1,720,963 research outputs found
Analysis programs used for the article Five Cytochrome 'Nanowires' Suffice for Prokaryotes to Breathe Rocks Microns Away
No full text<p>This repository contains the analysis scripts that were developed for the manuscript titled: Five Cytochrome ‘Nanowires’ Suffice for Prokaryotes to Breathe Rocks Microns Away.</p>
<p>The repository comprises four files/directories. </p>
<p>1) CompareExpAndCalcRedoxTitrationAnalysis.py : A python script to generate Figure 2, which compares simulated and measured spectroelectrochemical titration curves.</p>
<p>2) BioDCv2 : Version 2.0 of the BioDC program written by Matthew J. Guberman-Pfeffer.</p>
<p>3) RedoxCooperativityInOmcS.zip : An example of using BioDC to compute redox cooperativities. The data is in Figure 5 of the manuscript.</p>
<p>4) ComputeDiffusionConstantForAllPermutationsOfDeltaG.zip : A package of Python scripts that computes the diffusion constant for all possible sequences of a set of redox potentials. The resulting data is discussed in the manuscript.</p>
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Vibrational Coupling Modulation in n-Alkanethiolate Protected Au25(SR)180 Clusters
No full textWe have studied, both experimentally and theoretically, the Raman vibrational spectra of a series of nalkanethiolate protected Au25(SCnH2n+1)18 clusters, with n = 2, 3, 4, 5, 6, 8, 10, 12, and 14. The C−H stretching region of the infrared spectra reveals that, while shorter chains are flexible, longer chains are more ordered with a propensity toward extended all-trans conformation. The different behavior of long and short chains is also reflected in the low-frequency Raman spectra of the clusters, which are broadened for the longer
chains due to interchain interactions and formation of bundles. The experimental low-frequency modes in the Raman spectra, associated with Au−S stretching vibrations, change drastically and in an apparently unsystematic way as a function of chain length. For example, a band around 320 cm−1 associated with tangential Au−S stretching character shifts up in frequency, then down and then up again as the carbon chain is increased. DFT calculations reveal that this behavior is due to a nonlinear coupling of this mode to torsional and bending modes of the alkyl chain. The frequencies of these modes strongly depend on the chain length and, as a consequence, also their coupling with the Au−S stretching modes, which explains the erratic behavior of this
band in the spectra. This behavior is well described by calculations on a mimic cluster model that considers only one staple motif. For the ethanethiolate-protected cluster, the entire cluster was included in the calculation of the Raman spectrum, and this allowed for the first time to compare directly experimental and calculated Raman spectra of the same cluster. Furthermore, our study shows that the entire ligand has to be considered for the calculation of the low frequency vibrations of the Au−S interface, as this spectral region is sensitive to coupling with low-frequency ligand modes
Mechanisms of Porphyrinoid and Carotenoid Spectral Tuning Revealed with Quantum Chemistry
No full textContinued advances in a myriad of biomedical and technological fields require the rational design of molecules or supramolecular architectures with specific photophysical properties. Central to this endeavor is a mechanistic understanding of optical property modulation as a function of molecular structure, conformation, and environment. Natural pigments and protein-pigment complexes constitute a ‘solutions manual’ to challenges in electronic (optical) engineering that has been refined over a few billion years of evolution, and from which design principles can be deduced. In this thesis, unique mechanisms for modulating the optical properties of natural or synthetic porphyrinoid and carotenoid pigments are elucidated with quantum chemical methods. Our investigations add a new conformational mechanism, as well as design principles for regioisomer-dependent electronic substituent effects to the cannon of structural tools for regulating the optical properties of pyrrole-modified porphyrins. The lessons learned provide insight into analogous spectral tuning mechanisms found in nature. We also delineate the molecular factors optimally regulating light harvesting in a natural photosynthetic antenna complex. These discoveries have advanced the fundamental understanding and practical utilization of structure-optical property modulation mechanisms, and may aid the design of next-generation photonic-based technologies
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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