The main contributions in the field of first-row transition-metal-catalyzed (base-metal-catalyzed) carbonylative transformations have been summarized and discussed. The contents have been divided ...according to the electrophiles applied, followed by the different types of nucleophiles. Their reaction mechanisms and applications have been emphatically discussed.
Thermal barrier coatings (TBCs) can effectively protect the alloy substrate of hot components in aeroengines or land-based gas turbines by the thermal insulation and corrosion/erosion resistance of ...the ceramic top coat. However, the continuous pursuit of a higher operating temperature leads to degradation, delamination, and premature failure of the top coat. Both new ceramic materials and new coating structures must be developed to meet the demand for future advanced TBC systems. In this paper, the latest progress of some new ceramic materials is first reviewed. Then, a comprehensive spalling mechanism of the ceramic top coat is summarized to understand the dependence of lifetime on various factors such as oxidation scale growth, ceramic sintering, erosion, and calcium-magnesium-aluminium-silicate (CMAS) molten salt corrosion. Finally, new structural design methods for high-performance TBCs are discussed from the perspectives of lamellar, columnar, and nanostructure inclusions. The latest developments of ceramic top coat will be presented in terms of material selection, structural design, and failure mechanism, and the comprehensive guidance will be provided for the development of next-generation advanced TBCs with higher temperature resistance, better thermal insulation, and longer lifetime.
The development of highly selective procedures is one of the core goals in organic chemistry. Among the known organic transformations, carbonylation reactions present an ideal choice for the ...preparation of carbonyl‐containing compounds. In this review, the recent achievements on the control of the selectivity for carbonylation reactions have been summarized. The effects of ligands, solvents, and bases on the selectivity are been discussed.
Control switch: The recent achievements on the control of the selectivity for carbonylation reactions have been summarized. The effects of ligands, solvents, and bases on the selectivity are discussed.
Verticillium dahliae isolates are most virulent on the host from which they were originally isolated. Mechanisms underlying these dominant host adaptations are currently unknown. We sequenced the ...genome of V. dahliae Vd991, which is highly virulent on its original host, cotton, and performed comparisons with the reference genomes of JR2 (from tomato) and VdLs.17 (from lettuce).
Pathogenicity-related factor prediction, orthology and multigene family classification, transcriptome analyses, phylogenetic analyses, and pathogenicity experiments were performed.
The Vd991 genome harbored several exclusive, lineage-specific (LS) genes within LS regions (LSRs). Deletion mutants of the seven genes within one LSR (G-LSR2) in Vd991 were less virulent only on cotton. Integration of G-LSR2 genes individually into JR2 and VdLs.17 resulted in significantly enhanced virulence on cotton but did not affect virulence on tomato or lettuce. Transcription levels of the seven LS genes in Vd991 were higher during the early stages of cotton infection, as compared with other hosts. Phylogenetic analyses suggested that G-LSR2 was acquired from Fusarium oxysporum f. sp. vasinfectum through horizontal gene transfer.
Our results provide evidence that horizontal gene transfer from Fusarium to Vd991 contributed significantly to its adaptation to cotton and may represent a significant mechanism in the evolution of an asexual plant pathogen.
Functional group transfer reactions are an important synthetic tool in modern organic synthesis. Herein, we developed a new palladium-catalyzed intermolecular transthioetherification reaction of aryl ...halides with thioethers and thioesters. The synthetic utility and practicality of this catalytic protocol are demonstrated in a wide range of successful transformations (>70 examples). This catalytic protocol is applicable in carbonylative coupling processes as well, and the first example of carbonylative methylthioesterification of aryl halides has been achieved. Notably, this work also provides an approach to using natural products, such as methionine and selenomethionine, as the functional group sources.
Functional group transfer reactions are an important synthetic tool in modern organic synthesis.
Nitrile compounds containing ester and amide groups are important functionalized chemicals in synthetic and medicinal chemistry. In this article, an efficient and convenient palladium‐catalyzed ...carbonylative procedure toward 2‐cyano‐N‐acetamide and 2‐cyanoacetate compounds has been developed. The reaction proceeds under mild conditions via radical intermediate which is suitable for late‐stage functionalization. Gram‐scale experiment was performed successfully under low catalyst loading and gave the target product in excellent yield. Additionally, this transformation can be performed under atmospheric pressure and provide alternative routes to 7 drug precursors.
A new and convenient procedure for the palladium‐catalyzed carbonylation of bromoacetonitrile has been developed. A variety of valuable 2‐cyano‐N‐acetamide and 2‐cyanoacetate compounds were obtained in good to excellent yields under mild reaction conditions. Furthermore, this transformation can be carried out under atmospheric pressure and provides an alternative route to 7 drug compounds.
Owing to their outstanding comprehensive performance, polyimide (PI) composite films are widely used on the external surfaces of spacecraft to protect them from the adverse conditions of low Earth ...orbit (LEO). However, current PI composite films have inadequate mechanical properties and atomic oxygen (AO) resistance. Herein, this work fabricates a new PI‐based nanocomposite film with greatly enhanced mechanical properties and AO resistance by integrating mica nanosheets with PI into a unique double‐layer nacre‐inspired structure with a much higher density of mica nanosheets in the top layer. In addition, the unique microstructure and the intrinsic properties of mica also impart the nanocomposite film with favorable ultraviolet and high‐temperature resistance. The comprehensive performance of this material is superior to those of pure PI, single‐layer PI‐mica, and previously reported PI‐based composite films. Thus, the double‐layer nanocomposite film displays great potential as an aerospace material for use in LEO.
A polyimide‐mica (PI‐Mica) nanocomposite film with outstanding mechanical properties and atomic oxygen resistance is produced by integrating mica nanosheets with polyimide into a double‐layer nacre‐inspired structure with a much higher density of mica in the top layer. This unique microstructure and advantages of mica also impart the film with favorable resistance to ultraviolet, space debris, and high temperatures.
The re-emergence of Zika virus (ZIKV) in the Western Hemisphere has resulted in global public health crisis since 2015. ZIKV preferentially infects and targets human neural progenitor cells (hNPCs) ...and causes fetal microcephaly upon maternal infection. hNPCs not only play critical roles during fetal brain development, but also persist in adult brain throughout life. Yet the mechanism of innate antiviral immunity in hNPCs remains largely unknown. Here, we show that ZIKV infection triggers the abundant production of virus-derived small interfering RNAs in hNPCs, but not in the more differentiated progenies or somatic cells. Ablation of key RNAi machinery components significantly enhances ZIKV replication in hNPCs. Furthermore, enoxacin, a broad-spectrum antibiotic that is known as an RNAi enhancer, exerts potent anti-ZIKV activity in hNPCs and other RNAi-competent cells. Strikingly, enoxacin treatment completely prevents ZIKV infection and circumvents ZIKV-induced microcephalic phenotypes in brain organoid models that recapitulate human fetal brain development. Our findings highlight the physiological importance of RNAi-mediated antiviral immunity during the early stage of human brain development, uncovering a novel strategy to combat human congenital viral infections through enhancing RNAi.
Dyes can CO do it: Organic dyes and pigments are usually applied in textile dyeing, which can be dated back to the Neolithic period. Interestingly, the possibility to use organic dyes as photoredox ...catalysts has also been noticed by organic chemists and applied in organic synthesis. Carbonylation reactions as a powerful procedure in carbonyl‐containing compound preparation have also been studied. In this manuscript, the recent achievements in using organic dyes as visible‐light sensitizers in carbonylation chemistry are summarized and discussed.
Development of fluorometric chemosensors for the detection of hypochlorous acid.
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•The development and application of HOCl fluorescent probes were summarized.•These HOCl probes were ...divided according to various recognition groups.•Many large challenges still remain in the application of HOCl fluorescent probes for imaging in vivo.
As one of the reactive oxygen species, hypochlorous acid (HOCl) may be associated with various diseases. To understand the roles of HOCl in living organism, fluorescent probes for imaging HOCl in living systems have been developed fast in recent years owing to their high selectivity, excellent sensitivity and spectral resolution. In this review, we summarized and highlighted the recent advances in the development and application of HOCl fluorescent probes. This review is focused on the detection mechanisms of probes for HOCl. According to the various recognition groups, we divided the HOCl fluorescence probes into five parts and discussed detection mechanisms, respectively.
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