1,721,043 research outputs found
Mechanical squeezing of an elastomeric nanochannel device: numerical simulations and ionic current characterization
No full textPeculiar transport phenomena appear at nanoscale,
since surface effects strongly affect the behaviour of
fluids. Electrostatic and steric interactions, capillary forces
and entropic effects play a key role in the behaviour of
fluids and biomolecules. Since these effects strongly
depend on the size of the nanofluidic system, a careful
characterization of the fluidic environment is necessary.
Moreover, the possibility to dynamically modulate the size
of nanochannels is very appealing in the field of biomolecule
manipulation. Recently, we have developed a lab-onchip
made of poly(dimethylsiloxane) (PDMS). This polymeric
device is based on a tuneable nanochannel able to
dynamically change its dimension in order to fit the
application of interest. In fact, a mechanical compression
applied on the top of the elastomeric device squeezes the
nanochannel, reducing the channel cross section and
allowing a dynamical optimization of the nanostructures. In
this paper, this squeezing process is fully characterized
both numerically and experimentally. This analysis provides
information on the reduction of the nanochannel
dimensions induced by compression as a function of the
work of adhesion and of the stiffness of the materials
composing the device. Moreover, calculations demonstrate
the possibility to predict the change of the nanochannel size and shape induced by the compression. The possibility to
dynamically tune the channel size opens up new opportunities
in biomolecular sensing or sieving and in the study of
new hydrodynamics effects
A novel scaffold geometry for chondral applications: Theoretical model and in vivo validation
No full textA theoretical model of the 3D scaffold internal
architecture has been implemented with the aim to predict
the effects of some geometrical parameters on total porosity,
Young modulus, buckling resistance and permeability of the
graft. This model has been adopted to produce porous polycaprolacton
based grafts for chondral tissue engineering
applications, best tuning mechanical and functional features
of the scaffolds. Material prototypes were produced with an
internal geometry with parallel oriented cylindrical pores of
200mm of radius (r) and an interpore distance/pores radius
(d/r) ratio of 1. The scaffolds have been then extensively
characterized; progenitor cells were then used to test their
capability to support cartilaginous matrix deposition in an
ectopic model. Scaffold prototypes fulfill both the chemicalphysical
requirements, in terms of Young’s modulus and
permeability, and the functional needs, such as surface area
per volume and total porosity, for an enhanced cellular
colonization and matrix deposition. Moreover, the grafts
showed interesting chondrogenic potential in vivo, besides
offering adequate mechanical performances in vitro, thus
becoming a promising candidate for chondral tissues repair.
Finally, a very good agreement was found between the
prediction of the theoretical model and the experimental
data. Many assumption of this theoretical model, hereby
applied to cartilage, may be transposed to other tissue
engineering applications, such as bone substitutes
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
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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