Burgers-type equations are used to describe certain phenomena in gas dynamics, traffic flow, plasma astrophysics and ocean dynamics. In this paper, a (2
+
1)-dimensional generalized Burgers system ...with the variable coefficients in a fluid is investigated. We obtain the Painlevé-integrable constraints of the system with respect to the variable coefficients. Based on the truncated Painlevé expansions, an auto-Bäcklund transformation is constructed, along with some soliton solutions. Via a truncated Painlevé expansions, certain multiple kink solutions are derived. Via a complex-conjugate transformation, some breather solutions, half-periodic kink solutions and hybrid solutions composed of the breathers and kink waves are seen.
Covalent organic frameworks (COF) are complex functional systems constructed with atomic precision by linking well‐defined building blocks through robust covalent bonds. β‐cyclodextrin (β‐CD) is a ...most employed supramolecule which bears a hydrophobic cavity guiding molecular specific recognitions. Building COF with asymmetric β‐CD linkers is challenging and has never been reported. Here, β‐CD COF is grown with heptakis(6‐amino‐6‐deoxy)‐β‐CD and terephthalaldehyde in green solvents of water and ethanol at room temperature. The COF is characterized by powder X‐ray diffraction, which matches well with the simulated crystal structure. Weaving β‐CD into a framework through reticular chemistry allows the integration of a large amount of β‐CD units (50 mol %), much higher than β‐CD polymers. The β‐CD COF has larger surface area, more uniform pore size, and higher thermal stability than the non‐crystalline β‐CD polymer produced by the same reagents. Finally, the β‐CD COF holds abundant specific interaction sites enabling selective molecular adsorption.
Porous β‐cyclodextrin (CD) cubic poles: The first success of using an asymmetric supramolecular building block, β‐CD, for the construction of a covalent organic framework. The framework is built from heptakis(6‐amino‐6‐deoxy)‐β‐CD and terephthalaldehyde under acid catalysis in aqueous ethanol at room temperature. It exhibits a morphology of cubic poles, with an average width of 125 nm. The material has a high surface area, uniform pore size, and abundant β‐CD units, enabling highly selective molecular adsorption in water.
Photocatalytic reduction of CO2 to solar fuels and/or fine chemicals is a promising way to increase the energy supply and reduce greenhouse gas emissions. However, the conventional reaction system ...for CO2 photoreduction with pure H2O or sacrificial agents usually suffers from low catalytic efficiency, poor stability, or cost‐ineffective atom economy. A recent surge of developments, in which photocatalytic CO2 valorization is integrated with selective organic synthesis into one reaction system, indicates an efficient modus operandi that enables sufficient utilization of photogenerated electrons and holes to achieve the goals for sustainable economic and social development. In this Review we discuss current advances in cooperative photoredox reaction systems that integrate CO2 valorization with organics upgrading based on heterogeneous photocatalysis. The applications and virtues of this strategy and the underlying reaction mechanisms are discussed. The ongoing challenges and prospects in this area are critically discussed.
The photoredox‐catalyzed win–win coupling strategy, in which CO2 valorization is integrated with organic synthesis in one reaction system, provides a promising approach that enables sufficient utilization of excited electrons and holes to achieve feasible and sustainable light‐mediated artificial photosynthesis.
Abstract
With the goal of charting plant transcriptional regulatory maps (i.e. transcription factors (TFs), cis-elements and interactions between them), we have upgraded the TF-centred database ...PlantTFDB (http://planttfdb.cbi.pku.edu.cn/) to a plant regulatory data and analysis platform PlantRegMap (http://plantregmap.cbi.pku.edu.cn/) over the past three years. In this version, we updated the annotations for the previously collected TFs and set up a new section, ‘extended TF repertoires’ (TFext), to allow users prompt access to the TF repertoires of newly sequenced species. In addition to our regular TF updates, we are dedicated to updating the data on cis-elements and functional interactions between TFs and cis-elements. We established genome-wide conservation landscapes for 63 representative plants and then developed an algorithm, FunTFBS, to screen for functional regulatory elements and interactions by coupling the base-varied binding affinities of TFs with the evolutionary footprints on their binding sites. Using the FunTFBS algorithm and the conservation landscapes, we further identified over 20 million functional TF binding sites (TFBSs) and two million functional interactions for 21 346 TFs, charting the functional regulatory maps of these 63 plants. These resources are publicly available at PlantRegMap (http://plantregmap.cbi.pku.edu.cn/) and a cloud-based mirror (http://plantregmap.gao-lab.org/), providing the plant research community with valuable resources for decoding plant transcriptional regulatory systems.
Melatonin regulates broad aspects of plant responses to various biotic and abiotic stresses, but the upstream regulation of melatonin biosynthesis by these stresses remains largely unknown. Herein, ...we demonstrate that transcription factor heat‐shock factor A1a (HsfA1a) conferred cadmium (Cd) tolerance to tomato plants, in part through its positive role in inducing melatonin biosynthesis under Cd stress. Analysis of leaf phenotype, chlorophyll content, and photosynthetic efficiency revealed that silencing of the HsfA1a gene decreased Cd tolerance, whereas its overexpression enhanced plant tolerance to Cd. HsfA1a‐silenced plants exhibited reduced melatonin levels, and HsfA1a overexpression stimulated melatonin accumulation and the expression of the melatonin biosynthetic gene caffeic acid O‐methyltransferase 1 (COMT1) under Cd stress. Both an in vitro electrophoretic mobility shift assay and in vivo chromatin immunoprecipitation coupled with qPCR analysis revealed that HsfA1a binds to the COMT1 gene promoter. Meanwhile, Cd stress induced the expression of heat‐shock proteins (HSPs), which was compromised in HsfA1a‐silenced plants and more robustly induced in HsfA1a‐overexpressing plants under Cd stress. COMT1 silencing reduced HsfA1a‐induced Cd tolerance and melatonin accumulation in HsfA1a‐overexpressing plants. Additionally, the HsfA1a‐induced expression of HSPs was partially compromised in COMT1‐silenced wild‐type or HsfA1a‐overexpressing plants under Cd stress. These results demonstrate that HsfA1a confers Cd tolerance by activating transcription of the COMT1 gene and inducing accumulation of melatonin that partially upregulates expression of HSPs.
Abstract
The management of bacterial infections is becoming a major clinical challenge due to the rapid evolution of antibiotic resistant bacteria. As an excellent candidate to overcome antibiotic ...resistance, antimicrobial peptides (AMPs) that are produced from the synthetic and natural sources demonstrate a broad-spectrum antimicrobial activity with the high specificity and low toxicity. These peptides possess distinctive structures and functions by employing sophisticated mechanisms of action. This comprehensive review provides a broad overview of AMPs from the origin, structural characteristics, mechanisms of action, biological activities to clinical applications. We finally discuss the strategies to optimize and develop AMP-based treatment as the potential antimicrobial and anticancer therapeutics.
With the goal of providing a comprehensive, high-quality resource for both plant transcription factors (TFs) and their regulatory interactions with target genes, we upgraded plant TF database ...PlantTFDB to version 4.0 (http://planttfdb.cbi.pku.edu.cn/). In the new version, we identified 320 370 TFs from 165 species, presenting a more comprehensive genomic TF repertoires of green plants. Besides updating the pre-existing abundant functional and evolutionary annotation for identified TFs, we generated three new types of annotation which provide more directly clues to investigate functional mechanisms underlying: (i) a set of high-quality, non-redundant TF binding motifs derived from experiments; (ii) multiple types of regulatory elements identified from high-throughput sequencing data; (iii) regulatory interactions curated from literature and inferred by combining TF binding motifs and regulatory elements. In addition, we upgraded previous TF prediction server, and set up four novel tools for regulation prediction and functional enrichment analyses. Finally, we set up a novel companion portal PlantRegMap (http://plantregmap.cbi.pku.edu.cn) for users to access the regulation resource and analysis tools conveniently.
Solar‐driven syngas production by CO2 reduction provides a sustainable strategy to produce renewable feedstocks. However, this promising reaction often suffers from tough CO2 activation, sluggish ...oxidative half‐reaction kinetics and undesired by‐products. Herein, we report a function‐oriented strategy of deliberately constructing black phosphorus quantum dots‐ZnIn2S4 (BP/ZIS) heterostructures for solar‐driven CO2 reduction to syngas, paired with selectively oxidative C−N bond formation, in one redox cycle. The optimal BP/ZIS heterostructure features the enhanced charge‐carrier separation and enriched active sites for cooperatively photocatalytic syngas production with a tunable ratio of CO/H2 and efficient oxidation of amines to imines with high conversion and selectivity. This prominent catalytic performance arises from the efficient electronic coupling between black phosphorus quantum dots and ZnIn2S4, as well as the optimized adsorption strength for key reaction intermediates, as supported by both experimental and theoretical investigations. We also demonstrate a synergistic interplay between CO2 reduction and amine dehydrogenation oxidation, rather than simply collecting these two single half‐reactions in this dual‐functional photoredox system.
A function‐oriented strategy of engineering black phosphorus quantum dots‐ZnIn2S4 heterostructures for solar‐driven CO2 reduction to syngas, paired with selectively oxidative C−N bond formation, in one redox cycle is reported. The promoted charge‐carrier separation, enriched active sites and optimized adsorption strength of key reaction intermediates for CO2 reduction, as well as the cooperative photoredox manner, jointly contribute to the enhanced photoactivity and selectivity.
Described herein is a manganese‐catalyzed dehydrogenative 4+2 annulation of NH imines and alkynes, a reaction providing highly atom‐economical access to diverse isoquinolines. This transformation ...represents the first example of manganese‐catalyzed CH activation of imines; the stoichiometric variant of the cyclomanganation was reported in 1971. The redox neutral reaction produces H2 as the major byproduct and eliminates the need for any oxidants, external ligands, or additives, thus standing out from known isoquinoline synthesis by transition‐metal‐catalyzed CH activation. Mechanistic studies revealed the five‐membered manganacycle and manganese hydride species as key reaction intermediates in the catalytic cycle.
Hidden talents: The ability of manganese(I) to catalytically induce CH and NH bond cleavage, and CC and CN bond formation, has been recognized using the title reaction. The reaction produces H2 as the major by‐product and eliminates the need for any oxidants, external ligands, or additives, and thus tolerating a wide range of functionalities.
With advances in next-generation sequencing technologies, numerous novel transcripts in a large number of organisms have been identified. With the goal of fast, accurate assessment of the coding ...ability of RNA transcripts, we upgraded the coding potential calculator CPC1 to CPC2. CPC2 runs ∼1000 times faster than CPC1 and exhibits superior accuracy compared with CPC1, especially for long non-coding transcripts. Moreover, the model of CPC2 is species-neutral, making it feasible for ever-growing non-model organism transcriptomes. A mobile-friendly web server, as well as a downloadable standalone package, is freely available at http://cpc2.cbi.pku.edu.cn.
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