Despite the great potential of radical chemistry in organic synthesis, N‐heterocyclic carbene (NHC)‐catalyzed reactions involving radical intermediates are not well explored. This communication ...reports the three‐component coupling of aroyl fluorides, styrenes and the Langlois reagent (CF3SO2Na) to give various β‐trifluoromethylated alkyl aryl ketones with good functional group tolerance in moderate to high yields by cooperative photoredox/NHC catalysis. The alkene acyltrifluoromethylation proceeds via radical/radical cross coupling of ketyl radicals with benzylic C‐radicals. The ketyl radicals are generated via SET reduction of in situ formed acylazolium ions whereas the benzylic radicals derive from trifluoromethyl radical addition onto styrenes.
Photoredox and NHC catalysis in concert: A novel strategy for the preparation of β‐trifluoromethylketones via radical alkene acyltrifluoromethylation has been developed. The three‐component cascades proceed under mild conditions with readily available aroyl fluorides, styrenes and the Langlois reagent as the reaction partners.
Since its discovery in December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected more than 2 180 000 people worldwide and has caused more than 150 000 deaths as of ...April 16, 2020. SARS-CoV-2, which is the virus causing coronavirus disease 2019 (COVID-19), uses the angiotensin-converting enzyme 2 (ACE2) as a cell receptor to invade human cells. Thus, ACE2 is the key to understanding the mechanism of SARS-CoV-2 infection. This study is to investigate the ACE2 expression in various human tissues in order to provide insights into the mechanism of SARS-CoV-2 infection.
We compared ACE2 expression levels across 31 normal human tissues between males and females and between younger (ages ≤ 49 years) and older (ages > 49 years) persons using two-sided Student's t test. We also investigated the correlations between ACE2 expression and immune signatures in various tissues using Pearson's correlation test.
ACE2 expression levels were the highest in the small intestine, testis, kidneys, heart, thyroid, and adipose tissue, and were the lowest in the blood, spleen, bone marrow, brain, blood vessels, and muscle. ACE2 showed medium expression levels in the lungs, colon, liver, bladder, and adrenal gland. ACE2 was not differentially expressed between males and females or between younger and older persons in any tissue. In the skin, digestive system, brain, and blood vessels, ACE2 expression levels were positively associated with immune signatures in both males and females. In the thyroid and lungs, ACE2 expression levels were positively and negatively associated with immune signatures in males and females, respectively, and in the lungs they had a positive and a negative correlation in the older and younger groups, respectively.
Our data indicate that SARS-CoV-2 may infect other tissues aside from the lungs and infect persons with different sexes, ages, and races equally. The different host immune responses to SARS-CoV-2 infection may partially explain why males and females, young and old persons infected with this virus have markedly distinct disease severity. This study provides new insights into the role of ACE2 in the SARS-CoV-2 pandemic.
Methods that enable site selective acylation of sp
C-H bonds in complex organic molecules are not well explored, particularly if compared with analogous transformations of aromatic and vinylic sp
C-H ...bonds. We report herein a direct acylation of benzylic C-H bonds by merging N-heterocyclic carbene (NHC) and photoredox catalysis. The method allows the preparation of a diverse range of benzylic ketones with good functional group tolerance under mild conditions. The reaction can be used to install acyl groups on highly functionalized natural product derived compounds and the C-H functionalization works with excellent site selectivity. The combination of NHC and photoredox catalysis offers options in preparing benzyl aryl ketones.
The public's voluntary adoption of protective actions is key in risk management, especially when strict regulations no longer apply. This research uses a nationwide sample to understand how cultural ...worldview influences public adoption of four protective actions against the spread of coronavirus (COVID-19) following the end of the first lockdown in China. Relying on Grid-Group Cultural Theory of risk and the Protective Action Decision Model, this research finds that cultural worldview rarely influences protective behaviors directly. However, mediational analyses reveal that cultural worldview can influence protective behaviors via protective action perception and trust in stakeholders but not via risk perception. This research finds that protective action perception and trust in stakeholders increase protective behaviors and the positive correlation between trust in stakeholders and protective behaviors is mediated by protective action perception. Moreover, hierarchy increases protective action perception and trust in stakeholders, individualism increases protective action perception but decreases trust in stakeholders, and fatalism decreases protective action perception. Other correlations of cultural worldview with protective action perception and trust in stakeholders vary with types of protective actions. These findings provide implications for behavioral governance and risk communication among diverse cultural groups.
How does the organizational culture of local governments influence the type and extent of procedural justice in environmental policy processes? Using the culture theory developed by Mary Douglas and ...others, this research seeks to bring a new conception and new measures of organizational culture to the study of policy making by local governments. To contribute to the development of the conceptualization and measurement of procedural justice in the environmental policy processes of those governments, item response theory (IRT) graded response model (GRM) is used to show variations in difficulties and frequencies of adopting distinctive public participation strategies for improving procedural justice across local governments. In this study, original survey data is collected from Illinois municipalities and a finding is suggestive of cultural variables explaining the two dimensions of procedural justice, equal and authentic public participation, while other variables can, at best, explain only the equal public participation. Furthermore, as hypothesized, egalitarianism increases both equal and authentic public participation, individualism increases equal public participation, and fatalism decreases both.
Chronic stress refers to the non-specific systemic reaction that occurs when the body is stimulated by various internal and external negative factors over a long time. The physiological response to ...chronic stress exposure has long been recognized as a potent modulator in the occurrence of atherosclerosis. Furthermore, research has confirmed the correlation between atherosclerosis and cardiovascular events. Chronic stress is pervasive during negative life events and may lead to the formation of plaque. Several epidemiological studies have shown that chronic stress is an independent risk factor for the development of vascular disease and for increased morbidity and mortality in patients with pre-existing coronary artery disease. One possible mechanism for this process is that chronic stress causes endothelial injury, directly activating macrophages, promoting foam cell formation and generating the formation of atherosclerotic plaque. This mechanism involves numerous variables, including inflammation, signal pathways, lipid metabolism and endothelial function. The mechanism of chronic stress in atherosclerosis should be further investigated to provide a theoretical basis for efforts to eliminate the effect of chronic stress on the cardiocerebral vascular system.
The development of highly efficient, multifunctional, and biocompatible sonosensitizer is still a priority for current sonodynamic therapy (SDT). Herein, a defect‐rich Ti‐based metal–organic ...framework (MOF) (D‐MOF(Ti)) with greatly improved sonosensitizing effect is simply constructed and used for enhanced SDT. Compared with the commonly used sonosensitizer TiO2, D‐MOF(Ti) results in a superior reactive oxygen species (ROS) yield under ultrasound (US) irradiation due to its narrow bandgap, which principally improves the US‐triggered electron–hole separation. Meanwhile, due to the existence of Ti3+ ions, D‐MOF(Ti) also exhibits a high level of Fenton‐like activity to enable chemodynamic therapy. Particularly, US as the excitation source of SDT can simultaneously enhance the Fenton‐like reaction to achieve remarkably synergistic outcomes for oncotherapy. More importantly, D‐MOF(Ti) can be degraded and metabolized out of the body after completion of its therapeutic functions without off‐target toxicity. Overall, this work identifies a novel Ti‐familial sonosensitizer harboring great potential for synergistic sonodynamic and chemodynamic cancer therapy.
A defect‐rich Ti‐based metal–organic framework (MOF) (D‐MOF(Ti)) is successfully constructed by simple hydrogenation and serves as a new generation of robust sonosensitizer for enhanced sonodynamic therapy. Moreover, it also exhibits a high level of Fenton‐like activity to amplify production of reactive oxygen species under ultrasound irradiation. Besides, the degradability of D‐MOF(Ti) is a bright spot for promoting its clinical transformation.
We report herein that thermodynamic and kinetic isomerization of alkenes can be accomplished by the combination of visible light with Co catalysis. Utilizing Xantphos as the ligand, the most stable ...isomers are obtained, while isomerizing terminal alkenes over one position can be selectively controlled by using DPEphos as the ligand. The presence of the donor–acceptor dye 4CzIPN accelerates the reaction further. Transformation of exocyclic alkenes into the corresponding endocyclic products could be efficiently realized by using 4CzIPN and Co(acac)2 in the absence of any additional ligands. Spectroscopic and spectroelectrochemical investigations indicate CoI being involved in the generation of a Co hydride, which subsequently adds to alkenes initiating the isomerization.
A mild and highly efficient translocation of alkenes by dual visible‐light‐cobalt catalysis has been developed. By the proper choice of ligands, isomerization over one position or more than one position with tolerance of a variety of functional groups can be selectively achieved.
Purpose/significance Under the background of organizational networking and knowledge becoming the core element of the organization, it aims to visually recognize the present situation and development ...of knowledge network research at home and abroad, and provide an important basis for knowledge network research and network innovation and development. Method/process Based on the idea and method of scientific knowledge map, VOSviewer and CiteSpace were comprehensively used, and the "knowledge network" documents of management discipline collected in the core database of Web of Science from 2001 to 2020 were taken as samples to draw the knowledge map and analyze the literature contents, summarized the research status of international knowledge network, revealed its research hotspots, built its content integration framework, and explored its frontier trends. Result/conclusion Finally, four fields of knowledge network research of personal field, enterprise field, regional field and professional field, and four
We report the efficient carboxylation of bromides and triflates with K2CO3 as the source of CO2 in the presence of an organic photocatalyst in combination with a nickel complex under visible light ...irradiation at room temperature. The reaction is compatible with a variety of functional groups and has been successfully applied to the synthesis and derivatization of biologically active molecules. In particular, the carboxylation of unactivated cyclic alkyl bromides proceeded well with our protocol, thus extending the scope of this transformation. Spectroscopic and spectroelectrochemical investigations indicated the generation of a Ni0 species as a catalytic reactive intermediate.
Not only good for plants, CO2 (formed in situ from K2CO3) and light enabled the efficient and mild carboxylation of bromides and triflates in the presence of an organic fluorophore and a nickel complex (see scheme). A variety of functional groups were tolerated, and non‐activated cyclic alkyl bromides reacted well. The synthesis and derivatization of biologically active molecules demonstrated the applicability of the method in multistep synthesis.
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