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    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

    Crystal and molecular structure of tetrabutylammonium (3S,4S)-3-phenylacetamido-4-methyl-2-oxoazetidine-1-sulfonate

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    The crystal structure of the title compd. (I) was detd. and the spatial distant between the sulfonate group and the lactam carbonyl correlated to its antimicrobial activity

    Interconversion of the thiazine and thiazolidine system of β -lactam antibiotics. Electrochemical cleavage of Kamiya's disulfide promoted by bromide ion

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    A new transformation of Kamiya's disulphide (1) into the bromopenam derivative (4) has been carried out by electrolyzing the disulphide (1) in protic solvents in the presence of Me4NBr. The transformation occurs through an intermediate episulphonium-bromide ion pair in which the bromide appears to tightly linked to the sulphu
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