1,721,005 research outputs found
The synthesis of novel calix[4]arene tetra-acrylates and their potential use as macrocyclic platforms in the development of static and dynamic combinatorial libraries using reversible imine formation.
No full textGoing 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
Synthesis and capsule formation of upper rim substituted tetra-acrylamido calix[4]arenes
Full text linkSynthesis and spectral properties of novel Singapore Green analogues for protease detection
Full text linkHerein we describe the synthesis, characterisation and determination of fluorescence and photophysical properties of various novel analogues of the orphan fluorophore class Singapore Green. We equate the fluorescence properties of these novel fluorophores to their molecular structure and address the mechanisms through which their fluorescence is quenched and the effect this has on their quantum yields of fluorescence. Fluorescence quenching via acylation was also achieved, thereby providing conceptual proof of their utility as cores for future fluorescent probes. Additionally, we have produced and examined a number of unexpected acyl intermediates of variable photolytic stability. Furthermore, we have obtained proof of concept that the use of Singapore Greens for protease probe generation is feasible via demonstration of proteolytic cleavage of one of the acylated analogues
Synthesis and supramolecular chemistry of broader rim tetraolefinic calix[4]arenes.
No full textSynthesis of novel broader rim calix[4]arene derivatives has been carried out, initially, using palladium coupling reactions. Further derivatisation and investigation into host-guest chemistry of these novel compounds has also been accomplished. Conditions have been optimised for the coupling of both aromatic and aliphatic acrylates. Stereospecific formation of the all trans coupled product of an exclusively beta Heck coupling has been observed throughout. All compounds (of the type II) have been obtained in good yield. Synthetic methodology for the generation of receptor libraries (be they static or dynamic) via the coupling of both tertiary and secondary aciylamide species using a palladium catalyst has been accomplished. Some of the secondary aciylamides possess the capacity (by virtue of pre-arrangement of amidic hydrogen bonding motifs) to form dimers via H-bonding in non-polar solution. The binding of a commercial pesticide (TMTD) by an acrylamidocalix[4]arene is reported and corroborated by NMR and ESI-MS data. The ability to couple formyl functionalised acrylates to the broader rim has allowed the preparation of a small library of deep cavity receptors in the form of tetra-transimines. These deep cavity calix[4]arene receptors could be obtained and are folly characterised. In the case of dynamic combinatorial libraries the principle of utilising a guest molecule to template or at least effect a specific outcome of imine forming reactions at four aldehydic sites on the broader rim of the calix[4]arene has also been illustrated. This provides support for the principles of formation of dynamic combinatorial libraries and further proposes calix[4]arene building blocks as being useful in their construction
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
- …
