Search results for "coupling [Higgs particle]"
showing 10 items of 443 documents
Enhancing Optomechanical Coupling via the Josephson Effect
2013
Cavity optomechanics is showing promise for studying quantum mechanics in large systems. However, smallness of the radiation-pressure coupling is a serious hindrance. Here we show how the charge tuning of the Josephson inductance in a single-Cooper-pair transistor (SCPT) can be exploited to arrange a strong radiation pressure -type coupling $g_0$ between mechanical and microwave resonators. In a certain limit of parameters, such a coupling can also be seen as a qubit-mediated coupling of two resonators. We show that this scheme allows reaching extremely high $g_0$. Contrary to the recent proposals for exploiting the non-linearity of a large radiation pressure coupling, the main non-linearit…
Unprecedented Palladium-Catalyzed Cross-Coupling Reaction of α-Bromo Sulfoxides with Boronic Acids
2003
[reaction: see text] A new Suzuki-type palladium-catalyzed reaction of boronic acids with alpha-bromo sulfoxides has been developed using a protocol similar to the well-documented reaction of boronic acids with aryl halides. Both cross-coupling and homocoupling processes were observed. The best yields in cross-coupling products were obtained when the presence of oxygen was carefully excluded using degassed solvents. The oxidative addition palladium complex intermediate could be isolated and characterized by X-ray single-crystal diffraction.
Novel oxybispyridylboronic acids: synthesis and study of their reactivity in Suzuki-type cross-coupling reactions
2007
Abstract This paper sets forth the synthesis of novel oxybispyridylboronic acids, which are prepared from the corresponding halo-oxybispyridines via halogen–metal exchange using n-butyllithium and treatment with triisopropylborate. A range of efficient cross-coupling reactions of these novel boronic acids with selected aryl halides is described. This strategy produces novel pyridylethers of interest in cholinergic medicinal chemistry.
Direct arylation of heteroaromatic compounds with congested, functionalised aryl bromides at low palladium/triphosphane catalyst loading.
2011
International audience; A new ferrocenyl triphosphane ligand associated to palladium was found to be an efficient catalyst for the direct coupling of highly congested, functionalised aryl bromides with a variety of heteroarenes. These coupling reactions can generally be performed by using a low-loading (0.1-0.5 mol%) of the catalyst. The present protocol tolerates important and useful functional groups, which allows for further elaboration into more sophisticated heterocyclic molecules. The straightforward arylation of heteroaromatic compounds with congested ortho-substituted aryl bromides may permit further convergent syntheses of diverse ligands, biologically active molecules and molecula…
Cyclic Sulfoximine and Sulfonimidamide Derivatives by Copper‐Catalyzed Cross‐Coupling Reactions with Elemental Sulfur
2023
Copper-catalyzed cross-coupling reactions of α-bromoaryl NH-sulfoximines with elemental sulfur lead to benzo[d][1,3,2]dithiazole-1-oxides, which represent a new class of three-dimensional heterocycles. The reactions proceed under mild conditions showing good functional group and heterocycle tolerance. By imination/oxidation, the initial cross-coupling products can be converted to unprecedented cyclic sulfonimidamides derivatives. Furthermore, a seven-membered heterocycle was obtained by a ruthenium-catalyzed ring-expansion with ethyl propiolate. peerReviewed
Calculation of magnetic coupling constants with hybrid density functionals
2013
The currently available computational methods for the calculation of magnetic coupling constants with density functional theory have been reviewed. These methods include modern approximations to the exchangecorrelation functional, such as hybrid, range-separated and double-hybrid functionals, as well as approaches to treat the severe spin symmetry problems encountered in density functional calculations of magnetic interactions. In addition to the commonly used unrestricted Kohn–Sham formalism, density functional methods based on multireference wave functions and ensemble densities are also discussed. Performance of these models based on various studies has been summarized. The results indic…
Uncoupling Protein 2 as genetic risk factor for systemic lupus erythematosus: association with malondialdehyde levels and intima media thickness
2020
BACKGROUND Increased oxidative stress potentially leads to accelerated atherosclerosis and, consequently, cardiovascular diseases, the main cause of death in systemic lupus erythematous (SLE). To gain insight into these mechanisms, we studied the association of uncoupling protein (UCP) 2 genetic variants, gene involved in the mitochondrial production of reactive oxygen species, and oxidative stress with SLE and the presence of atherosclerosis. METHODS Genetic analysis of the UCP2 -866G/A and UCP2 Ins/Del polymorphisms was performed in 45 SLE patients and 36 healthy controls by RFLP-PCR. Oxidation status was determined by measuring malondialdehyde (MDA) levels. Presence of subclinical athero…
Wiener-Granger Causality in Network Physiology with Applications to Cardiovascular Control and Neuroscience
2016
Since the operative definition given by C. W. J. Granger of an idea expressed by N. Wiener, the Wiener–Granger causality (WGC) has been one of the most relevant concepts exploited by modern time series analysis. Indeed, in networks formed by multiple components, working according to the notion of segregation and interacting with each other according to the principle of integration, inferring causality has opened a window on the effective connectivity of the network and has linked experimental evidences to functions and mechanisms. This tutorial reviews predictability improvement, information-based and frequency domain methods for inferring WGC among physiological processes from multivariate…
1,1prime-Binaphthyl-2-methylpyridinium-based peroxophosphotungstate salts: synthesis, characterization, and their use as oxidation catalysts
2009
A series of 1,1′-binaphthyl-2-methylammonium and pyridinium salts 6, 7, and 8 was synthesized through the coupling reaction of 2-(bromomethyl)-1,1′-binaphthalene (5) with the dendritic tetraallyl pyridinedicarbinol dendron 2 as well as triethylamine and 4-tert-butylpyridine. Tetraallyl pyridinedicarbinol dendron 2 was prepared by allylation of commercially available diethyl pyridine-3,5-dicarboxylate (1). The allylation of 2 with allyltrimethylsilane in the presence of boron trifluoride was unsuccessful, as tetraallyl pyridinedicarbinol trifluoroboron adduct 3 was obtained instead of expected hexaallylpyridine compound 4. The catalytic hydrogenation of allyl groups of the ammonium salt of 2…
The strong coupling constant: State of the art and the decade ahead
2022
This document provides a comprehensive summary of the state-of-the-art, challenges, and prospects in the experimental and theoretical study of the strong coupling $\alpha_s$. The current status of the seven methods presently used to determine $\alpha_s$ based on: (i) lattice QCD, (ii) hadronic $\tau$ decays, (iii) deep-inelastic scattering and parton distribution functions fits, (iv) electroweak boson decays, hadronic final-states in (v) e+e-, (vi) e-p, and (vii) p-p collisions, and (viii) quarkonia decays and masses, are reviewed. Novel $\alpha_s$ determinations are discussed, as well as the averaging method used to obtain the PDG world-average value at the reference Z boson mass scale, $\…