We report herein the first examples of a palladium‐catalyzed enantioselective Cacchi reaction for the synthesis of indoles bearing a chiral C2‐aryl axis. In the presence of a catalytic amount of ...Pd(OAc)2 and (R,R)‐QuinoxP* ligand, reaction of N‐aryl(alkyl)sulfonyl‐2‐alkynylanilides with arylboronic acids under oxygen atmosphere afforded enantioenriched 2,3‐disubstituted indoles in high yields and enantioselectivity. The indole ring is constructed de novo in this process and a complexation‐induced chirality transfer is proposed to account for the observed enantioselectivity.
Axially chiral indoles: In the presence of a chiral QuinoxP*PdII complex, two simple achiral building blocks undergo cyclizative cross‐coupling to afford 2,3‐disubstituted indoles bearing a C2‐aryl chiral axis in high yields and enantioselectivity. The indole ring is constructed de novo in this process and a complexation‐induced chirality transfer is proposed to account for the observed enantioselectivity.
The coronavirus disease (COVID-19) has been identified as the cause of an outbreak of respiratory illness in Wuhan, Hubei Province, China beginning in December 2019. As of 31 January 2020, this ...epidemic had spread to 19 countries with 11 791 confirmed cases, including 213 deaths. The World Health Organization has declared it a Public Health Emergency of International Concern.
A scoping review was conducted following the methodological framework suggested by Arksey and O'Malley. In this scoping review, 65 research articles published before 31 January 2020 were analyzed and discussed to better understand the epidemiology, causes, clinical diagnosis, prevention and control of this virus. The research domains, dates of publication, journal language, authors' affiliations, and methodological characteristics were included in the analysis. All the findings and statements in this review regarding the outbreak are based on published information as listed in the references.
Most of the publications were written using the English language (89.2%). The largest proportion of published articles were related to causes (38.5%) and a majority (67.7%) were published by Chinese scholars. Research articles initially focused on causes, but over time there was an increase of the articles related to prevention and control. Studies thus far have shown that the virus' origination is in connection to a seafood market in Wuhan, but specific animal associations have not been confirmed. Reported symptoms include fever, cough, fatigue, pneumonia, headache, diarrhea, hemoptysis, and dyspnea. Preventive measures such as masks, hand hygiene practices, avoidance of public contact, case detection, contact tracing, and quarantines have been discussed as ways to reduce transmission. To date, no specific antiviral treatment has proven effective; hence, infected people primarily rely on symptomatic treatment and supportive care.
There has been a rapid surge in research in response to the outbreak of COVID-19. During this early period, published research primarily explored the epidemiology, causes, clinical manifestation and diagnosis, as well as prevention and control of the novel coronavirus. Although these studies are relevant to control the current public emergency, more high-quality research is needed to provide valid and reliable ways to manage this kind of public health emergency in both the short- and long-term.
Recently, ambient electrochemical N2 fixation has gained great attention. However, the commercial Pt‐based electrocatalyst hardly shows its potential in this field. Herein, it is found that the ...isolated Pt sites anchored on WO3 nanoplates exhibit the optimum electrochemical NH3 yield rate (342.4 µg h−1 mg−1Pt) and Faradaic efficiency (31.1%) in 0.1 m K2SO4 at −0.2 V versus RHE, which are about 11 and 15 times higher than their nanoparticle counterparts, respectively. The mechanistic analysis indicates that N2 conversion to NH3 follows an alternating hydrogenation pathway, and positively charged isolated Pt sites with special Pt−3O structure can favorably chemisorb and activate the N2. Furthermore, the hydrogen evolution reaction can be greatly suppressed on isolated Pt sites decorated WO3 nanoplates, which guarantees the efficient going‐on of nitrogen reduction reaction.
Isolated Pt atoms anchored on WO3 nanoplates exhibit highly active for ambient ammonia electrosynthesis, which is ascribed to facilitated chemisorption and activation of nitrogen and effective suppression for hydrogen evolution reaction (HER), immensely enhancing NH3 yield rate and Faradic efficiency. This groundbreaking research presents Pt‐based nanocatalysts for electroreduction of nitrogen and provides an idea for the HER depression.
Domino processes initiated by intramolecular nucleopalladation of alkynes have been developed into powerful synthetic tools for the synthesis of functionalized heterocycles. However, a catalytic ...enantioselective version of this class of reactions remains scarce. We report herein that reaction of 2‐alkynylanilines with prochiral cyclopentenes in the presence of a catalytic amount of Pd(OAc)2, a chiral bidentate pyrox ligand and O2 as terminal oxidant affords the structurally diverse indole‐cyclopentene conjugates bearing two stereocenters in a highly diastereo‐ and enantio‐selective manner. One of the products is converted to a heavily functionalized tetracyclic indolinone derivative.
Reaction of 2‐alkynylanilines with prochiral cyclopentenes in the presence of a catalytic amount of Pd(OAc)2, a chiral bidentate pyrox ligand and O2 as terminal oxidant affords structurally diverse indole‐cyclopentene conjugates bearing two stereocenters in a highly diastereo‐ and enantio‐selective manner.
Fredrickson and Roberts (1997) proposed objectification theory as an integrative framework for understanding how women's socialization and experiences of sexual objectification are translated into ...mental health problems. This article reviews the past decade of research grounded in objectification theory and highlights needed directions for future scholarship in this area. Specifically, this article reviews research organized according to the following themes: (a) self-objectification and its proposed consequences, (b) sexual objectification experiences as a proposed precursor, and (c) disconnections from bodily functions. An overview of emerging objectification theory research with men is also provided. The review concludes with needed directions for future theoretical and research efforts aimed to advance the psychology of women.
The consensus problem for multi-agent systems with input and communication delays is studied based on the frequency-domain analysis. Two decentralized consensus conditions are obtained, one of which ...is given for the systems based on undirected graphs with diverse input delays and the other is for the systems based on directed graphs with diverse communication delays and input delays. For the systems with both communication delays and input delays, the consensus condition is dependent on input delays but independent of communication delays.
Water splitting for the production of hydrogen and oxygen is an appealing solution to advance many sustainable and renewable energy conversion and storage systems, while the key fact depends on the ...innovative exploration regarding the design of efficient electrocatalysts. Reported herein is the growth of CoP mesoporous nanorod arrays on conductive Ni foam through an electrodeposition strategy. The resulting material of well‐defined mesoporosity and a high specific surface area (148 m2 g−1) can be directly employed as a bifunctional and flexible working electrode for both hydrogen and oxygen evolution reactions, showing superior activities as compared with noble metal benchmarks and state‐of‐the‐art transition‐metal‐based catalysts. This is intimately related to the unique nanorod array electrode configuration, leading to excellent electric interconnection and improved mass transport. A further step is taken toward an alkaline electrolyzer that can achieve a current density of 10 mA cm−2 at a voltage around 1.62 V over a long‐term operation, better than the combination of Pt and IrO2. This development is suggested to be readily extended to obtain other electrocatalysis systems for scale‐up water‐splitting technology.
Flexible, bifunctional electrodes with self‐supported CoP mesoporous nanorod arrays are fabricated through an electrodeposition strategy. The electrodes possess well‐structured mesoporosity and a high specific surface area, exhibiting high activities toward both electrochemical hydrogen and oxygen evolution reactions. In a further step, an alkaline electrolyzer with a current density of 10 mA cm−2 at 1.62 V in a long‐term operation is realized.
Summary
In order to enable the multi‐agents to elliptically circumnavigate the multi‐targets in more complex environment, we propose a geometric center estimator and an elliptical circumnavigation ...controller in two‐dimensional space by only employing bearing measurements without knowing the target's position and velocity. The stability of the algorithm is proved for both stationary targets and dynamic targets. Finally, a series of numerical simulations is presented to verify the correctness of the algorithm both in ideal networks and in networks with communication delays.
Functional magnetic resonance imaging data are commonly collected during the resting state. Resting state functional magnetic resonance imaging (rs‐fMRI) is very practical and applicable for a wide ...range of study populations. Rs‐fMRI is usually collected in at least one of three different conditions/tasks, eyes closed (EC), eyes open (EO), or eyes fixated on an object (EO‐F). Several studies have shown that there are significant condition‐related differences in the acquired data. In this study, we compared the functional network connectivity (FNC) differences assessed via group independent component analysis on a large rs‐fMRI dataset collected in both EC and EO‐F conditions, and also investigated the effect of covariates (e.g., age, gender, and social status score). Our results indicated that task condition significantly affected a wide range of networks; connectivity of visual networks to themselves and other networks was increased during EO‐F, while EC was associated with increased connectivity of auditory and sensorimotor networks to other networks. In addition, the association of FNC with age, gender, and social status was observed to be significant only in the EO‐F condition (though limited as well). However, statistical analysis did not reveal any significant effect of interaction between eyes status and covariates. These results indicate that resting‐state condition is an important variable that may limit the generalizability of clinical findings using rs‐fMRI.
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