1,720,955 research outputs found
A preliminary study on an innovative soft robotic artificial heart ventricle
No full textIn this work, we describe a soft robotic artificial heart ventricle whose novel pumping strategy is based on the programmable deformation of a fluid-containing and passive soft-shell. During pumping, the soft-shell collapses, showing the formation of inward folds that strongly contribute to the volumetric reduction of the soft-shell, thus to the pumping functionality. Our soft robotic artificial ventricle is a stand-alone system actuated by inverse pneumatic artificial muscles, that are arranged in a helical fashion around the soft-shell. We present a cable-driven soft pump as a study platform for preliminary investigation of the pumping strategy and the requirements for actuation. Three typologies of inverse pneumatic artificial muscles were fabricated and experimentally characterized as candidate actuators for the artificial ventricle. Finally, a ventricle prototype constituted by a soft-shell and an actuating system made of five inverse pneumatic actuators was designed and tested under physiologically relevant conditions of preload and afterload pressure. The experimental results demonstrated that our soft robotic artificial ventricle meets the functional requirements of a right heart ventricle operating in pulmonary circulation
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
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
A self-sensing inverse pneumatic artificial muscle for an actuation system of a soft robotic artificial ventricle
No full textNowadays, cardiovascular diseases, including heart diseases and stroke, are the primary cause of death worldwide. There are different solutions that are clinically available. They can consist of either a pharmacological treatment or a substitution of part or the entire organ, in the most severe cases. Unfortunately, when the transplant is the only solution, the limited availability of donors represents the most incident problem. These issues led to the development of mechanical circulatory support devices, such as ventricular assist devices (VADs), direct cardiac compression devices (DCCs) and Total Artificial Hearts (TAHs). However, due to the presence of rigid mechanical parts that come in contact with blood, commercially available devices present different drawbacks, such us the necessity of long-term blood-thinning medications. Indeed, today there is only one TAH that is FDA approved, but only as a bridge to transplantation therapy. This is mainly due to the fact that they are composed of hard materials and bulky sensors, which makes them not safe to be integrated in a human body. Furthermore, they fail to reproduce the physiological movement of real human heart due to their inflexible structure.
For these reasons, recently, the field of soft robotics has attracted considerable attention. Soft materials, indeed, represent a promising solution to current issues. Being inexpensive, lightweight, and intrinsically safe, they present advantageous characteristics for the development of TAHs and soft cardiac assistive devices. Indeed, softness may improve the adaptability of the system to the human body. To realize active soft devices, it is necessary to employ actuators presenting the same intrinsic nature. Emerging soft actuators enable applications in robotics, health care, haptics, assistive technologies, and many other areas. In this field, Inverse Pneumatic Artificial Muscles (IPAMs) represent a promising technology, especially for the wider motion range compared to traditional positive pneumatic actuators. IPAMs in the state of the art can reach up to 300% of strain. When they are pressurized, they elongate, while, when the pressure is decreased, their return elastic force is exploited for actuation in a reverse mode. To realize a complex and controllable device, a sensorization of the actuation system is needed. Besides self-sensing is a recognized highly desirable property for soft actuators to enable proprioception and to facilitate the soft robot's control, a self-sensing strategy for a soft inverse pneumatic muscle was still missing.
The first objective of this thesis consisted in the optimization of the performances of an inverse pneumatic artificial muscle, that was designed in a previous study. In this initial phase, different prototypes of the IPAM were realized to select the most performant material for the body of the actuator. Their performances have been evaluated in terms of stroke and maximum return elastic force they are able to exert, when the internal pressure is set to 0 bar. The fabrication process reported is easy and makes use of commercial materials and components. The second objective consisted in the realization of the first totally soft Self-sensing Inverse Pneumatic Artificial Muscle (Self-sensing IPAM). In the newly developed Self-sensing IPAM, the reinforcing but compliant element that guides its motion during actuation has not only a mechanical function but, being also electrically conductive, it endows the actuator with self-sensing. To realize it, a polymeric conductive wire was employed. The sensing of the actuator current deformation was possible thanks to the measurement of the resistance variation of the wire with the actuator stretch. The material employed for the realization of the main body of the Self-sensing IPAM was chosen considering its interaction with the polymeric wire. The results of the electro-mechanical characterization experiments performed both on the polymeric wire itself and on the Self-sensing IPAM are presented. In addition, we demonstrate its self-sensing capability in a dynamic setting, by predicting the actuator strain from its electric resistance variation, through a calibration model. Finally, the applicability of the developed IPAM for the realization of the actuating system of a soft robotic artificial ventricle simulator is demonstrated. Moreover, a dimensioning of the actuation layer for both a left and a right artificial ventricle is presented, together with an optimization of the simulator in terms of encumbrance and volume of air needed for actuation
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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