6,260 research outputs found
An analysis of astronaut performance capability in the lunar environment. Volume 1 - Performance problems and requirements for additional research
Analyzing data on expected astronaut performance in lunar environmen
An Analysis of Astronaut Performance Capability in the Lunar Environment. Volume 2 - Performance Capability Support Data
Astronaut performance capability in lunar environmen
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Direct Freeform Fabrication of Spatially Heterogeneous Living Cell-Impregnated Implants
The objectives of this work are the development of the processes, materials, and tooling to
directly “3-D print” living, pre-seeded, patient-specific implants of spatially heterogeneous
compositions. The research presented herein attempts to overcome some of the challenges to
scaffolding, such as the difficulty of producing spatially heterogeneous implants that require
varied seeding densities and/or cell-type distributions. In the proposed approach, living implants
are fabricated by the layer-wise deposition of pre-cell-seeded alginate hydrogel. Although
alginate hydrogels have been previously used to mold living implants, the properties of the
alginate formulations used for molding were not suitable for 3-D printing. In addition to changing
the formulation to make the alginate hydrogels “printable,” we developed a robotic hydrogel
deposition system and supporting CAD software to deposit the gel in arbitrary geometries. We
demonstrated this technology’s capabilities by printing alginate gel implants of multiple materials
with various spatial heterogeneities, including, implants with completely embedded material
clusters. The process was determined to be both viable (94±5% n=15) and sterile (less than one
bacterium per 0.9 µL after 8 days of incubation). Additionally, we demonstrated the printing of a
meniscus cartilage-shaped gel generated directly from a CT Scan. The proposed approach may
hold advantages over other tissue printing efforts [5,9]. This technology has the potential to
overcome challenges to scaffolding and could enable the efficient fabrication of spatially
heterogeneous, patient-specific, living implants.Mechanical Engineerin
Consideration of radar target glint from ST during OMV rendezvous
The nature of radar target glint and the factors upon which it depends when using the Hubble Space Telescope as a radar target is discussed. An analysis of the glint problem using a 35 MHz or 94 MHz radar on the orbital maneuvering vehicle is explored. A strategy for overcoming glint is suggested
NASP aeroservothermoelasticity studies
Some illustrative results obtained from work accomplished under the aerothermoelasticity work breakdown structure (WBS) element of the National Aerospace Plane (NASP) Technology Maturation Program (TMP) are presented and discussed. The objectives of the aerothermoelasticity element were to develop analytical methods applicable to aerospace plane type configurations, to conduct analytical studies to identify potential problems, to evaluate potential solutions to problems, and to provide an experimental data base to verify codes and analytical trends. Work accomplished in the three areas of experimental data base, unsteady aerodynamics, and integrated analysis methodology are described. Some of the specific topics discussed are: (1) transonic wind tunnel aeroelastic model tests of cantilever delta wing models, of an all-moveable delta-wing model, and of aileron buzz models; (2) unsteady aerodynamic theory correlation with experiment and theory improvements; and (3) integrated analysis methodology results for thermal effects on vibration, for thermal effects on flutter, and for improving aeroelastic performance by using active controls
Chemical reactivity of hydrogen, nitrogen and oxygen atoms at temperatures below 100 deg K Fifth semiannual technical report
Chemical reactivity of hydrogen, nitrogen, and oxygen atoms at temperatures below 100 deg
Space Station Facilities and Operations at the Kennedy Space Center
The Spaca Station Program potentially will a significant Impact on the Kennedy Space Canter Current and past programs have had their major Impact on KSC In the prelaunch and launch operations area with program support, subsequent to liftoff, generally performed at other locations. The Space Station Program also will Impact pre- launch and launch operations at KSC but, due to Its proposed 10-year operational lifetime, KSC also could have a significant role in support of the operational program. Support operations of the Space Station Program may be performed elsewhere; however, centralizing them at KSC has a number of attractive features which warrant study
A realistic evaluation : the case of protocol-based care
Background
'Protocol based care' was envisioned by policy makers as a mechanism for delivering on the service improvement agenda in England. Realistic evaluation is an increasingly popular approach, but few published examples exist, particularly in implementation research. To fill this gap, within this paper we describe the application of a realistic evaluation approach to the study of protocol-based care, whilst sharing findings of relevance about standardising care through the use of protocols, guidelines, and pathways.
Methods
Situated between positivism and relativism, realistic evaluation is concerned with the identification of underlying causal mechanisms, how they work, and under what conditions. Fundamentally it focuses attention on finding out what works, for whom, how, and in what circumstances.
Results
In this research, we were interested in understanding the relationships between the type and nature of particular approaches to protocol-based care (mechanisms), within different clinical settings (context), and what impacts this resulted in (outcomes). An evidence review using the principles of realist synthesis resulted in a number of propositions, i.e., context, mechanism, and outcome threads (CMOs). These propositions were then 'tested' through multiple case studies, using multiple methods including non-participant observation, interviews, and document analysis through an iterative analysis process. The initial propositions (conjectured CMOs) only partially corresponded to the findings that emerged during analysis. From the iterative analysis process of scrutinising mechanisms, context, and outcomes we were able to draw out some theoretically generalisable features about what works, for whom, how, and what circumstances in relation to the use of standardised care approaches (refined CMOs).
Conclusions
As one of the first studies to apply realistic evaluation in implementation research, it was a good fit, particularly given the growing emphasis on understanding how context influences evidence-based practice. The strengths and limitations of the approach are considered, including how to operationalise it and some of the challenges. This approach provided a useful interpretive framework with which to make sense of the multiple factors that were simultaneously at play and being observed through various data sources, and for developing explanatory theory about using standardised care approaches in practice
A case study evaluation of implementation of a care pathway to support normal birth in one English birth centre: anticipated benefits and unintended consequences
Background: The policy drive for the UK National Health Service (NHS) has focused on the need for high quality services informed by evidence of best practice. The introduction of care pathways and protocols to standardise care and support implementation of evidence into practice has taken place across the NHS with limited evaluation of their impact. A multi-site case study evaluation was undertaken to assess the impact of use of care pathways and protocols on clinicians, service users and service delivery. One of the five sites was a midwifery-led Birth Centre, where an adapted version of the All Wales Clinical Pathway for Normal Birth had been implemented.
Methods: The overarching framework was realistic evaluation. A case study design enabled the capture of data on use of the pathway in the clinical setting, use of multiple methods of data collection and opportunity to study and understand the experiences of clinicians and service users whose care was informed by the pathway. Women attending the Birth Centre were recruited at their 36 week antenatal visit. Episodes of care during labour were observed, following which the woman and the midwife who cared for her were interviewed about use of the pathway. Interviews were also held with other key stakeholders from the study site. Qualitative data were content analysed.
Results: Observations were undertaken of four women during labour. Eighteen interviews were conducted with clinicians and women, including the women whose care was observed and the midwives who cared for them, senior midwifery managers and obstetricians. The implementation of the pathway resulted in a number of anticipated benefits, including increased midwifery confidence in skills to support normal birth and promotion of team working. There were also unintended consequences, including concerns about a lack of documentation of labour care and negative impact on working relationships with obstetric and other midwifery colleagues. Women were unaware their care was informed by a care pathway.
Conclusion: Care pathways are complex interventions which generate a number of consequences for practice. Those considering introduction of pathways need to ensure all relevant stakeholders are engaged with this and develop robust evaluation strategies to accompany implementation
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