1,720,957 research outputs found
Effect of Porous Microstructures on the Biomechanical Characteristics of a Root Analogue Implant: An Animal Study and a Finite Element Analysis
No full textBackground: Full ceramic or metal custom-made root analogue implants (RAIs) are made by replicating the natural tooth geometry. However, it may lead to the stress shielding of the surrounding bone, and an RAI is unable to easily achieve primary stability. Therefore, to improve primary stability and reduce stress shielding, RAI porous structures are proposed. The purpose of this study was to evaluate the effect of porous microstructures on the biomechanical characteristics of the custom-made RAT. Methods: Porous and bulk titanium cylinders and porous RAI and conventional implants for in vivo tests were fabricated using a selective laser melting (SLM) technology. The elastic modulus and the compressive strength of porous titanium cylinders were evaluated. These samples were then implanted into rabbit femurs (cylinders) and beagle dog mandibles (RAI and conventional implants). A simplified three-dimensional geometry of the anterior maxilla of a patient was constructed. Then, based on the extracted standard template library (STL) data, five different RAI models were constructed: (A) smooth surface, (B) pit surface, (C) bulb surface, (D) threaded surface, and (E) porous surface. A conventional implant model was also constructed. A static load of 100 N was applied to the crown in the multivectoral direction. Results: The results of the in vivo experiment confirmed that the porous structure decreased the elastic modulus of Ti6AI4V. Additionally, the implantation of the porous custom-made RAIs resulted in increased new bone ingrowth and decreased bone resorption compared to conventional implants. Moreover, the 3D finite element analysis suggested that the bone surrounding porous custom-made RAIs was subjected to a more uniform stress distribution, and the strain values of the surrounding bone were more conducive to bone formation. Conclusion: Based on these findings, a custom-made RAI with a porous surface accelerates bone formation and might reduce the stress-shielding effect
Hydraulic conductivity of whole root system is better than hydraulic conductivity of single root in correlation with the leaf water status of maize
No full textUnder hydroponic culture conditions, we studied the relationship between two different types of root hydraulic conductivity of maize (Zea mays L.) and its leaf water status. The results have proved the inaccuracy of the single root hydraulic conductivity (Lp(sr)) to describe the ability of water uptake by maize roots, which can be better described by the whole root systems hydraulic conductivity (Lp(wr)). Moreover, Lp(wr) can be measured easier. Although the whole roots surface area (WRA), which integrated all the root characters, such as root dry weight, volume and length, represent the interaction between root and soil (or water in soil solutions) better, there is no significant relationship between WRA and Lp(wr), and leaf water potential because part of the roots has no activity for water uptake. However, active root surface area (ARA) truly reflects the level of root metabolic activity and root function efficiency, i.e., the ratio of the active roots to the whole roots. Hence, ARA has a significant linear correlation with Lp(wr). Because of the high plasticity of plant root systems architecture and metabolism under changed water and nutrition conditions, the relationship between single root Lp(sr) and whole root Lp(wr) and between WRA and ARA are not positively linear correlated. Results demonstrate that the whole root Lp(wr) described by ARA can reflect more accurately both the water uptake by plant roots and the leaf water status than the single root Lp(sr)
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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