The photocatalytic degradation of phenolic compounds

Semiconductor photocatalysis degrades phenolic pollutants to carbon dioxide and water, but the mechanisms of this potentially attractive method of environmental remediation remain unclear. This study aimed to elucidate the primary molecular events by HPLC analysis of the initial products of degradation in water or aqueous acetonitrile. The position of substituents relative to the hydroxyl group were found to influence the reaction rate and also primary oxidation steps, and hence the intermediate profile. 2,6- Dialkylated phenols reacted fastest and showed high conversion to dehydrodimeric products as a prelude to degradation. In contrast, 3,5-dialkylated phenols and 4-tert-butylphenol reacted more slowly and appeared to degrade directly to small polar compounds with little accumulation of primary carbocyclic intermediates. The rate of photocatalytic degradation of two isomeric dibromohydroxybenzonitriles was also influenced by substitution pattern. 3,5-Dibromo-2-hydroxybenzonitrile, however, is itself photolabile in daylight giving 3-bromo-2,5-dihydroxybenzonitrile in aqueous solution. The analogous reaction does not occur for 3,5-dibromo-4-hydroxybenzonitrile, the difference in behaviour being attributed to differences in the electronic spectra of the two compounds. The mechanism of photocatalysis appears to be influenced by the orientation of the substrate on the catalyst surface. For the alkyl phenols, particularly those with tert-butyl substitution, minimisation of disturbance to the polar network of the solvent directs the more hydrophobic parts of the molecule towards the oxidising surface of the catalyst. In addition, this effect encourages clustering of molecules with the subsequent formation of aggregated products. While part of the behaviour observed may be attributable to the presence of acetonitrile in the solvent, the hydrophobic profile of a substrate undergoing heterogeneous photocatalytic oxidation in water would seem to be a significant determinant of the molecular pathway selected in the first phase of its degradation

Developing and maintaining collaborative communities of practice in Art, Design & Media: The North West Network experience

This paper describes and explores the methodologies underpinning the development of the North West Network of the Higher Education Academy's Art, Design & Media Subject Centre(ADM-HEA). Founded in 2006 the network's members are drawn from a range of institutions across the North West(NW) including pre and post '92 Universities and Further Education (FEC) Colleges with Higher Education (HE) provision. To date it has completed and disseminated two major collaborative research projects looking at research informed teaching and aspects of the student experience. The network provides opportunities for staff working at different levels, in different areas of the sector, to work together, to share good practice and to feed these experiences into teaching. It provides a model of co-operation which circumvents the problems posed by increasing competition between institutions, the difficulties presented by limited funding, and time constraints. Here, in order to promote debate about the hierarchies and perceived barriers to collaboration, are outlined the means by which the group has been sustained; the network's research has been achieved; and the ethos of the group developed. The projects outlined here demonstrate that it is possible to provide opportunities for staff working at different levels, in different areas of the sector, to work together to undertake research and to share good practice

Experimental study of the performance and emissions characteristics of a small diesel genset operating in dual-fuel mode with three different primary fuels

A dual fuel engine is an internal combustion engine where the primary gaseous fuel source is pre-mixed with air as it enters the combustion chamber. This homogenous air fuel mixture is ignited by a small quantity of diesel known as the ‘pilot’ that is injected towards the end of the compression stroke. The diesel fuel ignites in the same way as in compression ignition (CI) engines, and the gaseous fuel is consumed by flame propagation in a similar manner to spark ignited engines. The motivation to dual-fuel a CI engine is partly economic due to the lower cost of the primary fuel, and partly environmental as some emissions characteristics are improved. In the present study, a direct injection four cylinder CI engine, typically used in genset applications, was fuelled with three different gaseous fuels; methane, propane and butane. The performance and emissions (NOx and smoke) characteristics of various gaseous concentrations were recorded at 1500rpm (synchronous speed) and at ¼, ½, and ¾ load. In order to invest igate the combustion performance under these different conditions, a three zone heat release rate analysis is proposed an applied to the data. The resulting mass burned rate, ignition delay and combustion duration are used to explain the emissions and performance characteristics of the engine. It will be shown that the highest gas substitution levels were achieved when using methane under all test conditions, but emissions of NOx and smoke were lower when using propane. Butane proved to be the most unsatisfactory of the three primary fuels, with the highest emissions of NOx and smoke

Canadian undergraduates' reports of co-curricular involvement across the degree

The present study investigated university student beliefs and behaviours with respect to co-curricular activities among incoming (n=983), mid-degree (n=173), and graduating (n=1006) students. When asked about their most significant learning experiences during their time at university, graduating students were more likely to report on co-curricular activities than those related to coursework. However, participation in co-curricular activities was not related to graduating students’ feelings of preparedness to undertake a job search or apply for post-graduate education. Incoming students reported clear intentions to participate in some types of co-curricular activities (e.g.,  volunteering, intramural sports, clubs) but were more uncertain about others (e.g.,  events or activities related to global awareness, or diversity and inclusion). Parallel findings were observed with respect to actual co-curricular involvement among mid-degree and graduating students. This research is discussed in the context of university efforts to promote co-curricular activities to students in order to develop career ready transferrable skills, and the relevance of particular patterns of involvement to the current job market

Students' willingness to engage with mathematical challenges :Implications for classroom pedagogies

As part of a project exploring various aspects of teachers’ choice and use of challenging mathematics tasks, we sought some responses from students on their preferences for the difficulty of tasks on which they might work and also on the ways of working. Despite the common finding that teachers are reluctant to pose challenges to their students for fear of adverse reactions, many students reported that they prefer tasks to be somewhat challenging and many prefer to work on the tasks before having the process explained by the teacher. An important finding was the diversity of student preferences. There are implications for the information that educators offer to teachers on structuring their lessons

Intracranial Injection of Dengue Virus Induces Interferon Stimulated Genes and CD8+ T Cell Infiltration by Sphingosine Kinase 1 Independent Pathways

Copyright: © 2017 Al-Shujairi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.We have previously reported that the absence of sphingosine kinase 1 (SK1) affects both dengue virus (DENV) infection and innate immune responses in vitro. Here we aimed to define SK1-dependancy of DENV-induced disease and the associated innate responses in vivo. The lack of a reliable mouse model with a fully competent interferon response for DENV infection is a challenge, and here we use an experimental model of DENV infection in the brain of immunocompetent mice. Intracranial injection of DENV-2 into C57BL/6 mice induced body weight loss and neurological symptoms which was associated with a high level of DENV RNA in the brain. Body weight loss and DENV RNA level tended to be greater in SK1-/- compared with wildtype (WT) mice. Brain infection with DENV-2 is associated with the induction of interferon-β (IFN-β) and IFN-stimulated gene (ISG) expression including viperin, Ifi27l2a, IRF7, and CXCL10 without any significant differences between WT and SK1-/- mice. The SK2 and sphingosine-1-phosphate (S1P) levels in the brain were unchanged by DENV infection or the lack of SK1. Histological analysis demonstrated the presence of a cellular infiltrate in DENV-infected brain with a significant increase in mRNA for CD8 but not CD4 suggesting this infiltrate is likely CD8+ but not CD4+ T-lymphocytes. This increase in T-cell infiltration was not affected by the lack of SK1. Overall, DENV-infection in the brain induces IFN and T-cell responses but does not influence the SK/S1P axis. In contrast to our observations in vitro, SK1 has no major influence on these responses following DENV-infection in the mouse brain

Interpretations of, and orientations to, “understanding mathematics in depth”: students in MEC programmes across institutions

In this paper we present initial findings from our study of interpretations and orientations to ‘understanding mathematics in depth’ among students in selected Mathematics Enhancement Courses (MEC) in the UK. The MEC is a 26-week pre-Initial Teacher Education (ITE) ‘mathematics subject knowledge for teaching’ course designed for, and undertaken by, graduates wishing to teach mathematics at secondary level, but do not have a Mathematics degree. It is completed before commencing with a PGCE. A common theme running through the MEC documentation is the importance of ‘understanding mathematics in depth’. We are interested in what and how MEC students interpret and orient themselves towards ‘understanding mathematics in depth’. In designing and conducting our empirical work we have drawn upon a related project in South Africa, which is exploring ‘mathematics for teaching’, specifically what and how mathematics and teaching are co-constituted in mathematics teacher education programmes. The MEC is an interesting empirical context for such study, as it is a mathematics course, or set of courses, specifically designed for future teachers. We have collected data through guided, semi-structured interviews with 18 students and 4 lecturing staff at three different institutions. The interpretations and orientations of MEC students towards mathematics and the notion of ‘understanding mathematics in depth’, we contend, provide additional insight into the developing notion of mathematical knowledge in and for teaching

Canadian Undergraduates' Reports of Co-curricular Involvement Across the Degree

The present study investigated university student beliefs and behaviours with respect to co-curricular activities among incoming (n=983), mid-degree (n=173), and graduating (n=1006) students. When asked about their most significant learning experiences during their time at university, graduating students were more likely to report on co-curricular activities than those related to coursework. However, participation in co-curricular activities was not related to graduating students’ feelings of preparedness to undertake a job search or apply for post-graduate education. Incoming students reported clear intentions to participate in some types of co-curricular activities (e.g.,  volunteering, intramural sports, clubs) but were more uncertain about others (e.g.,  events or activities related to global awareness, or diversity and inclusion). Parallel findings were observed with respect to actual co-curricular involvement among mid-degree and graduating students. This research is discussed in the context of university efforts to promote co-curricular activities to students in order to develop career ready transferrable skills, and the relevance of particular patterns of involvement to the current job market

Perlecan Domain V induces VEGf secretion in brain endothelial cells through integrin α5β1 and ERK-dependent signaling pathways.

Perlecan Domain V (DV) promotes brain angiogenesis by inducing VEGF release from brain endothelial cells (BECs) following stroke. In this study, we define the specific mechanism of DV interaction with the α(5)β(1) integrin, identify the downstream signal transduction pathway, and further investigate the functional significance of resultant VEGF release. Interestingly, we found that the LG3 portion of DV, which has been suggested to possess most of DV\u27s angio-modulatory activity outside of the brain, binds poorly to α(5)β(1) and induces less BEC proliferation compared to full length DV. Additionally, we implicate DV\u27s DGR sequence as an important element for the interaction of DV with α(5)β(1). Furthermore, we investigated the importance of AKT and ERK signaling in DV-induced VEGF expression and secretion. We show that DV increases the phosphorylation of ERK, which leads to subsequent activation and stabilization of eIF4E and HIF-1α. Inhibition of ERK activity by U0126 suppressed DV-induced expression and secretion of VEGR in BECs. While DV was capable of phosphorylating AKT we show that AKT phosphorylation does not play a role in DV\u27s induction of VEGF expression or secretion using two separate inhibitors, LY294002 and Akt IV. Lastly, we demonstrate that VEGF activity is critical for DV increases in BEC proliferation, as well as angiogenesis in a BEC-neuronal co-culture system. Collectively, our findings expand our understanding of DV\u27s mechanism of action on BECs, and further support its potential as a novel stroke therapy

High redshift X-ray cooling-core cluster associated with the luminous radio loud quasar 3C186

We present the first results from a new, deep (200ks) Chandra observation of the X-ray luminous galaxy cluster surrounding the powerful (L ~10^47 erg/s), high-redshift (z=1.067), compact-steep-spectrum radio-loud quasar 3C186. The diffuse X-ray emission from the cluster has a roughly ellipsoidal shape and extends out to radii of at least ~60 arcsec (~500 kpc). The centroid of the diffuse X-ray emission is offset by 0.68(+/-0.11) arcsec (5.5+/-0.9 kpc) from the position of the quasar. We measure a cluster mass within the radius at which the mean enclosed density is 2500 times the critical density, r_2500=283(+18/-13)kpc, of 1.02 (+0.21/-0.14)x10^14 M_sun. The gas mass fraction within this radius is f_gas=0.129(+0.015/-0.016). This value is consistent with measurements at lower redshifts and implies minimal evolution in the f_gas(z) relation for hot, massive clusters at 0<z<1.1. The measured metal abundance of 0.42(+0.08/-0.07) Solar is consistent with the abundance observed in other massive, high redshift clusters. The spatially-resolved temperature profile for the cluster shows a drop in temperature, from kT~8 keV to kT~3 keV, in its central regions that is characteristic of cooling core clusters. This is the first spectroscopic identification of a cooling core cluster at z>1. We measure cooling times for the X-ray emitting gas at radii of 50 kpc and 25 kpc of 1.7(+/-0.2)x10^9 years and 7.5(+/-2.6)x 10^8 years, as well as a nominal cooling rate (in the absence of heating) of 400(+/-190)M_sun/year within the central 100 kpc. In principle, the cooling gas can supply enough fuel to support the growth of the supermassive black hole and to power the luminous quasar. The radiative power of the quasar exceeds by a factor of 10 the kinematic power of the central radio source, suggesting that radiative heating may be important at intermittent intervals in cluster cores.Comment: 15 pages, 9 figures, ApJ in pres