1,979 research outputs found

    Dual-functional materials via CCTP and selective orthogonal thiol-Michael addition/epoxide ring opening reactions

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    Poly(glycidyl methacrylate) (PGMA) has been synthesised by cobalt catalysed chain transfer polymerisation (CCTP) yielding, in one step, polymers with two points for post polymerisation functionalisation; the activated terminal vinyl bond and in chain epoxide groups. Epoxide ring-opening and a combination of thiol-Michael addition and epoxide ring-opening has been used for the post-functionalisation with amines and thiols to prepare a range of functional materials

    Truncation of TRIM5 in the <i>Feliformia</i> explains the absence of retroviral restriction in cells of the domestic cat

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    TRIM5[alpha] mediates a potent retroviral restriction phenotype in diverse mammalian species. Here, we identify a TRIM5 transcript in cat cells with a truncated B30.2 capsid binding domain and ablated restrictive function which, remarkably, is conserved across the &lt;i&gt;Feliformia&lt;/i&gt;. Cat TRIM5 displayed no restriction activity, but ectopic expression conferred a dominant negative effect against human TRIM5[alpha]. Our findings explain the absence of retroviral restriction in cat cells and suggest that disruption of the TRIM5 locus has arisen independently at least twice in the &lt;i&gt;Carnivora&lt;/i&gt;, with implications concerning the evolution of the host and pathogen in this taxon

    Nuclear hormone receptor architecture - form and dynamics: The 2009 FASEB Summer Conference on Dynamic Structure of the Nuclear Hormone Receptors

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    Nuclear hormone receptors (NHRs) represent a large and diverse family of ligand-activated transcription factors involved in regulating development, metabolic homeostasis, salt balance and reproductive health. The ligands for these receptors are typically small hydrophobic molecules such as steroid hormones, thyroid hormone, vitamin D3 and fatty acid derivatives. The first NHR structural information appeared ~20 years ago with the solution and crystal structures of the DNA binding domains and was followed by the structure of the agonist and antagonist bound ligand binding domains of different NHR members. Interestingly, in addition to these defined structural features, it has become clear that NHRs also possess significant structural plasticity. Thus, the dynamic structure of the NHRs was the topic of a recent stimulating and informative FASEB Summer Research Conference held in Vermont

    Development and Validation of a Facebook Relational Maintenance Measure

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    This manuscript details the construction of a measure of Facebook relational maintenance behaviors. The first study generated an item pool by drawing from previous qualitative investigations and adapting an established relational maintenance scale. Participants were then invited to evaluate these items in order to establish face validity. During study two, participants were asked how often they used the behaviors represented in these items to maintain a specific friendship. Exploratory factor analysis was conducted to determine the underlying structure of these items; three latent factors emerged, social contact, response-seeking, and relational assurances. This factor structure was then assessed using confirmatory factor analysis during phase three. Study three participants were also asked to complete measures of friendship quality, Facebook intensity, and online social communication. The relationship of the three factors of Facebook relational maintenance to friendship quality, Facebook intensity, and online social communication suggests convergent and discriminant validity for the Facebook relational maintenance measure

    Analytical determination of coronal parameters using the period ratio P<sub>1</sub>/2P<sub>2</sub>

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    &lt;p&gt;Context. In transverse coronal loop oscillations, two periodicities have been measured simultaneously and are interpreted as the fundamental kink mode (with period P1) and the first harmonic (with period P2). Deviations of the period ratio P1/2P2 from unity provide information about the extent of longitudinal structuring within the loop.&lt;/p&gt; &lt;p&gt;Aims. Here we develop an analytical approximation that describes the shift in P1/2P2 in terms of the ratio L/Λc of the length 2L of a coronal loop and the density scale height Λc.&lt;/p&gt; &lt;p&gt;Methods. We study the MHD wave equations in a low β plasma using the thin tube approximation. Disturbances are described by a differential equation which may be solved for various equilibrium density profiles, obtaining dispersion relations in terms of Bessel functions. These dispersion relations may be used to obtain analytical approximations to the periods P1 and P2. We also present a variational approach to determining the period ratio and show how the WKB method may be used.&lt;/p&gt; &lt;p&gt;Results. Analytical approximations to the period ratio P1/2P2 are used to shed light on the magnitude of longitudinal structuring in a loop, leading to a determination of the density scale height. We apply our formula to the observations in Verwichte et al. (2004) and Van Doorsselaere et al. (2007), obtaining the coronal density scale height.&lt;/p&gt; &lt;p&gt;Conclusions. Our simple formula and approximate approaches highlight a useful analytical tool for coronal seismology. We demonstrate that P1/2P2 is linked to the density scale height, with no need for estimates of other external parameters. Given the accuracy of current observations, our formula provides a convenient means of determining density scale heights.&lt;/p&gt

    Saltation transport on Mars

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    We present the first calculation of saltation transport and dune formation on Mars and compare it to real dunes. We find that the rate at which grains are entrained into saltation on Mars is one order of magnitude higher than on Earth. With this fundamental novel ingredient, we reproduce the size and different shapes of Mars dunes, and give an estimate for the wind velocity on Mars.Comment: 4 pages, 3 figure

    Solar feature tracking in both spatial and temporal domains

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    A new method for automated coronal loop tracking, in both spatial and temporal domains, is presented. The reliability of this technique was tested with TRACE 171A observations. The application of this technique to a flare-induced kink-mode oscillation, revealed a 3500 km spatial periodicity which occur along the loop edge. We establish a reduction in oscillatory power, for these spatial periodicities, of 45% over a 322 s interval. We relate the reduction in oscillatory power to the physical damping of these loop-top oscillations

    Teamwork training in sport:A pilot intervention study

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    The purpose of this study was to test the efficacy of a novel team building intervention that targets teamwork in sport. Using a 10-week pilot nonrandomized controlled intervention design, 12 interdependent sports teams comprising 187 athletes were assigned to one of two conditions: an experimental condition in which teams participated in two teamwork training sessions at Weeks 2 and 6 of the study (6 teams, 94 athletes) or a no-training control condition (6 teams, 93 athletes). Teamwork was measured at Weeks 1, 5, and 10 of the study. Overall, significant improvements in teamwork were shown for the experimental teams from baseline to Week 5; these effects were maintained through Week 10 of the study. In contrast, no significant changes in teamwork were observed for teams in the control condition over these 10 weeks. The results provide evidence that teamwork training can enhance the extent to which members of a sports team work effectively together

    Efficacy of pimobendan in the prevention of congestive heart failure or sudden death in doberman pinschers with preclinical dilated cardiomyopathy (the PROTECT study)

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    &lt;p&gt;Background: The benefit of pimobendan in delaying the progression of preclinical dilated cardiomyopathy (DCM) in Dobermans is not reported.&lt;/p&gt; &lt;p&gt;Hypothesis: That chronic oral administration of pimobendan to Dobermans with preclinical DCM will delay the onset of CHF or sudden death and improve survival.&lt;/p&gt; &lt;p&gt;Animals: Seventy-six client-owned Dobermans recruited at 10 centers in the UK and North America.&lt;/p&gt; &lt;p&gt;Methods: The trial was a randomized, blinded, placebo-controlled, parallel group multicenter study. Dogs were allocated in a 1:1 ratio to receive pimobendan (Vetmedin capsules) or visually identical placebo.&lt;/p&gt; &lt;p&gt;The composite primary endpoint was prospectively defined as either onset of CHF or sudden death. Time to death from all causes was a secondary endpoint.&lt;/p&gt; &lt;p&gt;Results: The proportion of dogs reaching the primary endpoint was not significantly different between groups (P = .1). The median time to the primary endpoint (onset of CHF or sudden death) was significantly longer in the pimobendan (718 days, IQR 441–1152 days) versus the placebo group (441 days, IQR 151–641 days) (log-rank P = 0.0088). The median survival time was significantly longer in the pimobendan (623 days, IQR 491–1531 days) versus the placebo group (466 days, IQR 236–710 days) (log-rank P = .034).&lt;/p&gt; &lt;p&gt;Conclusion and Clinical Importance: The administration of pimobendan to Dobermans with preclinical DCM prolongs the time to the onset of clinical signs and extends survival. Treatment of dogs in the preclinical phase of this common cardiovascular disorder with pimobendan can lead to improved outcome.&lt;/p&gt

    On the period ratio P<sub>1</sub>/2P<sub>2</sub> in the oscillations of coronal loops

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    &lt;p&gt;Aims. With strong evidence of fast and slow magnetoacoustic modes arising in the solar atmosphere there is scope for improved determinations of coronal parameters through coronal seismology. Of particular interest is the ratio P&lt;sub&gt;1&lt;/sub&gt;/2P&lt;sub&gt;2&lt;/sub&gt;between the period P&lt;sub&gt;1&lt;/sub&gt; of the fundamental mode and the period P&lt;sub&gt;2&lt;/sub&gt; of its first harmonic; in an homogeneous medium this ratio is one, but in a more complex configuration it is shifted to lower values.&lt;/p&gt; &lt;p&gt;Methods. We consider analytically the effects on the different magnetohydrodynamic modes of structuring and stratification, pointing out that transverse or longitudinal structuring or gravitational stratification modifies the ratio P&lt;sub&gt;1&lt;/sub&gt;/2P&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt; &lt;p&gt;Results. The deviations caused by gravity and structure are studied for the fast and slow modes. Structure along the loop is found to be the dominant effect.&lt;/p&gt; &lt;p&gt;Conclusions. The departure of P&lt;sub&gt;1&lt;/sub&gt;/2P&lt;sub&gt;2&lt;/sub&gt; from unity can be used as a seismological tool in the corona. We apply our technique to the observations by Verwichte et al. (2004), deducing the density scale height in a coronal loop.&lt;/p&gt
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