Air speed and direction affect metabolic and thermoregulatory responses during walking and running in a temperate environment.

Revisiting classical experiments on the impact of air resistance on metabolic rate, we aimed to overcome limitations of previous research, notably: low participant numbers (n=1-3), highly turbulent wind, and confounding effects of rising body temperature. In a custom-built wind tunnel with reduced turbulence, 14 participants (8 males, 6 females) walked (5 km.h-1) and ran on a treadmill (70%V̇O2max) at 0, 2, 4 and 6 m.s-1 headwind or tailwind in a counterbalanced design, with rest-breaks between each exposure to avoid rises in body core temperature. Oxygen consumption (V̇O2) exhibited strong linear relationships versus wind direction, dynamic pressure and air speed squared(Vwr2), lower in magnitude for headwind than tailwind. A moderate linear relationship was observed between heart rate, wind direction, dynamic pressure and Vwr2. Below 4 m⸱s-1, the effect of wind was well within inter- and intra-individual variation and equipment uncertainty, and only at wind speeds ≥4 m⸱s-1 did the differences in physiological responses reach statistical significance. Our data indicate that at running speeds below 4 m⸱s-1 (14.4 km/h), indoor treadmill and outdoor running are comparable in terms of the metabolic impact of air movement relative to the person. However, this does not extend to the thermoregulatory effect of wind, with outdoor running providing a higher cooling rate due to the self-generated wind created during running. By removing the confounding impact of core temperature rises, the observed effects of headwind were lower and those of tailwind larger than observed previously. In the context of middle-distance running, headwind created by running at 21.5 km.h-1 would result in a 2.2% increase of V̇O2. A relative tailwind of the same speed would lead to a 3.1% reduction.

Mars 2020 Mission Biological Return Sample Contamination Control Approach and Verification.

The Mars 2020 Perseverance rover is equipped with a Sample Caching System (SCS) designed to collect and cache martian core and regolith samples for potential return to Earth. To ensure the integrity of these samples, the mission requirements for each encapsulated sample for return is less than one Earth-sourced viable organism (VO) and more than a 99.9% probability of being free of any Earth-sourced VO. To satisfy the stringent biological contamination requirements in support of return sample science investigations, special bioburden mitigation and reduction approaches were developed and implemented for SCS hardware that would directly contact or be in close proximity to the martian samples. In this study, we describe the implemented approaches for microbiological contamination reduction and mitigation, detail the processes of the SCS aseptic assembly, and report the estimated VO for each returned sample. We found that our conservative estimate of the computed probability of a single VO in the returned sample is more than one order of magnitude lower than the biological contamination requirement while the best estimate exceeds two orders of magnitude.

Planetary Protection Implementation and Verification Approach for the Mars 2020 Mission.

The Mars 2020 Flight System comprises a Cruise Stage; Aeroshell; Entry, Descent, and Landing system; Perseverance rover; and the Ingenuity helicopter. The Perseverance rover was successfully delivered to Jezero Crater on February 18, 2021. Among its science objectives, Perseverance is meant to search for rocks that are capable of preserving chemical traces of ancient life, if it existed, and to core and cache rock and regolith samples. The Perseverance rover is gathering samples for potential return to Earth as part of a Mars Sample Return campaign. Thus, controlling the presence of Earth-sourced biological contamination is important to protect the integrity of the scientific results as well as to comply with international treaty and NASA requirements governing Planetary Protection prior to launch. An unprecedented campaign of sampling and environmental monitoring occurred, which resulted in over 16,000 biological samples collected throughout spacecraft assembly. Engineering design, microbial reduction measures, monitoring, and process controls enabled the mission to limit the total spore bioburden to 3.73 × 105 spores, which provided 25.4% margin against the required limit. Furthermore, the total spore bioburden of all landed hardware was 3.86 × 104, which provided 87% margin against the required limit. This manuscript outlines the Planetary Protection implementation approach and verification methodologies applied to the Mars 2020 flight system and its surrounding environments.

The Isolation and Characterization of Rare Mycobiome Associated With Spacecraft Assembly Cleanrooms.

Ensuring biological cleanliness while assembling and launching spacecraft is critical for robotic exploration of the solar system. To date, when preventing forward contamination of other celestial bodies, NASA Planetary Protection policies have focused on endospore-forming bacteria while fungi were neglected. In this study, for the first time the mycobiome of two spacecraft assembly facilities at Jet Propulsion Laboratory (JPL) and Kennedy Space Center (KSC) was assessed using both cultivation and sequencing techniques. To facilitate enumeration of viable fungal populations and downstream molecular analyses, collected samples were first treated with chloramphenicol for 24 h and then with propidium monoazide (PMA). Among cultivable fungi, 28 distinct species were observed, 16 at JPL and 16 at KSC facilities, while 13 isolates were potentially novel species. Only four isolated species Aureobasidium melanogenum, Penicillium fuscoglaucum, Penicillium decumbens, and Zalaria obscura were present in both cleanroom facilities, which suggests that mycobiomes differ significantly between distant locations. To better visualize the biogeography of all isolated strains the network analysis was undertaken and confirmed higher abundance of Malassezia globosa and Cyberlindnera jadinii. When amplicon sequencing was performed, JPL-SAF and KSC-PHSF showed differing mycobiomes. Metagenomic fungal reads were dominated by Ascomycota (91%) and Basidiomycota (7.15%). Similar to amplicon sequencing, the number of fungal reads changed following antibiotic treatment in both cleanrooms; however, the opposite trends were observed. Alas, treatment with the antibiotic did not allow for definitive ascribing changes observed in fungal populations between treated and untreated samples in both cleanrooms. Rather, these substantial differences in fungal abundance might be attributed to several factors, including the geographical location, climate and the in-house cleaning procedures used to maintain the cleanrooms. This study is a first step in characterizing cultivable and viable fungal populations in cleanrooms to assess fungal potential as biocontaminants during interplanetary explorations. The outcomes of this and future studies could be implemented in other cleanrooms that require to reduce microbial burden, like intensive care units, operating rooms, or cleanrooms in the semiconducting and pharmaceutical industries.

Emergency department management of pediatric asthma at a university teaching hospital.

BACKGROUND: Asthma is a major health problem and the most frequent cause of chronic illness and emergency department (ED) visits in children. Limited data examining the ED management of pediatric asthma within university teaching hospitals across the US exist. OBJECTIVE: To compare the ED management of children (aged 1-17 y) with asthma at a university teaching hospital using National Asthma Education and Prevention Program (NAEPP) guidelines. METHODS: All cases of pediatric asthma that presented to the University of California, San Francisco, Medical Center ED between October 1, 2003, and October 31, 2004, were included. Patients who required hospital admission were excluded. Data pertaining to patient demographics, primary diagnosis, pharmacologic management, diagnostic tests performed, and follow-up plans were abstracted and compared with NAEPP guidelines issued in 1997 and updated topics released in 2002. RESULTS: A total of 141 cases were identified. Mean patient age was 5.8 years. Most (61.7%) patients were male and of African American ethnicity (31.9%). Asthma severity was typically mild (66.7%) or moderate (29.1%). In persons at least 6 years of age (n = 58), peak expiratory flow rate (PEFR) was performed in 25.9% of cases. Pulse oximetry, however, was always performed. Based on NAEPP guidelines, beta-agonists and corticosteroids should have been used, but were not, in 2.8% and 31.9% of cases, respectively. At discharge, no corticosteroid prescription was given in 40.4% of the cases, no written action plan was prepared in 80.1% of the cases, no formal device training was administered in 67.3% of cases, and no peak flow meter was provided for persons at least 6 years of age in 50.0% of cases. CONCLUSIONS: NAEPP guidelines were met in all patients regarding pulse oximetry and in most patients with respect to the use of beta-agonists. Improvements could be made, however, in the use of corticosteroids in the ED; in performing PEFR measurements for persons at least 6 years of age upon arrival; and in providing formal device training, a written action plan, prescriptions for steroids, and peak flow meters at discharge.