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Study of mineral and matrix maturation in dentin
Get PDFSpectroscopic analysis was used to study the patterns of changes in the mineral and matrix properties of dentin during maturation of the tissue. Fourier Transform Infrared Imaging (FTIRI) analyses on undecalcified semi-thin sections from fetal bovine incisors and developing mouse molars were performed. In addition, fetal bovine microdissected mantle and circumpulpal dentin specimens of successive tissue age were analyzed by Fourier Transform Infrared (FTIR) analysis and by amino acid and matrix phosphate assays. In the initial studies, the formation of mantle and circumpulpal dentin as two distinct dentin compartments in the developing fetal incisors was established through analysis of distribution of mineral:matrix and mineral crystallinity values. Changes in the mineral:matrix, mineral crystallinity, acidic phosphate substitution and carbonate substitution in the mineral of mantle and circumpulpal dentin during maturation were subsequently quantitatively analyzed from FTIRI results. In this study, separate patterns of changes in mineral properties were found for mantle and circumpulpal dentin, in terms of initial and final levels and rates of increase or decrease of mineral properties values. Spectroscopic analysis of different maturation stages microdissected mantle and circumpulpal dentin specimens showed a great decrease in the dentin relative water content, affecting the dentin matrix conformation. Chemical analyses of similar microdissected specimens showed a significant increase in the organic phosphate of dentin matrix occurring during maturation. This increase was associated with continuing phosphorylation of existing phosphoproteins without further changes in the protein density. Finally, the study of dentin maturation using 6 day-old mouse molars by FTIRI was validated. Reproducibility in the pattern of changes in the mineral properties examined was found to be highly dependent on the sectioning orienation of molars. It is likely that higher resolution analytical methods and/or slightly older animal age would enhance the analytical outcome in such studies
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
Development Of In Vitro Models To Examine Cell-Mineral Interaction And Cell-Mediated Mineral Formation
Get PDFThe development of hard tissues such as bone and teeth are examples of biomineralization processes in which organisms actively direct mineralization. The formation of hard tissues is a highly regulated process involving the coordination of extracellular matrix production by the cells and the mineralization of the matrix network regulated by proteins secreted by the cells. The formation of these tissues follows a sequence of events in a spatial and temporal manner dictated by cellular processes. In addition to the cells involved in the formation and remodeling of hard tissues, such as osteoblasts (OBs) and osteoclasts (OCs) in bone, other cell-types, such as breast and prostate tumor cells, can interact with bone. Two strategies were taken in this thesis to understand how cells are involved in the mineralization process. Cell culture systems were designed to examine cell-mineral interactions or to examine cell-mediated mineral formation. Chapter 1 discusses the requirements for sustaining cell viability and function as well as the various components involved in designing cell culture systems such as cell source, culture method, and mineral source. Culture systems to study cell-mineral interactions require an environment containing the mineral of interest for cells to be cultured upon. Hydroxyapatite (Ca10(PO4)6(OH)2, HA) is the main mineral component of bone and has been noted to change in size, shape, and crystallinity with age, anatomical location, and disease progression. Chapter 2 describes a two-step method for synthesizing hydroxyapatite nanoparticles with controlled shape, size, and crystallinity in order to evaluate how differences in HA crystal properties can affect cellular response. Three culture systems were developed and described in this work. Two systems were developed to utilize the synthetic hydroxyapatite nanoparticles (prepared in Chap. 2) for examining cell-mineral interactions. In Chapter 3, dry-annealed synthetic and commercial HA particles were combined with polylactide(co-glycolide) (PLG) and spin-coated onto glass substrates to form a film of PLG-HA to examine how changes in crystallinity can affect OB attachment and matrix production. Chapter 4 describes the integration of a series of hydrothermally aged HA nanoparticles into porous PLG scaffolds to examine breast cancer cell response to various HA nanoparticles with discrete sizes. Finally, Chapter 5 details the third system designed for culturing cells in a 3-D gel system that allows for the presence of 1-D gradients to study cell-mediated mineral formation with articular chondrocytes. Due to the breadth of components involved, designing culture systems for mineralization studies are complex and selection of cell source, culture method, and mineral source should be dictated by research questions of interest of particular aspects of these processes (Chapter 1). Chapter 2 demonstrates how controlling for reactant salts, reactant concentration, reaction duration, and reaction volume in the initial precipitation step leads to changes in shape (e.g., rounded to plate-like) and phase (e.g., brushite to HA) while further post-processing techniques can be applied to tune phase, size, crystallinity, and dispersity. Surfaces containing dry-annealed particles increased fibronectin secretion from osteoblasts in Chapter 3, however this response was not due solely to an increase in crystallinity, and other changes to the surfaces due to heat treatment need to be examined. Breast tumor cells in Chapter 4 attached better on scaffolds containing smaller, less crystalline HA, however interleukin-8 (IL-8) secretion was upregulated in cells cultured on scaffolds containing larger, more crystalline HA, indicating IL-8 as a potential factor in facilitating breast cancer tumor metastasis processes. Chapter 5 establishes a 3-D culture system which can support cell viability and matrix production with future work to optimize the system for culturing cells under mineralizing gradients
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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