The effect of diurnal variation in exercise-induced bronchoconstriction.

Objective: Exercise-induced bronchoconstriction (EIB) is an acute, transient narrowing of the airway as a result of exercise. Diurnal variation in asthma is well-established, however, few studies have investigated diurnal variability in EIB; no study has used eucapnic voluntary hyperpnea (EVH). The aim of this study was to examine circadian variability in EIB using EVH.Methods: Fourteen recreationally-active males with mild to moderate asthma and nine healthy controls were randomized to first complete either an AM (07:00-08:00) or PM (17:00-18:00) EVH challenge, followed by the alternate test 34 h to 7 days later. The EVH protocol comprised of six-minutes of hyperventilation of a 5% CO2 gas at a minimum ventilation rate of 21 × FEV1 min-1. The primary outcome measure was FEV1 pre- and post-EVH.Results: We observed no diurnal effect on EIB in the asthma group. The minimum observed post-EVH FEV1 in the asthma cohort was 3.58 ± 0.95 L in AM and 3.62 ± 0.87 L in PM tests, corresponding to a 15.0 ± 15.3% vs. 14.9 ± 14.7% reduction from baseline, respectively. The asthma group showed similar baseline FEV1 before AM (4.21 ± 0.79 L) and PM (4.25 ± 0.65 L) tests. No difference was observed in minute ventilation between AM (26.1 ± 3.4 × FEV1 min-1) and PM (25.6 ± 3.8 × FEV1 min-1) tests for the asthma cohort. Controls displayed no significant changes in FEV1 or minute ventilation between tests.Conclusions: When baseline pulmonary function is similar, this study suggests that time-of-day has no effect on EIB in mild to moderate asthma.

A techno-economic analysis of using mobile distributed pyrolysis facilities to deliver a forest residue resource.

Distributed mobile conversion facilities using either fast pyrolysis or torrefaction processes can be used to convert forest residues to more energy dense substances (bio-oil, bio-slurry or torrefied wood) that can be transported as feedstock for bio-fuel facilities. Results show that the levelised delivered cost of a forest residue resource using mobile facility networks can be lower than using conventional woodchip delivery methods under appropriate conditions. Torrefied wood is the lowest cost pathway of delivering a forest residue resource when using mobile facilities. Cost savings occur against woodchip delivery for annual forest residue harvests above 2.5 million m(3) or when transport distances greater than 300 km are required. Important parameters that influence levelised delivered costs are transport distances (forest residue spatial density), haul cost factors, and initial moisture content of forest residues. Relocating mobile facilities can be optimised for lowest cost delivery as transport distances of raw biomass are reduced.