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Synlett ◽  
2022 ◽  
Author(s):  
Jaideep Saha ◽  
Chenna Jagadeesh ◽  
Biplab Mondal

Capitalizing on the propensity of 1, 2-amino group migration in γ-aminocyclopentenone with a suitable promoter, gem-diaryl equipped systems unfolded an unprecedented avenue for the Lewis acid promoted displacement of γ-aniline group with nucleophiles such as indole. Such transformation, besides providing a means for direct γ-functionalization of cyclopentenones, presented innumerable scope for β, γ-annulation. Various tailored indolo bis-nucleophiles were explored in the current study that rendered an array of indole alkaloid-like compounds in excellent yields and selectivity through one-pot operation. Analysis of collective experimental observation along with designed control experiments strongly suggested the possibility of a retro aza-Piancatelli rearrangement, which is hitherto unknown in the context. Such repertoire could find potential applications in the synthesis of complex assemblies from the Piancatelli rearrangement and related processes. 1. Introduction 2. Aza-Piancatelli rearrangement and related domino processes 3. An unprecedented aza-Piancatelli-templated strategy for polycyclic assemblies 4. Summary and Outlook


2022 ◽  
Vol 12 ◽  
Author(s):  
Carmela Calabrese ◽  
Benoît G. Bardy ◽  
Pietro De Lellis ◽  
Mario di Bernardo

In human groups performing oscillatory tasks, it has been observed that the frequency of participants' oscillations reduces when compared to that acquired in solo. This experimental observation is not captured by the standard Kuramoto oscillators, often employed to model human synchronization. In this work, we aim at capturing this observed phenomenon by proposing three alternative modifications of the standard Kuramoto model that are based on three different biologically-relevant hypotheses underlying group synchronization. The three models are tuned, validated and compared against experiments on a group synchronization task, which is a multi-agent extension of the so-called mirror game.


2022 ◽  
Vol 119 (1) ◽  
pp. e2108653119
Author(s):  
Hyunseok Lee ◽  
Jeff Gore ◽  
Kirill S. Korolev

Most organisms grow in space, whether they are viruses spreading within a host tissue or invasive species colonizing a new continent. Evolution typically selects for higher expansion rates during spatial growth, but it has been suggested that slower expanders can take over under certain conditions. Here, we report an experimental observation of such population dynamics. We demonstrate that mutants that grow slower in isolation nevertheless win in competition, not only when the two types are intermixed, but also when they are spatially segregated into sectors. The latter was thought to be impossible because previous studies focused exclusively on the global competitions mediated by expansion velocities, but overlooked the local competitions at sector boundaries. Local competition, however, can enhance the velocity of either type at the sector boundary and thus alter expansion dynamics. We developed a theory that accounts for both local and global competitions and describes all possible sector shapes. In particular, the theory predicted that a slower on its own, but more competitive, mutant forms a dented V-shaped sector as it takes over the expansion front. Such sectors were indeed observed experimentally, and their shapes matched quantitatively with the theory. In simulations, we further explored several mechanisms that could provide slow expanders with a local competitive advantage and showed that they are all well-described by our theory. Taken together, our results shed light on previously unexplored outcomes of spatial competition and establish a universal framework to understand evolutionary and ecological dynamics in expanding populations.


2022 ◽  
Vol 258 ◽  
pp. 02007
Author(s):  
Edward Shuryak

Exclusive processes are traditionally described by perturbative hard blocks and “distribution amplitudes" (DAs), matrix elements of operators of various chiral structure and twist. One paper (with I.Zahed) calculate instanton contribution to hard blocks, which is found comparable to perturbative one in few-GeV2 Q2 region of interest. Another paper aims at comprehensive wave functions of mesons, baryons and pentaquarks. The last ones are also included as 5-quark component of the baryons. The calculation, using ’t Hooft operator, gives x-dependence and magnitude of the antiquark PDF. It explains long standing issue of strong flavor asymmetry of antiquark sea. The third paper (also with I.Zahed) is semi-review on the instanton-sphaleron processes in QCD and electroweak theories, with emphasis on their possible experimental observation via double diffractive events at LHC and RHIC. Insert your english abstract here.


Author(s):  
Nickolay V. Kinev ◽  
Kirill I. Rudakov ◽  
Lyudmila V. Filippenko ◽  
Valery P Koshelets

2021 ◽  
Vol 104 (6) ◽  
Author(s):  
Dafa Zhao ◽  
Shunzhong Xue ◽  
Dong Ruan ◽  
Jun Li ◽  
Dawei Lu ◽  
...  

2021 ◽  
Vol 933 ◽  
Author(s):  
Yanju Wei ◽  
Zhiqiang Mu ◽  
Yajie Zhang ◽  
Yajing Yang ◽  
Shenghua Liu ◽  
...  

This work reports experimental observation and theoretical explanation of the dynamics and morphology of a droplet passing through a soap film. During the process, the film undergoes four sequential responses: (1) film deformation upon droplet impact; (2) drop–film detachment; (3) coalescence of the film shell with the drop; (4) peel-off of the film shell. Physical models and the corresponding analytical expressions are developed to reveal the underlying physics for the observed four responses. It is identified that the film is an elongated catenoid under continuous stretch by the droplet, and that they separate at the fixed height of 5.8 times of the droplet radius while the detach point is located at the centre of the height. After separation, the droplet is wrapped with a film shell, which is then punctured by the ring tip of the converging surface wave at the impacting Weber number range of [45, 225]. The film shell then coalesces with the droplet, falls off with a fixed velocity and is eventually ejected as a bubble leaving the droplet with a transplanted surface of the soap solution.


2021 ◽  
Vol 104 (23) ◽  
Author(s):  
Huanhuan Yang ◽  
Lingling Song ◽  
Yunshan Cao ◽  
X. R. Wang ◽  
Peng Yan

Atoms ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 108
Author(s):  
Alexei V. Meremianin ◽  
Nikolai L. Manakov

The polarization dependence of the photoionization probability was analyzed in the case when a randomly oriented atom is irradiated by two crossing polarized monochromatic photon beams with the same frequency. It was found that the angular distributions of photoelectrons exhibit the effect of circular dichroism (CD), which consists of the dependence of the photoionization probability on the sign of the circular polarization degree of each beam. We demonstrate that the CD effect exists only for coherent crossing photon beams. It was shown that CD effects are strongly dependent on the phase difference between the electric field vectors of the photon beams and have a quite large magnitude. The possibilities of the experimental observation of CD effects are discussed.


2021 ◽  
Vol 7 (49) ◽  
Author(s):  
Julio Andrés Iglesias Martínez ◽  
Michael Fidelis Groß ◽  
Yi Chen ◽  
Tobias Frenzel ◽  
Vincent Laude ◽  
...  

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