1,720,960 research outputs found
Lipid-based core-shell nanoparticles: Evolution and potentialities in drug delivery
Full text linkOver the last decade, impressive progress in the field of nanomedicine has led to the development of novel biomaterials and nanotechnology platforms. However, lipid-based nanovectors, i.e. li- posomes, combining safety, versatility and delivery efficiency, remain the most “popular” ap- proach. Lipids, especially charged lipids, have been used to design nanoparticles characterized by a core-shell structure. In these nanoparticles a lipid shell interacts with a core based on different biomaterials. Drugs characterized by a net charge can be condensed in the core, which is then covered by the lipid shell. This approach has been investigated in relation to the delivery of different active molecules, among them macromolecular drug, e.g. nucleic acids, and small molecules, e.g. bisphosphonates. This review reports the progress that has been made in the development of this technology and its potential applications in drug delivery
Spontaneous Arrangement of a Tumor Targeting Hyaluronic Acid Shell on Irinotecan Loaded PLGA Nanoparticles
No full textThe arrangement of tumor targeting hyaluronic acid (HA) moieties on irinotecan (IRIN)-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) has been directed by means of a gradient of lipophilicity between the oil and water phases of the emulsion used to produce the NPs. PLGA constitutes the NP bulk while HA is superficially exposed, with amphiphilic poloxamers acting as a bridge between PLGA and HA. Differential scanning calorimetry, zeta potential analyses and ELISA tests were employed to support the hypothesis of polymer assembly in NP formulations. The presence of flexible HA chains on NP surface enhances NP size stability over time due to an enhanced electrostatic repulsion between NPs and a higher degree of hydration. IRIN in vitro release kinetics can be sustained up to 7-13 days. In vitro biologic studies indicated that HA-containing NPs were more toxic than bare PLGA NPs against CD44-overexpressing breast carcinoma cells (HS578T), therefore indicating their ability to target CD44 receptor
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
DEVELOPMENT OF INNOVATIVE FORMULATIONS BASED ON POLYSACCHARIDES FOR TUMOR TREATMENT
Full text linkThe development of a wide spectrum of new strategies based on controlled drug delivery systems for tumor treatment have attracted a great deal of interest thanks to their ability to encapsulate and control the release of a large array of anticancer drugs and to their targeting ability to many tumor sites. In the last years, the use of polysaccharides for the development of innovative formulations for drug delivery and targeting is rapidly growing. This could be probably attributed to their peculiar properties, such as biodegradability, biocompatibility, large availability as natural source, low cost manufacturing process and to the presence of multiple reactive groups in their structures, which make them suitable for an easy chemical functionalization. In this context, the overall aim of this thesis was to design, produce and characterize innovative formulations based on polysaccharides with potential application in tumors treatment. In particular, in the present thesis, two different strategies were envisaged.
The first one is based on the evidence that chemoattraction through the CXCR4-CXCL12 axis has been shown to be an important mechanism to direct circulating tumor cells toward distant sites. Thus, a fake metastatic niche made up of a gel loaded with CXCL12 was realized. This gel was engineered to create a steep concentration gradient of the chemokine in the proximity of the site of administration/injection thus diverting and capturing the circulating CXCR4+ tumor cells. To this aim, different thermo-responsive gels based on methylcellulose or poloxamers, with or without the polysaccharide hyaluronic acid, were designed, loaded with CXCL12 and their mechanical properties correlated with the ability to attract and capture in vitro CXCR4+ cells.
The second strategy concerned the use of polysaccharides both as structural and coating component for different types of nano-carriers, prepared with simple and easily up-scalable manufacturing process. In this context, two different polysaccharides were investigated, hyaluronic acid and enoxaparin. These polysaccharides, thanks to their ability to recognize and bind specific receptors and growth factors overexpressed in tumor cells, can favor a greater drug accumulation to target sites, thus promoting and improving the selectivity and effectiveness of the chemotherapy. The nano-carriers here investigated are chitosan-based polyelectrolyte complexes, poly (lactic-co-glycolic acid) polymeric nanoparticles and self-emulsifying drug delivery systems
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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