Showing papers by "Edinburgh Napier University published in 2012"

The revised classification of eukaryotes

Abstract: This revision of the classification of eukaryotes, which updates that of Adl et al. [J. Eukaryot. Microbiol. 52 (2005) 399], retains an emphasis on the protists and incorporates changes since 2005 that have resolved nodes and branches in phylogenetic trees. Whereas the previous revision was successful in re-introducing name stability to the classification, this revision provides a classification for lineages that were then still unresolved. The supergroups have withstood phylogenetic hypothesis testing with some modifications, but despite some progress, problematic nodes at the base of the eukaryotic tree still remain to be statistically resolved. Looking forward, subsequent transformations to our understanding of the diversity of life will be from the discovery of novel lineages in previously under-sampled areas and from environmental genomic information.

Ecotoxicity test methods for engineered nanomaterials: Practical experiences and recommendations from the bench

Abstract: Ecotoxicology research is using many methods for engineered nanomaterials (ENMs), but the collective experience from researchers has not been documented. This paper reports the practical issues for working with ENMs and suggests nano-specific modifications to protocols. The review considers generic practical issues, as well as specific issues for aquatic tests, marine grazers, soil organisms, and bioaccumulation studies. Current procedures for cleaning glassware are adequate, but electrodes are problematic. The maintenance of exposure concentration is challenging, but can be achieved with some ENMs. The need to characterize the media during experiments is identified, but rapid analytical methods are not available to do this. The use of sonication and natural/synthetic dispersants are discussed. Nano-specific biological endpoints may be developed for a tiered monitoring scheme to diagnose ENM exposure or effect. A case study of the algal growth test highlights many small deviations in current regulatory test protocols that are allowed (shaking, lighting, mixing methods), but these should be standardized for ENMs. Invertebrate (Daphnia) tests should account for mechanical toxicity of ENMs. Fish tests should consider semistatic exposure to minimize wastewater and animal husbandry. The inclusion of a benthic test is recommended for the base set of ecotoxicity tests with ENMs. The sensitivity of soil tests needs to be increased for ENMs and shortened for logistics reasons; improvements include using Caenorhabditis elegans, aquatic media, and metabolism endpoints in the plant growth tests. The existing bioaccumulation tests are conceptually flawed and require considerable modification, or a new test, to work for ENMs. Overall, most methodologies need some amendments, and recommendations are made to assist researchers.

Interspecies comparisons on the uptake and toxicity of silver and cerium dioxide nanoparticles

Abstract: An increasing number and quantity of manufactured nanoparticles are entering the environment as the diversity of their applications increases, and this will lead to the exposure of both humans and wildlife. However, little is known regarding their potential health effects. We compared the potential biological effects of silver (Ag; nominally 35 and 600–1,600 nm) and cerium dioxide (CeO2; nominally <25 nm and 1–5 µm) particles in a range of cell (human hepatocyte and intestinal and fish hepatocyte) and animal (Daphnia magna, Cyprinus carpio) models to assess possible commonalities in toxicity across taxa. A variety of analytical techniques were employed to characterize the particles and investigate their biological uptake. Silver particles were more toxic than CeO2 in all test systems, and an equivalent mass dose of Ag nanoparticles was more toxic than larger micro-sized material. Cellular uptake of all materials tested was shown in C3A hepatocytes and Caco-2 intestinal cells, and for Ag, into the intestine, liver, gallbladder, and gills of carp exposed via the water. The commonalities in toxicity of these particle types across diverse biological systems suggest that cross-species extrapolations may be possible for metal nanoparticle test development in the future. Our findings also suggest transport of particles through the gastrointestinal barrier, which is likely to be an important uptake route when assessing particle risk. Environ. Toxicol. Chem. 2012;31:144–154. © 2011 SETAC

The water vapour sorption properties of thermally modified and densified wood

Abstract: The water vapour sorption behaviour of Scots pine (Pinus sylvestris L.) and Scots pine that was densified, thermally-modified, or subjected to a combination of thermal modification and densification has been investigated. It was found that all modifications resulted in a decrease in the equilibrium moisture content of the wood samples throughout the hygroscopic range. The water vapour sorption isotherms were reproducible for the unmodified wood samples, but changed between the first and subsequent sorption cycles for the densified, thermally-modified and for wood subjected to a combination of the two treatments. This is the first time that changes in the sorption isotherm between the first and subsequent cycles have been reported for thermally-modified wood. Irrespective of the wood treatment the difference between the adsorption and desorption isotherm loops (sorption hysteresis) was the same and greater than that observed for the unmodified wood sample. After the first sorption cycle, the hysteresis decreased to the values observed for the unmodified wood, even though the isotherms were different. The sorption kinetic behaviour was also investigated and found to be accurately described using the parallel exponential kinetics (PEK) model. The PEK model describes the dynamic sorption behaviour in terms of a fast and slow kinetic process and this has been interpreted in terms of two Kelvin-Voigt elements coupled in series (i.e. relaxation-limited kinetics).

The influence of inter-particle friction and the intermediate stress ratio on soil response under generalised stress conditions

Abstract: Previous research studies have used either physical experiments or discrete element method (DEM) simulations to explore, independently, the influence of the coefficient of inter-particle friction (μ) and the intermediate stress ratio (b) on the behaviour of granular materials. DEM simulations and experiments using photoelasticity have shown that when an anisotropic stress condition is applied to a granular material, strong force chains or columns of contacting particles transmitting relatively large forces, form parallel to the major principal stress orientation. The combined effects of friction and the intermediate stress ratio upon the resistance of these strong force chains to collapse (buckling failure) are considered here using data from an extensive set of DEM simulations including triaxial and true triaxial compression tests. For all tests both μ and b affected the macro- and micro-scale response, however the mechanisms whereby the force chain stability was improved differ. While friction clearly enhances the inherent stability of the strong force chains, the intermediate stress ratio affects the contact density and distribution of orthogonal contacts that provide lateral support to the force chains.

Oral versus written assessments: a test of student performance and attitudes

Abstract: Student performance in and attitudes towards oral and written assessments were compared using quantitative and qualitative methods. Two separate cohorts of students were examined. The first larger cohort of students (n = 99) was randomly divided into ‘oral’ and ‘written’ groups, and the marks that they achieved in the same biology questions were compared. Students in the second smaller cohort (n = 29) were all examined using both written and oral questions concerning both ‘scientific’ and ‘personal development’ topics. Both cohorts showed highly significant differences in the mean marks achieved, with better performance in the oral assessment. There was no evidence of particular groups of students being disadvantaged in the oral tests. These students and also an additional cohort were asked about their attitudes to the two different assessment approaches. Although they tended to be more nervous in the face of oral assessments, many students thought oral assessments were more useful than written assessment...

In vitro assessment of engineered nanomaterials using a hepatocyte cell line: cytotoxicity, pro-inflammatory cytokines and functional markers

Abstract: Effects on the liver C3A cell line treated with a panel of engineered nanomaterials (NMs) consisting of two zinc oxide particles (ZnO; coated 100 nm and uncoated 130 nm), two multi-walled carbon nanotubes (MWCNTs), one silver (Ag < 20 nm), one 7 nm anatase, two rutile TiO2 nanoparticles (10 and 94 nm) and two derivatives with positive and negative covalent functionalisation of the 10 nm rutile were evaluated. The silver particles elicited the greatest level of cytotoxicity (24 h LC50 - 2 µg/cm(2)). The silver was followed by the uncoated ZnO (24 h LC50 - 7.5 µg/cm(2)) and coated ZnO (24 h LC50 - 15 µg/cm(2)) particles with respect to cytotoxicity. The ZnO NMs were found to be about 50-60% soluble which could account for their toxicity. By contrast, the Ag was <1% soluble. The LC50 was not attained in the presence of any of the other engineered NMs (up to 80 µg/cm(2)). All NMs significantly increased IL-8 production. Meanwhile, no significant change in TNF-α, IL-6 or CRP was detected. Urea and albumin production were measured as indicators of hepatic function. These markers were only altered by the coated and uncoated ZnO, which significantly decreased albumin production.

An in vitro liver model - assessing oxidative stress and genotoxicity following exposure of hepatocytes to a panel of engineered nanomaterials

Abstract: Background: Following exposure via inhalation, intratracheal instillation or ingestion some nanomaterials (NM) have been shown to translocate to the liver. Since oxidative stress has been implicated as a possible mechanism for NM toxicity this study aimed to investigate the effects of various materials (five titanium dioxide (TiO2), two zinc oxide (ZnO), two multi-walled carbon nanotubes (MWCNT) and one silver (Ag) NM) on oxidative responses of C3A cell line as a model for potential detrimental properties of nanomaterials on the liver. Results: We noted a dose dependant decrease in the cellular glutathione content following exposure of the C3A cells to Ag, the ZnO and the MWCNTs. Intracellular ROS levels were also measured and shown to increase significantly following exposure of the C3A to the low toxicity NMs (MWCNT and TiO2). The antioxidant Trolox in part prevented the detrimental effect of NMs on cell viability, and decreased the NM induced IL8 production after exposure to all but the Ag particulate. Following 4 hr exposure of the C3A cells to sub-lethal levels of the NMs, the largest amount of DNA damage was induced by two of the TiO2 samples (7 nm and the positively charged 10 nm particles). Conclusions: All ten NMs exhibited effects on the hepatocyte cell line that were at least in part ROS/oxidative stress mediated. These effects included mild genotoxicity and IL8 production for all NM except the Ag possibly due to its highly cytotoxic nature.

Effects of installing a marked crosswalk on road crossing behaviour and perceptions of the environment

Abstract: A two-pronged study was conducted to investigate (a) pedestrians’ road-crossing behaviour and (b) perceptions of the walking environment, both before and after the installation of a marked crosswalk (zebra crossing) at a single case-study location in Edinburgh, UK. The observational and questionnaire surveys indicated that: (a) pedestrians were significantly more likely to use the location to cross the road, waited significantly less time to cross, and walked significantly more slowly after the zebra had been installed compared with before; and (b) people felt safer, less vulnerable to traffic and more confident when crossing the road after the zebra had been installed. The results indicate that installing a marked crosswalk such as a zebra crossing can significantly enhance the road-crossing experience of pedestrians and therefore improve the walking journey more broadly.

Parameterising expertise in coaching: past, present and future.

Abstract: Research into expertise is increasing across a number of domains pertinent to sport. Whilst this increase is particularly apparent in coaching, a key question is how to identify an expert coach? Accordingly, this paper draws upon existing studies into expert coaches to address this issue; in particular, the criteria used to select expert coaches for research purposes and the methods used in expert coach research. Based on these data, we contend that the elements of expertise are not fully reflected within currently accepted criteria which, in turn, results in expert coaching research not necessarily identifying the appropriate individuals to study. The paper concludes with recommendations for more rigorous criteria for selecting expert coaches and highlights the associated implications for the future training and development of expert coaches.

Textile UWB Antenna Bending and Wet Performances

Abstract: The vision and ideas of wearable computing systems describe future electronic systems as an integral part of our everyday clothing that provides the wearer with such intelligent personal assistants. Recently, there has been growing interest in the antenna community to merge between wearable systems technology, ultrawideband (UWB) technology and textile technology. This work aimed to make closer steps towards real wearability by investigating the possibilities of designing wearable UWB antenna where textile materials are used for the substrate as well as the conducting parts of the designed antenna. Two types of conducting materials have been used for conducting parts, while a nonconducting fabric has been used as antenna substrate material. A set of comparative results of the proposed design were presented and discussed. Moreover, effects on the return loss by means of measurements for each fabricated antenna prototype under bent and fully wet conditions were discussed in more details.

Five critical questions of scale for the coastal zone

Abstract: Social and ecological systems around the world are becoming increasingly globalized. From the standpoint of understanding coastal ecosystem behavior, system boundaries are not sufficient to define causes of change. A flutter in the stock market in Tokyo or Hong Kong can affect salmon producers in Norway or farmers in Togo. The globalization of opportunistic species and the disempowerment of people trying to manage their own affairs on a local scale seem to coincide with the globalization of trade. Human-accelerated environmental change, including climate change, can exacerbate this sense of disenfranchisement. The structure and functioning of coastal ecosystems have been developed over thousands of years subject to environmental forces and constraints imposed mainly on local scales. However, phenomena that transcend these conventional scales have emerged with the explosion of human population, and especially with the rise of modern global culture. Here, we examine five broad questions of scale in the coastal zone: (1) How big are coastal ecosystems and why should we care? (2) Temporal scales of change in coastal waters and watersheds: Can we detect shifting baselines due to economic development and other drivers? (3) Are footprints more important than boundaries? (4) What makes a decision big? The tyranny of small decisions in coastal regions. (5) Scales of complexity in coastal waters: the simple, the complicated or the complex? These questions do not have straightforward answers. There is no single “scale” for coastal ecosystems; their multiscale nature complicates our understanding and management of them. Coastal ecosystems depend on their watersheds as well as spatially-diffuse “footprints” associated with modern trade and material flows. Change occurs both rapidly and slowly on human time scales, and observing and responding to changes in coastal environments is a fundamental challenge. Apparently small human decisions collectively have potentially enormous consequences for coastal environmental quality, and our success in managing the effects of these decisions will determine the quality of life in the coastal zone in the 21st century and beyond. Vigilant monitoring, creative synthesis of information, and continued research will be necessary to properly understand and govern our coastal environments into the future.

A rheological description of the water vapour sorption kinetics behaviour of wood invoking a model using a canonical assembly of Kelvin-Voigt elements and a possible link with sorption hysteresis

Abstract: The dynamic vapour sorption behaviour of two Malaysian hardwoods, acacia (Acacia mangium Wild) and sesendok (Endospermum malaccense Bent ex Mull. Arg.) was studied over a narrow temperature range (20-408C). The rate of sorption or desorption of water into or out of the wood cell wall was considered to be limited by the viscoelastic behav- iour of the material and the sorption kinetics was accordingly analysed in terms of a canonical series of Kelvin-Voigt ele- ments. A two series and three series model have been applied to the kinetic data and the results are compared. Character- istic times and moisture contents were obtained from the models. The Arrhenius equation was used in conjunction with the reciprocals of the characteristic times to calculate the activation energy and activation entropy of sorption, and the Gibbs free energy of activation for the sorption process was also determined. This is the first time that entropy of activation and Gibbs free energy of activation for sorption processes with wood have been reported. Interpretation of these data invokes a model describing the polymeric relax- ation processes occurring within the cell wall during adsorp- tion or desorption. A possible link between sorption kinetics, polymeric relaxation processes, and sorption hysteresis is discussed.

The cost of dominance: suppressing subordinate reproduction affects the reproductive success of dominant female banded mongooses

Abstract: Social species show considerable variation in the extent to which dominant females suppress subordinate reproduction. Much of this variation may be influenced by the cost of active suppression to dominants, who may be selected to balance the need to maximize the resources available for their own offspring against the costs of interfering with subordinate reproduction. To date, the cost of reproductive suppression has received little attention, despite its potential to influence the outcome of conflict over the distribution of reproduction in social species. Here, we investigate possible costs of reproductive suppression in banded mongooses, where dominant females evict subordinates from their groups, thereby inducing subordinate abortion. We show that evicting subordinate females is associated with substantial costs to dominant females: pups born to females who evicted subordinates while pregnant were lighter than those born after undisturbed gestations; pups whose dependent period was disrupted by an eviction attained a lower weight at independence; and the proportion of a litter that survived to independence was reduced if there was an eviction during the dependent period. To our knowledge, this is the first empirical study indicating a possible cost to dominants in attempting to suppress subordinate breeding, and we argue that much of the variation in reproductive skew both within and between social species may be influenced by adaptive variation in the effort invested in suppression by dominants.

Invasive Ponto-Caspian amphipods and fish increase the distribution range of the acanthocephalan Pomphorhynchus tereticollis in the River Rhine.

Abstract: Non-indigenous species that become invasive are one of the main drivers of biodiversity loss worldwide. In various freshwater systems in Europe, populations of native amphipods and fish are progressively displaced by highly adaptive non-indigenous species that can perform explosive range extensions. A total of 40 Ponto-Caspian round gobies Neogobius melanostomus from the Rhine River near Dusseldorf, North Rhine-Westphalia, Germany, were examined for metazoan parasites and feeding ecology. Three metazoan parasite species were found: two Nematoda and one Acanthocephala. The two Nematoda, Raphidascaris acus and Paracuaria adunca, had a low prevalence of 2.5%. The Acanthocephala, Pomphorhynchus tereticollis, was the predominant parasite species, reaching a level of 90.0% prevalence in the larval stage, correlated with fish size. In addition, four invasive amphipod species, Corophium curvispinum (435 specimens), Dikerogammarus villosus (5,454), Echinogammarus trichiatus (2,695) and Orchestia cavimana (1,448) were trapped at the sampling site. Only D. villosus was infected with P. tereticollis at a prevalence of 0.04%. The invasive goby N. melanostomus mainly preys on these non-indigenous amphipods, and may have replaced native amphipods in the transmission of P. tereticollis into the vertebrate paratenic host. This study gives insight into a potential parasite-host system that consists mainly of invasive species, such as the Ponto-Caspian fish and amphipods in the Rhine. We discuss prospective distribution and migration pathways of non-indigenous vertebrate (round goby) and invertebrates (amphipods) under special consideration of parasite dispersal.

Ageing, skills and participation in work-related training in Britain: assessing the position of older workers:

Abstract: Policy makers have introduced a number of measures to encourage older workers to stay in the labour market, with improving access to training a particular priority. Policy action appeared justified by evidence that older workers are less likely to participate in training, and more likely to have never been offered training by employers – a key finding of Taylor and Urwin’s (2001) review of Labour Force Survey (LFS) data from 1997. This article models LFS data from 2007 to assess whether age remained a predictor of inequalities in training. It finds that men over 50 remained among those least likely to have been offered training by employers. There were other significant inequalities in participation, suggesting a polarization in access to jobs that offer opportunities for training and progression. The article concludes that policies promoting ‘active ageing’ need to challenge negative employer attitudes and acknowledge fundamental inequalities in access to skills.

Qualitative Secondary Analysis and Social Explanation

Abstract: The current paper takes as a focus some issues relating to the possibility for, and effective conduct of, qualitative secondary data analysis. We consider some challenges for the re-use of qualitat...

Approaches for dealing with missing data in health care studies

Abstract: Aim. The aims of this study were to highlight the problems associated with missing data in healthcare research and to demonstrate the use of several techniques for dealing with missing values, through the use of an illustrative example. Background. In healthcare research studies, it is almost impossible to avoid at least some missing values during data collection, which in turn can threaten the validity of the study conclusions. A range of methods for reducing the impact of missing data on the validity of study findings have been developed, depending on the nature and patterns which the missing values may take. Design. A discursive study. Methods. Several techniques designed to deal with missing data are described and applied to an illustrative example. These methods include complete-case analysis, available-case analysis, as well as single and multiple imputation. Conclusions. If research data contain missing values that are not randomly distributed, then the study results are likely to be biased unless an effective approach to dealing with the missing values is implemented. Relevance to clinical practice. If nursing and healthcare practice is to be informed by research findings, then these findings must be reliable and valid. Researchers should report the details of missing data, and appropriate methods for dealing with missing values should be incorporated into the data analysis

Learning Disability Liaison Nursing Services in south-east Scotland: a mixed-methods impact and outcome study.

Abstract: Background There have been significant concerns about the care and treatment of people with intellectual disabilities (ID) when attending general hospitals, which have led to inquiries that highlight service and systems failures. One response has been the development of Learning Disability Liaison Nursing (LDLN) Services across the UK that aim to ensure that additional, specialist support is available for patients, their carers and general healthcare professionals. Methods A mixed-methods study to investigate the impact of LDLN Services across four Scottish NHS boards was undertaken. In total, 323 referrals made over 18 months were analysed along with qualitative data drawn from interviews and focus groups with a sample of 85 participants including patients with ID (n = 5), carers (n = 16), primary care healthcare professionals (n = 39) and general hospital professionals (n = 19) and learning disability liaison nurses (n = 6). Results The referral patterns to the four liaison nursing services closely matched the known health needs of adults with ID, with common admissions being due to neurological, respiratory and gastrointestinal issues. The LDLN role was seen to be complex and impacted on three key areas: (i) clinical patient care; (ii) education and practice development; and (iii) strategic organisational developments. Specific patient outcomes were linked to issues relating to capacity and consent to treatment, fostering person-centred adjustments to care, augmenting communication and the liaison nurses acting as positive role models and ambassadors for people with ID. Conclusions The LDLN Services were valued by stakeholders by achieving person-centred outcomes. With their expert knowledge and skills, the liaison nurses had an important role in developing effective systems and processes within general hospital settings. The outcomes highlight the importance of supporting and promoting LDLN Services and the challenges in delivering the multifaceted elements of the role. There is a need to take account of the complex and multidimensional nature of the LDLN role and the possible tensions between achieving clinical outcomes, education and practice developments and organisational strategic initiatives.

Cellulose microfibril angles and cell-wall polymers in different wood types of Pinus radiata

Abstract: Four corewood types were examined from sapling trees of two clones of Pinus radiata grown in a glasshouse. Trees were grown either straight to produce normal corewood, tilted at 45° from the vertical to produce opposite corewood and compression corewood, or rocked to produce flexure corewood. Mean cellulose microfibril angle of tracheid walls was estimated by X-ray diffraction and longitudinal swelling measured between an oven dry and moisture saturated state. Lignin and acetyl contents of the woods were measured and the monosaccharide compositions of the cell-wall polysaccharides determined. Finely milled wood was analysed using solution-state 2D NMR spectroscopy of gels from finely milled wood in DMSO-d6/pyridine-d5. Although there was no significant difference in cellulose microfibril angle among the corewood types, compression corewood had the highest longitudinal swelling. A lignin content >32 % and a galactosyl residue content >6 % clearly divided severe compression corewood from the other corewood types. Relationships could be drawn between lignin content and longitudinal swelling, and between galactosyl residue content and longitudinal swelling. The 2D NMR spectra showed that the presence of H-units in lignin was exclusive to compression corewood, which also had a higher (1 → 4)-β-d-galactan content, defining a unique composition for that corewood type.