1,720,963 research outputs found
Physicochemical properties of nanosized polymeric drug carrier systems
No full textThis chapter is to explore the utilization of biodegradable nanostructured polymers and their associated physicochemical properties in pharmaceutical application. The main hub of the pharma industry is involved in the development of innovative biodegradable and biocompatible polymers that have targeting ability and a predictable release profile of an incorporated active pharmaceutical ingredient or therapeutic agents. Moreover, the pharmaceutical and biological efficiency of the nano-drug delivery system varies with the inherent properties of the polymer. The foremost, important physicochemical properties of biodegradable polymers include molecular weight, hydrophobicity, surface charge, and size. Nevertheless, these properties can be manipulated to modify the kinetics of the delivery system by selecting an optimum polymer (based on physicochemical properties) for a specific purpose
Biodegradable Composite Scaffolds: A Strategy to Modulate Stem Cell Behaviour
No full textThe application of new biomaterial technologies offers the potential to direct the stem cell fate, targeting the
delivery of cells and reducing immune rejection, thereby supporting the development of regenerative medicine. Cells respond
to their surrounding structure and with nanostructures exhibit unique proliferative and differentiation properties.
This review presents the relevance, the promising perspectives and challenges of current biodegradable composite scaffolds
in terms of material properties, processing technology and surface modification, focusing on significant recent patents
in these fields.
It has been reported how biodegradable porous composite scaffolds can be engineered with initial properties that reproduce
the anisotropy, viscoelasticity, tension-compression non-linearity of different tissues by introducing specific nanostructures.
Moreover the modulation of electrical, morphological, surface and topographic scaffold properties enables specific
stem cell response.
Recent advances in nanotechnology have allowed to engineer novel biomaterials with these complexity levels. Understanding
the specific biological response triggered by various aspects of the fibrous environment is important in guiding
the design and engineering of novel substrates that mimic the native cell matrix interactions in vivo
Use of alginate, chitosan and cellulose nanocrystals as emulsion stabilizers in the synthesis of biodegradable polymeric nanoparticles
Get PDFBiopolymeric nanoparticles (NPs) based on a biodegradable poly(dl-Lactide-co-Glycolide) PLGA copolymer matrix combined with alginate, chitosan and nanostructured cellulose crystals as three different natural emulsion stabilizers, were synthesized by a double emulsion (water/oil/water) method with subsequent solvent evaporation. The morphological, thermal, chemical and rheological properties of the novel designed NPs and the effect of the different emulsion stabilizers used during the synthesis were deeply investigated in order to optimize the synthesis procedure and the development of biodegradable nanoparticles coated with natural polymers. The morphological analysis of the produced nanoparticles showed that all the different formulations presented a spherical shape with smooth surface. Infrared spectroscopy investigations showed that the PLGA copolymer maintained its backbone structure and confirmed the presence of chitosan, alginate and cellulose nanocrystals (CNC) on the nanoparticle surface. The obtained results suggest that PLGA nanoparticles with CNC as emulsion stabilizer might represent promising formulations opening new perspective in the field of self-assembly of biodegradable nanomaterials for medical and pharmaceutical applications.Peer Reviewe
Multifunctional nanostructured PLA materials for packaging and tissue engineering
No full textThis review reports the promising prospects of poly(lactic acid) (PLA) based nanostructured materials considering two of their main potential uses, packaging and tissue engineering. The review initially discusses the significant progresses in the development of PLA bionanocomposites for packaging applications. The review then continues with a comprehensive analysis of the recent advances in tissue engineering applications focusing in the synthesis of PLA nanoparticles, the processing of PLA based multifunctional nanocomposites and PLA surface modification techniques. In summary, the review presents the current state of nanostructured PLA materials and establishes the exciting present and future prospects of these materials at the interface of chemistry, biology and material science
Engineering Biodegradable Polymers to Control Their Degradation and Optimize Their Use as Delivery and Theranostic Systems
No full text
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
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