1,721,003 research outputs found
PROBE MOLECULES LOADING INTO RED CELLS TROUGH HYDRODYNAMIC FOCUSING: A COMPUTATIONAL EVALUATION - Oral presentations - XLII Annual ESAO Congress, 2-5 September 2015, Leuven, Belgium
No full textIntroduction: This work aims at studying the fluid-dynamic conditions allowing
the encapsulation of probing molecules (PM) into Red Blood Cells (RBCs)
by applying shear stresses (τ) on their membrane. Indeed, it is well-known
in the literature that this process enhances the opening of the pores, thus
allowing the diffusion of solutes. In our microdevice τ were applied through
a single passage in a sheath flow focuser, designed to drift the cells to a controlled
τ solicitation zone.
Material and methods: A computational model using Comsol Multiphysics
was developed; the geometry is a cross-shaped microchannel (MC) with
50*50 μm cross-section and 87 mm length. Velocity (v), volume fraction of
dispersed phase (rd) and τ for a suspension of RBCs and PM (FITC-Dextran) in
a Phosphate Buffer were evaluated, varying the flow rate of RBCs suspension
(Qb), sheath flow (Qf) and Ht. When the pair of τ values and time results subhaemolytic
(according to Tillman Diagram (TD)), and the RBCs transit time is
higher than the time required for PM diffusion into RBCs, encapsulation can
be promoted. A dedicated efficiency index was used to evaluate the flow
conditions (v, rd, τ) that are thought to increase the encapsulation rate.
Results: Taking into account the efficiency index, the position on TD and the
overall pressure drop, suitable fluid-dynamics conditions were: Qb = 40 μl/
min, Qf = 7 μl/min, PM 2 mM for Ht = 5% or Qb = 33 μl/min, Qf = 5,5 μl/min,
PM 4 Mm, and Ht = 10%. In these conditions the area occupied by RBCs is the
75% of the channel section. The resistance of the MC and their connections
to the pumping system to the high pressure evaluated through CFD (respectively
of 4 and 3 atm) was verified.
Discussion: The model allows the characterization of RBCs fluid-dynamic in
simple microfluidic devices and to identify the optimal conditions to promote
PM encapsulation. This model will be used to define appropriate test conditions
Shear-promoted drug encapsulation into red blood cells: a CFD model and μ-PIV analysis
Full text linkThe present work focuses on the main parameters that influence shear-promoted encapsulation of drugs into erythrocytes. A CFD model was built to investigate the fluid dynamics of a suspension of particles flowing in a commercial micro channel. Micro Particle Image Velocimetry (μ-PIV) allowed to take into account for the real properties of the red blood cell (RBC), thus having a deeper understanding of the process. Coupling these results with an analytical diffusion model, suitable working conditions were defined for different values of haematocrit
Modular implant design affects metal ion release following metal-on-metal hip arthroplasty: a retrospective study on 75 cases
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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
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