1,720,981 research outputs found
The development of novel PVA hydrogel for biomedical and drug delivery applications
Full text linkHydrogels have been used widely in biomaterial applications, mainly due to their low interfacial tension, useful swelling properties and high lubricity. In addition to their promising biocompatibility characteristics, certain hydrogels are desirable in the biomedical field due to their sensitivity to the physiological or biological environment where they are used. There are many current applications for hydrogels, and this includes 8,000 different kinds of medical devices and 40,000 different pharmaceutical preparations. This research aims to develop and characterise the physically cross-linked PVA hydrogels with different sizes range from centi- to micro- to nano- meter in macroscopic, microscopic and nanoscopic viewpoint for drug delivery applications (Figure 1). Freeze-thawing and thermal annealing were the physical crosslinking methods used to prepare the PVA hydrogels. Water-soluble drugs (i.e. caffeine, doxorubicin hydrochloride, propolis extract) and poorly water-soluble drugs (i.e. ciprofloxacin, clarithromycin) were incorporated into these PVA hydrogels to study their drug release kinetics.
In the macro point of view, although freeze-thawed hydrogels have been deeply studied in the literature, uniaxial stretching hydrogels in between freeze-thawing cycles could further improve its mechanical properties. It suggested that the orientated PVA hydrogel provided an immediate full caffeine release in 15-20 min. Furthermore, PVA hydrogel was made into spheres to increase its surface area. The PVA spheres provide an immediate full ciprofloxacin or caffeine release within 60 min. Both orientated PVA hydrogels and PVA spheres followed Hixson-Crowell release kinetics and were found to be non-toxic to NIH 3T3 fibroblast cells.
The field of biomedical applications for hydrogels required the development of nanostructures with specific controlled diameter and mechanical properties. Nanofibres were ideal candidates for these advanced requirements, and one of the easiest techniques that can produce nanostructured materials in fibrous form was the electrospinning process. Electrospinning demonstrated extreme versatility, allowing the use of different polymers for tailoring properties and applications. The thermal annealed PVA/PAA bilayer nanofibres gave a dual drug delivery of clarithromycin and doxorubicin hydrochloride for osteosarcoma treatment. The U2OS osteosarcoma cells viability was effectively decreased with the combination of both drugs. Furthermore, the freeze-thawed PVA+propolis nanofibres showed a bi-phasic drug release with an initial burst drug release in first 30 min and followed by a much slower release for 8 h.
Finally, all these novel hydrogels have the potential to be produced as new commercialise products in biomedical area mainly in drug delivery applications because of their tunable hydrogel preparation process, intrinsic biocompatible and non-toxic characteristics
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
Electrospun natural polysaccharide for biomedical applications.
Full text linkElectrospinning is a simple and versatile technique in nanotechnology for fabricating nanofibers scaffolds for tissue regenerations, drug delivery systems, wound healing, and cancer therapy. This chapter provides a synopsis and overview of using various type of natural polysaccharides from human, animals, plants, seaweeds and microbe origins for electrospinning. The electrospun natural polysaccharide nanofibers are widely used in the biomedical fields due to their biocompatibility, high porosity, large surface area-to-volume, improved drug encapsulation and excellent cell proliferation. The topics presented in this book chapter are focused on illustrating the chemical structures of several natural polysaccharides from different origins. In addition, an outline is present of previous research activities and the potential biomedical applications of these electrospun natural polysaccharide nanofibers. The electrospinning of solely polysaccharides present challenges because of chain entanglements and viscosity, so it is essential to blend with other natural and synthetic polymers to overcomes these aspects.ye
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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