human body. The model has been developed for one dimensional steady state flow of heat in human dermal parts with appropriate boundary conditions containing the factors of effect of humidity. Matlab program has been used to simulate the model and obtain numerical results with graphs.