75 research outputs found

    HyPer - a Green Monopropellant for Small Satellite Propulsion

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    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

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    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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    https://spiral.lynn.edu/conservatory_otherseasonalconcerts/1039/thumbnail.jp

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

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    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.

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    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.

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    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 components on resistance exercise therapies for tendinopathy management: a systematic review and meta-analysis.

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    The purpose 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 research was undertaken through a systematic review and meta-analysis, comprising an extensive search of databases and trial registries. Eligibility criteria for selecting studies included randomised and non-randomised controlled trials investigating resistance exercise as the dominant treatment class and reporting sufficient information regarding at least two components of exercise dose (intensity, frequency, volume). Non-controlled standardised mean difference effect sizes were calculated across a range out outcome domains and combined with Bayesian hierarchical meta-analysis models for domains generating large (disability; function; pain) and small (range of motion; physical function capacity; and quality of life) effect size values. Meta-regressions were used to estimate differences in pooled mean values across categorical variables quantifying intensity, frequency and volume. Ninety-one studies presented sufficient data to be included in meta-analyses, comprising 126 treatment arms (TAs) and 2965 participants. Studies reported on five tendinopathy locations (Achilles: 39 TAs, 31.0%; rotator cuff: 39 TAs, 31.0%; lateral elbow: 25 TAs, 19.8%; patellar: 19 TAs, 15.1%; and gluteal: 4 TAs, 3.2%). 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: 0.39 [95% CrI: 0.00 to 0.82; p = 0.976]; small effect size domains (0.09 [95% CrI: -0.20 to 0.37; p = 0.723]) when data were combined across tendinopathy locations or analysed separately. Consistent evidence of greater pooled mean effect sizes was also identified for the lowest frequency (less than daily) compared with mid (daily) and high frequencies (more than daily) for both large effect size domain ( -0.66 [95% CrI: -1.2 to -0.19; p >0.999]; -0.54 [95% CrI:-0.99 to -0.10; p >0.999]) and small effect size domains ( -0.51 [95% CrI: -0.78 to -0.24; p >0.999]; -0.34 [95% CrI: -0.60 to -0.06; p = 0.992]) when data were combined across tendinopathy locations or analysed separately. Minimal and inconsistent evidence was obtained for differences for a moderating effect of training volume. The study concluded that resistance exercise dose is poorly reported within the tendinopathy management literature. However, this large meta-analysis identified some consistent patterns indicating greater efficacy on average with therapies prescribing higher intensities (through the inclusion of additional external loads) and lower frequencies, potentially creating stronger stimuli and facilitating adequate recovery

    Which treatments are most effective for common tendinopathies? A systematic review and network meta-analysis protocol.

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    This is a preprint for a protocol. The purpose of the study described by the protocol was to compare the effectiveness of different treatment classes across a range of tendinopathies and outcomes, to better establish a treatment hierarchy. Where sufficient data were obtained, the potential for covariates - including patient demographics and condition specifics (e.g. symptom severity) - to explain statistical heterogeneity was explored

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

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    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

    Exercise therapy for tendinopathy: a scoping review mapping interventions and outcomes.

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    The aim of this research was to comprehensively map exercise interventions and outcomes across all tendinopathies. The study took the form of a scoping review. Eligibility criteria (PCC) included: 1) participants - any age or gender, with any tendinopathy; 2) concept - supervised or unsupervised exercise, of any type or format, delivered by any professional and any outcome used to evaluate any exercise intervention; 3) context - any setting in any country listed as very high on the human development index. The study used nine databases, four trial registries and six grey literature sources. At least two reviewers independently conducted title, abstract and full text screening. Data extraction was conducted using a bespoke tool developed for this review, informed by the TIDieR checklist and ICON health-related domains, to interpret exercise reporting and outcomes across included studies. Extracted data from 555 included studies from 31 countries incorporated 25,490 participants with mean study ages ranging from 15-65 years. A range of exercise interventions including strengthening, flexibility, aerobic, proprioceptive, and motor control were identified; showing rotator cuff-related shoulder pain, Achilles, patellar and lateral elbow tendinopathies were most studied. A range of health-related domains were measured by numerous outcome tools, with little consistency within domains or tendinopathies. Reporting of participant characteristics, interventions and adherence was highly variable. This first comprehensive map of exercise and outcomes for tendinopathy has identified four recommendations to be considered for future tendinopathy research: 1) Specific robust high quality research study designs; (2) Comprehensive research reporting; 3) Patient/practitioner lived experience; and 4) comprehensive high quality evidence synthesis
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