1,720,957 research outputs found
External fixation as a definitive treatment for humeral shaft fractures: Radiographic and functional results with analysis of outcome predictors
No full textTo evaluate the results obtained using unilateral external fixation as a definitive treatment for humeral shaft fractures and to identify possible predictors of radiographic and functional outcomes
Evaluation of the structural behaviour of a unilateral external fixator for osteosynthesis
Get PDFBackground: External fixation is an osteosynthesis technique particularly useful in trauma surgery and Damage Control Orthopedics (DCO). However, complications, such as pin loosening and pin tract infections, are fairly common. For reducing thermal damage and infection rates, monocortical pins have been proposed as an alternative to the most used bicortical pins. However, there is a lack of studies regarding their mechanical properties. Objective: The aim of the study is to assess the static and dynamic stability of a unilateral external fixator experimentally when applied through monocortical pins for the reduction of femur and tibia fractures. Methods: A modular unilateral external fixator was used and a total number of 6 pins were used per test. The static tests were performed in displacement control by applying a vertical displacement to the upper fixture at 1 mm/min until a tension load of 380 N was reached. The dynamic tests were performed by applying a sinusoidal displacement. During each test, forces and crosshead displacements were acquired. Two different stiffness indexes were assessed. Results: By comparing the two anatomic regions, it was found that the fixator behaves stiffer when mounted on the femur, regardless of the pins used, while stiffnesses comparable to the femur ones are reached by the tibia when 4 mm diameter pins are used. Static analysis revealed excellent fixator stability when implanted with 4 mm diameter monocortical pins on both anatomic regions. On the contrary, two tibia and one femur samples showed failures at the bone-pin interface when 3 mm diameter pins were used. Conclusion: Dynamic analysis showed no substantial difference between the tested configurations and confirmed the fixator's ability to sustain cyclic loading without further damage to the sample
Cortical bone screws constructive characteristics - A comparative study
Get PDFOsteosynthesis is a surgical technique for the treatment of skeletal fractures through the implant of mechanical devices, such as plates and screws, in order to stabilize and fix the injured skeletal segment. It is preferred to the conservative treatment when the fracture requires immediate surgical correction or when, blocking the joints, degenerative changes could occur. Bone screws have different shapes and sizes depending on the intended use. In this study, six types of cortical bone screws were tested to determine the torque transmitted to the bone during the insertion. One Ti6Al4V tapered (Ø 6 mm) and five AISI 316L stainless steel - two straight (Ø 4 and 6 mm) and three tapered (Ø 4, 5, and 6 mm) - screws were used during the tests. Screws have been screwed into Sawbones (Sawbones® Pacific Research Laboratories, Inc., Vashon, USA) solid foam-type cylinders (external diameter 30 mm and thickness 3.5 mm) simulating the cortical bone diaphysis. Each of the 26 screws tested was inserted in a Sawbone cylinder five times, in five previously drawn equally spaced points, without any pilot holes. The experiment design was based on the ASTM standard for medical bone screws; two experienced orthopedic surgeons performed the insertions and removals of the screws using a hand-drill at 1 rev/s, aided by a metronome, and the torque was measured with a torsiometer throughout the tests. The mean and maximum torque resulted to be higher for larger diameter screws. Considering the same diameter, tapered screws showed a higher torque required for the extraction, which indicates stronger retention. However, in some cases, the Sawbones cylinder was fractured during the insertion of screws with a 6 mm diameter. Therefore, the use of medium-size tapered screws might be the most advisable compromise
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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