1,720,962 research outputs found
Protective effect of casein phosphopeptide-amorphous calcium phosphate on enamel erosion: Atomic force microscopy studies
No full textThe aim of this study was to investigate the in vitro effect of a casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste (GC Tooth Mousse- TM, GC Corporation, Tokyo, Japan) on preventing enamel erosion, by using Atomic Force Microscopy (AFM). 30 human incisors, were equally assigned to 6 groups: intact enamel, enamel + soft drink, enamel + TM, enamel + TM + soft drink, enamel + soft drink + TM, enamel + soft drink + TM + soft drink. Specimens were observed through atomic force microscopy (AFM). The most common topographical parameters were determined, such as the surface roughness (Rrms ). The use of soft drink on intact enamel has roughened the surface of the sample. The application of the CPP-ACP paste on non-treated enamel made the surface smoother. A significant decrease in roughness was seen after remineralization with CPP-ACP paste. Significant differences were recorded when comparing softened enamel with softened enamel remineralized with CPP-ACP paste. Comparing eroded enamel with demineralized/remineralized specimens, the application of a CPP-ACP paste leads to a significant reduction in roughness values. AFM images of enamel surface treated with CPP-ACP resulted in less morphological changes of the tooth substrate when compared with the only eroded enamel surface morphology; thus, indicating that CPP-ACP paste promoted remineralization. Specimens' surface roughness remained similar regardless that the protective agent is used before or after exposure to coke or between two demineralizing cycles. The results confirmed the effectiveness of the CPP-ACP paste on preventing enamel erosion produced by soft drinks. SCANNING 9999:XX-XX, 2015. © 2015 Wiley Periodicals, Inc
Protective effects of a zinc-hydroxyapatite toothpaste on enamel erosion: SEM study
Full text linkAim. The aim of the present in vitro study was to
evaluate the protective effects of a zinc-hydroxyapatite
toothpaste against an erosive challenge
produced by a soft drink (Coca-Cola) using Scanning
Electron Microscopy (SEM).
Methods. Forty specimens were assigned to 4
groups of 10 specimens each (group 1: no erosive
challenge, no toothpaste treatment, group 2:
erosive challenge, no toothpaste treatment, group
3: erosive challenge, fluoride toothpaste treatment,
group 4: erosive challenge, zinc-hydroxyapatite
toothpaste treatment). The surface of each
specimen was imaged by SEM. A visual rating
system was used to evaluate the condition of the
enamel surface; results were analyzed by nonparametric
statistical methods.
Results. Statistically significant differences were
found between the samples untreated and those
immersed in Coca-Cola (group 1, 2); the highest
grade of damage was found in group 2, while the
lowest grade was recorded in the samples of
group 4. Comparing the groups, the two analyzed
toothpaste tended to protect in different extend.
Conclusions. In this study treatment of erosively
challenged enamel with Zn-Hap toothpaste
showed a clear protective effect. This was greater
than the effect observed for a normal fluoride
toothpaste and confirmed the potential benefit Zn-HAP technology can provide in protecting ena -
mel from erosive acid challenges
Effect of self-assembling peptide P11 -4 on enamel erosion: AFM and SEM studies
No full textThe aim of the present in vitro study was to evaluate the protective effect of self-assembling peptide P11 -4 (CurodontTM Protect/Credentis) on enamel erosion produced by a soft-drink, by using Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM). Thirty human incisors were equally and randomly assigned to 6 groups. Group 1: intact enamel, group 2: soft drink, group 3: Curodont(TM) Protect applied, group 4: Curodont(TM) Protect applied + soft drink, group 5: soft drink + Curodont(TM) Protect applied, group 6: soft drink + Curodont(TM) Protect applied + soft drink. Specimens were observed through atomic force microscopy (AFM). The root mean-square roughness (Rrms) was obtained from the AFM images and the differences in the averaged values among the groups were analyzed by Shapiro-Wilk test in order to assess the normality of the distribution. Parametric ANOVA and post hoc Tuckey test were performed to assess the differences between the different groups. After demineralization process, enamel demonstrated a high degree of surface porosity. This morphological aspect was reflected in the increase of Rrms values. No significant differences (p > 0.05) were reported between intact enamel and enamel only treated with P11 -4 and between eroded enamel and enamel treated with P11 -4 and then demineralized. However significant differences (p < 0.05) were recorded when comparing softened enamel with softened enamel further remineralized with biomimetic self-assembling peptides and enamel treated with the protective paste between two acid attacks. The use of P11 -4 remineralizing may offer a degree of protection from enamel erosion. SCANNING 9999:1-8, 2015. © 2015 Wiley Periodicals, Inc
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
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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