Electrochemiluminescence (ECL) plays a key role in analysis and sensing because of its high sensitivity and low background. Its wide applications are however limited by a lack of highly tunable ECL ...luminophores. Here we develop a scalable method to design ECL emitters of covalent organic frameworks (COFs) in aqueous medium by simultaneously restricting the donor and acceptor to the COFs' tight electron configurations and constructing high-speed charge transport networks through olefin linkages. This design allows efficient intramolecular charge transfer for strong ECL, and no exogenous poisonous co-reactants are needed. Olefin-linked donor-acceptor conjugated COFs, systematically synthesized by combining non-ECL active monomers with C
or C
symmetry, exhibit strong ECL signals, which can be boosted by increasing the chain length and conjugation of monomers. The present concept demonstrates that the highly efficient COF-based ECL luminophores can be precisely designed, providing a promising direction toward COF-based ECL phosphors.
Covalent organic frameworks (COFs) have been proposed for electrochemical energy storage, although the poor conductivity resulted from covalent bonds limits their practical performance. Here, we ...propose to introduce noncovalent bonds in COFs through a molecular insertion strategy for improving the conductivity of the COFs as supercapacitor. The synthesized COFs (MI−COFs) establish equilibriums between covalent bonds and noncovalent bonds, which construct a continuous charge transfer channel to enhance the conductivity. The rapid charge transfer rate enables the COFs to activate the redox sites, bringing about excellent electrochemical energy storage behavior. The results show that the MI−COFs exhibit much better performance in specific capacitance and capacity retention rate than those of most COFs‐based supercapacitors. Moreover, through simply altering inserted guests, the mode and strength of noncovalent bond can be adjusted to obtain different energy storage characteristics. The introduction of noncovalent bonds is an effective and flexible way to enhance and regulate the properties of COFs, providing a valuable direction for the development of novel COFs‐based energy storage materials.
A molecular insertion strategy is used by introducing non‐covalent interactions in COFs to form a continuous charge transfer channel and accelerate the charge transfer rate. Meanwhile, the enhanced conductivity activates the redox sites in the COF skeleton, resulting in excellent energy storage performance. In addition, the energy storage behavior can be accurately regulated by changing the type of insertion guests.
At present, poor stability and carrier transfer efficiency are the main problems that limit the development of perovskite‐based photoelectric technologies. In this work, hydrogen‐bonded ...cocrystal‐coated perovskite composite (PeNCs@NHS‐M) is easily obtained by inducing rapid crystallization of melamine (M) and N‐hydroxysuccinimide (NHS) with PeNCs as the nuclei. The outer NHS‐M cocrystal passivates the undercoordinated lead atoms by forming covalent bonds, thereby greatly reducing the trap density while maintaining good structure stability for perovskite nanocrystals. Moreover, benefiting from the interfacial covalent band linkage and long‐range ordered structures of cocrystals, the charge transfer efficiency is effectively enhanced and PeNCs@NHS−M displays superior photoelectric performance. Based on the excellent photoelectric performance and abundant active sites of PeNCs@NHS−M, photocatalytic reduction of uranium is realized. PeNCs@NHS−M exhibits U(VI) reduction removal capability of up to 810.1 mg g−1 in the presence of light. The strategy of cocrystals trapping perovskite nanocrystals provides a simple synthesis method for composites and opens up a new idea for simultaneously improving the stability and photovoltaic performance of perovskite.
The CsPbBr3 nanocrystals (PeNCs) are coated with hydrogen‐bonded cocrystals (N‐hydroxysuccinimide‐melamine, NHS‐M) to achieve defect passivation and structural stability enhancement. Moreover, this covalently linked heterostructure further promotes the electron transport of PeNCs and realizes the photocatalytic reduction of uranium through the binding sites on the cocrystal.
Maternal obesity has adverse effects on oocyte quality, embryo development, and the health of the offspring.
To understand the underlying mechanisms responsible for the negative effects of maternal ...obesity, we investigated the DNA methylation status of several imprinted genes and metabolism-related genes.
Using a high-fat-diet (HFD)-induced mouse model of obesity, we analyzed the DNA methylation of several imprinted genes and metabolism-related genes in oocytes from control and obese dams and in oocytes and liver from their offspring. Analysis was performed using combined bisulfite restriction analysis (COBRA) and bisulfite sequencing.
DNA methylation of imprinted genes in oocytes was not altered in either obese dams or their offspring; however, DNA methylation of metabolism-related genes was changed. In oocytes of obese mice, the DNA methylation level of the leptin (Lep) promoter was significantly increased and that of the Ppar-α promoter was reduced. Increased methylation of Lep and decreased methylation of Ppar-α was also observed in the liver of female offspring from dams fed the high-fat diet (OHFD). mRNA expression of Lep and Ppar-α was also significantly altered in the liver of these OHFD. In OHFD oocytes, the DNA methylation level of Ppar-α promoter was increased.
Our results indicate that DNA methylation patterns of several metabolism-related genes are changed not only in oocytes of obese mice but also in oocytes and liver of their offspring. These data may contribute to the understanding of adverse effects of maternal obesity on reproduction and health of the offspring.
Due to its strong abiotic stress tolerance, common vetch is widely cultivated as a green manure and forage crop in grass and crop rotation systems. The comprehensive molecular mechanisms activated in ...common vetch during cold adaptation remain unknown.
We investigated physiological responses and transcriptome profiles of cold-sensitive (Lanjian No. 1) and cold-tolerant (Lanjian No. 3) cultivars during cold acclimation to explore the molecular mechanisms of cold acclimation. In total, 2681 and 2352 differentially expressed genes (DEGs) were identified in Lanjian No. 1 and Lanjian No. 3, respectively; 7532 DEGs were identified in both lines. DEGs involved in "plant hormone signal transduction" were significantly enriched during cold treatment, and 115 DEGs involved in cold-processed hormone signal transduction were identified. Common vetch increased the level of indoleacetic acid (IAA) by upregulating the transcriptional regulator Aux/IAA and downregulating GH3, endowing it with stronger cold tolerance. An auxin-related DEG was overexpressed in yeast and shown to possess a biological function conferring cold tolerance.
This study identifies specific genes involved in Ca
signaling, redox regulation, circadian clock, plant hormones, and transcription factors whose transcriptional differentiation during cold acclimation may improve cold tolerance and contributes to the understanding of common and unique molecular mechanisms of cold acclimation in common vetch. The candidate genes identified here also provide valuable resources for further functional genomic and breeding studies.
Electrochemiluminescence (ECL), as an advanced sensing process, can selectively control the generation of excited states by changing the potential. However, most of the existing ECL systems rely on ...poisonous coreactants to provide radicals for luminescence; although the ECL efficiency was improved, the athematic coreactants will cause unpredictable interference to the accurate analysis of trace targets. Herein, we realized the ECL of nonemitting molecules by performing intramolecular electron transfer in the olefin-linked covalent organic frameworks (COFs), with a high efficiency of 63.7%. Employing internal dissolved oxygen as the coreactant, it is well suitable for the analysis of various complex samples in the environment. Taking nuclear contamination analysis as the goal orientation, we further illustrated a design of a “turn-on” uranyl ion monitoring system integrating fast response, low detection limit, and high selectivity, showing that new ECL-COFs are promising to facilitate environment-related sensing analysis and structure-feature correlation mechanism exploration.
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•The SnS2-covalent organic framework van der Waals heterojunction (SnS2COF) was constructed.•With good photoelectric properties, SnS2COF can realize separation and transfer of ...electron-hole.•The electron flow path of heterojunction conforms to Z-scheme by experimental study and theoretical calculation.•SnS2COF can effectively reduce and remove U (VI) from rare earth tailings wastewater under UV/Vis light.
Uranium removal by photocatalytic reduction is one of the most promising methods to reduce radioactive contamination in wastewater. Herein, a Z-scheme van der Waals heterojunction photocatalyst (SnS2COF) was synthesized in situ by combining covalent organic frameworks (COF) with semiconductor (SnS2) for U (VI) reduction in rare earth tailings wastewater. The synthesis method of van der Waals heterojunction is simple and solves the problem of no hanging bond in composite components. In this heterojunction, large areas of van der Waals interaction form high-speed electron transport channels. In addition, it is deduced that SnS2COF fits the Z-scheme heterojunction electron transport mode through the theoretical calculation of the ground state and excited state electron density difference and the related band structure. Under the photoexcitation, the direction of electron flow is reversed, which further promotes the separation of the photogenerated electron (e−)-hole (h+) under the action of the built-in electric field, maintains the high reducibility of the conduction band, and avoids the photocorrosion of SnS2. Compared with inorganic-inorganic heterojunction, SnS2COF has a wider light absorption range, more active sites, and higher e−-h+ separation and transfer efficiency. Therefore, it had a higher U (VI) reduction removal capacity, up to 1123.3 mg g−1, far surpassing the SnS2 and COF counterparts under ultraviolet/visible light. And the U (VI) removal rate reached 98.5 % in rare earth tailings wastewater. The design concept of organic–inorganic heterojunction materials provides an alternative strategy for improving the photocatalytic performance.
In this work, a sensitive electrochemiluminescence (ECL) biosensor was proposed to detect protein kinase activity utilizing the signal amplification of bull serum albumin-templated gold nanoclusters ...(BSA-Au NCs) for graphite-like carbon nitride material (g-C3N4). In this system, g-C3N4 was utilized as a cathodic ECL emitter, and BSA-AuNCs were anchored to the phosphorylated peptides modified g-C3N4/GCE by AuS bond in the presence of adenosine 5′-γ-thio triphosphate (ATP-s) and protein kinase A (PKA). Attributed to the outstanding catalytic activity of BSA-AuNCs in the ECL process, the ECL intensity of this system shows 4.5-fold enhancement than that without BSA-AuNCs. Such enhancement in combination with the intensity of ECL signal and protein kinase activity enables us to fabricate an ultrasensitive ECL biosensor to detect PKA with low background. The proposed ECL platform can be utilized to analyse PKA activity of biological sample quantitatively and screen kinase inhibition qualitatively.
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•ECL biosensor based on the interaction between g-C3N4 and Au NCs has been designed.•Au NCs can act as a catalyst to efficiently magnify the ECL intensity of g-C3N4.•It provided a highly sensitive strategy for PKA activity detecting with a low detection limit.•The method proved excellent performance on the kinase inhibitor assay.
Background
The mechanism driving dysthyroid optic neuropathy (DON) is unclear. Diffusion‐tensor imaging (DTI) allows for noninvasively assessing the microstructure of the entire visual pathway and ...may facilitate a better understanding of the mechanism of DON.
Purpose
To assess microstructural changes of the whole visual pathway and to investigate the potential mechanism of trans‐synaptic damage（TSD） pathogenesis in DON with DTI.
Study Type
Cross‐sectional.
Population
Sixty‐four patients with bilateral thyroid‐associated ophthalmopathy (TAO), 30 with and 34 without DON, and 30 age‐ and sex‐matched healthy controls (HCs).
Field Strength/Sequence
3 T/DTI (A single‐shot diffusion‐weighted echo‐planar imaging sequence).
Assessment
Differences in DTI parameters including fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) in each segment (optic nerve, tract, and radiation) of the entire visual pathway among the groups were compared. The parameters of visual evoked potentials (VEPs), visual field tests, and mean retinal nerve fiber layer (mRNFL) thickness on optical coherence tomography were also compared across patients.
Statistical Tests
Student's t‐test, chi‐square test; ANOVA with post‐hoc testing, interclass correlation coefficient, and correlation analysis. Significance level: P < 0.05.
Results
TAO patients with DON showed significantly reduced mRNFL thickness and abnormal VEPs. There was a tendency for gradually reduced FA and AD, and increased RD and MD from HCs, with non‐DON to with DON in optic nerve and tract, statistically. For radiation, the RD and MD showed statistical increase, the AD and FA just showed numerical decrease (P = 0.119 and 0.059, respectively). For DON, the FA and MD of visual pathway segments showed correlations with abnormal VEPs.
Data Conclusion
DTI may be a useful tool for detecting microstructural changes in the entire visual pathway in DON. The changes in RNFL thickness and DTI parameters suggested TSD as a potential pathogenic mechanism of DON.
Evidence Level: 4
Technical Efficacy: Stage 5
The RNA‐dependent RNA polymerase (RdRp) is a crucial element in the replication and transcription of RNA viruses. Although the RdRps of lethal human coronaviruses severe acute respiratory syndrome ...coronavirus 2 (SARS‐CoV‐2), SARS‐CoV, and Middle East respiratory syndrome coronavirus (MERS‐CoV) have been extensively studied, the molecular mechanism of the catalytic subunit NSP12, which is involved in pathogenesis, remains unclear. In this study, the biochemical and cell biological results demonstrate the interactions between SARS‐CoV‐2 NSP12 and seven host proteins, including three splicing factors (SLU7, PPIL3, and AKAP8). The entry efficacy of SARS‐CoV‐2 considerably decreased when SLU7 or PPIL3 was knocked out, indicating that abnormal splicing of the host genome was responsible for this occurrence. Furthermore, the polymerase activity and stability of SARS‐CoV‐2 RdRp were affected by the three splicing factors to varying degrees. In addition, NSP12 and its homologues from SARS‐CoV and MERS‐CoV suppressed the alternative splicing of cellular genes, which were influenced by the three splicing factors. Overall, our research illustrates that SARS‐CoV‐2 NSP12 can engage with various splicing factors, thereby impacting virus entry, replication, and gene splicing. This not only improves our understanding of how viruses cause diseases but also lays the foundation for the development of antiviral therapies.
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