Growing human-scale scala tympani-like in vitro cell constructs

Emerging materials and electrode technologies have potential to revolutionise development of higher resolution next-generation, bionic devices. However, barriers associated with the extended timescales, regulatory constraints, and opportunity costs of preclinical and clinical studies, can inhibit such innovation. Development of in vitro models that mimic human tissues would provide an enabling platform to overcome many of these barriers in the product development pathway. This research aimed to develop human-scale tissue engineered cochlea models for high throughput evaluation of cochlear implants on the bench. Novel mould-casting techniques and stereolithography three-dimensional (3D) printing approaches to template hydrogels into spiral-shaped structures resembling the scala tympani were compared. While hydrogels are typically exploited to support 3D tissue-like structures, the challenge lies in developing irregular morphologies like the scala tympani, in which the cochlear electrodes are commonly implanted. This study successfully developed human-scale scala tympani-like hydrogel structures that support viable cell adhesion and can accommodate cochlear implants for future device testing

Saltmarsh plant responses to eutrophication

In saltmarsh plant communities, bottom-up pressure from nutrient enrichment is predicted to increase productivity, alter community structure, decrease biodiversity, and alter ecosystem functioning. Previous work supporting these predictions has been based largely on short-term, plot-level (e.g., 1-300 m(2)) studies, which may miss landscape-level phenomena that drive ecosystem-level responses. We implemented an ecosystem-scale, nine-year nutrient experiment to examine how saltmarsh plants respond to simulated conditions of coastal eutrophication. Our study differed from previous saltmarsh enrichment studies in that we applied realistic concentrations of nitrate (70-100 mu M NO3-), the most common form of coastal nutrient enrichment, via tidal water at the ecosystem scale (similar to 60,000 m(2) creeksheds). Our enrichments added a total of 1,700 kg N.creek(-1).yr(-1), which increased N loading 10-fold vs. reference creeks (low-marsh, 171 g N.m(-2).yr(-1); high-marsh, 19 g N.m(-2).yr(-1)). Nutrients increased the shoot mass and height of low marsh, tall Spartina alterniflora; however, declines in stem density resulted in no consistent increase in aboveground biomass. High-marsh plants S. patens and stunted S. alterniflora did not respond consistently to enrichment. Nutrient enrichment did not shift community structure, contrary to the prediction of nutrient-driven dominance of S. alterniflora and Distichlis spicata over S. patens. Our mild responses may differ from the results of previous studies for a number of reasons. First, the limited response of the high marsh may be explained by loading rates orders of magnitude lower than previous work. Low loading rates in the high marsh reflect infrequent inundation, arguing that inundation patterns must be considered when predicting responses to estuarine eutrophication. Additionally, we applied nitrate instead of the typically used ammonium, which is energetically favored over nitrate for plant uptake. Thus, the form of nitrogen enrichment used, not just N-load, may be important in predicting plant responses. Overall, our results suggest that when coastal eutrophication is dominated by nitrate and delivered via flooding tidal water, aboveground saltmarsh plant responses may be limited despite moderate-to-high water-column N concentrations. Furthermore, we argue that the methodological limitations of nutrient studies must be considered when using results to inform management decisions about wetlands

Hydrazine decomposition and other reactions

This invention relates to the catalytic decomposition of hydrazine, catalysts useful for this decomposition and other reactions, and to reactions in hydrogen atmospheres generally using carbon-containing catalysts

Home care and elderly people : the experiences of home helps and old people in Salford

My study is concerned not simply with the what and the how of hone carefor the elderly but also with the I ask about how the domiciliaryservices operate: what home helps do for elderly people and how theyfeel about their caring role, and, what the circumstances of elderlypeople needing care are and how they feel about using help. But I alsowant to know why home help operates in this way: why home helps care inthe way they do and why elderly people feel as they do about using thatcare?Such an approach cannot fail to take into consideration the widerecological and structural context within which elderly people and homehelps live and work. Part one of my thesis, composed of three chapters,therefore provides this backcloth. I use it to introduce the locationof the study, to present a brief history and discussion of thedevelopment of domiciliary services for the elderly in Britain, and 10describe the philosophy and policy shaping domiciliary provision withinSalford Social Services Department. As I shall show, current Governmenteconomic policy is inextricably woven into the fabric of this backcloth.In Part Two, I detail the findings of my fieldwork, painting a pictureof the lives of the frail and impaired elderly people using domiciliarycare, and of the work of the home helps providing that care. As far aspossible, I have used the interviewees' own words to explain perceptions of (in)dependence and need, of stiqma and taboo, of material andideological motivations, and of emotional involvements and commitments.A number of writers have argued that dependency - a concept at thecentre of inquiries into the care of the elderly - is a sociallyconstructed relationship, both with respect to elderly users and femaleproviders of care. In Part Three, I question whether and in what waythe evidence supports or denies this claim. I ask what are theimplications of my findings for social policy. I also justify the useof anthropological perspectives in policy-related research.Finally, I present an account of my experience as a researcher which canbe approached from a number of different levels., At a'basic level, itrepresents an immediate account of doing fieldwork. It is also myaccount, as a post-graduate, of the experience of writing-up a thesis.I consider the effect of the passing of time on context andconsciousness and hci this feeds into the analysis and presentation, ofwork. And I attempt to address concerns with the writer/reader/subjectrelationship which pose questions to do with communication

An assertion language for constraint logic programs

In an advanced program development environment, such as that discussed in the introduction of this book, several tools may coexist which handle both the program and information on the program in different ways. Also, these tools may interact among themselves and with the user. Thus, the different tools and the user need some way to communicate. It is our design principie that such communication be performed in terms of assertions. Assertions are syntactic objects which allow expressing properties of programs. Several assertion languages have been used in the past in different contexts, mainly related to program debugging. In this chapter we propose a general language of assertions which is used in different tools for validation and debugging of constraint logic programs in the context of the DiSCiPl project. The assertion language proposed is parametric w.r.t. the particular constraint domain and properties of interest being used in each different tool. The language proposed is quite general in that it poses few restrictions on the kind of properties which may be expressed. We believe the assertion language we propose is of practical relevance and appropriate for the different uses required in the tools considered

Compulsive versifying after treatment of transient epileptic amnesia

Compulsive production of verse is an unusual form of hypergraphia that has been reported mainly in patients with right temporal lobe seizures. We present a patient with transient epileptic amnesia and a left temporal seizure focus, who developed isolated compulsive versifying, producing multiple rhyming poems, following seizure cessation induced by lamotrigine. Functional neuroimaging studies in the healthy brain implicate left frontotemporal areas in generating novel verbal output and rhyme, while dysregulation of neocortical and limbic regions occurs in temporal lobe epilepsy. This case complements previous observations of emergence of altered behavior with reduced seizure frequency in patients with temporal lobe epilepsy. Such cases suggest that reduced seizure frequency has the potential not only to stabilize or improve memory function, but also to trigger complex, specific behavioral alterations

Independence in CLP Languages

Studying independence of goals has proven very useful in the context of logic programming. In particular, it has provided a formal basis for powerful automatic parallelization tools, since independence ensures that two goals may be evaluated in parallel while preserving correctness and eciency. We extend the concept of independence to constraint logic programs (CLP) and prove that it also ensures the correctness and eciency of the parallel evaluation of independent goals. Independence for CLP languages is more complex than for logic programming as search space preservation is necessary but no longer sucient for ensuring correctness and eciency. Two additional issues arise. The rst is that the cost of constraint solving may depend upon the order constraints are encountered. The second is the need to handle dynamic scheduling. We clarify these issues by proposing various types of search independence and constraint solver independence, and show how they can be combined to allow dierent optimizations, from parallelism to intelligent backtracking. Sucient conditions for independence which can be evaluated \a priori" at run-time are also proposed. Our study also yields new insights into independence in logic programming languages. In particular, we show that search space preservation is not only a sucient but also a necessary condition for ensuring correctness and eciency of parallel execution

SPIDER VII - Revealing the Stellar Population Content of Massive Early-type Galaxies out to 8Re

Radial trends of stellar populations in galaxies provide a valuable tool to understand the mechanisms of galaxy growth. In this paper, we present the first comprehensive analysis of optical-optical and optical-NIR colours, as a function of galaxy mass, out to the halo region (8Re) of early-type galaxies (ETGs). We select a sample of 674 massive ETGs (M*>3x10^10MSun) from the SDSS-based SPIDER survey. By comparing with a large range of population synthesis models, we derive robust constraints on the radial trends in age and metallicity. Metallicity is unambiguously found to decrease outwards, with a measurable steepening of the slope in the outer regions (Re<R<8Re). The gradients in stellar age are found to be more sensitive to the models used, but in general, the outer regions of ETGs feature older populations compared to the cores. This trend is strongest for the most massive galaxies in our sample (M*>10^11MSun). Furthermore, when segregating with respect to large scale environment, the age gradient is more significant in ETGs residing in higher density regions. These results shed light on the processes leading from the formation of the central core to the growth of the stellar envelope of massive galaxies. The fact that the populations in the outer regions are older and more metal-poor than in the core suggests a process whereby the envelope of massive galaxies is made up of accreted small satellites (i.e. minor mergers) whose stars were born during the first stages of galaxy formation.Comment: 20 pages, 13 figures, 10 tables. Accepted for publication in MNRA

Evaluating the Value of Dynamic Terrain Simulation on Training Quality

Warfighters perform a variety of civilian duties, such as construction. For example, in Iraq, from 2004-2011, the US Army carried out over 5,000 construction projects. Training warfighters on heavy construction equipment is a timeconsuming task that contrasts with shrinking military budgets. Simulation-based training offers improved training for fewer resources. Simulators can decrease time to task proficiency by up to 90%. Identifying the pertinent features needed for a construction equipment trainer is challenging. For example, a critical skill is identifying different soil types. Lifting too much soil can damage equipment while not taking enough can cause significant delays. An experimental study investigated the effectiveness of a virtual excavator trainer with particular attention to the use of a high-fidelity soil simulation and its effect on learning. The experiments included two soil types: clay (hard to handle, high mechanical integrity) and sand (easy to handle, reduced mechanical integrity). Participants used the Dynamic Environments (DE) Testbed with the Construction Equipment Virtual Trainer (CEVT) for the experiments. Randomly assigned participants worked with clay, sand, or both materials as well as using the CEVT or watching video for their training tasks. Participants attended three separate training sessions and completed decision tasks to assess their level of knowledge in identifying different soils and operating a virtual excavator correctly. Results showed that while the high-fidelity simulation did not dramatically improve learning, use of the simulation-based trainer did allow participants to estimate better the time required to conduct tasks based on different terrain types. The authors recommend: (1) designing training scenarios that limit the effect of contamination by prior experience, (2) improved simulator controls, (3) enhanced simulator graphic fidelity, and (4) an increased number of participants provide results with the desired consistency in improving training quality