1,721,000 research outputs found
Conventional methods for preparing liposomes of various types (MLVs, LUVs, SUVs) : What, where, how and when
No full textLiposomes are well-established vesicular systems widely investigated as drug carriers. The possibility of loading compounds of different nature and their peculiar biocompatible structure have made them appealing at both academic and industrial level. However, despite the huge number of publications in the literature, less than 50 liposomal formulations are currently available on the market. Indeed, while they may show enormous versatility in administration, depending on their composition, their potential may be hampered by the manufacturing process, which may be time-consuming, non-scalable and/or inefficient in drug loading. With that in mind, this chapter is meant to bring insights on the conventional methods for liposome production adopted by scientists so far, highlighting their advantages and disadvantages. Together with Chapter 22 (Microfluidic methods for liposomes formation) and Chapter 23 (Supercritical fluids and other novel methods for liposome formation), it will provide an overview of the current state of the art in terms of liposome production in small and large batches
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
New lipid nanovesicles as topical delivery sistems for ant-inflammatory drugs
Full text linkThe purpose of the present study was to formulate new vesicular carriers to optimize the topical delivery of anti-inflammatory drugs: diclofenac, quercetin and curcumin.
In the first work concentrated and interconnected penetration enhancer containing vesicles (PEVs) are proposed as carriers for dermal delivery of diclofenac. PEVs were prepared by using a commercial phosphatidylcholine mixture (180 mg/m) and transcutol in different amounts. Conventional liposomes were also prepared and tested as control. All vesicles showed a mean size ranging from 75 to 253 nm with fairly narrow size distribution, negative zeta potential value, and drug loading capacity between 48 and 70%. SWAXS studies showed that composition affected vesicle structure and morphology: 10 and 30% transcutol PEVs were unilamellar while liposomes and 20% transcutol PEVs were multilamellar. Rheological studies demonstrated that control liposomes and 10 and 30% transcutol containing PEVs behaved as Newtonian fluids while 20% transcutol containing PEVs showed a plastic behavior. Ex vivo (trans)dermal delivery experiments showed an improved skin deposition of diclofenac when PEVs were used. Vesicle toxicity and
uptake of fibroblasts, target of inflammation treatment, were evaluated by MTT test and fluorescence
microscopy. Control liposomes and PEVs were both able to interact and being internalized by the 3T3
fibroblasts at all time exposure tested. Furthermore, PEVs showed to be able to reduce the in vitro drug
toxicity.
The aim of the second study was to improve the knowledge of drug–glycol–phospholipid-interactions and their effects in lamellar vesicle suitability as drug delivery systems. Liposomes were prepared using hydrogenated soy phosphatidylcholine (P90H, 60 mg/ml) and diclofenac sodium salt at two con-centrations (5–10 mg/ml). To obtain innovative vesicles two permeation enhancers with glycol group, diethyleneglycol monoethyl ether and propylene glycol, were added to the water phase at different ratios (5%, 10%, and 20%). Vesicle organization was deeply investigated by physico-chemical characterization, including differen-tial scanning calorimetry and small-angle diffraction signal analysis while macroscopic structure behavior was evaluated by rheological studies. Results evidenced that the presence of the penetration enhancer and diclofenac sodium salt led to structural rearrangements within and among vesicles forming a tridi-mensional and complex architecture in which vesicles were closely packed and interconnected. This new design allowed a change in the physical state of dispersions that became highly viscous liquid or soft-solid-like, thus forming an ideal system for topical application able of both adhering to the skin and delivering the drug. © 2013 Elsevier B.V. All rights reserved.
In the last work biocompatible quercetin and curcumin nanovesicles were developed as a novel approach to prevent and restore skin tissue defects on chronic cutaneous pathologies. Stable and suitable quercetin- and curcumin-loaded phospholipid vesicles, namely liposomes and penetration enhancercontaining vesicles (PEVs), were prepared. Vesicles were made from a highly biocompatible mixture of phospholipids and alternatively a natural polyphenol, quercetin or curcumin. Liposomes were obtained by adding water, while PEVs by adding polyethylene glycol 400 and Oramix_CG110 to the water phase. Transmission electron microscopy, cryogenic-transmission electron microscopy and small- and wideangle X-ray scattering showed that vesicles were spherical, oligo- or multilamellar and small in size (112–220 nm). In vitro and in vivo tests underlined a good effectiveness of quercetin and curcumin nanovesicles in counteracting phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) induced lesions and inflammation. Myeloperoxydase activity, used to gauge inflammation, was markedly inhibited by quercetin liposomes (59%) and curcumin liposomes and polyethylene glycol (PEG)-PEVs (_68%). Histology showed that PEG-PEVs provided an extensive re-epithelization of the TPA-damaged skin, with multiple layers of thick epidermis. In conclusion, nanoentrapped polyphenols prevented the formation of skin lesions abrogating the various biochemical processes that cause epithelial loss and skin damage
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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