1,720,959 research outputs found
Evaluation of a Torsional-Vibrating Technique for the Hemorheological Characterization
Full text linkClinical measurement of blood viscosity is an important parameter in the diagnosis of different diseases (e.g., diabetes,
hypertension, cardiovascular diseases). The significance of blood viscosity in the microcirculatory flow is also of great
importance. Thus, a simple and accurate evaluation of hemorheological properties could be an important challenge in clinical
practice. Nowadays, validated measurements of plasma viscosity are commonly carried out with rotational viscometers by
means of the various geometric configurations. However, red blood cells deform under mechanical force and this aspect could
lead to an artificial variation in the apparent viscosity. In this work, an evaluation of a new technique for the viscosity determination
is focused. In particular, a torsional oscillation viscometer was adopted (VM10AL, CBC Europe) in the presence and in
the absence of stirring conditions at thermostated conditions. The profile of the rheological behaviour as a function of time was
recorded and compared with that obtained using a cone-plate rotational viscometer (AR300, TA Instrument)
Valutazione della viscosità ematica sistemica correlata alla presenza di ulcere da pressione.
No full textModificazioni sulla viscosità ematica sistemica in soggetti allettati con ulcera da pressione
No full textComparison of blood viscosity using a torsional oscillation viscometer and a rheometer
Full text linkThe absence of a simple and clinically practical method to determine whole blood viscosity can partly justify why
the medical community has been slow in realizing the significance of whole blood viscosity. For this reason, the availability of a
technique able to evaluate blood viscosity in a rapid and direct manner is welcome. To evaluate the feasibility in hemorheological
laboratory of a new torsional oscillation viscometer, it was compared with a conventional cone–plate system. The viscosity
comparison has been related to hematocrit value both on whole blood and suspended blood in a saline solution. The results
showed a good repeatability and reproducibility of the new equipment, with a best-fitting data of the hematocrit 0–100% range
characterized by coefficient of determinations, r2 > 0.95. Furthermore, a comparison of whole blood viscosity as measured
by the two instruments was done on blood samples collected from hospitalized patients. Reasonable agreement for the viscosity
values was found between the two methods with linear determination coefficients between the two measurement methods
comprised between r2 = 0.7329 and 0.9263, depending on shear stress phase and the corresponding shear rate
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
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
Characterization of the metallo-β-lactamase determinant of Acinetobacter baumannii AC-54/97 reveals the existence of bla(IMP) allelic variants carried by gene cassettes of different phylogeny
No full textThe metallo-β-lactamase determinant of Acinetobacter baumannii AC- 54/97, a clinical isolate from Italy that was previously shown to produce an enzyme related to IMP-1, was isolated by means of a PCR methodology which targets amplification of gene cassette arrays inserted into class I integrons. Sequencing revealed that this determinant was an allelic variant (named bla(IMP-2)) of bla(IMP) found in Japanese isolates and that it was divergent from the latter by 12% of its nucleotide sequence, which evidently had been acquired independently. Similar to bla(IMP), bla(IMP-2) was also carried by an integron-borne gene cassette. However, the 59-base element of the bla(IMP-2) cassette was unrelated to those of the bla(IMP) cassettes found in Japanese isolates, indicating a different phylogeny for the gene cassettes caring the two allelic variants. Expression of the integron-borne bla(IMP-2) gene in Escherichia coli resulted in a significant decrease in susceptibility to a broad array of β-lactams (ampicillin, carbenicillin, cephalothin, cefoxitin, ceftazidime, cefepime, and carbapenems). The IMP-2 enzyme was purified from an Escherichia coli strain carrying the cloned determinant, and kinetic parameters were determined with several β-lactam substrates. Compared to IMP-1, the kinetic parameters of IMP-2 were similar overall with some β-lactam substrates (cefoxitin, ceftazidime, cefepime, and imipenem) but remarkably different with others (ampicillin, carbenicillin, cephaloridine, and meropenem), revealing a functional significance of at least some of the mutations that differentiate the two IMP variants. Present findings suggest that the environmental reservoir of bla(IMP) alleles could be widespread and raise a question about the global risk of their transfer to clinically relevant species
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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