170 research outputs found
Electrospinning of Functional Nanofibers for Regenerative Medicine: From Bench to Commercial Scale
Nanofibers are an important material for regenerative medicine as they have a commensurate morphology to that of the macromolecular matrix that supports and houses the growth of cells and tissues within the body. Electrospinning is widely used to fabricate non-woven structures on the nanoscale and the versatility of the technique has widened the application of nanofibers. This is due to ease of extending nanofiber functionality through the incorporation of active materials both during and after electrospinning. Recent developments in electrospinning devices, such as needle-free systems, have reinvigorated research as these advances now allow fabrication of nanofibers at commercial scales. The process of electrospinning has a number of operating parameters that are adjusted in optimisation to achieve ideal fibres and a multitude of instrument configurations can be adopted to achieve the required manufacture. The innate properties of nanofibers, such as high surface area to volume ratio, have many proven benefits for regenerative medicine and the chapter examines these before discussing how functionality can be further improved. Numerous materials can be incorporated in the manufacture of electrospun mats, however when choosing materials for regenerative medicine, biocompatibility and biodegradability are the dominant functionalities that are required
Quantum Heat Engines and the Generalized Uncertainty Principle
We study the effects of the generalized uncertainty principle (GUP) on the
efficiency of quantum heat engines based on a particle in an infinite square
well using the partition function approach. In particular, we study the Carnot
and Otto heat engines. For the system we used, the GUP-corrected efficiencies
turned out to be lower than efficiencies without the GUP effects. However, as
expected, GUP effects increase as the temperature of the cold heat bath
decreases and as the width of the potential well decreases.Comment: 20 pages, 6 figure
Enantioselective one-carbon expansion of aromatic rings by simultaneous formation and chromoselective irradiation of a transient coloured enolate
Enantioenriched seven-membered carbocycles are motifs in many molecules of structural and biological interest. We report a simple, practical, transition metal-free and mechanistically unusual method for the enantioselective synthesis of substituted cycloheptatrienes. By forming a coloured enolate with an appropriate absorption band and selectively irradiating in situ, we to initiate a tandem, asymmetric anionic and photochemical ring expansion of readily accessible N-benzylbenzamides. The cascade of reactions leading to the products entails enantioselective benzylic deprotonation with a chiral lithium amide, dearomatizing cyclization of the resulting configurationally defined organolithium to give an extended amide enolate, and photochemically induced formal [1,7]-sigmatropic rearrangement and 6π-electrocyclic ring-opening – the latter all evidently being stereospecific – to deliver enantioenriched cycloheptatrienes with embedded benzylic stereocentres
Scotland’s History of Animation: An Exploratory Account of the Key Figures and Influential Events
Scotland’s history of animation is a forgotten past accomplishment in the animation/VFX sector, with key influential animation professionals having had an impact both at home and abroad. Yet, to date, this history has not been meaningfully documented and such documentation can help inform policy initiatives to help nurture and develop the industry. These developments could help ensure that the importance and accomplishments of its achievements will not be forgotten or remain undeveloped. Indeed, it is argued here that Scotland suffers from historical amnesia with regard to the country’s past accomplishments and missed opportunities, but that public funding and further investment in talent development and retention can help establish the industry as a key player in society and economy. This article presents the results from an investigative literature collection and consultation with central figures in the Scottish animation industry, providing for the first time a clearer picture of the importance of animation in Scotland both for the country and for the industry worldwide. Discussing the initiatives and funding models of other European countries such as France, the article concludes by suggesting ways in which future policy initiatives could help assist Scotland’s animation industry grow and establish itself both for the future development of animation in Scotland and worldwide
A cleaner burning biomass-fuelled cookstove intervention to prevent pneumonia in children under 5 years old in rural Malawi (the Cooking and Pneumonia Study): a cluster randomised controlled trial
Medical Research Council, UK Department for International Development, and Wellcome Trust
Learning to Teach Argumentation: Research and development in the science classroom
The research reported in this study focuses on an investigation into the teaching of argumentation in secondary science classrooms. Over a one-year period, a group of 12 teachers from schools in the greater London area attended a series of workshops to develop materials and strategies to support the teaching of argumentation in scientific contexts. Data were collected at the beginning and end of the year by audio and video recording lessons where the teachers attempted to implement argumentation. To assess the quality of argumentation, analytical tools derived from Toulmin's argument pattern (TAP) were developed and applied to classroom transcripts. Analysis shows there was development in teachers' use of argumentation across the year. Results indicate that the pattern of use of argumentation is teacher-specific, as is the nature of change. To inform future professional development programmes, transcripts of five teachers, three showing a significant change and two no change, were analysed in more detail to identify features of teachers' oral contributions that facilitated and supported argumentation. The analysis showed that all teachers attempted to encourage a variety of processes involved in argumentation and that the teachers whose lessons included the highest quality of argumentation (TAP analysis) also encouraged higher order processes in their teaching. The analysis of teachers' facilitation of argumentation has helped to guide the development of in-service materials and to identify the barriers to learning in the professional development of less experienced teachers
Can we derive an 'exchange rate' between descriptive and preference-based outcome measures for stroke? Results from the transfer to utility (TTU) technique
<p>Abstract</p> <p>Background</p> <p>Stroke-specific outcome measures and descriptive measures of health-related quality of life (HRQoL) are unsuitable for informing decision-makers of the broader consequences of increasing or decreasing funding for stroke interventions. The quality-adjusted life year (QALY) provides a common metric for comparing interventions over multiple dimensions of HRQoL and mortality differentials. There are, however, many circumstances when – because of timing, lack of foresight or cost considerations – only stroke-specific or descriptive measures of health status are available and some indirect means of obtaining QALY-weights becomes necessary. In such circumstances, the use of regression-based transformations or mappings can circumvent the failure to elicit QALY-weights by allowing predicted weights to proxy for observed weights. This regression-based approach has been dubbed 'Transfer to Utility' (TTU) regression. The purpose of the present study is to demonstrate the feasibility and value of TTU regression in stroke by deriving transformations or mappings from stroke-specific and generic but descriptive measures of health status to a generic preference-based measure of HRQoL in a sample of Australians with a diagnosis of acute stroke. Findings will quantify the additional error associated with the use of condition-specific to generic transformations in stroke.</p> <p>Methods</p> <p>We used TTU regression to derive empirical transformations from three commonly used descriptive measures of health status for stroke (NIHSS, Barthel and SF-36) to a preference-based measure (AQoL) suitable for attaching QALY-weights to stroke disease states; based on 2570 observations drawn from a sample of 859 patients with stroke.</p> <p>Results</p> <p>Transformations from the SF-36 to the AQoL explained up to 71.5% of variation in observed AQoL scores. Differences between mean predicted and mean observed AQoL scores from the 'severity-specific' item- and subscale-based SF-36 algorithms and from the 'moderate to severe' index- and item-based Barthel algorithm were neither clinically nor statistically significant when 'low severity' SF-36 transformations were used to predict AQoL scores for patients in the NIHSS = 0 and NIHSS = 1–5 subgroups and when 'moderate to severe severity' transformations were used to predict AQoL scores for patients in the NIHSS ≥ 6 subgroup. In contrast, the difference between mean predicted and mean observed AQoL scores from the NIHSS algorithms and from the 'low severity' Barthel algorithms reached levels that could mask minimally important differences on the AQoL scale.</p> <p>Conclusion</p> <p>While our NIHSS to AQoL transformations proved unsuitable for most applications, our findings demonstrate that stroke-relevant outcome measures such as the SF-36 and Barthel Index can be adequately transformed to preference-based measures for the purposes of economic evaluation.</p
Cooperative, cross-boundary management facilitates large-scale ecosystem restoration efforts
In California and across the United States, landscape restoration projects often require
cross-boundary cooperation, though successful examples are rare and not well understood.
This case study describes the Burney Gardens timber harvesting plan, a cooperative,
cross-boundary meadow restoration project undertaken by private corporate forest landowners
in Northern California as part of a larger collaborative restoration effort. The project
is notable because it (1) received institutional support — both financial and political
— from federal, regional and local sources and (2) engaged a diverse group of stakeholders
in pre-project planning with multiple agency partners. This approach enabled the project
plan to pass through the rigorous California regulatory system in an unusually rapid
fashion despite its complexity. The collaborative model of the Burney Gardens project
is relevant to other restoration efforts, particularly as diverse ownerships across
the West implement large-scale projects that cross property boundaries, including
those of federal and private lands
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