100,442 research outputs found
Joshua Davis: Author of Spare Parts
No full textCitation: K-State First (2016). Joshua Davis: Author of Spare Parts [Flier]. Manhattan, Kansas: K-State First.Flyer advertising Joshua Davis's author talk at Kansas State University
Steven Johnson Author Talk Poster
No full textK-State Book NetworkA poster advertising an author talk by Steven Johnson at Kansas State University on September 3, 2014. Steven Johnson's book "The Ghost Map" was the 2014-2015 common book
Common recognition topology of mex transporters of Pseudomonas aeruginosa revealed by molecular modelling
No full textThe secondary transporters of the resistance-nodulation-cell division (RND) superfamily mediate multidrug resistance in Gram-negative bacteria like Pseudomonas aeruginosa. Among these RND transporters, MexB, MexF, and MexY, with partly overlapping specificities, have been implicated in pathogenicity. Only the structure of the former has been resolved experimentally, which together with the lack of data about the functional dynamics of the full set of transporters, limited a systematic investigation of the molecular determinants defining their peculiar and shared features. In a previous work (Ramaswamy et al., Front. Microbiol., 2018, 9, 1144), we compared at an atomistic level the two main putative recognition sites (named access and deep binding pockets) of MexB and MexY. In this work, we expand the comparison by performing extended molecular dynamics (MD) simulations of these transporters and the pathologically relevant transporter MexF. We employed a more realistic model of the inner phospholipid membrane of P. aeruginosa and more accurate force-fields. To elucidate structure/dynamics-activity relationships we performed physico-chemical analyses and mapped the binding propensities of several organic probes on all transporters. Our data revealed the presence, also in MexF, of a few multifunctional sites at locations equivalent to the access and deep binding pockets detected in MexB. Furthermore, we report for the first time about the multidrug binding abilities of two out of five gates of the channels deputed to peripheral (early) recognition of substrates. Overall, our findings help to define a common “recognition topology” characterizing Mex transporters, which can be exploited to optimize transport and inhibition propensities of antimicrobial compounds
Unravelling the Role of Sterically Encumbered Ligands in Tuning the Magnetic Properties of Lanthanide‐Based D 5h Single‐Ion Magnets
No full textAbstract Isostructural Dy(III) and Er(III) complexes [L 1 2 Ln(H 2 O) 5 ][I] 3 ⋅ L 1 2 ⋅ (CH 2 Cl 2 ) (Ln=Dy ( 1 ), Er ( 3 )) and [L 2 2 Ln(H 2 O) 5 ][I] 3 ⋅ L 2 2 ⋅ (CH 2 Cl 2 ) 2 (Ln=Dy ( 2 ), Er ( 4 )), with distorted pentagonal bipyramidal geometry ( D 5h ) around the central metal were synthesized by utilizing two bulky phosphonamide ligands, adamantyl phosphonamide, (Ad)P(O)(NH i Pr) 2 ( L 1 ) and carbazolyl phosphoramide (Cz)P(O)(NH i Pr) 2 ( L 2 ). The resultant complexes were investigated for their magnetic properties in order to elucidate the impact of modification of the coordinating P−O bond environment either by increasing steric bulk and/or introduction of a third P−N bond at the central phosphorus atom. Magnetic studies revealed substantial energy barriers ( U eff ) of 640 K and 491 K for Dy compounds 1 and 2 , respectively, rendering them as some of the best‐performing air‐stable SIMs amongst the class of SIMs with D 5h symmetry. Compounds 1 and 2 exhibit magnetization blocking ( T B ) at 6.5 K and 6 K, respectively, at a sweep rate of 20 Oe/s. Compound 1 benefits from increased lattice intermetallic distances due to bulky adamantyl substituent, but exhibits a significant deviation from linear axial (P)O−Dy−O(P) geometry (173.7(1)°). In addition to the deviation from linearity, the incorporation of a bulky adamantane (or carbazole) ligand in complex 1 (or 2 ) was found to result in relatively strong Dy…H−C agostic interactions, with distances of 3.698 Å (3.376 Å). These interactions are expected to induce transverse anisotropy. Ab initio CASSCF/RASSI‐SO/SINGLE_ANISO calculations offer valuable insights into the dynamics of magnetic relaxation and the impact of axial bulkiness on the anisotropy of D 5h systems. Beyond highlighting the crucial role of crystal field and symmetry in achieving high‐temperature SIMs, this study also explores how the secondary coordination sphere can be engineered to create novel SIMs.Indian Institute of Technology Delhi https://doi.org/10.13039/501100007488Deutsche Forschungsgemeinschaft https://doi.org/10.13039/501100001659Science and Engineering Research Board https://doi.org/10.13039/50110000184
CCDC 1024708: Experimental Crystal Structure Determination
No full textRelated Article: Sandeep K. Gupta, Subramaniam Kuppuswamy, James P. S. Walsh, Eric J. L. McInnes, Ramaswamy Murugavel|2015|Dalton Trans.|44|5587|doi:10.1039/C4DT03379
CCDC 1030578: Experimental Crystal Structure Determination
No full textRelated Article: Sandeep K. Gupta, Subramaniam Kuppuswamy, James P. S. Walsh, Eric J. L. McInnes, Ramaswamy Murugavel|2015|Dalton Trans.|44|5587|doi:10.1039/C4DT03379
CCDC 1024704: Experimental Crystal Structure Determination
No full textRelated Article: Sandeep K. Gupta, Subramaniam Kuppuswamy, James P. S. Walsh, Eric J. L. McInnes, Ramaswamy Murugavel|2015|Dalton Trans.|44|5587|doi:10.1039/C4DT03379
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
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