1,720,984 research outputs found
Nanomaterials and scaffolds for tissue engineering and regenerative medicine
No full textTissue engineering and regenerative medicine have caused a revolution in biomedicine over the past decade; the fabrication of tissue substitutes in the laboratory is now possible by using various cells, biomaterial scaffolds, and bioactive molecules. With the advent of nanotechnology, it has become possible to manufacture tissue-engineered constructs with the ability to improve cellular functions and subsequently accelerate tissue healing. Nanoscale materials are currently being used in diverse tissue-engineering applications, including the fabrication of three-dimensional scaffolds and the delivery of therapeutic molecules and drugs. Moreover, the surface modification of tissue-engineered constructs by applying nano-topographies is recognized as an effective strategy to elicit desirable biological responses, including better cell attachment and proliferation. Similar to other new technologies, the health benefits and risks of nanotechnology should be carefully evaluated before its extensive use and regulations and guidelines are needed. In this chapter, we have tried to present briefly the current state and progress of nanotechnology-assisted tissue engineering and regenerative medicine in the biomedical setting
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
Hydroxyapatite (HAp) nanoparticles: Promises in cancer diagnosis and therapy
No full textHydroxyapatite (HAp) nanoparticles have recently achieved a unique position in cancer diagnosis and therapy (theranostics). In vitro experiments have shown that HAp nanoparticles can enter tumor cells and cause programmed cell death (apoptosis). To improve the anticancer effects of HAp nanoparticles, bioengineers and biomedical scientists incorporate particular elements (e.g., iron (Fe)) into theranostic HAp nanoparticles. Accordingly, HAp nanoparticles can be employed in different cancer therapy approaches like photothermal therapy and photodynamic therapy, either alone or in combination with other materials (e.g., biopolymers). Moreover, HAp nanoparticles can serve as suitable vectors for targeted delivery of anticancer chemicals and drugs. Adding some elements, such as gadolinium and europium, to the HAp composition makes it a suitable imaging agent for bio-imaging applications like magnetic resonance imaging. Various surface modifications can be applied to improve the biocompatibility of HAp nanoparticles and prevent their aggregation. In addition, targeted therapy seems possible with HAp nanoparticles having the surface modified with specific ligands (e.g., anti-Herceptin antibody). In conclusion, HAp nanoparticles are showing great promise in cancer theranostic strategies; however, doing animal and clinical trials is suggested as a key step forward to take benefit from these stunning materials
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
Antioxidant Effects of Bioactive Glasses (BGs) and Their Significance in Tissue Engineering Strategies
Get PDFElevated levels of oxidative stress are usually observed following injuries, leading to impaired tissue repair due to oxidation-related chronic inflammation. Several attempts have been made to manage this unfavorable situation, and the use of biomaterials with antioxidant activity is showing great promise in tissue engineering and regenerative medicine approaches. Bioactive glasses (BGs) are a versatile group of inorganic substances that exhibit an outstanding regenerative capacity for both hard and soft damaged tissues. The chemical composition of BGs provides a great opportunity for imparting specific biological activities to them. On this point, BGs may easily become antioxidant substances through simple physicochemical modifications. For example, particular antioxidant elements (mostly cerium (Ce)) can be added to the basic composition of the glasses. On the other hand, grafting natural antioxidant substances (e.g., polyphenols) on the BG surface is feasible for making antioxidant substitutes with promising results in vitro. Mesoporous BGs (MBGs) were demonstrated to have unique merits compared with melt-derived BGs since they make it possible to load antioxidants and deliver them to the desired locations. However, there are actually limited in vivo experimental studies on the capability of modified BGs for scavenging free radicals (e.g., reactive oxygen species (ROS)). Therefore, more research is required to determine the actual potential of BGs in decreasing oxidative stress and subsequently improving tissue repair and regeneration. The present work aims to highlight the potential of different types of BGs in modulating oxidative stress and subsequently improving tissue healing
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