Structure and function in primary open angle glaucoma

The study utilised a Normal group, an Ocular Hypertensive (OHT) group and a Primary Open Angle Glaucoma (POAG) group to investigate two aspects. Firstly, the within- and between-visit variability for stereometric measurements of the optic nerve head (ONH) using the Heidelberg Retina Tomograph (HRT); retinal nerve fibre layer (RNFL) thickness using the HRT and using optical coherence tomography with the Optical Coherence Tomography Scanner (OCT); the visual field using white-on-white (W-W), short-wavelength (SWAP) and Frequency Doubling perimetry (FDT); and retinal haemodynamics using the Heidelberg Retinal Flowmeter (HRF). Secondly, the association demonstrated between some of the derived variables. The within- and between-visit variability for stereometric measurements of the entire ONH and the between-visit variability for sectoral measurements were similar for Normals and OHTs but greater for POAGs. The within-visit variability of the visual field pointwise parameters for SWAP were greater than for W-W and FDT particularly with increase in eccentricity and for the OHT group. The between-visit variability increased with increase in defect depth for the POAG group, across all types of perimetry. The MS was greater, the MD and PSD smaller and the examination duration shorter in FDT compared to W-W and SWAP across all groups. The within-visit variability was less than the between-visit variability for the OCT circumferential and sector RNFL thickness using the 1.5R, 2.0R and the fixed 1.73mm circular scan radii, across the three groups. The variability increased with decrease in the RNFL thickness, and was least for the 2.0R scan radius.

Verification and validation of numerical models of the transport of insulation debris

Damage to insulation materials located near to a primary circuit coolant leak may compromise the operation of the emergency core cooling system (ECCS). Insulation material in the form of mineral wool fiber agglomerates (MWFA) maybe transported to the containment sump strainers, where they may block or penetrate the strainers. Though the impact of MWFA on the pressure drop across the strainers is minimal, corrosion products formed over time may also accumulate in the fiber cakes on the strainers, which can lead to a significant increase in the strainer pressure drop and result in cavitation in the ECCS. An experimental and theoretical study performed by the Helmholtz-Zentrum Dresden-Rossendorf and the Hochschule Zittau/Görlitz is investigating the phenomena that maybe observed in the containment vessel during a primary circuit coolant leak. The study entails the generation of fiber agglomerates, the determination of their transport properties in single and multi-effect experiments and the long-term effect that corrosion and erosion of the containment internals by the coolant has on the strainer pressure drop. The focus of this paper is on the verification and validation of numerical models that can predict the transport of MWFA. A number of pseudo-continuous dispersed phases of spherical wetted agglomerates represent the MWFA. The size, density, the relative viscosity of the fluid-fiber agglomerate mixture and the turbulent dispersion all affect how the fiber agglomerates are transported. In the cases described here, the size is kept constant while the density is modified. This definition affects both the terminal velocity and volume fraction of the dispersed phases. Note that the relative viscosity is only significant at high concentrations. Three single effect experiments were used to provide validation data on the transport of the fiber agglomerates under conditions of sedimentation in quiescent fluid, sedimentation in a horizontal flow and suspension in a horizontal flow. The experiments were performed in a rectangular column for the quiescent fluid and a racetrack type channel that provided a near uniform horizontal flow. The numerical models of sedimentation in the column and the racetrack channel found that the sedimentation characteristics are consistent with the experiments. For channel suspension, the heavier fibers tend to accumulate at the channel base even at high velocities, while lighter phases are more likely to be transported around the channel.

Multiple roles of charged amino acids in cytoplasmic loop 7 for expression and function of the multidrug and organic anion transporter MRP1 (ABCC1)

Multidrug resistance protein MRP1 mediates the ATP-dependent efflux of many chemotherapeutic agents and organic anions. MRP1 has two nucleotide binding sites (NBSs) and three membrane spanning domains (MSDs) containing 17 transmembrane helices linked by extracellular and cytoplasmic loops (CL). Homology models suggest that CL7 (amino acids 1141-1195) is in a position where it could participate in signaling between the MSDs and NBSs during the transport process. We have individually replaced eight charged residues in CL7 with Ala, and in some cases, an amino acid with the same charge, and then investigated the effects on MRP1 expression, transport activity, and nucleotide and substrate interactions. A triple mutant in which Glu(1169), Glu(1170), and Glu(1172) were all replaced with Ala was also examined. The properties of R1173A and E1184A were comparable with those of wild-type MRP1, whereas the remaining mutants were either poorly expressed (R1166A, D1183A) or exhibited reduced transport of one or more organic anions (E1144A, D1179A, K1181A, (1169)AAQA). Same charge mutant D1183E was also not expressed, whereas expression and activity of R1166K were similar to wild-type MRP1. The moderate substrate-selective changes in transport activity displayed by mutants E1144A, D1179A, K1181A, and (1169)AAQA were accompanied by changes in orthovanadate-induced trapping of [alpha-(32)P]azidoADP by NBS2 indicating changes in ATP hydrolysis or release of ADP. In the case of E1144A, estradiol glucuronide no longer inhibited trapping of azidoADP. Together, our results demonstrate the extreme sensitivity of CL7 to mutation, consistent with its critical and complex dual role in both the proper folding and transport activity of MRP1.

International business research and risky investments, an analysis of FDI in conflict zones

The purpose of this paper is to examine the determinants of a firm's strategy to invest in a conflict location. To the best of our knowledge, this has not been done before. We examine this using a standard model of international business, overlaid with the fundamental approach to corporate social responsibility. We start with the population of multinationals who have chosen to invest in low income countries with weak institutions. We then split this sample in order to distinguish between firms that have invested in conflict regions compared to those that have not. Our analysis then proceeds to explain the decision of those firms to invest in conflict locations using a simple Probit model. We find that countries with weaker institutions and less concern about corporate social responsibility (CSR) are more likely to invest in conflict regions. Finally, firms with more concentrated ownership are more likely to invest in such locations. © 2012 Elsevier Ltd.

Political leadership:character and performance. A comparative analysis of British political leadership, 1997-2010.

Classical and contemporary scholarship on leadership has referred to political performance and the ability of political actors to deploy the self to political purpose. Literature on contemporary British politics (Hennessy, 2001; Marquand, 2008, King, 2009) has highlighted the qualitative shift in political leadership from the mid-1990s towards a focus upon the image, style, celebrity and performance of political leaders, and the shift towards the presidentialisation or semi-presidentialisation of the prime minister (Foley, 2001). However, the literature has lacked a focus upon political performance and a methodology for assessing leadership performance within cultural and institutional contexts. This thesis assesses British political leadership performance from 1997-2010 through the proposal of a framework of political performance to suit comparative purpose. The framework consisting of culture, institutions and performance is used to assess the performance of the case studies (Tony Blair, Gordon Brown and David Cameron, and Gordon Brown, David Cameron and Nick Clegg in the televised Leaders’ Debates of 2010). The application of the framework to the case studies will allow us to a) analyse political performance within given cultural and institutional contexts; b) establish the character traits and other aspects of a politician’s political persona; and c) appraise the role and effects of performance and persona upon the political process.

Regional competitiveness:theories and methodologies for empirical analysis

A significant forum of scholarly and practitioner-based research has developed in recent years that has sought both to theorize upon and empirically measure the competitiveness of regions. However, the disparate and fragmented nature of this work has led to the lack of a substantive theoretical foundation underpinning the various analyses and measurement methodologies employed. The aim of this paper is to place the regional competitiveness discourse within the context of theories of economic growth, and more particularly, those concerning regional economic growth. It is argued that regional competitiveness models are usually implicitly constructed in the lineage of endogenous growth frameworks, whereby deliberate investments in factors such as human capital and knowledge are considered to be key drivers of growth differentials. This leads to the suggestion that regional competitiveness can be usefully defined as the capacity and capability of regions to achieve economic growth relative to other regions at a similar overall stage of economic development, which will usually be within their own nation or continental bloc. The paper further assesses future avenues for theoretical and methodological exploration, highlighting the role of institutions, resilience and, well-being in understanding how the competitiveness of regions influences their long-term evolution.

Teachers and organisational change (an analysis):an analysis

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Does metabolic reprogramming underpin age-associated changes in T cell phenotype and function?

T cells are required for an effective adaptive immune response. The principal function of T cells is to promote efficient removal of foreign material by identifying and mounting a specific response to nonself. A decline in T cell function in aging is thought to contribute to reduced response to infection and vaccination and an increase in autoimmunity. This may in part be due to the age-related decrease in naïve CD4+ T cells and increase in antigen-experienced CD4+ T cells, loss of redox homeostasis, and impaired metabolic switching. Switching between subsets is triggered by the integration of extracellular signals sensed through surface receptors and the activation of discrete intracellular metabolic pathways. This article explores how metabolic programming and loss of redox homeostasis during aging may contribute to age-associated changes in T cell phenotype and function. © 2014 Elsevier Inc.

Seventeen a-subunit isoforms of paramecium V-ATPase provide high specialization in localization and function

In the Paramecium tetraurelia genome, 17 genes encoding the 100-kDa-subunit (a-subunit) of the vacuolar-proton-ATPase were identified, representing by far the largest number of a-subunit genes encountered in any organism investigated so far. They group into nine clusters, eight pairs with >82% amino acid identity and one single gene. Green fluorescent protein-tagging of representatives of the nine clusters revealed highly specific targeting to at least seven different compartments, among them dense core secretory vesicles (trichocysts), the contractile vacuole complex, and phagosomes. RNA interference for two pairs confirmed their functional specialization in their target compartments: silencing of the trichocyst-specific form affected this secretory pathway, whereas silencing of the contractile vacuole complex-specific form altered organelle structure and functioning. The construction of chimeras between selected a-subunits surprisingly revealed the targeting signal to be located in the C terminus of the protein, in contrast with the N-terminal targeting signal of the a-subunit in yeast. Interestingly, some chimeras provoked deleterious effects, locally in their target compartment, or remotely, in the compartment whose specific a-subunit N terminus was used in the chimera.

Verification and validation of numerical models of the transport of insulation debris

A combination of the two-fluid and drift flux models have been used to model the transport of fibrous debris. This debris is generated during loss of coolant accidents in the primary circuit of pressurized or boiling water nuclear reactors, as high pressure steam or water jets can damage adjacent insulation materials including mineral wool blankets. Fibre agglomerates released from the mineral wools may reach the containment sump strainers, where they can accumulate and compromise the long-term operation of the emergency core cooling system. Single-effect experiments of sedimentation in a quiescent rectangular column and sedimentation in a horizontal flow are used to verify and validate this particular application of the multiphase numerical models. The utilization of both modeling approaches allows a number of pseudocontinuous dispersed phases of spherical wetted agglomerates to be modeled simultaneously. Key effects on the transport of the fibre agglomerates are particle size, density and turbulent dispersion, as well as the relative viscosity of the fluid-fibre mixture.

Plant closures and taskforce responses:an analysis of the impact of and policy response to MG Rover in Birmingham

This paper explores the socio-economic impacts and associated policy responses to the collapse of MG Rover at Longbridge in Birmingham. Critically, it attempts to move beyond a ‘standard’ taskforce narrative that emphasizes the role of the regional response. While recognizing that significant policy ‘successes’ were indeed evident at the regional level in anticipating and responding to the crisis, a wider perspective is required that situates this taskforce response in (1) a fuller understanding of labour market precariousness (that in turn mitigates some of its policy ‘successes’), and (2) more local perspectives that highlight the local impacts of closure, the role of the neighbourhood level officials and the third sector in mediating these. Taking this broader perspective suggests that longer-term, workers face a precarious situation and the need for policies to create and sustain ‘good quality’ jobs remains paramount. Adding in more local perspectives, a key lesson from the Longbridge experience for dealing with closures more generally is that the public policy responses must be: multidimensional in that they transcend narrow sector-based concerns and addresses broader spatial impacts; inclusive in that they build on a broad coalition of economic and social stakeholders; and long-term in that they acknowledge that adaptation takes many years. If anything, the Birmingham Longbridge experience demonstrates the difficulty of achieving such responses in the context of crisis where action is imperative and deliberation a luxury.

Phytoestrogens modulate breast cancer resistance protein expression and function at the blood-cerebrospinal fluid barrier

PURPOSE: Breast cancer resistance protein (BCRP/ABCG2) is a drug efflux transporter expressed at the blood cerebrospinal fluid barrier (BCSFB), and influences distribution of drugs into the central nervous systems (CNS). Current inhibitors have failed clinically due to neurotoxicity. Novel approaches are needed to identify new modulators to enhance CNS delivery. This study examines 18 compounds (mainly phytoestrogens) as modulators of the expression/function of BCRP in an in vitro rat choroid plexus BCSFB model. METHODS: Modulators were initially subject to cytotoxicity (MTT) assessment to determine optimal non-toxic concentrations. Reverse-transcriptase PCR and confocal microscopy were used to identify the presence of BCRP in Z310 cells. Thereafter modulation of the intracellular accumulation of the fluorescent BCRP probe substrate Hoechst 33342 (H33342), changes in protein expression of BCRP (western blotting) and the functional activity of BCRP (membrane insert model) were assessed under modulator exposure. RESULTS: A 24 hour cytotoxicity assay (0.001 µM-1000 µM) demonstrated the majority of modulators possessed a cellular viability IC50 > 148 µM. Intracellular accumulation of H33342 was significantly increased in the presence of the known BCRP inhibitor Ko143 and, following a 24 hour pre-incubation, all modulators demonstrated statistically significant increases in H33342 accumulation (P < 0.001), when compared to control and Ko143. After a 24 hour pre-incubation with modulators alone, a 0.16-2.5-fold change in BCRP expression was observed for test compounds. The functional consequences of this were confirmed in a permeable insert model of the BCSFB which demonstrated that 17-β-estradiol, naringin and silymarin (down-regulators) and baicalin (up-regulator) can modulate BCRP-mediated transport function at the BCSFB. CONCLUSION: We have successfully confirmed the gene and protein expression of BCRP in Z310 cells and demonstrated the potential for phytoestrogen modulators to influence the functionality of BCRP at the BCSFB and thereby potentially allowing manipulation of CNS drug disposition.

SentiCircles for contextual and conceptual semantic sentiment analysis of Twitter

Lexicon-based approaches to Twitter sentiment analysis are gaining much popularity due to their simplicity, domain independence, and relatively good performance. These approaches rely on sentiment lexicons, where a collection of words are marked with fixed sentiment polarities. However, words' sentiment orientation (positive, neural, negative) and/or sentiment strengths could change depending on context and targeted entities. In this paper we present SentiCircle; a novel lexicon-based approach that takes into account the contextual and conceptual semantics of words when calculating their sentiment orientation and strength in Twitter. We evaluate our approach on three Twitter datasets using three different sentiment lexicons. Results show that our approach significantly outperforms two lexicon baselines. Results are competitive but inconclusive when comparing to state-of-art SentiStrength, and vary from one dataset to another. SentiCircle outperforms SentiStrength in accuracy on average, but falls marginally behind in F-measure. © 2014 Springer International Publishing.