1,720,959 research outputs found
L-nucleosides
No full textThis chapter provides an overview concerning the synthesis of L-nucleosides and their analogues. The first section deals with L-nucleosides, which maintain a close relationship with ribose and deoxyribose derivatives. The second section covers furanose nucleosides without the 2′ and 3′ hydroxyl groups. The third section talks about carbovir, which has been reported as the first carbocyclic nucleoside analogue, with potent anti-HIV activity in vitro; its discovery provided a base for the synthesis of other carbocyclic analogues. Among all types of aza-nucleosides, five-membered pyrrolidine-type nucleosides have been investigated particularly because of their high similarity with naturally occurring nucleosides. Next, the chapter talks about the thionucleosides. Several purine and pyrimidine-L-dioxolane nucleosides have been reported using the acetoxy dioxolane 370 as a glycosyl donor for condensation under classical Vorbrüggen conditions. The final section talks about the oxathiolanyl nucleosides
Labeling Deoxyadenosine for the Preparation of Functional Conjugated Oligonucleotides
No full textHerein we present a versatile synthetic method for the 8-thioalkylation of (deoxy)adenosine with a short carbon linker having on the other side a variety of mols. (psoralen, acridine) and functional groups (alkyne). After conventional protections, the modified adenosine can be phosphytylated and inserted into an oligonucleotide without affecting the std. protocols for supported oligonucleotide synthesis. The hybridization properties of a generic oligonucleotide contg. the above conjugated moieties toward both DNA and RNA are evaluated both in the case of a perfectly complementary strand and in the case of a single mismatch. This methodol. is suitable for the prepn. of several types of derivs. and-through the alkynyl moiety-provides fast access to click-chem. transformations
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
Synthesis and exon‐skipping properties of a 3′‐ursodeoxycholic acid‐conjugated oligonucleotide targeting dmd pre‐mrna: Pre‐synthetic versus post‐ synthetic approach
No full textSteric blocking antisense oligonucleotides (ASO) are promising tools for splice modulation such as exon‐skipping, although their therapeutic effect may be compromised by insufficient delivery. To address this issue, we investigated the synthesis of a 20‐mer 2′‐OMe PS oligonucleotide conjugated at 3′‐end with ursodeoxycholic acid (UDCA) involved in the targeting of human DMD exon 51, by exploiting both a pre‐synthetic and a solution phase approach. The two approaches have been compared. Both strategies successfully provided the desired ASO 51 3′‐UDC in good yield and purity. It should be pointed out that the pre‐synthetic approach insured better yields and proved to be more cost‐effective. The exon skipping efficiency of the conjugated oligonucleotide was evaluated in myogenic cell lines and compared to that of unconjugated one: a better performance was determined for ASO 51 3′‐UDC with an average 9.5‐fold increase with respect to ASO 51
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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