1,720,984 research outputs found
Effect of Bio-Oss with or without platelet-derived growth factor on bone formation by "guided tissue regeneration" : a pilot study in rats
No full textTo investigate the effect of Bio-Oss with and without the local application of recombinant human platelet-derived growth factor (rhPDGF-BB) on bone formation under Teflon capsules.
MATERIALS AND METHODS:
Eight male, 6-month-old, Wistar strain rats were used in the study. In each animal, the lateral aspect of the mandibular ramus was exposed and small perforations were produced in the bone. A rigid, non-porous hemispherical teflon capsule (diameter 7 mm) was placed on the ramus in both sides of the animals. The capsule placed on the one side of the jaw was filled with Bio-Oss granules soaked in a solution of PDGF-BB (20 microg/capsule) and autogenous blood prior to placement. The capsules placed on the other side of the jaw were filled with Bio-Oss granules soaked in autogenous blood only (controls). Four rats were sacrificed after 3 months and the remaining four after 5 months. Undecalcified sections containing the capsule and surrounding tissues were prepared and analysed in the microscope.
RESULTS:
Histologic analysis revealed limited amounts of bone formation. Most of the space underneath the capsules was occupied by Bio-Oss particles surrounded by fibrovascular connective tissue. Given the small sample size statistical analysis was not possible, however, the mean amount of mineralized new bone in the control group (20.8%) appeared to be larger than that in the test group (6.7%). After 5 months the amount of newly formed bone appeared similar in the two groups (23.0% test, 26.0% controls). The Bio-Oss particles occupied between 31.4% and 41.1% of the capsule area at 3 months and between 34.0% and 34.7% at 5 months. Only particles adjacent to the mandibular ramus were incorporated in newly formed bone.
CONCLUSION:
Limited bone formation was present in the capsules grafted with Bio-Oss with or without the growth factor
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
Vertical ridge augmentation with guided bone regeneration in association with dental implants : an experimental study in dogs
No full textAim: To evaluate the effect of using guided bone regeneration (GBR) with a titanium-reinforced e-PTFE membrane in alveolar bone defects with titanium implants. Material and methods: Following extraction of three mandibular premolars and a molar on both sides of the jaw in three dogs, alveolar bone defects (depth: 5-7 mm) were produced. After 4 months, three implants were inserted into each defect to a depth of approximately 4 mm, so that their coronal portion was protruding about 5 mm. Four sides in the dogs were assigned to a test group and the remaining two sides to a control group. The 12 implants in the test group were covered with a reinforced e-PTFE membrane. The space under the membrane was filled with peripheral venous blood from the animal, and the flaps were sutured over the membrane. The six control implants received no membrane before the suturing of the flaps to complete wound closure. The animals were sacrificed after 6 months, and non-decalcified histological specimens of the implants and surrounding tissues were prepared. Results: Histologic and histomorphometric analyses revealed a significantly (Mann-Whitney test; P=0.08) larger amount of bone fill in the test group (mean=57.42%) than in the controls (mean=11.65%), and clinical evaluation of one test site showed that the implants were completely covered with tissue resembling bone. In most of the specimens, bone had grown in height close to, or in direct contact with the membrane. However, the new bone generally was not in direct contact with the implants. Regularly, a zone of dense connective tissue was interposed between the implants and the newly formed bone. Conclusion: The formation of even considerable amounts of bone following vertical ridge augmentation with GBR and implants was not accompanied by predictable osseointegration of the implants
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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