1,721,038 research outputs found
Preclinical pharmacokinetics, pharmacodynamics and safety of sucroferric oxyhydroxide
No full textSucroferric oxyhydroxide (VELPHORO®) is a polynuclear iron-based phosphate binder recently approved for the treatment of hyperphosphataemia in patients with chronic kidney disease (CKD). As a number of the available phosphate binders do not provide the optimal combination of good efficacy, adequate tolerability and low pill burden, sucroferric oxyhydroxide constitutes a promising alternative. Among the attributes of an ideal phosphate binder is minimal absorption and, hence, low risk of systemic toxicity. Accordingly, the iron-releasing properties and absorption, distribution, metabolism and excretion (ADME) profile of sucroferric oxyhydroxide, as well as the possibility of iron accumulation and toxicity, were investigated in a series of preclinical studies. The effect of sucroferric oxyhydroxide on the progression of vascular calcification was also investigated. Sucroferric oxyhydroxide exhibited a high phosphate-binding capacity and low iron-releasing properties across the physiological pH range found in the gastrointestinal tract. In the ADME studies, uptake of 59Fe-radiolabelled sucroferric oxyhydroxide was low in rats and dogs (<1% from a 50 mg Fe/kg bodyweight dose), with the majority of absorbed iron located in red blood cells. Long-term (up to 2 years) administration of sucroferric oxyhydroxide in rats and dogs was associated with modest increases in tissue iron levels and no iron toxicity. Moreoever, in uraemic rats, sucroferric oxyhydroxide was associated with reduced progression of vascular calcification compared with calcium carbonate. In conclusion, sucroferric oxyhydroxide offers a new option for the treatment of hyperphosphataemia, with a high phosphate-binding capacity, minimal iron release, and low potential for iron accumulation and toxicity
A comparison between analytical solutions for lightning-induced voltage calculation
No full textAn exact closed form solution for the calculation of lightning-induced voltages on overhead lines has been recently proposed by A. Andreotti et al. (2012). Predictions of this exact formulation are compared here to those based on approximate analytical solutions proposed in the literature. DOI: http://dx.doi.org/10.5755/j01.eee.20.5.296
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
On the constraints imposed by the close electric field signature on the equivalent corona current in lightning return stroke models
No full textLightning-Induced Disturbances in Buried Cables Part I: Theory
No full textIn this paper, we present a review of theoretical methods to compute lightning induced currents and voltages on buried cables. The evaluation of such induced disturbances requires the calculation of the electric field produced by lightning along the cable path. We show that the Cooray’s simplified formula is capable of predicting accurately the horizontal electric field penetrating the ground, at distances as close as 100 m. Regarding the parameters of the buried cable, a comparison of several approximations of the ground impedance is presented.We show that the Pollaczek expression corresponds to the Sunde general expression, when the displacement current is neglected. The analysis shows also that all the proposed approximations provide very similar results for the considered range of frequencies (up to 30 MHz). Most of the approximate formulas neglect the contribution of the displacement current and, therefore, predict values for the ground impedance which tend to infinity at higher frequencies. This corresponds in the time domain to a singularity of the ground transient resistance at t = 0. By analogy to the Sunde approximation for the ground impedance of overhead lines, we propose a logarithmic approximation for the ground impedance of a buried cable. In addition, unlike most of the considered approximations, the proposed formula has an asymptotic behavior at high frequencies; therefore, the corresponding transient ground resistance in the time domain has no singularity at t = 0. It is also demonstrated that within the frequency range of interest, the wire impedance can be neglected, due to its small contribution to the overall longitudinal impedance of the line. The ground admittance, however, can play an important role at high frequencies (1 MHz or so) especially in the case of poor ground conductivity. The ground admittance needs to be taken into account in the calculation of lightning induced currents and voltages on buried cables. This is in contrast with the case of overhead lines in which its contribution is generally negligible, even in the MHz range. We also investigate the time-domain representation of field-totransmission line coupling equations. The coupling model includes the effect of ground admittance which appears in terms of an additional convolution integral. An analytical expression for the ground transient resistance in the time domain is also proposed which is shown to be sufficiently accurate and nonsingular. Finally, we present a time domain solution of field-to-buried cable coupling equations using the point-centered finite difference time domain (FDTD) method, and a frequency domain solution using Green’s functions. In our companion paper (Part II), we compare both solutions to experimental waveforms obtained using triggered lightning
Variations on the Author
Full text link“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
Full text linkWe 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
Full text linkWe 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
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