162,128 research outputs found
DIFFERENTIATION BETWEEN ISOMERIC METHYLATED PURINE DERIVATIVES BY MEANS OF CHEMICAL IONIZATION AND COLLISION INDUCED DISOCIATION
No full textInvestigation of bis(diphenylphosphino)methane Pt(II) complexes by electrospray and fast atom bombardment mass spectrometry
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ion bombardment and collision‐induced dissociation
No full text[Ru(bpy)3(X)2] and [Fe(bpy)3(X)2] complex salts (bpy=2,2′bipyridine; X = ClO 4−, PF 6−, Cl−) were investigated by means of Cs+ fast‐ion bombardment and mass‐selected collision‐induced dissociation (CID). A number of dissociation channels which can be attributed to the loss of intact counterions, bpy neutral ligands and to the insertion of formal O 2−, fluoride or chloride from the counterions ClO 4−, PF 6−, Cl− are evident in both the fast‐ion bombardment and CID spectra. Formation of doubly charged intact cations is also observed for all the compounds investigated. The relative intensities of the major desorbed ions are monitored as a function of the Cs+ kinetic energy in the range 10–30 keV. Copyright © 1994 John Wiley & Sons, Ltd
Variations on the Author
No full text“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
Characterization of mixtures of illicit drug substances by capillary zone electrophoresis (CZE) /electrospray mass spectrometry (ES-MS).
No full textCharacterization of mixtures of illicit drug substances by capillary zone electrophoresis (CZE) /electrospray mass spectrometry (ES-MS)
Monitoring complexation between some proteins and naphtalene dye by electrospray mass spectrometry
No full textComplexation of the hydrophobic fluorescent dye 1-anilinonaphthalene-8-sulphonate with a number of proteins was examined by electrospray ionization mass spectrometry (ESMS). The apparent agreement between the present data and those obtained by fluorescence spectroscopy underlines the role of ESMS in the overall approach to protein folding and unfolding
Investigation of Some Steroids By Means of Thermospray and Tandem Mass-spectrometry
No full textThe detection limits of a number of steroids have been determined by means of loop-injection thermospray (TS) mass spectrometry. The measured limits were found to be in the range 1 pg-10 ng/muL. Combined positive-ion TS/tandem mass spectrometry yielded clear qualitative differences between mass selected protonated testosterone and estriol ions, both of which have the same nominal molecular weight. These differences are necessary for the correct identification of either species which may be present within a complex mixture. The heights of the peaks due to the two competing reaction channels, [M + H]+ and [M + NH4]+. were monitored as a function of the repeller voltage in the range 100-350 V, and the implications of the acquired data are discussed
Capillary zone electrophoresis/electrospray ionization mass spectrometry for the characterization of drugs of forensic interest.
No full textComparison of KeV and eV Collision-induced Dissociation of Some Protonated Isomeric Cyclopropane Derivatives
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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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