1,720,963 research outputs found
NMR-Based Structure Determination of an Intertwined Coordination Cage Resembling a Double Trefoil Knot
No full textDFG [IRTG 1422
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
Development and application of novel NMR methodology for elucidation of protein structure and dynamics
Full text linkThe design of a novel drug is a creative act. The difference between a researcher and an artist, besides the pursuit of a particular goal, is that his/her creativity is based on scientific knowledge and technology. Until today, drug discovery was mainly dominated by trial and error, based on empirically derived rules. Today, the “trial and error” approach is being replaced by a conscious design based on improved predictions. These improvements in the prediction of the structure of a drug molecule are mainly based on the increasing knowledge about molecular mechanisms. [1] This increase of mechanistic knowledge is also caused by the progress of structure elucidation techniques like NMR-spectroscopy or X-ray crystallography. So far, our understanding of molecular mechanisms is based on the justified principle: Structure determines function. The number of deposited protein structures grows exponentially. Nevertheless, the ratio between solved and unsolved human protein structures is in the single-digit percentage range. [2] This relative number is even lower for proteins that are insoluble and at the same time amorphous in the solid-state, such as fibrils or membrane proteins. The structure of such proteins of great importance is not accessible by X-ray crystallography or liquid-state NMR-spectroscopy. In order to close this gap, a new NMR methodology has been developed over the last two decades, the proton-detected fast-magic-angle-spinning solid-state NMR-spectroscopy. This new method enables the structure-elucidation of such amorphous and insoluble proteins. In this context, Bernd Reif et al., Rasmus Linser et al., Guido Pintacuda et al., and others did the pioneering work. In this line, an important objective of this thesis was to contribute to the continuous development of this methodology. The key to well-resolved protein structure from NMR-spectroscopy is precise distance restraints. However, till date, solid state NMR-spectroscopy has only been able to provide qualitative restraints, grouping the internuclear distance as close, medium, or far. Opposed to the general picture, with the help of Suresh K. Vasa, Evgeny Nimerovsky, Himanshu Singh, Beat Vögeli, and others, I developed a user-friendly approach to determine accurate distance restraints in solid-state NMR. Hereby, all site-specific errors that occur during magnetization transfer are addressed by an integrated approach. The approximations to be made are carefully validated by numerical simulations. Further, in order to address challenging protein targets where the assignment might be ambiguous and incomplete, I have performed the first kinetic hydrogen-deuterium exchange measurements in solid-state NMR-spectroscopy in collaboration with Suresh K. Vasa, Himanshu Singh, and others. The method reports on the over-all positioning of exchangeable protons within the protein by information on the presence in the hydrophobic core or on the hydrophilic surface and on the presence and strength of structural hydrogen bonds. Therefore, this information can be used for assignment purposes and for structure determination. Hereby, it was crucial to be able to separate exchange hindrance due to hydrophobic shielding from the hindrance due to hydrogen bonding. Experimental site-specific information about hydrogen bond strength is valuable for determination of protein structure and dynamics simultaneously. In addition to a well-defined distance restraint, a hydrogen bond also reports on the rigidity of structural elements. In particular, the stabilization of functionally important loop tips by sidechain-to-backbone hydrogen bonds is investigated in this work.
While the interplay of protein structure and function is well accepted and understood, the current state of understanding how local motion contribute to functional mechanisms leaves much to be discovered. In this context, NMR spectroscopy is one of the techniques of choice. Nowadays detailed information on directional protein motions is provided primarily by the theoretically based MD simulations. Another part of this work is dedicated to advance and apply NMR-spectroscopic methods, which have been developed to determine these directional dynamics and lead towards interpretations of the biological function. Along these lines, in liquid-state protein NMR, Vögeli et al. recently developed an approach that provides distance restraints with such accuracy that differences between distance restraints and average atomic positions are no longer associated with experimental error but with protein dynamics. With the help of Cornelia Hebrank, Snehal Patel, and Lars V. Schäfer, this method was applied to the protein binding domain SH3, yielding interesting mechanistic insights regarding ligand binding. For the first time, the novel method was evaluated using state-of-the-art MD simulations and further compared with the dynamics data using other NMR approaches. In addition to providing mechanistical insides for the protein SH3, the value of this new approach, which is the first experimental method for the determination of spatial dynamics, is emphasized.
In general, the main objective of this work was to develop applicable methods for the benefit of other researchers and thus for the benefit of science and humanity
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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