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Performance of a whole-body human dust inhalation challenge exposure chamber.

ABSTRACT: Background:Evaluation of the performance of a whole-body human dust exposure chamber is presented in this report. Methods:The volume of the chamber is 2.13?m3 and it is operated at a flow rate of 1.0?m3/min. Makeup and exhaust air were filtered. A Wright Dust Feeder was used to generate fly ash, the testing agent. An elutriator was used to maintain particles in the respirable range. A Rupprecht and Patashnick PM-10 TEOM, a direct reading instrument, was used to monitor particle concentration. Particle size distributions were determined by a QCM cascade impactor. The evenness of dust concentrations in the chamber was determined gravimetrically. Results:Dust concentrations measured at different points within the chamber were associated with variability less than 10%. Dust concentrations measured by the TEOM, in ?g/m3, at 0.2, 0.4, 0.8 and 1.6 RPMs of the Wright Dust Feeder, were 110?±?2.8, 173?±?8.5, 398?±?20 and 550?±?17, respectively. Particle size distributions (MMD and GSD) were 1.27??m and 2.35, 1.39 and 2.22, 1.46 and 2.08, 1.15 and 2.2, respectively. Total dust concentrations measured gravimetrically in ?g/m3, were 135?±?21, 200?±?35, 333?±?18 and 891?±?27, respectively. Conclusion:The whole-body human exposure chamber offers several advantages and has better performance than most of the inhalation challenge systems previously described.

SUBMITTER: Pieretti LF

PROVIDER: S-EPMC6086143 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Performance of a whole-body human dust inhalation challenge exposure chamber.

Pieretti Luis F LF Hammad Yehia Y YY

Toxicology reports 20180725

<h4>Background</h4>Evaluation of the performance of a whole-body human dust exposure chamber is presented in this report.<h4>Methods</h4>The volume of the chamber is 2.13 m<sup>3</sup> and it is operated at a flow rate of 1.0 m<sup>3</sup>/min. Makeup and exhaust air were filtered. A Wright Dust Feeder was used to generate fly ash, the testing agent. An elutriator was used to maintain particles in the respirable range. A Rupprecht and Patashnick PM-10 TEOM, a direct reading instrument, was used ...[more]

PMID: 30105210

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Project description:Propargyl alcohol (PA) is a high production volume chemical used in synthesis of many industrial chemicals and agricultural products. Despite the potential for prolonged or accidental exposure to PA in industrial settings, the toxicity potential of PA was not well characterized. To address the knowledge gaps relevant to the toxicity profile of PA, the National Toxicology Program (NTP) conducted 2-week, 14-week and 2-year studies in male and female F344/N rats and B6C3F1/N mice. For the 2-week inhalation study, the rats and mice were exposed to 0, 31.3, 62.5, 125, 250 or 500ppm. Significant mortality was observed in both rats and mice exposed to ≥125ppm of PA. The major target organ of toxicity in both mice and rats was the liver with exposure-related histopathological changes (250 and 500ppm). Based on the decreased survival in the 2-week study, the rats and mice were exposed to 0, 4, 8, 16, 32 or 64ppm of PA in the 14-week study. No treatment-related mortality was observed. Mean body weights of male (≥8ppm) and female mice (32 and 64ppm) were significantly decreased (7-16%). Histopathological changes were noted in the nasal cavity, and included suppurative inflammation, squamous metaplasia, hyaline droplet accumulation, olfactory epithelium atrophy, and necrosis. In the 2-year inhalation studies, the rats were exposed to 0, 16, 32 and 64ppm of PA and the mice were exposed to 0, 8, 16 and 32ppm of PA. Survival of male rats was significantly reduced (32 and 64ppm). Mean body weights of 64ppm male rats were significantly decreased relative to the controls. Both mice and rats showed a spectrum of non-neoplastic changes in the nose. Increased neoplastic incidences of nasal respiratory/transitional epithelial adenoma were observed in both rats and mice. The incidence of mononuclear cell leukemia was significantly increased in male rats and was considered to be treatment-related. In conclusion, the key findings from this study indicated that the nose was the primary target organ of toxicity for PA. Long term inhalation exposure to PA led to nonneoplastic changes in the nose, and increased incidences of respiratory/transitional epithelial adenomas in both mice and rats. Increased incidences of harderian gland adenoma may also have been related to exposure to PA in male mice.

Project description:BackgroundNo literature reviews have systematically identified and evaluated research on the psychological determinants of endurance performance, and sport psychology performance enhancement guidelines for endurance sports are not founded on a systematic appraisal of endurance-specific research.ObjectiveA systematic literature review was conducted to identify practical psychological interventions that improve endurance performance and to identify additional psychological factors that affect endurance performance. Additional objectives were to evaluate the research practices of the included studies, to suggest theoretical and applied implications, and to guide future research.MethodsElectronic databases, forward-citation searches and manual searches of reference lists were used to locate relevant studies. Peer-reviewed studies were included when they chose an experimental or quasi-experimental research design; a psychological manipulation; endurance performance as the dependent variable; and athletes or physically active, healthy adults as participants.ResultsConsistent support was found for using imagery, self-talk and goal setting to improve endurance performance, but it is unclear whether learning multiple psychological skills is more beneficial than learning one psychological skill. The results also demonstrated that mental fatigue undermines endurance performance, and verbal encouragement and head-to-head competition can have a beneficial effect. Interventions that influenced perception of effort consistently affected endurance performance.ConclusionsPsychological skills training could benefit an endurance athlete. Researchers are encouraged to compare different practical psychological interventions, to examine the effects of these interventions for athletes in competition and to include a placebo control condition or an alternative control treatment. Researchers are also encouraged to explore additional psychological factors that could have a negative effect on endurance performance. Future research should include psychological mediating variables and moderating variables. Implications for theoretical explanations for endurance performance and evidence-based practice are described.

Dataset Information

Performance of a whole-body human dust inhalation challenge exposure chamber.

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Performance of a whole-body human dust inhalation challenge exposure chamber.

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