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The aim of this study was to evaluate the impact of using a cooling vest during physical exercise (per-cooling) in humid and temperate conditions (≈22°C, ≈80% relative humidity) on perceptual and physiological responses (tissue oxygenation and heart rate). 20 physically active men performed twice a 30-min cycling exercise at 70% of their theoretical maximum heart rate while using an activated (experimental condition) and a deactivated (control condition) cooling system in a randomized crossover study. Heart rate and tissue (cerebral and muscular) oxygenation were continuously measured during exercise and recovery, and skin temperature was measured every 10 min. Perception of temperature, humidity and comfort were assessed at the end of the recovery period. Results showed a decrease in trunk skin temperature (p<0.05), a faster heart rate recovery and an increase in the concentration of total hemoglobin at the brain level (p<0.05) compared with control condition. Moreover, an improved subjective rating of thermal sensations, wetness and comfort compared to control values (p<0.05) was noted. In conclusion, wearing a cooling vest during submaximal exercise improves perceptual and physiological responses in humid temperate conditions, which may be due to a better blood perfusion at the brain level and a better parasympathetic reactivation. [ABSTRACT FROM AUTHOR]

Airborne nanoparticles represent a new danger in occupational health. Numerous theoretical and experimental studies have been conducted on the efficiency of filtering media used for respiratory protection, but few have focused on media used for skin protective equipment. Indeed, a significant proportion of airborne nanoparticles can end up on the skin, causing local effects and eventually penetrating the human body. Following experimental data obtained with sodium chloride nanoparticles, the authors propose an empirical model to evaluate the penetration of airborne nanoparticles through medium used in disposable coveralls. This study presents an adaptation of the conventional filtration theory used for filtering media used in respirators. The authors' model is compared with Wang et al.'s and Brochot's models and demonstrates improvements in their descriptive ability. Moreover, a domain of validity of the proposed model was determined that will enable the evaluation of the efficiency of similar protective apparel material structures against airborne nanoparticles. [ABSTRACT FROM AUTHOR]

Elastomers used in protective gloves can be sensitive to the action of solvents used to disperse commercial solutions of nanoparticles. These effects may include the swelling of the polymer, leading to a modification of its mechanical and chemical properties. Modifications to the properties of the polymer will impact the protection provided by the protective gloves. The goal of this work was therefore to study the swelling of several elastomers when exposed to commercial solutions of nanoparticles. The study involved four elastomers and three commercial solutions of colloidal titanium dioxide (TiO2). Swelling was assessed by measurements of mass gain and length change. Tests were also performed with technical and ultrapure solvents corresponding to the liquid carriers. The solutions had a significant effect on the swelling of nitrile rubber, latex, and neoprene. A large mass gain was recorded for short immersion times, indicating a possible penetration of the nanoparticle liquid carrier into these elastomers. Length change measurements revealed a swelling anisotropy effect with nitrile rubber and latex in the solutions of colloidal TiO2. No effect was measured with butyl rubber. The results show that great care must be taken when selecting protective gloves for the handling of nanoparticle dispersions. [ABSTRACT FROM AUTHOR]