276 research outputs found

    Blue Obelisk - Interoperability in chemical informatics

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    The Blue Obelisk Movement (http://www.blueobelisk.org/) is the name used by a diverse Internet group promoting reusable chemistry via open source software development, consistent and complimentary chemoinformatics research, open data, and open standards. We outline recent examples of cooperation in the Blue Obelisk group:  a shared dictionary of algorithms and implementations in chemoinformatics algorithms drawing from our various software projects; a shared repository of chemoinformatics data including elemental properties, atomic radii, isotopes, atom typing rules, and so forth; and Web services for the platform-independent use of chemoinformatics programs

    Probing the role of grain boundaries in single Cu nanoparticle oxidation by in situ plasmonic scattering

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    Grain boundaries determine physical properties of bulk materials including ductility, diffusivity, and electrical conductivity. However, the role of grain boundaries in nanostructures and nanoparticles is much less understood, despite the wide application of nanoparticles in nanophotonics, nanoelectronics, and heterogeneous catalysis. Here, we investigate the role of high-angle grain boundaries in the oxidation of Cu nanoparticles, using a combination of in situ single particle plasmonic nanoimaging and postmortem transmission electron microscopy image analysis, together with ab initio and classical electromagnetic calculations. We find an initial growth of a 5-nm-thick Cu2O shell on all nanoparticles, irrespective of different grain morphologies. This insensitivity of the Cu2O shell on the grain morphology is rationalized by extraction of Cu atoms from the metal lattice being the rate limiting step, as proposed by density functional theory calculations. Furthermore, we find that the change in optical scattering intensity measured from the individual particles can be deconvoluted into one contribution from the oxide layer growth and one contribution that is directly proportional to the grain boundary density. The latter contribution signals accumulation of Cu vacancies at the grain boundaries, which, as corroborated by calculations of the optical scattering, leads to increased absorption losses and thus a decrease of the scattering, thereby manifesting the role of grain boundaries as vacancy sinks and nuclei for Kirkendall void formation at a later stage of the oxidation process

    Effectively incorporating selected multimedia content into medical publications

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    Until fairly recently, medical publications have been handicapped by being restricted to non-electronic formats, effectively preventing the dissemination of complex audiovisual and three-dimensional data. However, authors and readers could significantly profit from advances in electronic publishing that permit the inclusion of multimedia content directly into an article. For the first time, the de facto gold standard for scientific publishing, the portable document format (PDF), is used here as a platform to embed a video and an audio sequence of patient data into a publication. Fully interactive three-dimensional models of a face and a schematic representation of a human brain are also part of this publication. We discuss the potential of this approach and its impact on the communication of scientific medical data, particularly with regard to electronic and open access publications. Finally, we emphasise how medical teaching can benefit from this new tool and comment on the future of medical publishing

    Temporal binding and the perception/cognition boundary

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    Temporal binding occurs when people observe two events that they believe to be causally connected: They underestimate the length of the interval between those two events, when compared with their estimates of the length of intervals between events they believe to be causally unrelated. I discuss temporal binding in the context of Dennett and Kinsbourne’s (1992) influential argument levelled at what they call ‘Cartesian Materialism’. In particular, I argue that Dennett and Kinsbourne’s argument trades on a representational conception of perceptual experience, which blurs the boundary between perception and judgement, and that temporal binding can serve as a case study for developing an alternative, relational, conception of perceptual experience and of its relation to judgement. Based on research on the mechanisms underlying temporal binding, I provide an explanation of the phenomenon in which perception and judgement play clearly distinct roles

    Evaluation of a new arterial pressure-based cardiac output device requiring no external calibration

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    <p>Abstract</p> <p>Background</p> <p>Several techniques have been discussed as alternatives to the intermittent bolus thermodilution cardiac output (CO<sub>PAC</sub>) measurement by the pulmonary artery catheter (PAC). However, these techniques usually require a central venous line, an additional catheter, or a special calibration procedure. A new arterial pressure-based cardiac output (CO<sub>AP</sub>) device (FloTrac™, Vigileo™; Edwards Lifesciences, Irvine, CA, USA) only requires access to the radial or femoral artery using a standard arterial catheter and does not need an external calibration. We validated this technique in critically ill patients in the intensive care unit (ICU) using CO<sub>PAC </sub>as the method of reference.</p> <p>Methods</p> <p>We studied 20 critically ill patients, aged 16 to 74 years (mean, 55.5 ± 18.8 years), who required both arterial and pulmonary artery pressure monitoring. CO<sub>PAC </sub>measurements were performed at least every 4 hours and calculated as the average of 3 measurements, while CO<sub>AP </sub>values were taken immediately at the end of bolus determinations. Accuracy of measurements was assessed by calculating the bias and limits of agreement using the method described by Bland and Altman.</p> <p>Results</p> <p>A total of 164 coupled measurements were obtained. Absolute values of CO<sub>PAC </sub>ranged from 2.80 to 10.80 l/min (mean 5.93 ± 1.55 l/min). The bias and limits of agreement between CO<sub>PAC </sub>and CO<sub>AP </sub>for unequal numbers of replicates was 0.02 ± 2.92 l/min. The percentage error between CO<sub>PAC </sub>and CO<sub>AP </sub>was 49.3%. The bias between percentage changes in CO<sub>PAC </sub>(ΔCO<sub>PAC</sub>) and percentage changes in CO<sub>AP </sub>(ΔCO<sub>AP</sub>) for consecutive measurements was -0.70% ± 32.28%. CO<sub>PAC </sub>and CO<sub>AP </sub>showed a Pearson correlation coefficient of 0.58 (<it>p </it>< 0.01), while the correlation coefficient between ΔCO<sub>PAC </sub>and ΔCO<sub>AP </sub>was 0.46 (<it>p </it>< 0.01).</p> <p>Conclusion</p> <p>Although the CO<sub>AP </sub>algorithm shows a minimal bias with CO<sub>PAC </sub>over a wide range of values in an inhomogeneous group of critically ill patients, the scattering of the data remains relative wide. Therefore, the used algorithm (V 1.03) failed to demonstrate an acceptable accuracy in comparison to the clinical standard of cardiac output determination.</p

    BID-F1 and BID-F2 Domains of Bartonella henselae Effector Protein BepF Trigger Together with BepC the Formation of Invasome Structures

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    The gram-negative, zoonotic pathogen Bartonella henselae (Bhe) translocates seven distinct Bartonella effector proteins (Beps) via the VirB/VirD4 type IV secretion system (T4SS) into human cells, thereby interfering with host cell signaling [1], [2]. In particular, the effector protein BepG alone or the combination of effector proteins BepC and BepF trigger massive F-actin rearrangements that lead to the establishment of invasome structures eventually resulting in the internalization of entire Bhe aggregates [2], [3]. In this report, we investigate the molecular function of the effector protein BepF in the eukaryotic host cell. We show that the N-terminal [E/T]PLYAT tyrosine phosphorylation motifs of BepF get phosphorylated upon translocation but do not contribute to invasome-mediated Bhe uptake. In contrast, we found that two of the three BID domains of BepF are capable to trigger invasome formation together with BepC, while a mutation of the WxxxE motif of the BID-F1 domain inhibited its ability to contribute to the formation of invasome structures. Next, we show that BepF function during invasome formation can be replaced by the over-expression of constitutive-active Rho GTPases Rac1 or Cdc42. Finally we demonstrate that BID-F1 and BID-F2 domains promote the formation of filopodia-like extensions in NIH 3T3 and HeLa cells as well as membrane protrusions in HeLa cells, suggesting a role for BepF in Rac1 and Cdc42 activation during the process of invasome formation

    Sensitivity to change of the Neck Pain and Disability Scale

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    The Neck Pain and Disability Scale (NPAD) is a 20-item instrument to measure neck pain and related disability. The aim of this study was to assess sensitivity to change of the NPAD. A total of 411 participants from 15 general practices in the middle of Germany completed a multidimensional questionnaire including the German version of the NPAD and self-reported demographic and clinical information. Sensitivity to change was analysed by linear regression analysis of the NPAD at follow-up and educational level, age class, depression, anxiety, and deficits in social support, respectively, and by Pearson’s correlation analyses between mean change in NPAD at follow-up and mean change in prognostic markers. Those having more than basic education (regression coefficient −7.2, p < 0.001) and/or being in a younger age class (−2.9, p = 0.020) consistently reported significantly lower average NPAD scores at follow-up compared to those with basic education and/or a older age class. In contrast, those who were classified to be depressed (regression coefficient 2.1, p < 0.001), anxious (1.9, p < 0.001), or having deficits in social support (5.5, p = 0.004) reported significantly higher NPAD scores. Change in depression, anxiety, and social support scale between baseline and follow-up was significantly correlated with change in the NPAD score. Hence, these data are in the direction anticipated across all baseline factors investigated. In conclusion, the NPAD seems to be a sensitive measure for use in clinical practice and future studies of neck pain and related disability
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