1,720,974 research outputs found
Chemotaxonomic evaluation by volatolomics analysis of fifty-two genotypes of myrtus communis l
No full textA population of 52 genotypes of Myrtle (Myrtus communis L.), selected in the framework of a domestication program and growing in the same collection field at Oristano (Central Western Sardinia, 39◦ 54′ N 8◦ 35′ E), was analyzed by GC/MS for leaf essential oil composition. The chemical composition of essential oils was quite variable with a number of compounds ranging from 31 to 78 depending on cultivar. One hundred and eighteen compounds were globally identified in the various genotypes. However, α-pinene, limonene, 1,8-cineole, α-terpineol, and linalool always resulted as main components with few differences among samples. Minor compounds have been the determining factors in differentiating or associating genotypes in the outputs of a principal component analysis (PCA), where the results of another analysis of fruit essential oils of the same genotypes were also jointly used. Genotypes were discriminated according to mother plant characterization or ecological variables, such as site altitude, soil nature, and presence or absence of calcareous soils in the substrate of the localities of origin
A different approach to enhance the characterization of essential oils. Comparison between computer aided 13C NMR and GC-MS data from Helichrysum italicum (Roth) G. Don subsp. microphyllum (Willd.) Nyman growing wild in Sardinia
No full textEnantiomerically pure pyridine and 2,2'-bipyridine thioethers: new N-S chiral ligands for asymmetric catalysis. Palladium catalyzed allylic alkylation
No full textVANADIUM(IV) AND VANADIUM(V) COMPLEXES OF DEFEROXAMINE-B IN AQUEOUS-SOLUTION
No full textComplex;formation between oxovanadium(IV) and vanadate(V) with deferoxamine B was investigated in aqueous solution by EPR, electronic absorption spectroscopy, V-51 NMR, and pH-potentiometry. The reaction scheme implies that In very acidic media, reversible oxygen displacement occurs on the metal ion to yield nonoxo V(IV) or V(V)complexes, which exhibit distinct EPR and V-51 NMR spectral features, respectively. In these species,the bare vanadium ions are coordinated to the three hydroxamic functions of the ligand. With increasing pH, oxo coordination is restored and ''normal'' VO(IV) and VO2(V) complexes are formed with metal bonding to one or two hydroxamic functions of the ligand
Unusual Dirhodium Tetraacetate Catalyzed Intramolecular Cyclization of Isoquinoline Diazoamides
No full textUnderstanding oscillatory phenomena in molecular hydrogen generation via sodium borohydride hydrolysis
No full textModular Approach toward the Construction of the Core Motifs of Annonaceous Acetogenins and Variants Thereof
No full text
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
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