130,472 research outputs found
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Construction of chiral polysubstituted oxacycles by novel jocic reactions and synthesis of a new cytochrome-p450 photoaffinity label
No full textElectronic Thesis or DissertationThe preparation of a novel cytochrome P-450 photoaffinity label is described. The targeted azidoquinone was to be used as a photo-reactive label to specifically identify peptides associated with the oxidation binding site within cytochrome bc1, and consequently determine the unique catalytic mechanism of quinol oxidation processes and the intermediates involved. The synthetic route features a Diels-Alder cyclization/alkylation/decyclization approach to prepare the mimic of naturally occurring ubiquinone. The synthesis is accomplished in 6 steps from commercially available 4-methylcatechol and involves incorporation of azide in the final synthetic step to prepare the novel azidoquinone. (S)–Wynberg lactone was used to prepare the potent CERT inhibitor (1R,3S)-HPA-12. The route featured the preparation of an optically active azidolactone through a Corey-Link reaction accompanied by nucleophilic acyl substitution. The synthesis was accomplished in 5 steps, and proceeded in 33% overall yield from (S)–Wynberg lactone. (R)-Wynberg lactone was used to prepare chiral polysubstituted oxacycles through a novel Jocic-type reaction. The route featured a directed 1,3-reduction of a β-hydroxyketone followed by ruthenium-catalyzed cross metathesis and osmium-catalyzed asymmetric dihydroxylation. A modified olefin metathesis procedure to suppress undesired byproduct formation is described in detail. A variety of functionalized olefins were prepared by the modified procedure in yields commonly exceeding 80%. Functionalized tetraols were prepared by a modified Sharpless asymmetric dihydroxylation reaction with yields commonly exceeding 80%, and diastereomeric ratios typically exceeding 85:15. Stereoselectivity in the dihydroxylation of terminal mono-substituted olefins can be enhanced with a pre-formed phenyl boronic ester adduct. Conditions for enhancing the stereoselectivity with this class of substrates are described in detail. The final synthetic step en route to the targeted tetrahydopyran derivatives involves intramolecular cyclization through a novel Jocic-type reaction, and commonly proceeds in > 80% yield. Work towards the cyclization of all classes of prepared tetraols is currently in progress. Terminal alkylsulfanyl alcohols were prepared in one step from an aliphatic trichloromethyl carbinol in yields exceeding 85%. These results further demonstrate the utility of gem-dichloroepoxide intermediates in Jocic-type reactions, and lay the groundwork for future transformations. Work in this area is currently underway
A Jocic-type approach for a practical and scalable synthesis of pyrrolonaphthoxazepine (PNOX)-based potent proapoptotic agents
No full textWe developed a Jocic-type protocol for the construction of the pyrrolonaphthoxazepine (PNOX) core. After an initial investigation based on the isolation of a trichloromethyl carbinol derivative, we shifted our attention towards a multicomponent single-step protocol. Screening of a variety of bases and solvents led to the identification of the optimum conditions for the preparation of the key α-aryloxy carboxylic acids to undergo intramolecular cyclization. The novel chemical route significantly improved overall yields for the preparation of PNOX-based compounds and was successfully extended to the preparation of 1,4-benzoxazinone-based templates
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
Microgel-based surface modifying system for stimuli-responsive functional finishing of cotton
No full textAn innovative strategy for functional finishing of textile materials is based on the incorporation of a thin layer of surface modifying systems (SMS) in the form of stimuli-sensitive microgels or hydrogels. Since the copolymerization of poly(N-isopropylacrylamide) with an ionizable polymer, such as chitosan, results in a microgel that is responsive to both temperature and pH, the microparticulate hydrogel of poly-NiPAAmchitosan copolymer (PNCS) was synthesized using surfactant-free emulsion method. The microparticle size in dry (collapsed) state is estimated at 200nm by SEM and TEM, and effect of temperature and pH on microparticles was investigated by DLS and UV–vis spectrophotometry. The incorporation of PNCS microparticles to cotton material was done by a simple pad-dry-cure procedure from aqueous microparticle dispersion that contained 1,2,3,4-butanetetracarboxylic acid (BTCA) as a crosslinking agent. This application method provided sufficient integrity to coating by maintaining the responsiveness of surface modifying system. The stimuli-responsiveness of modified cotton fabric has been confirmed in terms of regulating its water uptake in dependence of pH and temperature
Scholarly Communication and Publishing Lunch and Learn Talk #11: The ULS Open Access Author Fee Fund
No full textAt the May 2014 talk, you will learn about the ULS Open Access Author Fee Fund--what it is, why we do it, how it works, and how the program is going so far
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