1,408 research outputs found

    Teleglaucoma: ready to go?

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    Telemedicine technologies and services allow today's ophthalmic clinicians to remotely diagnose, manage and monitor several ophthalmic conditions from a distance. But is this the case for glaucomas? There has been a proliferation of telemedicine friendly devices in recent years that improves the capabilities of the clinician in managing glaucomas. The existing instruments still need to align themselves with accepted industry standards. There are successful programmes running in several areas of the world. The safety and efficacy of these programmes needs further exploration. The inability of a single device or test to diagnose glaucomas satisfactorily has also hampered progress in remotely diagnosing these conditions. There is, however, significant potential for telemedicine-friendly devices to remotely monitor the progress of glaucoma and, thereby, reduce some of the workload on an overstretched health service

    Spiropyran modified micro-fluidic chip channels as photonically controlled self-indicating system for metal ion accumulation and release

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    In this paper, we show how through integrating the beneficial characteristics of micro-fluidic devices and spiropyrans dyes, a simple and very innovative chip configured as an on-line photonically controlled self-indicating system for metal ion accumulation and release can be realised. The micro-fluidic device consists of five independent 94 μm depth, 150 μm width channels fabricated in polydimethylsiloxane. The spiropyran 1’-(3-carboxypropyl)-3,3’-dimethyl-6-nitrospiro-1-benzopyran-2,2’-indoline is immobilised by physical adsorption into a polydimethylsiloxane matrix and covalently on the ozone plasma activated polydimehylsiloxane micro-channel walls. When the colourless, inactive, spiropyran coating absorbs UV light it switches to the highly coloured merocyanine form, which also has an active binding site for certain metal ions. Therefore metal ion uptake can be triggered using UV light and subsequently reversed on demand by shining white light on the coloured complex, which regenerates the inactive spiropyran form, and releases the metal ion. When stock solutions of several metal ions (Ca2+, Zn2+, Hg2+, Cu2+, Co2+) are pumped independently through the five channels, different optical responses were observed for each metal, and the platform can therefore be regarded as a micro-structured device for online self-indicating metal ion complexation, accumulation and release

    Population-based studies of myocardial hypertrophy: high resolution cardiovascular magnetic resonance atlases improve statistical power

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    BACKGROUND: Cardiac phenotypes, such as left ventricular (LV) mass, demonstrate high heritability although most genes associated with these complex traits remain unidentified. Genome-wide association studies (GWAS) have relied on conventional 2D cardiovascular magnetic resonance (CMR) as the gold-standard for phenotyping. However this technique is insensitive to the regional variations in wall thickness which are often associated with left ventricular hypertrophy and require large cohorts to reach significance. Here we test whether automated cardiac phenotyping using high spatial resolution CMR atlases can achieve improved precision for mapping wall thickness in healthy populations and whether smaller sample sizes are required compared to conventional methods. METHODS: LV short-axis cine images were acquired in 138 healthy volunteers using standard 2D imaging and 3D high spatial resolution CMR. A multi-atlas technique was used to segment and co-register each image. The agreement between methods for end-diastolic volume and mass was made using Bland-Altman analysis in 20 subjects. The 3D and 2D segmentations of the LV were compared to manual labeling by the proportion of concordant voxels (Dice coefficient) and the distances separating corresponding points. Parametric and nonparametric data were analysed with paired t-tests and Wilcoxon signed-rank test respectively. Voxelwise power calculations used the interstudy variances of wall thickness. RESULTS: The 3D volumetric measurements showed no bias compared to 2D imaging. The segmented 3D images were more accurate than 2D images for defining the epicardium (Dice: 0.95 vs 0.93, P < 0.001; mean error 1.3 mm vs 2.2 mm, P < 0.001) and endocardium (Dice 0.95 vs 0.93, P < 0.001; mean error 1.1 mm vs 2.0 mm, P < 0.001). The 3D technique resulted in significant differences in wall thickness assessment at the base, septum and apex of the LV compared to 2D (P < 0.001). Fewer subjects were required for 3D imaging to detect a 1 mm difference in wall thickness (72 vs 56, P < 0.001). CONCLUSIONS: High spatial resolution CMR with automated phenotyping provides greater power for mapping wall thickness than conventional 2D imaging and enables a reduction in the sample size required for studies of environmental and genetic determinants of LV wall thickness

    A biologically relevant rapid quantification of physical and biological stress profiles on rocky shores.

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    Different combinations and intensities of physical (e.g. thermal) and biological (e.g.competition or predation) stress operate on organisms in different locations. Variation in these stresses can occur over small to medium spatial scales (cm to 10s m) in heterogeneous environments such as rocky shores, due to differences in sun and wave exposure, shore topography and/or recruitment. In this study we demonstrate how simple measurements can be taken that represent physical and biological stresses (stress profiles)in a given location. Using a bootstrapped principal component analysis, we identified significantly different stress profiles at four sites separated by only 10s to 100s of metres on the Shek O peninsula in Hong Kong. We then measured response to thermal stress, as determined by detachment temperature, in the limpet Cellana grata (which is known to be a sensitive indicator species to thermal stress) from each location. Significant differences in stress profile between locations were also seen in thermal stress tolerance of limpets from those locations. At locations where the major stresses are likely to be more physical or less biological in nature (e.g. southerly facing aspect or lower density of grazers), the mean detachment temperature was higher, whereas detachment temperature was lower at sites with more biological or less physical stress. This method is, therefore, able to determine biologically meaningful differences in stress profiles over small to medium spatial scales, and demonstrates that localised adaptation (i.e. post planktonic settlement) or acclimation of species may occur in response to these different stress profiles. The technique can be adapted to different environments and smaller or larger spatial scales as long as the stress experienced by the study species is relevant to these scales

    Whither Capitalism? Financial externalities and crisis

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    As with global warming, so with financial crises – externalities have a lot to answer for. We look at three of them. First the financial accelerator due to ‘fire sales’ of collateral assets -- a form of pecuniary externality that leads to liquidity being undervalued. Second the ‘risk- shifting’ behaviour of highly-levered financial institutions who keep the upside of risky investment while passing the downside to others thanks to limited liability. Finally, the network externality where the structure of the financial industry helps propagate shocks around the system unless this is checked by some form of circuit breaker, or ‘ring-fence’. The contrast between crisis-induced Great Recession and its aftermath of slow growth in the West and the rapid - and (so far) sustained - growth in the East suggests that successful economic progress may depend on how well these externalities are managed

    Age and trust as moderators in the relation between procedural justice and turnover: a large-scale longitudinal study

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    Item does not contain fulltextThe current study investigated the moderating roles of age and trust in the relation of procedural justice with turnover. It was expected that the relation between procedural justice and turnover was weaker for older workers and those with high prior trust in their leader. Older workers are better at regulating their emotions, and focus more on positive aspects of their relationships with others, and therefore react less intensely to unfair treatment. Moreover, people with high trust are more likely to attribute unfair treatment to circumstances instead of deliberate intention than people with low trust. Finally, we expected a three-way interaction between age, trust, and procedural justice in relation to turnover, where older workers with high trust would have less strong reactions than younger workers and older workers with low trust. Results from a three-wave longitudinal survey among 1,597 Dutch employees indeed revealed significant interactions between trust and procedural justice in relation to turnover. Furthermore, the three-way interaction was significant, with negative relations for younger workers, but a non-significant relation was found for older workers with low trust. Contrary to expectations, negative relations were found between procedural justice and turnover for older workers with high trust

    Investor Competition Over Information and the Pricing of Information Asymmetry

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    Whether the information environment affects the cost of capital is a fundamental question in accounting and finance research. Relying on theories about competition between informed investors as well as the pricing of information asymmetry, we hypothesize a cross-sectional variation in the pricing of information asymmetry that is conditional on competition. We develop and validate empirical proxies for competition using the number and concentration of institutional investor ownership. Using these proxies, we find a lower pricing of information asymmetry when there is more competition. Overall, our results suggest that competition between informed investors has an important effect on how the information environment affects the cost of capital.Deloitte Foundatio

    Key role of T cell defects in age-related vulnerability to West Nile virus

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    West Nile virus (WNV) infection causes a life-threatening meningoencephalitis that becomes increasingly more prevalent over the age of 50 and is 40–50× more prevalent in people over the age of 70, compared with adults under the age of 40. In a mouse model of age-related vulnerability to WNV, we demonstrate that death correlates with increased viral titers in the brain and that this loss of virus control with age was the result of defects in the CD4 and CD8 T cell response against WNV. Specific age-related defects in T cell responses against dominant WNV epitopes were detected at the level of cytokine and lytic granule production, each of which are essential for resistance against WNV, and in the ability to generate multifunctional anti-WNV effector T cells, which are believed to be critical for robust antiviral immunity. In contrast, at the peak of the response, old and adult T cells exhibited superimposable peptide sensitivity. Most importantly, although the adult CD4 or CD8 T cells readily protected immunodeficient mice upon adoptive transfer, old T cells of either subset were unable to provide WNV-specific protection. Consistent with a profound qualitative and quantitative defect in T cell immunity, old brains contained at least 12× fewer total effector CD8 T cells compared with adult mice at the peak of brain infection. These findings identify potential targets for immunomodulation and treatment to combat lethal WNV infection in the elderly
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