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Dichloro[hydrotris(l-pyrazolyl)borato]sulfidotechnetium-(V): The First Technetium Complex Containing A Tc=S Bond
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Structural overview of technetium compounds (1993-1999)
No full textThis paper investigates the structural aspects of technetium-containing complexes. The focus is on the description of the various coordination environments around the technetium center. The complexes are divided according to the coordination sphere and the most significant structural parameters are reviewed and discussed. The review covers the crystallographic determinations published in the years between 1993 and 1999. (C) 2001 Elsevier Science B.V. All rights reserved
Mononuclear six-coordinated Ga(III) complexes: A comprehensive survey
No full textGiven the commercial availability of (68)Ge-(68)Ga generators, in principle analogous to the worldwide utilized (99)Mo-(99m)Tc generator, it is surprising that few (68)Ga agents have been developed beyond basic research toward clinical application. The use of the unconventional (68)Ga positron emitter would allow for a cost-effective production of (68)Ga radiotracers far from a cyclotron facility. Moreover, the use of (67)Ga radiopharmaceuticals for imaging studies, and the application of non-radioactive gallium compounds in the treatment of important disorders, including a number of cancer and infectious diseases, make studies on trivalent Ga coordination chemistry attractive for the design of novel gallium-based drugs. The aim of this review is to survey the reported crystal data of six-coordinated Ga(III) complexes in order to gain information to be used in the design of novel Ga complexes of medicinal interes
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
Synthesis and biological evaluation of new [Tc(N)(PS)]-based mixed-ligand compounds useful in the design of target-specific radiopharmaceuticals: the 2-methoxyphenylpiperazine dithiocarbamate derivatives as an example
No full textThis study presents the first application of a general procedure based on the use of the [Tc(N)Cl(PS)(PPh3)] species (PS is an alkyl phosphinothiolate ligand) for the prepn. of Tc(N) target-specific compds. [Tc(N)Cl(PS)(PPh3)] selectively reacts with an appropriate dithiocarbamate ligand (S-Y) to give [Tc(N)(PS)(S-Y)] compds. 1-(2-Methoxyphenyl)piperazine, which displays a potent and specific affinity for 5HT1A receptors, was selected as a functional group and conjugated to the dithiocarbamate unit through different spacers (Ln). [99mTc(N)(PS)(Ln)] complexes were prepd. in high yield (more than 90%). The chem. identity of 99mTc complexes was detd. by HPLC comparison with the corresponding 99gTc complexes. All complexes are inert toward trans-chelation with an excess of glutathione and cysteine. No notable biotransformation of the native compd. into different species by the in vitro action of the serum and liver enzymes was shown. Nanomolar affinity for the 5HT1A receptor was obtained for [99mTc(N)(PSiso)L3] (IC50 = 1.5 nM); a redn. of the affinity was obsd. for the other complexes as a function of the shortening of the alkyl chain interposed between the dithiocarbamate and the pharmacophore. Negligible brain uptake was found from in vivo distribution data of [99mTc(N)(PSiso)L3]. The key finding of this study is that the complexes maintained good affinity and selectivity for 5HT1A receptors, and the IC50 value for [99gTc(N)(PSiso)L3] being comparable to the IC50 value found for WAY 100635. This result confirmed the possibility of prepg. [99mTc(N)(PS)]-based target-specific compds. without affecting the affinity and selectivity of the bioactive mols. for the corresponding receptors
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
ESI/MSn in the structural characterisation of some nitrido-Re heterocomplexes
No full textSix different nitride-containing rhenium heterocomplexes with a mixed coordination sphere comprising heterodiphosphines (PNP) and dithiocarbamates (DTC) or halides (X) have been studied by means of electrospray mass spectrometry and collisional experiments. Two compounds are neutral intermediates of the type [Re(N)Cl2(PNP)], and four are cationic species of general formula [Re(N)(DTC)(PNP)]+, obtained after treatment of the intermediate species with dithiocarbamate. Both Cl-containing intermediates do not show the formation of molecular ions, being the [M−Cl]+ and [M−2Cl]+ ions the only species detected in the ESI spectra. This behaviour, already observed for some Cl-containing Pt complexes, has been explained by ReCl bond cleavage activated by the high positive charge density present on the ESI droplet surface. However, the four mixed heterocomplexes display only the molecular cation with no detectable fragmentation. Further MSn spectra of all compounds show instead specific fragmentation processes, mainly related to the different outer sphere substituents. Comparison with the fragmentation profiles of isostructural technetium complexes evidence similar primary cleavage followed by quite different decomposition pathways
Synthesis and structural characterization of copper(I) complexes bearing N-methyl-1,3,5-triaza-7-phosphaadamantane (mPTA) Cytotoxic activity evaluation of a series of water soluble Cu(I) derivatives containing PTA, PTAH and mPTA ligands
No full textNew copper(I) complexes containing the water soluble N-methyl-1,3,5-triaza-7-phosphaadamantane (mPTA) phosphine have been synthesized by ligand-exchange reactions starting from [Cu(CH(3)CN)(4)][BF(4)] or [Cu(CH(3)CN)(4)][PF(6)] precursors and (mPTA)X (X=CF(3)SO(3), I). Depending on the ligand counter ion, the hydrophilic [Cu(mPTA)(4)][(CF(3)SO(3))(4)(BF(4))] 3a and [Cu(mPTA)(4)][(CF(3)SO(3))(4)(PF(6))] 3c complexes or the iodine-coordinated [Cu(mPTA)(3)I]I(3)4 species were obtained respectively and fully characterized by spectroscopic methods. Single crystal structural characterization was undertaken for [Cu(mPTA)(3)I]I(3).H(2)O, 4.H(2)O, and [Cu(mPTA)(4)][(CF(3)SO(3))(2)(BF(4))(3)] .0.25H(2)O, 3b.0.25H(2)O, the latter obtained by crystallization of [Cu(mPTA)(4)][(CF(3)SO(3))(4)(BF(4))] 3a. The cytotoxicity of analogous tetrahedral homoleptic Cu(I) derivatives [Cu(PTA)(4)](BF(4)) 1, [Cu(PTAH)(4)][Cl(4)(BF(4))] 2, [Cu(mPTA)(4)][(CF(3)SO(3))(4)(BF(4))] 3a and [Cu(mPTA)(4)][(CF(3)SO(3))(4)(PF(6))] 3c was evaluated against a panel of several human tumor cell lines. All the complexes showed in vitro antitumor activity comparable to that of the reference metallodrug cisplatin. Tests performed on cisplatin sensitive and resistant cell lines showed that against human ovarian 2008/C13(*) cell line pair, the resistance factor of copper derivatives was roughly 7-fold lower than that of cisplatin, whereas against human cervix cancer A431/A431-Pt cell line pair it was about 2.5-fold lower. These results, confirming the circumvention of cisplatin resistance, support the hypothesis that phosphine copper(I) complexes follow different cytotoxic mechanisms than do platinum drugs
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