1,720,973 research outputs found
Hyperici herba extract interaction with artificial lipid bilayers
No full textHyperici herba (Hyp) is the aerial part collected during the flowering period from the well-known herb, Hypericum perforatum. Black lipid membrane experiments were performed to investigate the effect of the ethanolic Hyp extract on the electrical properties (capacitance and conductance) of artificial lipid bilayers. Hyp extract (1-10 μg mL-1) induced a concentration-dependent increase of both specific transmembrane capacitance and conductance in phosphatidylcholine (PC) membranes. The effect on conductance was enhanced when the Hyp extract (3 μg mL-1) was present on both sides of the membrane (Gm=77.89±8.81 nS cm-2, n=5) compared with single-sided application (Gm=36.48±2.41 nS cm-2, n=5). In bilayers containing PC and phosphatidylserine (PS), PC:PS, the Hyp extract effect was greater than on pure PC bilayers, although the surface charge was not the determining factor of this enhanced activity. Adding cholesterol to the PC:PS mixture reverted the conductance increase induced by the Hyp extract in a dose-dependent manner. The specific pattern of the Hyp extract interaction with lipid bilayers has possible consequences concerning its absorption and bioavailability, as well as its pharmacodynamic effects on neuronal excitability
Extracellular trypsin increases ASIC1a selectivity for monovalent versus divalent cations
No full textSustained proton activation of native ASIC channels in primary sensory neurons or HEK293 cells leads to a reduction in the peak amplitude of transient inward currents and the progressive development of a persistent component, which hinders titration experiments in pharmacological studies. Here we report that extracellular trypsin applied for 5 min at 10–45 μg/ml and/or a short exposure to high Ca2+ (75 mM for less than 1 min) alleviate the persistent component, improving reproducibility of acid-elicited transients. Selectivity measurements performed in current clamp mode, in essentially bi-ionic conditions, prove that these two treatments decrease hASIC1a permeability for divalent but not for monovalent cations, producing a significant change in PNa/PCa from 8.2 ± 2.1 (mean ± S.D.) to 26.0 ± 7.8 (trypsin) or 24.5 ± 11.1 (high Ca2+). The slope conductance of the unit inward Ca2+ transient was also lowered from 5.7 to 2.7 pS after trypsin
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
TRPV1 properties in thoracic dorsal root ganglia neurons are modulated by intraperitoneal capsaicin administration in the late phase of Type-1 autoimmune diabetes.
No full textPharmacological therapies in type 1 diabetes for efficient control of glycemia and changes in pain alterations due to diabetic neuropathy are a continuous challenge. Transient receptor potential vanilloid type 1 (TRPV1) from dorsal root ganglia (DRG) neurons is one of the main pharmacological targets in diabetes, and its ligand capsaicin can be a promising compound for blood-glucose control. Our goal is to elucidate the effect of intraperitoneal (i.p.) capsaicin administration in type 1 diabetic mice against TRPV1 receptors from pancreatic DRG primary afferent neurons. A TCR+/−/Ins-HA+/− diabetic mice (dTg) was used, and patch-clamp and immunofluorescence microscopy measurements have been performed on thoracic T9–T12 DRG neurons. Capsaicin (800 μg/kg, i.p. three successive days) administration in the late-phase diabetes reduces blood-glucose levels, partly reverses the TRPV1 current density and recovery time constant, without any effect on TRPV1 expression general pattern, in dTg mice. A TRPV1 hypoalgesia profile was observed in late-phase diabetes, which was partly reversed to normoalgesic profile upon capsaicin i.p. administration. According to the soma dimensions of the thoracic DRG neurons, a detailed analysis of the TRPV1 expression upon capsaicin i.p. treatment was done, and the proportion of large A-fiber neurons expressing TRPV1 increased in dTg capsaicin-treated mice. In conclusion, the benefits of low-dose capsaicin intraperitoneal treatment in late-phase type-1 diabetes should be further exploited
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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