1,720,954 research outputs found
Gibt es einen Einfluss von Knochenersatzmaterialien auf die Anzahl der Osteozyten?
No full textHypothese: Osteozyten, die im Knochen am häufigsten vorkommenden Zellen, spielen eine zentrale Rolle beim Knochenumbau. Ihre Bedeutung bei der Knochenregeneration ist jedoch weitgehend unklar. Die Konsolidierung von Knochenersatzmaterialien im Rahmen einer Sinus-Augmentation basiert auf dem Prinzip der Knochenregeneration.
Diese wird von den Knochenersatzmaterialien beeinflusst. Es wäre daher denkbar, dass sich dieser Einfluss auch in einer veränderten Anzahl und Form der Osteozytenlakunen widerspiegelt.
Methodik: Wir versuchten herauszufinden, ob die beiden Knochenersatzmaterialien "Ostim®" (resorbierbar) und "Bio-Oss®" (nicht-resorbierbar) die Entstehung von Osteozyten beeinflussen.
Ausgehend von bereits bestehenden histologischen Schliffen wurden nach einem Sinuslift im Minischweinekiefer Anzahl und Form der Osteozytenlakunen im neugebildeten Knochen bei sechs und zwölf Wochen erhoben.
Ergebnisse: Zwischen Bio-Oss® und Ostim® konnte weder bei sechs (Bio-Oss®: 1852,4 299,4 und Ostim®: 1585,2 154) (p =0,101) noch bei 12 Wochen (Bio-Oss®: 1361,8 245,4 und Ostim®: 1084,4 154,1) (p = 0,091) ein signifikanter Unterschied in der Anzahl der Osteozytenlakunen gezeigt werden. Der Unterschied der medianen absoluten Osteozytenlakunenfläche zwischen den beiden Gruppen war zum Zeitpunkt sechs Wochen [Bio-Oss®: 58,7 (30,6 - 97,2) und Ostim®: 58,1 (31,1 - 102,1)] statistisch nicht signifikant (0,120). Hingegen konnte zwischen beiden Gruppen bei 12 Wochen ein signifikanter Unterschied (p = 0,000) in der medianen absoluten Osteozytenlakunenfläche festgestellt werden.
Bio-Oss® [46,3 (28,1 - 69,1)] zeigte im Vergleich zu Ostim® [56,3 (31,44 - 95,14)] eine signifikant verminderte mediane absolute Osteozytenlakunenfläche.
Konklusion: Unsere Ergebnisse deuten darauf hin, dass Knochenersatzmaterialien die Größe der Osteozytenlakunen verändern, während die Anzahl der Osteozytenlakunen gleich bleibt. Dies könnte bedeuten, dass sich die Unterschiede in den beobachteten Parametern in einem veränderten Reifungsgrad des Geflechtknochens während der Einheilung des Transplantats widerspiegeln.Hypothesis: Osteocytes, the most common cells of the bone, have a central role in bone remodeling. Their role in bone regeneration, however, is unknown. We can postulate that changes in bone formation result in altered numbers of osteocytes lacunae and altered areas of the osteocytes lacunae. Consequently, bone substitutes having an impact on bone formation should result in altered numbers of osteocytes lacunae and altered areas of the osteocytes lacunae, as well.
Materials and methods: We investigated the possible impact of bone substitutes - resorbable and non-resorbable materials - on the number and area of osteocytes lacunae in the augmented sinus. Therefore we re-evaluated histological specimens, six and twelve weeks after the sinus of mini-pig jawbone was augmented with Bio-Oss®, a deproteinized bovine bone mineral, and Ostim®, an aqueous paste of synthetic nanoparticular hydroxyapatite. The number of osteocytes lacunae and the area of the corresponding lacunae within areas of woven bone were determined.
Results: The number of osteocytes lacunae in woven bone was similar between the two groups after six weeks: 1852.4 299.4 in the Bio-Oss® group and 1585.2 154 in the Ostim® group (p =0.101). There was also no significant difference in the number of osteocytes after 12 weeks:
1361.8 245.4 in the Bio-Oss® group and 1084.4 154.1 in the Ostim® group (p = 0.091). After six weeks the median area of the osteocytes lacunae was similar in both groups: 58.7 (30.6 - 97.2) in the Bio-Oss® group and 58.1 (31.1 - 102.1) in the Ostim® group (p = 0.120). The median area of the osteocytes lacunae was significantly higher for the Ostim® group with 56.3 (31.4 - 95.1) than in the Bio-Oss® group with 46.3 (28.1 - 69.1) at 12 weeks (p = 0.000).
Conclusion: In conclusion, these results suggest that bone substitutes alter areas of the osteocytes lacunae, while the number of osteocytes lacunae remains unchanged. Thus, the observed difference in analyzed parameters might reflect progress in maturation of woven bone during graft consolidation.eingereicht von Gerd PfingstnerAbweichender Titel laut Übersetzung der Verfasserin/des VerfassersZusammenfassung in engl. SpracheWien, Med. Univ., Dipl.-Arb., 2011(VLID)171608
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
Osteocyte lacunar density and area in newly formed bone of the augmented sinus
No full textOBJECTIVES
Osteocytes, the most common cells of the bone, are buried in lacunae. Density and area of the osteocyte lacunae change with increasing maturation of the newly formed bone. Evaluation of osteocyte lacunae can therefore provide insights into the process of graft consolidation.
MATERIALS AND METHODS
Here, we determined the osteocyte lacunar density (number of osteocyte lacunae per bone area; N.Ot/BAr) and the osteocyte lacunar area in μm(2) (Lac.Ar) in histological specimens 6 and 12 weeks after the sinuses of 10 minipigs were augmented with Bio-Oss(®) , a deproteinized bovine bone mineral, and Ostim(®) , an aqueous paste of synthetic nanoparticular hydroxyapatite. The region of interest was defined by the following criteria: (i) >1 mm from the host bone, (ii) >0.5 mm from the sinus mucosa, (iii) minimum area of 0.2 mm(2) , and (iv) bone tissue spanning at least two bone substitute particles.
RESULTS
The overall osteocyte lacunar density was significantly higher in the Bio-Oss(®) group than in the Ostim(®) group and decreased during the observation period at a similar range in both groups. The osteocyte lacunar area was smaller in the Bio-Oss(®) group than the Ostim(®) group but there was no significant change within the groups over time.
CONCLUSIONS
These results suggest that bone substitutes affect the osteocyte lacunar density and the osteocyte lacunar area in the newly formed bone within the augmented sinus in this particular model situation. These measures can provide insights into the maturation of newly formed bone in the augmented sinus
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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