Fluorinated ketones are widely prevalent in numerous biologically interesting molecules, and the development of novel transformations to access these structures is an important task in organic ...synthesis. Herein, we report the multicomponent radical acylfluoroalkylation of a variety of olefins in the presence of various commercially available aromatic aldehydes and fluoroalkyl reagents through N‐heterocyclic carbene organocatalysis. With this protocol, over 120 examples of functionalized ketones with diverse fluorine substituents have been synthesized in up to 99 % yield with complete regioselectivity. The generality of this catalytic strategy was further highlighted by its successful application in the late‐stage functionalization of pharmaceutical skeletons. Excellent diastereoselectivity could be achieved in the reactions forging multiple stereocenters. In addition, preliminary results have been achieved on the catalytic asymmetric variant of the olefin difunctionalization process.
Organocatalytic acylfluoroalkylation: A multicomponent radical acylfluoroalkylation of olefins through NHC organocatalysis was developed, and over 120 examples of fluoroketones were facilely accessed from simple materials. Moreover, a dearomative difunctionalization of indoles could be readily achieved in a highly diastereoselective manner. The generality and practicality were highlighted by the late‐stage modification of drug skeletons.
AMFlow is a Mathematica package to numerically compute dimensionally regularized Feynman integrals via the recently proposed auxiliary mass flow method. In this framework, integrals are treated as ...functions of an auxiliary mass parameter and their results can be obtained by constructing and solving linear differential systems with respect to this parameter, in an automatic way. The usage of this package is described in detail through an explicit example of double-box family involved in two-loop tt¯ hadroproduction.
Program title:AMFlow
CPC Library link to program files:https://doi.org/10.17632/nrkrw83bw5.1
Developer's repository link:https://gitlab.com/multiloop-pku/amflow
Licensing provisions: MIT
Programming language:Wolfram Mathematica 11.3 or higher
External routines:Wolfram Mathematica 1, FiniteFlow 2, LiteRed 3, Kira 4, FIRE 5
Nature of problem: Automatically obtaining high-precision numerical results for dimensionally regularized Feynman integrals at arbitrary points in phase-space.
Solution method: The program implements recently proposed auxiliary mass flow method, which introduces an auxiliary mass parameter to Feynman integrals and solves differential equations with respect to this parameter to obtain physical results.
1http://www.wolfram.com/mathematica, commercial algebraic software.2https://github.com/peraro/finiteflow, open source.3http://www.inp.nsk.su/~lee/programs/LiteRed, open source.4https://gitlab.com/kira-pyred/kira, open source.5https://bitbucket.org/feynmanIntegrals/fire, open source.
The direct functionalization of inert C(sp3)−H bonds under environmentally benign catalytic conditions remains a challenging task in synthetic chemistry. Here, we report an organocatalytic remote ...C(sp3)−H acylation of amides and cascade cyclization through a radical‐mediated 1,5‐hydrogen atom transfer mechanism using N‐heterocyclic carbene as the catalyst. Notably, a diversity of nitrogen‐containing substrates, including simple linear aliphatic carbamates and ortho‐alkyl benzamides, can be successfully applied to this organocatalytic system. With the established protocol, over 120 examples of functionalized δ‐amino ketones and isoquinolinones with diverse substituents were easily synthesized in up to 99 % yield under mild conditions. The robustness and generality of the organocatalytic strategy were further highlighted by the successful acylation of unactivated C(sp3)−H bonds and late‐stage modification of pharmaceutical molecules. Then, the asymmetric control of the radical reaction was attempted and proven feasible by using a newly designed chiral thiazolium catalyst, and moderate enantioselectivity was obtained at the current stage. Preliminary mechanistic investigations including several control reactions, KIE experiments, and computational studies shed light on the organocatalytic radical reaction mechanism.
An N‐heterocyclic carbene catalyzed remote C(sp3)−H acylation of amides was developed, and also combined with a cascade cyclization. Over 120 functionalized δ‐amino ketones and isoquinolinones with diverse substituents were synthesized in up to 99 % yield under mild conditions. Preliminary mechanistic investigations shed light on the organocatalytic radical reaction mechanism.
The neuroanatomical basis behind acupuncture practice is still poorly understood. Here, we used intersectional genetic strategy to ablate NPY+ noradrenergic neurons and/or adrenal chromaffin cells. ...Using endotoxin-induced systemic inflammation as a model, we found that electroacupuncture stimulation (ES) drives sympathetic pathways in somatotopy- and intensity-dependent manners. Low-intensity ES at hindlimb regions drives the vagal-adrenal axis, producing anti-inflammatory effects that depend on NPY+ adrenal chromaffin cells. High-intensity ES at the abdomen activates NPY+ splenic noradrenergic neurons via the spinal-sympathetic axis; these neurons engage incoherent feedforward regulatory loops via activation of distinct adrenergic receptors (ARs), and their ES-evoked activation produces either anti- or pro-inflammatory effects due to disease-state-dependent changes in AR profiles. The revelation of somatotopic organization and intensity dependency in driving distinct autonomic pathways could form a road map for optimizing stimulation parameters to improve both efficacy and safety in using acupuncture as a therapeutic modality.
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•Intersectional genetic manipulation of NPY+ sympathetic cells•Electroacupuncture stimulation (ES) drives distinct sympathetic pathways•ES operates in somatotopy- and intensity-dependent manners•NPY+ noradrenergic neurons bidirectionally modulate systemic inflammation
Liu et al. reveals a neuroanatomical basis for acupuncture practice, showing that electroacupuncture stimulation can drive distinct autonomic pathways and modulate systemic inflammation in somatotopy-, stimulation-intensity-, and disease-state-dependent manners.
We propose a novel method to compute multi-loop master integrals by constructing and numerically solving a system of ordinary differential equations, with almost trivial boundary conditions. Thus it ...can be systematically applied to problems with arbitrary kinematic configurations. Numerical tests show that our method can not only achieve results with high precision, but also be much faster than the only existing systematic method sector decomposition. As a by product, we find a new strategy to compute scalar one-loop integrals without reducing them to master integrals.
Abstract
Kilonovae are generally believed to originate from the ejecta of binary neutron stars (NSs) or black hole–NS mergers. Free neutrons might be retained in the outermost layer of the ejecta to ...produce a precursor via
β
decay. During the propagation of kilonovae to observers, a small percentage of them might be gravitationally lensed by foreground objects. In this paper, three lens models, i.e., the point-mass model, the singular isothermal sphere (SIS) model, and the Chang–Refsdal model, were taken into consideration to explore the light curves and polarizations of gravitationally lensed kilonovae. We found that, if the time delay between two images exceeds the ejecta-heating timescale for the lens mass ∼10
10
M
⊙
in the SIS model, a tiny bump-like signal will be generated in the light curve, and the total luminosity will be magnified in all cases. The polarization of lensed kilonovae is significantly enhanced in most cases. Future detections of lensed kilonovae will impose constraints on the morphology of the ejecta and aid in the determination of the nature of compact object mergers and the search for strong gravitational lenses.
Perovskite light‐emitting didoes (PeLEDs) have shown considerable potential in solution‐processable display applications. However, the performance of blue PeLEDs in terms of efficiency and stability ...hinders their practicality on account of severe trap‐mediated nonradiative recombination losses and halide phase segregation. To ameliorate these issues, mixed‐halide sky‐blue perovskite materials are strategically modulated through crystal defect passivation with a trifurcate isocyanate oligomer, which leads to the synergistical suppression of charge trap density and halide ion migration. The proposed approach enables the performance improvement for sky‐blue PeLEDs, exhibiting a peak external quantum efficiency of 14.82% and spectrally stable emission at 487 nm. In addition, prolonged operational lifetime and enhanced capability of moisture resistance are achieved simultaneously, approaching a half‐lifetime of ≈2900 s at an initial brightness of 178 cd m–2.
A trifurcate isocyanate oligomer is proposed for modulating mixed‐halide sky‐blue perovskite materials by passivating crystal defects, suppressing halide ion migration, and resisting moisture simultaneously. Sky‐blue perovskite light‐emitting diodes achieve a high external quantum efficiency of 14.82% and distinctly improved operational stability with a half‐lifetime of ≈3000 s.
By introducing an auxiliary parameter, we find a new representation for Feynman integrals, which defines a Feynman integral by analytical continuation of a series containing only vacuum integrals. ...The new representation therefore conceptually translates the problem of computing Feynman integrals to the problem of performing analytical continuations. As an application of the new representation, we use it to construct a novel reduction method for multiloop Feynman integrals, which is expected to be more efficient than the known integration-by-parts reduction method. Using the new method, we successfully reduced all complicated two-loop integrals in the gg→HH process and gg→ggg process.
The recent discovery of possible high-temperature superconductivity in single-layer FeSe films has generated significant experimental and theoretical interest. In both the cuprate and the iron-based ...high-temperature superconductors, superconductivity is induced by doping charge carriers into the parent compound to suppress the antiferromagnetic state. It is therefore important to establish whether the superconductivity observed in the single-layer sheets of FeSe--the essential building blocks of the Fe-based superconductors--is realized by undergoing a similar transition. Here we report the phase diagram for an FeSe monolayer grown on a SrTiO3 substrate, by tuning the charge carrier concentration over a wide range through an extensive annealing procedure. We identify two distinct phases that compete during the annealing process: the electronic structure of the phase at low doping (N phase) bears a clear resemblance to the antiferromagnetic parent compound of the Fe-based superconductors, whereas the superconducting phase (S phase) emerges with the increase in doping and the suppression of the N phase. By optimizing the carrier concentration, we observe strong indications of superconductivity with a transition temperature of 65±5 K. The wide tunability of the system across different phases makes the FeSe monolayer ideal for investigating not only the physics of superconductivity, but also for studying novel quantum phenomena more generally.
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