9,478 research outputs found
Intellectual Colonialism or Liberatory Education? An Exploration of Adult Education in an International Context
We examine colonialism through pedagogy, method, curriculum and knowledge and conclude by identifying potential for developing and developed countries to collaborate in knowledge creation. As a case study, we draw on the Commonwealth Youth Programme’s Diploma in Youth in Development. Does it deliver liberatory education or intellectual colonialism
Cassini detection of Enceladus' cold water-group plume ionosphere
This study reports direct detection by the Cassini plasma spectrometer of freshly-produced water-group ions (O+, OH+, H2O+, H3O+) and heavier water dimer ions (HxO(2))(+) very close to Enceladus where the plasma begins to emerge from the plume. The data were obtained during two close ( 52 and 25 km) flybys of Enceladus in 2008 and are similar to ion data in cometary comas. The ions are observed in detectors looking in the Cassini ram direction exhibiting energies consistent with the Cassini speed, indicative of a nearly stagnant plasma flow in the plume. North of Enceladus the plasma slowing commences about 4 to 6 Enceladus radii away, while south of Enceladus signatures of the plasma interaction with the plume are detected 22 Enceladus radii away. Citation: Tokar, R. L., R. E. Johnson, M. F. Thomsen, R. J. Wilson, D. T. Young, F. J. Crary, A. J. Coates, G. H. Jones, and C. S. Paty ( 2009), Cassini detection of Enceladus' cold water-group plume ionosphere, Geophys. Res. Lett., 36, L13203, doi:10.1029/2009GL038923
Development of Methods for Retinal Ganglion Cell Replacement in Glaucoma
A sub population of human Müller glia contained within the neural retina is known to exhibit stem cell characteristics. Previous studies in the host laboratory have investigated their ability to differentiate into different retinal populations in vitro, providing a potential source of cells for development of therapies to treat retinal degenerative diseases. This study investigated molecular factors involved in differentiation of retina ganglion cells (RGCs) derived from human Müller stem cells. It also aimed to explore the feasibility of transplanting RGC derived from Müller stem cells into large mammalian eyes, using collagen based cellular scaffolds. These objectives ultimately aimed to study the potential application of Müller stem cells for treatment of late stage glaucoma. As determined by microarray analysis of total RNA specimens, in vitro culture of Müller stem cells undergoing Notch inhibition in the presence or absence of bFGF, led to alteration in microRNA (miRNA) profiles. These are short RNA molecules synthesised within cells that play a role in various cellular processes. MicroRNAs associated with Notch signalling, cell cycling and differentiation, were enriched in Müller cell populations undergoing Notch inhibition, conditions previously shown to induce RGC development. Elevated expression of these specific miRNAs suggests the emergence of novel targets under the regulation of the Notch pathway in Müller stem cells. These constitute factors that could be potentially used to develop therapies which facilitate endogenous neural differentiation of the latent Müller stem cell population in the human neural retina. Collagen based cellular scaffolds were developed to deliver RGCs derived from Müller stem cells onto the inner retina of the large mammalian eye. Collagen is a ubiquitous protein found within numerous tissues types, acting as a framework for cellular support and adhesion. Delivery of grafted cells onto retinal explants in vitro, and transplantation of scaffolds into the rabbit eye in vivo, was examined by confocal microscopy and showed that plastic compressed collagen scaffolds served as a potential suitable substrate for transfer of cells to the host retina. Integration was observed in some cases and rarely observed into host tissue, facilitated by degradation of the extracellular matrix by chondroitinase ABC and by the use of the anti-inflammatory agent triamcinolone in vivo. In conclusion, the present study showed that standardised protocols used to differentiate Müller stem cells into RGC promoted alterations in Müller stem cell miRNAs associated with RGC development and maturation. In addition, compressed collagen scaffolds were shown to aid delivery of RGCs onto the inner retinal surface. These observations pave the way for further investigations to promote endogenous retina regeneration and refinement of transplantation strategies to apply these cells to the development of human therapies
Oligoclonal expansions of CD8(+) T cells in chronic HIV infection are antigen specific
Acute HIV infection is associated with a vigorous immune response characterized by the proliferation of selected T cell receptor V beta (BV)-expressing CD8(+) T cells. These 'expansions', which are commonly detected in the peripheral blood, can persist during chronic HIV infection and may result in the dominance of particular clones. Such clonal populations are most consistent with antigen-driven expansions of CD8(+) T cells. However, due to the difficulties in studying antigen-specific T cells in vivo, it has been hard to prove that oligoclonal BV expansions are actually HIV specific. The use of tetrameric major histocompatibility complex-peptide complexes has recently enabled direct visualization of antigen-specific T cells ex vivo but has not provided information on their clonal composition. We have now made use of these tetrameric complexes in conjunction with anti-BV chain-specific monoclonal antibodies and analysis of cytotoxic T lymphocyte lines/clones to show that chronically clonally expanded CD8(+) T cells are HIV specific in vivo
Evaluation of bone mineral density in cystic fibrosis patients
Patients with cystic fibrosis (CF) have an increasing life span and osteoporosis has become a more recognised problem in these patients. The pathogenesis of low bone mineral density (BMD) in CF seems to be multifactorial and the aim of this study was to assess the prevalence of low BMD in a group of CF outpatients and to relate the findings with the variables studied. The study included 22 patients aged between 14 and 45 years (mean age 26.3). Two of the subjects were lung transplant patients. BMD was assessed by dual-energy X-ray absorptiometry (DEXA) at the lumbar spine (LS) and femoral neck (FN). This data was correlated with serum 25-hydroxy vitamin D (25-OHD) levels, BMI and the forced expiratory volume in one second (FEV1). BMD (Z-score and T-score) ranged from 0.6 to -6 and from 0.5 to -6.7 at LS; at FN the scores ranged from 0.6 to -3.9 and from 0.6 to -4.1. The mean serum 25-OHD concentration (12,57 ng/ml) was at the low end of the normal range (10-60 ng/ml). On average patients did not present with malnutrition, however BMI ranged from 15.2 to 33.7 kg/m2. Lung function status was assessed by FEV1; 64% of patients had FEV1 below 80% and within this group four patients had a FEV1 under 40%. There was a positive correlation between low BMD and 25-OHD concentrations and also between BMD and FEV1. There was no linear correlation between BMD and BMI
Environmental determinants of active travel in youth: a review and framework for future research.
BACKGROUND: Many youth fail to meet the recommended guidelines for physical activity. Walking and cycling, forms of active travel, have the potential to contribute significantly towards overall physical activity levels. Recent research examining the associations between physical activity and the environment has shown that environmental factors play a role in determining behaviour in children and adolescents. However, links between the environment and active travel have received less attention. METHODS: Twenty four studies were identified which examined the associations between the environment (perceived or objectively measured) and active travel among youth aged 5-18 years. Findings were categorised according to the location of the environmental measure examined; attributes of the neighbourhood, destination and the route between home and destination. RESULTS: Results from the reviewed studies indicated that youth active travel is positively associated with social interactions, facilities to assist active travel and urban form in the neighbourhood as well as shorter route length and road safety en-route. A conceptual framework is presented which highlights the associations between active travel behaviours and environmental factors, drawing upon both existing and hypothesised relationships. CONCLUSION: We provide a review of the available literature and present a novel theoretical framework that integrates the environment into the wider decision making process around travel choices for children and adolescents. Further work should explore associations where gaps in understanding have been identified, and account for the main moderators of behaviour so hypothesised associations can be confirmed.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
School grounds and physical activity: Associations at secondary schools, and over the transition from primary to secondary schools.
This paper aims to further understanding of the physical environments of secondary schools and their associations with young peoples' physical activity. Accelerometer-derived physical activity measurements from 299 participants in the SPEEDY study (Norfolk, UK) were obtained from baseline measurements (age 9-10y) and +4y follow-up. These were linked to objective measures of primary and secondary school environments as measured by the SPEEDY grounds audit tool. We saw considerable differences in the nature of school grounds between primary and secondary schools. Cross-sectional associations were seen between active travel provision scores and commuting time moderate-to-vigorous physical activity (MVPA) for 13-14 year old boys and adolescents living further from school. However, few associations were seen between changes in school grounds scores and changes in school-based MVPA.Funding: The SPEEDY study is funded by the National Prevention Research Initiative (http://www.npri.org.uk), consisting of the following Funding Partners: British Heart Foundation; Cancer Research UK; Department of Health; Diabetes UK; Economic and Social Research Council; Medical Research Council; Health and Social Care Research and Development Office for the Northern Ireland; Chief Scientist Office, Scottish Government Health Directorates; Welsh Assembly Government and World Cancer Research Fund. This work was also supported by the Medical Research Council (Unit Programme numbers MC_UU_12015/7, MC_UU_12015/4, and MC_UU_12015/3) and the Centre for Diet and Activity Research (CEDAR), a UKCRC Public Health Research: Centre of Excellence. Funding from the British Heart Foundation, Economic and Social Research Council, Medical Research Council, the National Institute for Health Research, and the Wellcome Trust, under the auspices of the UK Clinical Research Collaboration, is gratefully acknowledged (grant code RES-590-28-002).This is the final version of the article. It first appeared from Elsevier via https://doi.org/10.1016/j.healthplace.2016.02.00
An integrated and multi-purpose microscope for the characterization of atomically thin optoelectronic devices
This is the author accepted manuscript. The final version is available from AIP Publishing via the DOI in this record.Optoelectronic devices based on graphene and other two-dimensional (2D) materials, such as transition metal dichalcogenides (TMDs) are the focus of wide research interest. They can be the key to improving bandwidths in telecommunications, capacity in data storage, new features in consumer electronics, safety devices and medical equipment. The characterization these emerging atomically thin materials and devices strongly relies on a set of measurements involving both optical and electronic instrumentation ranging from scanning photocurrent mapping to Raman and photoluminescence (PL) spectroscopy. Current state-of-the-art commercial instruments offer the ability to characterize individual properties of these materials with no option for the in situ characterization of a wide enough range of complementary optical and electrical properties. Presently, the requirement to switch atomically-thin materials from one system to another often radically affects the properties of these uniquely sensitive materials through atmospheric contamination. Here, we present an integrated, multi-purpose instrument dedicated to the optical and electrical characterization of devices based on 2D materials which is able to perform low frequency electrical measurements, scanning photocurrent mapping, Raman, absorption and PL spectroscopy in one single set-up with full control over the polarization and wavelength of light. We characterize this apparatus by performing multiple measurements on graphene, transition metal dichalcogenides (TMDs) and Si. The performance and resolution is equivalent to commercially available instruments with the significant added value of being a compact, multi-purpose unit. Our design offers a versatile solution to face the challenges imposed by the advent of atomically-thin materials in optoelectronic devices
Homogeneously Bright, Flexible, and Foldable Lighting Devices with Functionalized Graphene Electrodes.
Alternating current electroluminescent technology allows the fabrication of large area, flat and flexible lights. Presently the maximum size of a continuous panel is limited by the high resistivity of available transparent electrode materials causing a visible gradient of brightness. Here, we demonstrate that the use of the best known transparent conductor FeCl3-intercalated few-layer graphene boosts the brightness of electroluminescent devices by 49% compared to pristine graphene. Intensity gradients observed for high aspect ratio devices are undetectable when using these highly conductive electrodes. Flat lights on polymer substrates are found to be resilient to repeated and flexural strains.S. Russo and M.F. Craciun acknoweldge
financial support from EPSRC (Grant no. EP/J000396/1, EP/K017160/1, EP/K010050/1,
EPG036101/1, EP/M001024/1, EPM002438/1) and from the Leverhulme Trust (Research grant
title Quantum Drums)
The changing relationship between rainfall and children's physical activity in spring and summer: a longitudinal study.
BACKGROUND: Weather conditions, along with day length, are proposed as the main drivers of the seasonal patterns in children's physical activity (PA), but little is known about how they affect children at different ages. This study examines the relationship between rainfall and PA in a longitudinal cohort of initially 9-10 year-old children in Norfolk, UK. METHODS: Participants were 283 children from the SPEEDY study who wore accelerometers ≤7 days on three occasions in the summer of 2007, 2008 and 2011 at ages 9-10, 10-11, and 13-14y. Daily weather data were obtained for two local weather stations. Relationships between rainfall and PA (moderate-to-vigorous-PA (MVPA; ≥2000) vigorous PA (VPA; ≥4000), counts per minute (cpm)) and sedentary time were assessed in multiple-membership multilevel models. PA was assessed over the whole day, and over parts of the school day; commute time (8 am-9 am and 3 pm-4 pm), lunchtime (12noon-2 pm), and after school (4 pm-9 pm). RESULTS: At ages 9-10 and 10-11y, PA declined with increasing rainfall, with an average of 14.0 (SE 2.9) and 11.4 (3.0) minutes less MVPA on the wettest days (≥1.7 mm rain) compared to dry days respectively. There was no significant trend in MVPA across rainfall categories at age 13-14 years. Between ages 9-10 and 13-14, MVPA decline was largest on dry days (-15.2 (2.7) minutes). These patterns were also apparent during school lunchtime and after school, however they were not seen during school commute times. Similar patterns were seen for other PA intensities. CONCLUSIONS: Increased rainfall is associated with significant decreases in PA among primary school children, but not secondary school children. PA declines most steeply between the ages of 9-10 and 13-14 on dry days. Interventions to increase activity on wet days may be most relevant at primary schools. Our results also highlight the importance of habitualising behavior to make children more resilient both to bad weather, and potentially age-related decline in activity.The SPEEDY study is funded by the National Prevention Research Initiative
(http://www.npri.org.uk), consisting of the following Funding Partners: British
Heart Foundation; Cancer Research UK; Department of Health; Diabetes UK;
Economic and Social Research Council; Medical Research Council; Health and
Social Care Research and Development Office for the Northern Ireland; Chief
Scientist Office, Scottish Government Health Directorates; Welsh Assembly
Government and World Cancer Research Fund. This work was also supported
by the Medical Research Council (Unit Programme numbers MC_UU_12015/7,
MC_UU_12015/4, and MC_UU_12015/3) and the Centre for Diet and Activity
Research (CEDAR), a UKCRC Public Health Research: Centre of Excellence.
Funding from the British Heart Foundation, Economic and Social Research
Council, Medical Research Council, the National Institute for Health Research,
and the Wellcome Trust, under the auspices of the UK Clinical Research
Collaboration, is gratefully acknowledged.This is the final published version. It first appeared at http://www.ijbnpa.org/content/12/1/41
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