1,720,988 research outputs found
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
Experimental Assessment of Gold Nanorods for Optoacoustic Imaging in a Tissue-mimicking Phantom
No full textVariations 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
An Innovative Ultrasound Signal Processing Technique to Selectively Detect Nanosized Contrast Agents in Echographic Images
No full textThe aim of this paper was to optimize the employment of a novel algorithm for acquisition and processing of medical ultrasound (US) signals to facilitate its clinical translation. The implemented procedure is dedicated to selective enhancement of nanoparticle (NP) contrast agents in echographic images and is based on the differences in US signal backscatter between NP-containing targets and more homogeneous
objects. Previous preliminary studies verified the feasibility of this approach on silica nanospheres (SiNSs) dispersed at a constant volume concentration (0.7%) in agarose gel samples. The present extended these evaluations, addressing two issues of direct clinical interest: 1) safety: SiNSs were coated with a biocompatible layer made of polyethylene glycol (PEG) and the adopted NP volume concentration was reduced to 0.2%, which is in the nontoxic range and 2) reproducibility: a different phantom configuration was used, to verify the independence of algorithm performance from a specific target region shape. The obtained results demonstrated that the proposed method can be effectively
applied to enhance the presence of PEG-coated SiNSs in the diameter range 160–660 nm at a low and biocompatible volume concentration: the combined employment of a phantom with a different geometry and a lower concentration of PEG-coated NPs, in fact, caused only slight variations in the suppression patterns of noncontrast echoes, without affecting the final diagnostic effectiveness of the investigated contrast detection scheme. This approach also provides specific advantages with respect to the available measurement techniques dedicated to the enhancement of targeted US contrast agents for molecular imaging purposes
Magnetically-coated silica nanospheres for dual-mode imaging at low ultrasound frequency
No full textTo experimentally investigate the acoustical behavior of different dual-mode nanosized contrast agents (NPCAs) for echographic medical imaging at low ultrasound (US) frequency
EEG Signal Processing and Acquisition for Detecting Abnormalities via Bio-implantable Devices
No full textThe proposed research illustrates an innovating implantable micro-apparatus to be encompassed under the scalp for
monitoring and retrieving electrical cerebral activities. The illustrated system considers its theoretical realization including, design of
circuital electronic components and energy harvesting, 3D package, chemical aspects concerning the utilization of UHMWPE (Ultra
High Molecular Weight Polyethylene) polymeric materials for packaging including mechanical simulations and comparison with
titanium material, and electromagnetic aspects regarding the Wi-Fi radiation. A full description of necessary circuitry is included. Moreover, for chemical viewpoint, requirements of polymeric nanomaterials, embedding silver or copper nanoparticles to be used for its fabrication, are discussed illustrating antibacterial and electromagnetic wall barrier properties. The study of the proposed work concerns the whole design of the system
Model Simulations and Comparative Evaluations of Susceptibility-based and Gadolinium Contrast Enhancement for High-Resolution Brain Venography
No full textThe MRI signal, in terms of amplitude and phase, was simulated for susceptibility-based brain venography (BV) without
and with administration of contrast agent (CA) under standard clinical parameters and field magnitude of 1.5 T (Tesla). Then, in
order to compare the enhancement due to CA and that one obtained through susceptibility weighted magnitude image (SWI)
processing, exploiting only the intrinsic magnetic susceptibility differences between blood and surrounding tissue, the simulated
signal was processed with a well-known phase masking technique to increase signal differences as a function of tissue type, thus
generating better image contrast. The simulation was carried out adopting a well-established bi-compartmental model, described by
a set of analytical formulas. The based simulated signal was processed with the SWI technique considering a conventional
masking procedure available in literature and a different masking method designed and described in our previous work. The
resulting enhanced signals in terms of image contrast obtained with these two different phase masking procedures and with the
administration of conventional CA were compared. The new designed mask (DM), compared with the conventional one, allows
to get better results in terms of image contrast for all blood volume fractions considered in the simulation. Additionally, better
results can be obtained also with respect to the case of CA administration only. Results from model simulations demonstrate
the effectiveness of masking techniques to improve image contrast regarding all vessel sizes of clinical interest in the high resolution
susceptibility-based brain venography possibly avoiding, in some cases, the need for CA administration
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
Experimental investigations of nonlinearities and destruction mechanisms of an experimental phospholipid-based ultrasound contrast agent
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