263 research outputs found
Solubilised bright blue-emitting iridium complexes for solution processed OLEDs
EZ-C acknowledges the University of St Andrews for financial support. IDWS and AKB acknowledge support from EPSRC (EP/J01771X). The authors would like to thank the Engineering and Physical Sciences Research Council for financial support for Adam Henwood: EPSRC DTG Grants: EP/J500549/1; EP/K503162/1; EP/L505097/1.Combining a sterically bulky, electron-deficient 2-(2,4-difluorophenyl)-4-(2,4,6- trimethylphenyl)pyridine (dFMesppy) cyclometalating C^N ligand with an electron rich, highly rigidified 1,1’-(α,α’-o-xylylene)-2,2’-biimidazole (o-xylbiim) N^N ligand gives an iridium complex, [Ir(dFMesppy)2(o-Xylbiim)](PF6), that achieves extraordinarily bright blue emission (ΦPL = 90%; λmax = 459 nm in MeCN) for a cationic iridium complex. This complex is compared with two reference complexes bearing 4,4’-di-tert-butyl-2,2’- bipyridine, and solution-processed organic light emitting diodes (OLEDs) have been fabricated from these materials.Publisher PDFPeer reviewe
Questioning policy, youth participation and lifestyle sports
Young people have been identified as a key target group for whom participation in sport and physical activity could have important benefits to health and wellbeing and consequently have been the focus of several government policies to increase participation in the UK. Lifestyle sports represent one such strategy for encouraging and sustaining new engagements in sport and physical activity in youth groups, however, there is at present a lack of understanding of the use of these activities within policy contexts. This paper presents findings from a government initiative which sought to increase participation in sport for young people through provision of facilities for mountain biking in a forest in south-east England. Findings from qualitative research with 40 young people who participated in mountain biking at the case study location highlight the importance of non-traditional sports as a means to experience the natural environments through forms of consumption which are healthy, active and appeal to their identities. In addition, however, the paper raises questions over the accessibility of schemes for some individuals and social groups, and the ability to incorporate sports which are inherently participant-led into state-managed schemes. Lifestyle sports such as mountain biking involve distinct forms of participation which present a challenge for policy-makers who seek to create and maintain sustainable communities of youth participants
DFT Study of Planar Boron Sheets: A New Template for Hydrogen Storage
We study the hydrogen storage properties of planar boron sheets and compare
them to those of graphene. The binding of molecular hydrogen to the boron sheet
(0.05 eV) is stronger than that to graphene. We find that dispersion of alkali
metal (AM = Li, Na, and K) atoms onto the boron sheet markedly increases
hydrogen binding energies and storage capacities. The unique structure of the
boron sheet presents a template for creating a stable lattice of strongly
bonded metal atoms with a large nearest neighbor distance. In contrast, AM
atoms dispersed on graphene tend to cluster to form a bulk metal. In particular
the boron-Li system is found to be a good candidate for hydrogen storage
purposes. In the fully loaded case this compound can contain up to 10.7 wt. %
molecular hydrogen with an average binding energy of 0.15 eV/H2.Comment: 19 pages, 7 figures, and 3 table
Increased waterborne blaNDM-1 resistance gene abundances associated with seasonal human pilgrimages to the Upper Ganges River
Antibiotic resistance (AR) is often rooted in inappropriate antibiotic use, but poor water quality and inadequate sanitation exacerbate the problem, especially in emerging countries. An example is increasing multi-AR due to mobile carbapenemases, such as NDM-1 protein (coded by blaNDM-1 genes), which can produce extreme drug-resistant phenotypes. In 2010, NDM-1 positive isolates and blaNDM-1 genes were detected in surface waters across Delhi and have since been detected across the urban world. However, little is known about blaNDM-1 levels in more pristine locations, such as the headwaters of the Upper Ganges River. This area is of particular interest because it receives massive numbers of visitors during seasonal pilgrimages in May/June, including visitors from urban India. Here we quantified blaNDM-1 abundances, other AR genes (ARG) and coliform bacteria in sediments and water column samples from seven sites in the Rishikesh-Haridwar region of the Upper Ganges and five sites on the Yamuna River in Delhi to contrast blaNDM-1 levels and water quality conditions between season and region. Water quality in the Yamuna was very poor (e.g., anoxia at all sites), and blaNDM-1 abundances were high across sites in water (5.4 ± 0.4 log(blaNDM-1·mL-1); 95% confidence interval) and sediment (6.3 ± 0.7 log(blaNDM-1·mg-1)) samples from both seasons. In contrast, water column blaNDM-1 abundances were very low across all sites (2.1 ± 0.6 log(blaNDM-1·mL-1)) in February in the Upper Ganges and water quality was good (e.g., near saturation oxygen). However, per capita blaNDM-1 levels were 20 times greater in June in the Ganges water column relative to February and blaNDM-1 levels significantly correlated with fecal coliform levels (r=0.61; p=0.007). Given waste management infrastructure is limited in Rishikesh-Haridwar; data imply blaNDM-1 levels are higher in visitor's wastes than local residents, which results in seasonally higher blaNDM-1 levels in the river. Pilgrimage areas without adequate waste treatment are possible "hot spots" for AR transmission, and waste treatment must be improved to reduce broader AR dissemination via exposed returning visitors
Pain Input After Spinal Cord Injury (SCI) Undermines Long-Term Recovery and Engages Signal Pathways That Promote Cell Death
Pain (nociceptive) input caudal to a spinal contusion injury increases tissue loss and impairs long-term recovery. It was hypothesized that noxious stimulation has this effect because it engages unmyelinated pain (C) fibers that produce a state of over-excitation in central pathways. The present article explored this issue by assessing the effect of capsaicin, which activates C-fibers that express the transient receptor potential vanilloid receptor-1 (TRPV1). Rats received a lower thoracic (T11) contusion injury and capsaicin was applied to one hind paw the next day. For comparison, other animals received noxious electrical stimulation at an intensity that engages C fibers. Both forms of stimulation elicited similar levels of c-fos mRNA expression, a cellular marker of nociceptive activation, and impaired long-term behavioral recovery. Cellular assays were then performed to compare the acute effect of shock and capsaicin treatment. Both forms of noxious stimulation increased expression of tumor necrosis factor (TNF) and caspase-3, which promotes apoptotic cell death. Shock, but not capsaicin, enhanced expression of signals related to pyroptotic cell death [caspase-1, inteleukin-1 beta (IL-1ß)]. Pyroptosis has been linked to the activation of the P2X7 receptor and the outward flow of adenosine triphosphate (ATP) through the pannexin-1 channel. Blocking the P2X7 receptor with Brilliant Blue G (BBG) reduced the expression of signals related to pyroptotic cell death in contused rats that had received shock. Blocking the pannexin-1 channel with probenecid paradoxically had the opposite effect. BBG enhanced long-term recovery and lowered reactivity to mechanical stimulation applied to the girdle region (an index of chronic pain), but did not block the adverse effect of nociceptive stimulation. The results suggest that C-fiber input after injury impairs long-term recovery and that this effect may arise because it induces apoptotic cell death
MOST detects corotating bright spots on the mid-O type giant {\xi} Persei
We have used the MOST (Microvariability and Oscillations of STars)
microsatellite to obtain four weeks of contiguous high-precision broadband
visual photometry of the O7.5III(n)((f)) star {\xi} Persei in November 2011.
This star is well known from previous work to show prominent DACs (Discrete
Absorption Components) on time-scales of about 2 d from UV spectroscopy and NRP
(Non Radial Pulsation) with one (l = 3) p-mode oscillation with a period of 3.5
h from optical spectroscopy. Our MOST-orbit (101.4 min) binned photometry fails
to reveal any periodic light variations above the 0.1 mmag 3-sigma noise level
for periods of hours, while several prominent Fourier peaks emerge at the 1
mmag level in the two-day period range. These longer-period variations are
unlikely due to pulsations, including gravity modes. From our simulations based
upon a simple spot model, we deduce that we are seeing the photometric
modulation of several co-rotating bright spots on the stellar surface. In our
model, the starting times (random) and lifetimes (up to several rotations) vary
from one spot to another yet all spots rotate at the same period of 4.18 d, the
best-estimated rotation period of the star. This is the first convincing
reported case of co-rotating bright spots on an O star, with important
implications for drivers of the DACs (resulting from CIRs - Corotating
Interaction Regions) with possible bright-spot generation via a breakout at the
surface of a global magnetic field generated by a subsurface convection zone.Comment: 9 pages, 4 figures, 2 tables, MNRAS in pres
Corporate governance and inequality: The impact of financialization and shareholder value
Copyright © 2017 by Emerald Group Publishing Limited. Purpose - The purpose of this chapter is to analyse how in recent years the rediscovery that extreme inequality is returning to advanced economies and has become widespread. What is at issue are the causes of this inequality. It is becoming clear that the wider population, particularly in Anglo-American economies have not shared in the growing wealth of the countries concerned, and that the majority of this wealth is being transferred on a continuous and systemic basis to the very rich. Corporate governance and the pursuit of shareholder value it is argued has become a major driver of inequality. Methodology/approach - The current statistical evidence produced by leading authorities including the US Federal Reserve, World Economic Forum, Credit Suisse and Oxfam are examined. The policy of shareholder value and the mechanisms by which the distributions from business take place are investigated from a critical perspective. Findings - While the Anglo-American economies are seeing a return to the extremes of inequality last witnessed in the 19th century, the causes of this inequality are changing. In the 19th century great fortunes often were inherited, or derived by entrepreneurs from the ownership and control of productive assets. By the late 20th century as Atkinson, Piketty and Saez (2011) and others have highlighted, the sustained and rapid inflation in top income shares have made a significant contribution to the accelerating rate of income and wealth inequality. Research implications - The intensification of inequality in advanced industrial economies, despite the consistent work of Atkinson and others, was largely neglected until the recent research of Picketty which has attracted international attention. It is now acknowledged widely that inequality is a serious issue; however, the contemporary causes of inequality remain largely unexplored. Practical/social implications - The significance of inequality, now that it is recognized, demands policy and practical interventions. However, the capacity or even willingness to intervene is lacking. Further analysis of the debilitating consequences of inequality in terms of the efficiency and stability of economies and societies may encourage a more robust approach, yet the resolve to end extreme inequality is not present. Originality/value - The analysis of inequality has not been neglected and this chapter represents a pioneering effort to relate the shareholder value orientation now dominant in corporate governance to the intensification of inequality
Human cultured dendritic cells show differential sensitivity to chemotherapy agents as assessed by the MTS assay
Assessment of the chemosensitivity of dendritic cells (DC) may allow more rational development of combined chemotherapy and immunotherapy protocols. Human monocyte-derived DC generated reproducible results in the MTS (Owen’s reagent) assay, which was then used to study DC survival after treatment with four different chemotherapy agents. DC preparations from three different donors were used per drug. DC were sensitive to doxorubicin (concentration range 0.1–50 μM) with variation in sensitivity between donors (IC50 244–1100 nM). The most extreme variation was seen for vinblastine (concentration range 250–0.025 μM with IC50 0.15–17.25 μM). In contrast, there was relative resistance to etoposide (concentration range 0.2–200 μM) and 5-fluorouracil (concentration range 0.7–7700 μM) with no toxicity seen until 50 μM and 770 μM respectively. The function of DC in allogeneic mixed leucocyte reactions closely paralleled results from the MTS assays. The differential sensitivity to chemotherapy agents did not appear to be due to expression of P-glycoprotein. These results suggest that etoposide or 5-fluorouracil is less likely to reduce the immunotherapeutic potential of DC and may be valuable in the design of prodrug activation therapy. © 1999 Cancer Research Campaig
N-type graphene induced by dissociative H-2 adsorption at room temperature
Studies of the interaction between hydrogen and graphene have been increasingly required due to the indispensable modulation of the electronic structure of graphene for device applications and the possibility of using graphene as a hydrogen storage material. Here, we report on the behaviour of molecular hydrogen on graphene using the gate voltage-dependent resistance of single-, bi-, and multi-layer graphene sheets as a function of H-2 gas pressure up to 24 bar from 300 K to 345 K. Upon H-2 exposure, the charge neutrality point shifts toward the negative gate voltage region, indicating n-type doping, and distinct Raman signature changes, increases in the interlayer distance of multi-layer graphene, and a decrease in the d-spacing occur, as determined by TEM. These results demonstrate the occurrence of dissociative H-2 adsorption due to the existence of vacancy defects on graphene.open12
- …