HyPer - a Green Monopropellant for Small Satellite Propulsion

The theory, experimentation, and implementation of a green monopropellant propulsion system for small satellites is described, including the environmental testing and integration of the system onto a CubeSat slated to launch in early 2022. HyPer, named after its propellant hydrogen peroxide, was specifically designed with the smaller size, lower power availability, and challenging launch conditions of CubeSats in mind. Instead of using a traditional monopropellant management system –pressurized reactive liquid forced to a catalyst bed – HyPer uses the vacuum of space to boil the stored liquid hydrogen peroxide, delivering a highly-tunable flow of reactive vapor to the catalyst. This lower flow rate enables HyPer to target the millinewton range of thrust without many of the hydrodynamic complications (e.g., droplet and bubble formation, and thermocapillary flows) that prevent full decomposition in low-thrust liquid systems. This thrust range allows for a wide variety of mission-enabling maneuvers for low mass systems, including (1) constellation management, (2) formation flying, (3) rendezvous, (4) extended mission durations, and (5) orbit reconfiguration. Due to the reaction at the catalyst bed, HyPer still retains the performance associated with a monopropellant system, which allows for a smaller total propulsion package. The HyPer flight unit is exhaustively detailed from design decisions to performance metrics. There are several unique design elements due to the novelty of the concept. These include a propellant management device that controls the flow of vapor for propulsive activities and also allows for oxygen venting during long storage intervals, commercial-off-the-shelf components adapted for the harsh hydrogen peroxide environment, and a nozzle assembly designed to retain as much heat as possible in the catalyst bed. Performance was characterized by direct measurements of pressure, temperature, and mass flow rate in a vacuum environment. Launch survivability and on-orbit operability were verified with vibration, thermal cycle, leak rate, and life testing. On-board flight software and ground commanding were tested prior to integration to ensure appropriate timing and activation of safety features in case of an anomaly. HyPer’s checkout testing at different levels of satellite integration and propellant loading plan are also outlined

Personalising laboratory medicine in the ‘real world’:assessing clinical utility, by clinical indication, of serum total B12 and Active-B12® (holotranscobalamin) in the diagnosis of vitamin B12 deficiency

BACKGROUND: Assessing the pre- and post-test probability of disease in the context of routine health care is challenging. We wished to study how test performance parameters relating to clinical utility vary by clinical indication in a ‘real-world’ setting. METHODS: The diagnostic accuracy of serum total B(12) and Active-B(12)® (holotranscobalamin) was evaluated in a primary care population, using serum methylmalonic acid as the reference standard. We used electronic requesting to establish the clinical indication for each request. Routine requests from primary care for serum total B(12) were included if creatinine was also measured and estimated glomerular filtration rate was at least 60 mL/min/1.73 m(2). RESULTS: Clinical indications included peripheral neuropathy (n = 168), anaemia (n = 168), cognitive decline (n = 125), suspected dietary deficiency (n = 76), other (n = 362). For peripheral neuropathy, the area under the receiver operator curve ± 95% confidence interval (AUC ± CI) was 0.63 (0.54–0.71) (P = 0.002) for total B(12) and 0.68 (0.60–0.77) (P < 0.0001) for Active-B(12)®. For anaemia, AUC ± CI was 0.56 (0.47–0.66) (P = 0.10) for total B(12) and 0.69 (0.59–0.78) (P < 0.0001) for Active-B(12)®. For cognitive decline, AUC ± CI was 0.54 (0.43–0.65) (P = 0.26) for total B(12) and 0.69 (0.58–0.80) (P = 0.0002) for Active-B(12)®. The pre–post-test change in probability of disease varied by clinical indication. CONCLUSION: Combining diagnostic accuracy studies and electronic testing in a ‘real-world’ setting allows clinical utility to be assessed by clinical indication. Wider application of this would permit more personalised laboratory medicine. In this study, diagnostic performance of total B(12) and Active-B(12)® varied across all indications. Active-B(12)® provided better discrimination, but this may have reflected the cut-offs used

2005-2006 Happy Birthday, Dear Amadeus

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Feasibility and acceptability of exercise interventions for adults with tendinopathy: a mixed methods review.

This is a protocol for a review that aims to explore the feasibility and acceptability of any exercise intervention for the treatment of any tendinopathy. The first specific review question is: What is the current knowledge about the feasibility of delivering exercise interventions for tendinopathy from the perspective of those delivering and receiving interventions? Specifically: a) How feasible is the delivery of exercise therapy for tendinopathy in terms of rates (e.g. of adherence, attendance, fidelity); and b) What are patients' and healthcare professionals' perceptions of the feasibility of exercise therapy for tendinopathy? The second specific review question is: What is the current knowledge about acceptability of receiving exercise therapy for tendinopathy from the perspective of people with tendinopathy? Specifically: a) How acceptable is exercise therapy in terms of tolerability; and b) What are patients' and healthcare professionals' perceptions of the acceptability of exercise therapy for tendinopathy

The effectiveness of exercise interventions for tendinopathy.

This is a protocol for a study that aimed to determine: 1) which exercise interventions are most effective across all tendinopathies; 2) does the type/location of the tendinopathy, or other specific covariates, affect which are the most effective exercise therapies. The protocol was intended to guide a scoping review, and was then meant to be updated for the effectiveness review

Comparison of exercise therapies across multiple tendinopathies: a systematic review and network meta-analysis protocol.

This is a preprint for a protocol. The study described by the protocol aimed to use network structures to compare exercise treatments and treatment classes in attempts to identify a treatment hierarchy. Additionally, the large amount of data synthesised was used to explore relevant factors that may explain statistical heterogeneity

The effect of dose on resistance exercise therapies for tendinopathy: a systematic review and meta-analysis protocol.

This is a preprint for a protocol. The purpose of the study described by the protocol was to investigate the effect of resistance exercise dose across multiple common tendinopathies (rotator cuff, lateral elbow, patellar or Achilles), where the frequency, volume and intensity can be accurately quantified. By combining a large data set with contemporary meta-analysis and meta-regression approaches (including relevant covariates within models), the systematic review attempted to explore statistical heterogeneity and better assess potential dose-response relationships that may exist. Where placebo and no-treatment arms were included, these studies were used to reduce heterogeneity and provide sensitivity analyses to support or refute analyses with larger, but more complex data

Empirically derived guidelines for interpreting the effectiveness of exercise therapy for tendinopathies: a protocol.

This is a preprint for a protocol. The aim of the study described by the protocol was to perform a large synthesis of the available research investigating exercise therapy for tendinopathies, creating empirically derived thresholds to benchmark interventions and explore potential differences across tendinopathy types and outcome domains

Antenatal Determinants of Bronchopulmonary Dysplasia and Late Respiratory Disease in Preterm Infants

RATIONALE: Mechanisms contributing to chronic lung disease after preterm birth are incompletely understood. OBJECTIVES: To identify antenatal risk factors associated with increased risk for bronchopulmonary dysplasia (BPD) and respiratory disease during early childhood after preterm birth, we performed a prospective, longitudinal study of 587 preterm infants with gestational age less than 34 weeks and birth weights between 500 and 1,250 g. METHODS: Data collected included perinatal information and assessments during the neonatal intensive care unit admission and longitudinal follow-up by questionnaire until 2 years of age. MEASUREMENTS AND MAIN RESULTS: After adjusting for covariates, we found that maternal smoking prior to preterm birth increased the odds of having an infant with BPD by twofold (P = 0.02). Maternal smoking was associated with prolonged mechanical ventilation and respiratory support during the neonatal intensive care unit admission. Preexisting hypertension was associated with a twofold (P = 0.04) increase in odds for BPD. Lower gestational age and birth weight z-scores were associated with BPD. Preterm infants who were exposed to maternal smoking had higher rates of late respiratory disease during childhood. Twenty-two percent of infants diagnosed with BPD and 34% of preterm infants without BPD had no clinical signs of late respiratory disease during early childhood. CONCLUSIONS: We conclude that maternal smoking and hypertension increase the odds for developing BPD after preterm birth, and that maternal smoking is strongly associated with increased odds for late respiratory morbidities during early childhood. These findings suggest that in addition to the BPD diagnosis at 36 weeks, other factors modulate late respiratory outcomes during childhood. We speculate that measures to reduce maternal smoking not only will lower the risk for preterm birth but also will improve late respiratory morbidities after preterm birth

Effect of resistance exercise dose components for tendinopathy management: a systematic review with meta-analysis.

The objective of this study was to investigate potential moderating effects of resistance exercise dose components - including intensity, volume and frequency - for the management of common tendinopathies. The study was conducted through a systematic review with meta-analysis and meta-regressions, using sources that included (but were not limited to) MEDLINE, CINAHL, SPORTDiscus, ClinicalTrials.gov and the ISRCTN Registry. Selection criteria were based on randomised and non-randomised controlled trials investigating resistance exercise as the dominant treatment class, reporting sufficient information regarding two or more components of exercise dose. A total of 110 studies were included in meta-analyses (148 treatment arms (TAs), 3953 participants), reporting on five tendinopathy locations (rotator cuff: 48 TAs; Achilles: 43 TAs; lateral elbow: 29 TAs; patellar: 24 TAs; gluteal: 4 TAs). Meta-regressions provided consistent evidence of greater pooled mean effect sizes for higher intensity therapies comprising additional external resistance compared to body mass only (large effect size domains: βBodyMass:External = 0.50 [95% CrI: 0.15 to 0.84; p = 0.998]; small effect size domains βBodyMass:External = 0.04 [95% CrI: -0.21 to 0.31; p = 0.619]) when combined across tendinopathy locations or analysed separately. Greater pooled mean effect sizes were also identified for the lowest frequency (less than daily) compared with mid (daily) and high frequencies (more than once per day) for both effect size domains, when combined or analysed separately (p ≥ 0.976). Evidence for associations between training volume and pooled mean effect sizes was minimal and inconsistent. The study found that resistance exercise dose is poorly reported within tendinopathy management literature. However, this large meta-analysis identified some consistent patterns indicating greater efficacy on average with therapies prescribing higher intensities (through inclusion of additional loads) and lower frequencies, potentially creating stronger stimuli and facilitating adequate recovery