1,721,279 research outputs found
Maxillary sinus floor augmentation using a nano-crystalline hydroxyapatite silica gel: Case series and 3-month preliminary histological results
No full text
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
Ridge preservation with magnesium-enriched hydroxyapatite: histological evaluation at different time-points
No full textBackground: Ridge preservation has shown to reduce alveolar crest resorption after tooth extraction. Magnesium-enriched hydroxyapatite, due to its chemical properties similar to natural bone, was demonstrated to be suitable for ridge preservation. However, lack of evidence still remains regarding the best timing for implant insertion after grafting.
It has been proven that early vascularization and angiogenesis of the material leads to earlier osteogenesis and provides natural bone quality. Caveolin-1 is a protein found in the plasma membrane of vessels which participates in bone metabolism; thus, Caveolin-1 antibody was considered an ideal marker for angiogenesis.
Aim: To histologically and immunohistologically analyze the early angiogenesis–osteogenesis interplay in post-extraction ridge preservation using Magnesium-enriched hydroxyapatite to better understand the correct timing for implant insertion.
Materials and method: A randomized controlled trial was conducted involving 10 post-extraction sites grafted with Magnesium-enriched hydroxyapatite. Sites were randomly divided in two balanced groups and bone specimens were collected two or four months post-surgery. Sections were stained with hematoxylin/eosin, Masson Goldner trichrome and tartrate-resistant acid phosphatase, respectively. Furthermore, indirect immunohistochemistry was performed using alkaline phosphatase, CD34 and caveolin-1 antibodies. Blind histological and histomorphometric evaluation was undertaken by two independent investigators.
Mean values and standard deviations were calculated for each outcome variable. Data were compared using one way ANOVA test. P < 0.05 was considered statistically significant.
Results: Ten patients (6 female and 4 male; mean age 53.5 ±16.4 years) were recruited; no drop-out occurred. Histomorphometric analysis presented a 5.1 fold increase in regenerated bone between 2 (15.0% ± 3.5) and 4 months (77.4% ± 8.6) post-surgery (P < 0.001). At the same time, a non-significant reduction in graft material was observed from 21.7% to 11.6%, while the area of connective tissue/marrow spaces reduced significantly from 63.3 % to 11 % (P = 0.003). Caveolin-1 expression in vessel-like structures reduced significantly from 645 (±33) to 255 (± 94) (P = 0.008). Changes in CD34 expression from 301 ± 95 to 88 ± 24 (P = 0.046) confirmed these findings.
Conclusions and clinical implications: Within the limits of the present study, histologically it may be concluded that blood vessel density developed in opposite to osteogenesis and that high vascularization after two months could provide a highly accelerated ossification. Thus, clinically, it may be concluded that magnesium-enriched hydroxyapatite is suitable for post-extraction bone crest preservation and ensures early angiogenesis and osteogenesis, suggesting that implant placement could be appropriate even after two months
- …
