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Efficient synthesis of ortho-carborane by reaction of propiolic acid tert-butyl ester with decaborane(14)
No full textReaction of propiolic acid tert-butyl ester I and decaborane(14) at 90 degreesC did not give the expected carborane carboxylic acid tert-butyl ester 3 but directly unsubstituted ortho-carborane 2 which was isolated in 52% yield as pure material, An in situ de-tert-butoxycarbonylation of the first formed carborane carboxylic acid tert-butyl ester 3 via a six membered transition state is suggested for this domino process
Efficient synthesis of ortho-carborane by reaction of propiolic acid tert-butyl ester with decaborane(14)
No full textReaction of propiolic acid tert-butyl ester I and decaborane(14) at 90 degreesC did not give the expected carborane carboxylic acid tert-butyl ester 3 but directly unsubstituted ortho-carborane 2 which was isolated in 52% yield as pure material, An in situ de-tert-butoxycarbonylation of the first formed carborane carboxylic acid tert-butyl ester 3 via a six membered transition state is suggested for this domino process
Novel carboranyl C-glycosides for the treatment of cancer by boron neutron capture therapy
No full textThe synthesis of the novel unprotected carboranyl C-glycosides 2 and 20 24 starting from ethynyl C-glycosides 1, 5-8, 10, and 13 is described. The new compounds are highly water-soluble and display only a very low cytotoxicity, which makes them promising candidates for use in boron neutron capture therapy for the treatment of cancer
Novel carboranyl C-glycosides for the treatment of cancer by boron neutron capture therapy
No full textThe synthesis of the novel unprotected carboranyl C-glycosides 2 and 20-24 starting from ethynyl C-glycosides 1, 5-8, 10, and 13 is described. The new compounds are highly water-soluble and display only a very low cytotoxicity, which makes them promising candidates for use in boron neutron capture therapy for the treatment of cancer
Novel carboranes with a DNA binding unit for the treatment of cancer by boron neutron capture therapy
No full textThe synthesis and biological evaluation of two ortho-carborane derivatives which contain a 5,6,7-trimethoxyindole (TMI) unit for use in boron neutron capture therapy is described. The TMI moiety is known to be the DNA-binding part of the highly potent anticancer agent duocarmycin A. The ortho-carborane derivatives were prepared from amino alkynes which were bound to a protected TMI carboxylic acid. Addition of decaborane(14) to the alkyne triple bond with subsequent removal of the tert-butoxy-carbonyl (Boc) and benzyl protecting groups gave the desired product. Boron uptake from the ortho-carborane derivatives into B-16 melanoma cells was higher and faster than that observed with L-p-boronophenylalanine (BPA), which is in use in the clinic
Carboranyl bisglycosides for the treatment of cancer by boron neutron capture therapy
No full textBoron neutron capture therapy is a special type of radiotherapy for the treatment of cancer by using boron compounds. Problems often arise from the: low water solubility of these compounds, their unselective uptake into the cancer cells, and their toxicity Here we describe the novel water-soluble ortho-carboranyl bisglycosides 7 and 10 containing either lactose or glucose and the mixed bisglycosides 1 and 28 containing glucose mannose, and galactose. The carboranyl bisglycosides show almost no toxicity toward bronchial carcinoma cells of line A549 up to a concentration of 0.50 mM As anticipated, these compounds exhibit nearly no uptake into C6 glioma cells; they can therefore be used for a selective delivery into malignant cells:by using conjugates of glycohydrolases and monoclonal antibodies which bind to tumor-associated antigens, since by enzymatic hydrolysis the bisglycosides are transformed into lipophilic compounds
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
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