1,720,983 research outputs found
Synthesis, structures and antitumor activity of the first crown ester-linked bipyridyl platinum complexes
No full textThree new crown ester-linked bipyridine homologs with three, four or five ethylene glycol units, which are bulky and soluble in both hydrophilic and lipophilic;media, were synthesized. The reaction of the appropriate macrocycles with K2PtCl4 in water gave yellow cisplatin analogs in good yield. These complexes were converted to carboplatin analogs by exchange of the leaving group. All the compounds were characterized by elemental analysis and various spectroscopic methods. Carboplatin analogs showed good solubility in both hydrophilic and lipophilic media. The crystal structure of 2c, the carboplatin analog with macrocycles containing five ethylene glycol units, was determined by X-ray diffraction: space group P (1) over bar, a = 9.798(1), b = 12.580(3), c = 13.945(2) Angstrom, alpha =108.61(2), beta = 94.59(1), gamma = 97.42(2)degrees, Z = 2, R = 0.0618. Some of platinum complexes Showed a moderate cytotoxic effect on both murine leukemia L1210 and P388 even though they do not have any NH proton. (C) 1999 Elsevier Science Inc. All rights reserved.Korea Research Foundation and the Korea Science and Engineering Foundatio
HETEROLEPTIC CROWN THIOETHER COMPLEXES - SYNTHESIS AND CHARACTERIZATION OF [M(CO)3(9S3)] (M = CR, MO, W) - CRYSTAL-STRUCTURE OF [W(CO)3 (9S3)](9S3 = 1,4,7-TRITHIACYCLONONANE)
No full textThis work was in part supported by the Korea Science and Engineering Foundation. YD thanks Yun Am Cultural Foundation
HETERODINUCLEAR GROUP-6 METALLACARBORANES - SYNTHESIS AND CHARACTERIZATION OF [CLOSO-3,3,3-(CO)3-3-SNPH3-3,1,2-MC2B9H11]-(M = CR, MO, W)
No full textHeterodinuclear group 6 metallacarborane anions [closo-3,3,3-(CO)3-3-SnPh3-3,1,2-MC2B9H11]-(M = Cr, 2; Mo, 3; W, 4) were prepared from the equimolar reaction systems of Tl2C2B9H11/M(CO)3(MeCN)3/SnPh3Cl/(PPN)Cl in MeCN as the [PPN]+ (PPN+ = bis(triphenylphophoranylidene ammonium cation) salts and were characterized by various means including multinuclear NMR and single-crystal X-ray diffraction. Crystals of [PPN].4 are monoclinic, C2/c, with a = 45.777(4), b = 11.669(1), c = 26.826(3) angstrom, beta = 125.134(2)degrees, V = 11718 angstrom 3 and Z = 8. Convergence was achieved with R (R(w)) = 6.7 (8.0)% for 5487 (I > 3-sigma(I)) observed reflections. The nido anion C2B9H11(2-) interacts with W via the C2B3 pentagonal] plane and forms the closo WC2B9 geometry. The W-Sn distance of 2.825(1) angstrom and the observation of 1J(Sn-119-W-183) = 262 Hz in Sn-119 NMR spectrum of 4 establish the presence of a W-Sn bonding interaction. The structural integrities of 2, 3 and 4 are similar and each compound remains intact in solution.Korea Science and Engineering
Foundation and in part by the Office of Naval Researc
Sensitivity Enhancement of a Miniaturized Surface Plasmon Resonance Sensor Using Combination of Self-Assembled Mono layer and Protein G
No full textThe detection capabilities of surface plasmon resonance (SPR) sensor chips modified with protein G, a self-assembled monolayer (SAM), and a combination of protein G and a SAM were investigated and compared using a miniaturized SPR sensor system. The miniaturized SPR system had two flow channels, with one used as a reference. To immobilize the antibodies on the SPR sensor chip for the detection of C-reactive protein (CRP), different linker molecules were formed on the gold SPR sensor chip at the beginning of the experiment. The CRP has been reported as a biomarker of future cardiovascular events. The antibody of CRP and bovine serum albumin (BSA) were then sequentially injected. The responses to CRP at concentrations of 0.5, 1, 3, and 5 μg/ml were observed and the sensitivities of each system compared. The SPR sensor chips modified with the protein G on the SAM layer exhibited the highest sensitivity and a stable linearity. The results demonstrated the feasibility of using the proposed SPR immunosensors for detecting CRP for early diagnosis without any additional chemical treatments. Copyright © 2012 American Scientific Publishers.
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
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
