975 research outputs found

    Conjoint analysis of researchers' hidden preferences for bibliometrics, altmetrics, and usage metrics

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    The amount of annually published scholarly articles is growing steadily, as is the number of indicators through which impact of publications is measured. Little is known about how the increasing variety of available metrics affects researchers' processes of selecting literature to read. We conducted ranking experiments embedded into an online survey with 247 participating researchers, most from social sciences. Participants completed series of tasks in which they were asked to rank fictitious publications regarding their expected relevance, based on their scores regarding six prototypical metrics. Through applying logistic regression, cluster analysis, and manual coding of survey answers, we obtained detailed data on how prominent metrics for research impact influence our participants in decisions about which scientific articles to read. Survey answers revealed a combination of qualitative and quantitative characteristics that researchers consult when selecting literature, while regression analysis showed that among quantitative metrics, citation counts tend to be of highest concern, followed by Journal Impact Factors. Our results suggest a comparatively favorable view of many researchers on bibliometrics and widespread skepticism toward altmetrics. The findings underline the importance of equipping researchers with solid knowledge about specific metrics' limitations, as they seem to play significant roles in researchers' everyday relevance assessments

    Some Secrets of Fluorescent Proteins: Distinct Bleaching in Various Mounting Fluids and Photoactivation of cyan fluorescent proteins at YFP-Excitation

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    Background
The use of spectrally distinct variants of green fluorescent protein (GFP) such as cyan or yellow mutants (CFP and YFP, respectively) is very common in all different fields of life sciences, e.g. for marking specific proteins or cells or to determine protein interactions. In the latter case, the quantum physical phenomenon of fluorescence resonance energy transfer (FRET) is exploited by specific microscopy techniques to visualize proximity of proteins.

Methodology/Principal Findings
When we applied a commonly used FRET microscopy technique - the increase in donor (CFP)-fluorescence after bleaching of acceptor fluorophores (YFP), we obtained good signals in live cells, but very weak signals for the same samples after fixation and mounting in commercial microscopy mounting fluids. This observation could be traced back to much faster bleaching of CFP in these mounting media. Strikingly, the opposite effect of the mounting fluid was observed for YFP and also for other proteins such as Cerulean, TFP or Venus. The changes in photostability of CFP and YFP were not caused by the fixation but directly dependent on the mounting fluid. Furthermore we made the interesting observation that the CFP-fluorescence intensity increases by about 10 - 15% after illumination at the YFP-excitation wavelength – a phenomenon, which was also observed for Cerulean. This photoactivation of cyan fluorescent proteins at the YFP-excitation can cause false-positive signals in the FRET-microscopy technique that is based on bleaching of a yellow FRET acceptor.

Conclusions/Significance
Our results show that photostability of fluorescent proteins differs significantly for various media and that CFP bleaches significantly faster in commercial mounting fluids, while the opposite is observed for YFP and some other proteins. Moreover, we show that the FRET microscopy technique that is based on bleaching of the YFP is prone to artifacts due to photoactivation of cyan fluorescent proteins under these conditions

    Bis(7-meth­oxy-1-methyl-4,9-dihydro-3H-β-carbolinium) tetra­chloridozincate

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    In the title compound, (C13H15N2O)2[ZnCl4], also known as di(harmalinium) tetra­chloridozincate, the ZnII atom is in a distorted tetrahedral coordination of the chlorido ligands. In the cation, the meth­oxy and methyl groups are both coplanar with with rings to which they are attached [maximum deviations of 0.232 (4) and 0.259 (4) Å, respectively]. In the crystal, the alkaloid cations and metal complex anions inter­act by way of N—H⋯Cl hydrogen bonds involving each Cl atom, resulting in a network structure

    Sex-related differences in respiratory symptoms: results from the BOLD Study

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    For both males and females, the pathway to diagnosis and treatment of lung disease often begins with the reporting of respiratory symptoms to their physician. Males and females with impaired lung function may experience the same symptoms but perceive and/or report them differently

    Bis(6-meth­oxy-1-methyl-2,3,4,9-tetra­hydro-1H-β-carbolin-2-ium) tetra­chloridozincate(II) dihydrate

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    The asymmetric unit of the title compound, (C13H17N2O)2[ZnCl4]·2H2O, contains two tetra­hydro­harmine cations, one tetra­chloro­zincate(II) anion and two water mol­ecules. In the cations, the two 1H-indole ring systems are essentially planar, with maximum deviations of 0.016 (2) and 0.018 (2) Å, and both tetra­hydro­pyridinium rings show a half-chair conformation. The ZnII complex anion has a distorted tetra­hedral geometry. In the crystal, inter­molecular N—H⋯O, N—H⋯Cl, O—H⋯O, O—H⋯Cl and C—H⋯O hydrogen bonds link the components into a three-dimensional network. A π–π inter­action with a centroid–centroid distance of 3.542 (14) Å is also observed

    Varicella-Zoster viruses associated with post-herpetic neuralgia induce sodium current density increases in the ND7-23 Nav-1.8 neuroblastoma cell line

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    Post-herpetic neuralgia (PHN) is the most significant complication of herpes zoster caused by reactivation of latent Varicella-Zoster virus (VZV). We undertook a heterologous infection in vitro study to determine whether PHN-associated VZV isolates induce changes in sodium ion channel currents known to be associated with neuropathic pain. Twenty VZV isolates were studied blind from 11 PHN and 9 non-PHN subjects. Viruses were propagated in the MeWo cell line from which cell-free virus was harvested and applied to the ND7/23-Nav1.8 rat DRG x mouse neuroblastoma hybrid cell line which showed constitutive expression of the exogenous Nav 1.8, and endogenous expression of Nav 1.6 and Nav 1.7 genes all encoding sodium ion channels the dysregulation of which is associated with a range of neuropathic pain syndromes. After 72 hrs all three classes of VZV gene transcripts were detected in the absence of infectious virus. Single cell sodium ion channel recording was performed after 72 hr by voltage-clamping. PHN-associated VZV significantly increased sodium current amplitude in the cell line when compared with non-PHN VZV, wild-type (Dumas) or vaccine VZV strains ((POka, Merck and GSK). These sodium current increases were unaffected by acyclovir pre-treatment but were abolished by exposure to Tetrodotoxin (TTX) which blocks the TTX-sensitive fast Nav 1.6 and Nav 1.7 channels but not the TTX-resistant slow Nav 1.8 channel. PHN-associated VZV sodium current increases were therefore mediated in part by the Nav 1.6 and Nav 1.7 sodium ion channels. An additional observation was a modest increase in message levels of both Nav1.6 and Nav1.7 mRNA but not Nav 1.8 in PHN virally infected cells

    COPD care delivery pathways in five European Union countries : mapping and health care professionals' perceptions

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    Background: COPD is among the leading causes of chronic morbidity and mortality in the European Union with an estimated annual economic burden of €25.1 billion. Various care pathways for COPD exist across Europe leading to different responses to similar problems. Determining these differences and the similarities may improve health and the functioning of health services. Objective: The aim of this study was to compare COPD patients’ care pathway in five European Union countries including England, Ireland, the Netherlands, Greece, and Germany and to explore health care professionals’ (HCPs) perceptions about the current pathways. Methods: HCPs were interviewed in two stages using a qualitative, semistructured email interview and a face-to-face semistructured interview. Results: Lack of communication among different health care providers managing COPD and comorbidities was a common feature of the studied care pathways. General practitioners/family doctors are responsible for liaising between different teams/services, except in Greece where this is done through pulmonologists. Ireland and the UK are the only countries with services for patients at home to shorten unnecessary hospital stay. HCPs emphasized lack of communication, limited resources, and poor patient engagement as issues in the current pathways. Furthermore, no specified role exists for pharmacists and informal carers. Conclusion: Service and professional integration between care settings using a unified system targeting COPD and comorbidities is a priority. Better communication between health care providers, establishing a clear role for informal carers, and enhancing patients’ engagement could optimize current care pathways resulting in a better integrated system

    Video Capsule Retention in a Zenker Diverticulum

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    We report the case of a video capsule endoscope lodged within a Zenker diverticulum. The system that was equipped with a real-time viewer showed an unchanging image unlike esophageal or gastric mucosa, suggesting that the capsule was elsewhere. The presence of cervical discomfort suggested video capsule retention in a Zenker diverticulum. The capsule was removed endoscopically and reinserted using a hood-assisted endoscope and the procedure was completed
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