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141.
Pfeifer P Aston L Banks M Barker S Burress J Carter S Coleman J Crockett S Faulhaber C Flavin J Gordon M Hardcastle L Kallenborn Z Kemiki M Lapilli C Pobst J Schott R Shah P Spellerberg S Suppes G Taylor D Tekeei A Wexler C Wood M Buckley P Breier T Downing J Eastman S Freeze P Graham S Grinter S Howard A Martinez J Radke D Vassalli T Ilavsky J 《Chaos (Woodbury, N.Y.)》2007,17(4):041108
142.
Improved rejection of multiply scattered photons in confocal microscopy using dual-axes architecture
We perform Monte Carlo simulations to show that the dual-axes (DA) confocal architecture has superior rejection of multiply scattered photons in tissue to that of single axis. As a result, the DA configuration provides improved signal-to-noise ratio and dynamic range, and thus is sensitive to ballistic photons from deeper within tissue, features that are particularly useful for performing vertical cross-sectional reflectance images in tissue. 相似文献
143.
Luke Gordon Joel B. Varley John L. Lyons Anderson Janotti Chris G. Van de Walle 《固体物理学:研究快报》2015,9(8):462-465
Achieving high levels of n‐type conductivity in AlN and high Al‐content nitride alloys is a long standing problem; significant decreases in conductivity are observed as the Al content is increased, a phenomenon that has been attributed to donors such as oxygen or silicon forming DX centers. We address this problem through a comprehensive first‐principles hybrid density functional study of potential n‐type dopants, identifying SN and SeN as two elements which are potential shallow donors because they do not undergo a DX transition. In particular, SN is highly promising as an n‐type dopant because it also has a low formation energy and hence a high solubility. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
144.
This paper presents the oil uptake of porous sorbent polymer sheets consisting of ultra‐high molecular weight polyethylene. A comprehensive set of experiments are performed showing the saturation contact time, retention value, mechanical properties, oil pick‐up ratio, pick‐up density, and dynamic dripping profile. Kinetic modeling of the oil sorption is also provided. The experimental results show a good correlation with the pseudo‐second order model. The sheets exhibit high oil uptake speeds, requiring less than 2 min in contact with the oil to reach saturation. The sheets fulfill the criteria of high uptake kinetics, high sorption capacity, and high mechanical strength simultaneously. Those characteristics enable their use in practical spill response. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
145.
146.
Unprecedented 1,14‐seco‐Crotofolanes from Croton insularis: Oxidative Cleavage of Crotofolin C by a Putative Homo‐Baeyer–Villiger Rearrangement
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Dr. Lidiya A. Maslovskaya Dr. Andrei I. Savchenko Carly J. Pierce Dr. Victoria A. Gordon Dr. Paul W. Reddell Prof. Peter G. Parsons Prof. Craig M. Williams 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(44):14226-14230
EBC‐162 isolated from Croton insularis, obtained from the northern rainforest of Australia, was structurally affirmed as crotofolin C ( 4 ). Novel oxidative degradation products, EBC‐233 and EBC‐300, which are the first crotofolane endoperoxides, were also isolated. Both endoperoxides were found to be stable intermediates, which are proposed to undergo an unprecedented homo‐Baeyer–Villiger biosynthetic rearrangement to give a new class of 1,14‐seco‐crotofolane diterpenes. Prolonged storage of all isolates assisted in authenticating their natural product status. Anticancer activities of reported compounds are presented. 相似文献
147.
Functionalized Graphene as a Gatekeeper for Chiral Molecules: An Alternative Concept for Chiral Separation
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Andreas W. Hauser Narbe Mardirossian Julien A. Panetier Martin Head‐Gordon Alexis T. Bell Peter Schwerdtfeger 《Angewandte Chemie (International ed. in English)》2014,53(37):9957-9960
We propose a new method of chiral separation using functionalized nanoporous graphene as an example. Computational simulations based on density functional theory show that the attachment of a suitable chiral “bouncer” molecule to the pore rim prevents the passage of the undesired enantiomer while letting its mirror image through. 相似文献
148.
Racemic and Quasi‐Racemic X‐ray Structures of Cyclic Disulfide‐Rich Peptide Drug Scaffolds
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Conan K. Wang Gordon J. King Susan E. Northfield Paola G. Ojeda Prof. Dr. David J. Craik 《Angewandte Chemie (International ed. in English)》2014,53(42):11236-11241
Cyclic disulfide‐rich peptides have exceptional stability and are promising frameworks for drug design. We were interested in obtaining X‐ray structures of these peptides to assist in drug design applications, but disulfide‐rich peptides can be notoriously difficult to crystallize. To overcome this limitation, we chemically synthesized the L ‐ and D ‐forms of three prototypic cyclic disulfide‐rich peptides: SFTI‐1 (14‐mer with one disulfide bond), cVc1.1 (22‐mer with two disulfide bonds), and kB1 (29‐mer with three disulfide bonds) for racemic crystallization studies. Facile crystal formation occurred from a racemic mixture of each peptide, giving structures solved at resolutions from 1.25 Å to 1.9 Å. Additionally, we obtained the quasi‐racemic structures of two mutants of kB1, [G6A]kB1, and [V25A]kB1, which were solved at a resolution of 1.25 Å and 2.3 Å, respectively. The racemic crystallography approach appears to have broad utility in the structural biology of cyclic peptides. 相似文献
149.
Dr. Lyle M. Gordon Jessica K. Román Dr. R. Michael Everly Michael J. Cohen Dr. Jonathan J. Wilker Dr. Derk Joester 《Angewandte Chemie (International ed. in English)》2014,53(43):11506-11509
Metastable precursors are thought to play a major role in the ability of organisms to create mineralized tissues. Of particular interest are the hard and abrasion‐resistant teeth formed by chitons, a class of rock‐grazing mollusks. The formation of chiton teeth relies on the precipitation of metastable ferrihydrite (Fh) in an organic scaffold as a precursor to magnetite. In vitro synthesis of Fh under physiological conditions has been challenging. Using a combination of X‐ray absorption and electron paramagnetic resonance spectroscopy, we show that, prior to Fh formation in the chiton tooth, iron ions are complexed by the organic matrix. In vitro experiments demonstrate that such complexes facilitate the formation of Fh under physiological conditions. These results indicate that acidic molecules may be integral to controlling Fh formation in the chiton tooth. This biological approach to polymorph selection is not limited to specialized proteins and can be expropriated using simple chemistry. 相似文献
150.