Simple, Accurate, and Robust Nonparametric Blind Super-Resolution

This paper proposes a simple, accurate, and robust approach to single image nonparametric blind Super-Resolution (SR). This task is formulated as a functional to be minimized with respect to both an intermediate super-resolved image and a nonparametric blur-kernel. The proposed approach includes a convolution consistency constraint which uses a non-blind learning-based SR result to better guide the estimation process. Another key component is the unnatural bi-l0-l2-norm regularization imposed on the super-resolved, sharp image and the blur-kernel, which is shown to be quite beneficial for estimating the blur-kernel accurately. The numerical optimization is implemented by coupling the splitting augmented Lagrangian and the conjugate gradient (CG). Using the pre-estimated blur-kernel, we finally reconstruct the SR image by a very simple non-blind SR method that uses a natural image prior. The proposed approach is demonstrated to achieve better performance than the recent method by Michaeli and Irani [2] in both terms of the kernel estimation accuracy and image SR quality

Bench-to-bedside review : targeting antioxidants to mitochondria in sepsis

Peer reviewedPublisher PD

Search for gravitational waves associated with gamma-ray bursts detected by Fermi and Swift during the LIGO–Virgo run O3b

We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC–2020 March 27 17:00 UTC). We conduct two independent searches: a generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate

Fluorous Synthesis: Fluorous Protocols for the Ugi and Biginelli Multicomponent Condensations

A new protocol for multicomponent condensation reactions that uses fluorous (highly fluorinated) substrates is introduced. This method takes advantage of the ease of purification of fluorous compounds by liquid-liquid extractions between fluorous and organic solvents. The application of this method to the Ugi and Biginelli reactions is described. The condensation products of these two reactions, amino acid amides and dihydropyrimidines, are easily obtained without chromatography in high purities, even though the other reagents are used in very large excesses. This is the first demonstration of the suitability of fluorous phase methods for combinatorial synthesis of "druglike" organic molecules

Memory of chirality in rebound cyclizations of α-amide radicals

Reduction of (S)-N-(2-bromoallyl)-N-(tert-butyl)-2-methyl-3- phenylpropanamide with tributyltin hydride provides (3S,4S)-3-benzyl-1-(tert- butyl)-3,4-dimethylpyrrolidin-2-one with about 80% retention of chirality at the stereocenter adjacent to the amide carbonyl group. This memory of chirality is suggested to occur by transfer of chirality from a stereocenter to an axis, then from the axis back to a new stereocenter. © 2012 Published by NRC Research Press

Determination of the absolute configuration of 1,3,5,7-tetramethyl-1,3- dihydroindol-2-one by optical rotation computation

The absolute configuration of 1,3,5,7-tetramethyl-1,3-dihydroindol-2-one was determined by quantum chemical calculations of specific rotation angles with coupled-perturbed Hartree-Fock methods. The computation used molecular geometries obtained from ab initio calculations as well as from molecular mechanics and semi-empirical optimization. In addition to the dependence on geometry optimization strategies, the basis set dependence of the computed rotation angle was examined

Fluorous parallel synthesis of a piperazinedione-fused tricyclic compound library

A fluorous-linker-assisted solution-phase protocol has been developed and applied to parallel synthesis of a piperazinedione-fused tricyclic compound library. The one-pot [3 + 2] cycloaddition of fluorous amino esters, aldehydes, and maleimides afforded bicyclic proline derivatives. The intermediates were subjected to N-acylation with chloroacetyl chloride, followed by displacement reactions with amines. Linker cleavage with concomitant lactamization yielded the final products. Microwave heating was employed to facilitate several reaction steps and fluorous solid phase extraction (F-SPE) was employed to purify the intermediates. During the method development, a small library containing sixteen analogs was prepared. The optimized conditions were applied to the synthesis of a production library containing ninety analogs. © 2009 American Chemical Society