1,721,002 research outputs found
Computational Vascular Fluid Dynamics: Problems, Models and Methods
No full textIn the cardiovascular system, morphology and functionality are closely related. Altered flow conditions play an important role in the development of arterial disease. In turn, these flow conditions are modified by arterial wall changes. A detailed understanding of the local hemodynamic environment, the influence of wall modifications on flow patterns and the long-term adaptations of the vascular wall after surgical procedures can have useful clinical applications, especially in view of reconstruction and revascularization operations. Some of these alterations are not well-understood, making it quite difficult to foresee short- and long-term evolution of the atherosclerotic disease and to plan an aggressive approach. Computational fluid dynamics (CFD) allows the carrying out of simulations at low cost and in completely controlled conditions. Three different issues are relevant to this subject and are addressed in this paper: (1) the definition of suitable mathematical models; (2) pre-processing of clinical data; and (3) the development of appropriate numerical technique
Bassini and the vanished art of pure tissue inguinal hernioplasty
No full textL.A. Danto, in a communication published in this journal,
1 denounced the potential danger of all those surgical
strategies meant to prevent the chronic inguinodynia arising
after an inguinal hernia repair with the use of a prosthetic
mesh, and the almost complete abandon of the traditional
inguinal hernioplasty. As reported in many series, the incidence
of postoperative inguinodynia is not the only increased
complication after mesh hernioplasty. The nature
and properties of the prosthetic material pose in fact a high
risk of complications as protrusion, extrusion, infection and
intestinal fistulization, and most importantly, once in place,
is rigid, passive, adynamic, and aphysiological. In turn, this
increase in complications seems not to have been counterbalanced
by a long-lasting decrease in the recurrence rate.2
Assumed as standard of care, the mesh placement distorted
the fundamental principles of surgery, and shifted
inguinal hernia from a disease itself to a risk factor. Surgery
of inguinal hernia is in fact becoming surgery of prevention
of complications from mesh placement, forgetting that the
mesh itself is the main complication of the hernia surgery.
Surgery remains an art technically based on 4 principles:
what is united is separated (dieresis); what is separated is
united (synthesis); what is exceeding is removed (exeresis);
and what is missed is added (prosthesis). The use of prosthetic
materials has thus its main indication in case of lack
of tissue to prevent recurrence. Bassini, following these
basic principles, showed that in most patients this lack of
tissue is only apparent, and that surgery of hernia is a
surgery of synthesis and not of prosthesis. He showed that
the mobilization and the use of the musculoaponeurotic
triple layer for the repair is sufficient and effective.3,4 His
astonishing results (2% of recurrences) 100 years ago show
the way of the future and offer a valid alternative to the use
of mesh.
With this indiscriminate use of prosthetic materials arises
also an important bioethical problem. The goal of medicine
is beneficence. The first step to reach this goal is “primum
non nocere” (nonmaleficence).5 It is also well known that
there are several situations in medicine where decisions
cannot be made without the risk of inflicting some burden to
patients. This does not seem to be the case with inguinal
hernioplasty. In fact, most of the procedures can be performed
with cooptation of viable tissue (synthesis) without
the insertion of a foreign body (prosthesis). Unfortunately, it
seems that many surgeons have forgotten the surgical principles
of Parè, thus failing to reach the real goal at stake: the
good of the patient
Numerical Modeling of 1D Arterial Networks Coupled with a Lumped Parameters Description of the Heart
No full textBlood Flow Simulations on Reconstructed geometries and Comparison with MRI Velocity Data.
No full textMeasurable models of abdominal aortic aneurysms on the web
Full text linkIn this paper we describe a method for 3D reconstruction and web distribution of vessel structures specifically designed to allow the remote measurement of parameters of surgical interest. Deformable models are used for segmentation, while VRML and ECMA scripting are used to obtain 3D models that are not only viewable from any VRML97 enabled browser, but that also allow users to interact with the model, navigate along the vessel lumen and perform guided measurements of distance and angles
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
Ethics of ambiguity and the formation of the subject in contemporary society
No full textIl saggio è una riflessione sull'idea dell'etica dell'ambiguità elaborata dalla filosa francese Simone de Beauvoir. Obiettivo del saggio è analizzare la rilevanza dell'etica dell'ambiguità per la formazione del soggetto.The essay is a reflection on simone de Beauvoir's idea of ethics of ambiguity to verify its relevance to the formation of subjectivity in contemporary society
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
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