1,720,981 research outputs found
Characterization of water soluble dendrimer formulations of an insoluble thiocarbamate derivative with moderate anti HIV-1 activity: an overview
No full textDrug delivery is an engineered technology focused on the development of Drug Delivery Systems (DDSs) able to transport, release and maintain for long time the useful load of therapeutics in the body as needed for safe playing out the desired therapeutic effects. Nanosized dendritic polycationic polymers such as commercially available PAMAMs, are the most exploited materials for preparing smart DDSs, but unfortunately, the excessive cationic feature of the inner framework results in a high level of cytotoxicity. Nowadays, not charged amino acid-modified dendrimer scaffolds are considered as better solutions. These dendrimers have a more controlled number of nitrogen atoms and can be protonated at physiological pH. In order to improve the water solubility of the thiocarbamate non-nucleoside HIV-1 reverse transcriptase inhibitor 1 (Figure 1)1 five prodrugs were prepared by its entrapment inside not PAMAM amino acids-modified core-shell hydrophilic2 (Figure 2) and amphiphilic3 (Figure 3) dendrimers. As detailed in this communication an overview, organized in tables, graphs and NMR spectra of the physicochemical properties which identified obtained dendriplexes (DPXs) was provided. As estimated by NMR analysis, DPXs showed good load capacity. Mean size of their particles is suitable for avoiding rapid renal clearance while the release profile of the drug is favourable to a low spreading of drug in blood and to a massive release only within the cell. DPXs are soluble in water, EtOH and MeOH, have proper but not excessive cationic character and an optimal buffer capacity for enhanced cellular up take and pH-responsive endosomal escape once inside the cell. References: [1] A. Spallarossa, A. Ranise, et al., Eur. J. Med. Chem. 2009, 44, 1650-1663. [2] S. Alfei, S. Catena, 2018, submitted to Polym. Advan. Technol. 2018: https://doi.org/10.1002/pat.4396. [3] S. Alfei, S. Catena, 2018, submitted to Polym. Int. 2018, https://doi.org: 10.1002/pi.5680
Hydrophilic and amphiphilic water-soluble dendrimer formulations of a not-soluble thiocarbamate derivative with moderate anti HIV activity for biomedical applications.
No full textThe engineered technology known as Drug delivery concerns the approaches, formulations, technologies and systems for transporting therapeutics in the body and delivering them as needed. Advanced controlled Drug Delivery Systems (DDSs) able to release an effective load of drug and to maintain its concentration for long time in a limited area around the target site have been developed. These “smart” DDSs allowed to reduce dosages, administrations frequency and drugs toxicity and to improve therapeutic efficacy. Nanosized and dendritic polycationic polymers such as PAMAMs are the most exploited materials for getting advanced smart DDSs and can covalently bind or encapsulate drugs. However, the high number of protonable nitrogen atoms widespread on the whole matrix involves high cytotoxicity. The modern research is increasingly oriented towards the use of not charged dendrimer scaffolds decorated with biocompatible amino acids protonable at physiological pH. Thiocarbamate 1 (Figure 1) is a non-nucleoside HIV-1 reverse transcriptase inhibitor (EC50 = 27 μM) characterized by a free carboxylic group and endowed with poor water solubility.1 With the aim at improving both its solubility and activity, derivative 1 was physically incorporated inside not-toxic amino acid-modified core-shell hydrophilic (2,3)2 and amphiphilic (4-6)3 dendrimers. The encapsulation procedure is a straightforward protocol that involves stirring derivative 1 and the starting dendrimer at r.t. in methanol (Figure 1). The obtained dendriplexes (DPXs 7-11) showed a very good DL%, a proper particle size, an adequate buffer capacity and above all were well soluble in water. Therefore, they represent an appealing and promising crew of new smart DDSs for safe in vivo clinical administrations of 1.
References:
[1] A. Spallarossa, A. Ranise, et al., Eur. J. Med. Chem. 2009, 44, 1650-1663.
[2] S. Alfei, S. Catena, 2018, submitted to Polym. Advan. Technol. 2018: https://doi.org/10.1002/pat.4396.
[3] S. Alfei, S. Catena, 2018, submitted to Polym. Int. 2018, https://doi.org: 10.1002/pi.5680
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
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
Unexpected behaviour of the methoxymethoxy group in the metalation reactions of 3-methoxymethoxyanisole
No full text- …
