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Prokaryotic ubiquitin-like protein (Pup) is the first identified prokaryotic protein that is functionally analogous to ubiquitin. Recent studies have shed light on the Pup activation and conjugation to target proteins to be a signal for the selective degradation proteins in Mycobacterium tuberculosis (Mtb). By covalently conjugating the Pup, pupylation functions as a critical post-translational modification (PTM) conserved in actinomycetes. Detecting pupylation sites is crucial and fundamental for understanding the molecular mechanisms of Pup. Yet comparative studies with other PTM suggest that the development of accurate and complete repertories of pupylation is still in its early stages. Unbiased screening for pupylation sites by experimental methods is time consuming and expensive; in silico prediction can provide highly potential candidates and reduce the number of potential candidates that require further in vivo or in vitro confirmation. Here, we present an effective classifier of PupPred for predicting pupylation sites, which shows better performance than existing classifiers. Importantly, this work not only investigates the sequential, structural and evolutionary hallmarks around pupylation sites but also compares the differences of pupylation and ubiquitylation from the environmental, conservative and functional characterization of substrates. These prediction and analysis results may be helpful for further experimental investigation of degradation proteins in prokaryotes. Finally, the PupPred server is available at http://bioinfo.ncu.edu.cn/PupPred.aspx. [ABSTRACT FROM AUTHOR]

Motivation: Systematic dissection of the ubiquitylation proteome is emerging as an appealing but challenging research topic because of the significant roles ubiquitylation play not only in protein degradation but also in many other cellular functions. High-throughput experimental studies using mass spectrometry have identified many ubiquitylation sites, primarily from eukaryotes. However, the vast majority of ubiquitylation sites remain undiscovered, even in well-studied systems. Because mass spectrometry–based experimental approaches for identifying ubiquitylation events are costly, time-consuming and biased toward abundant proteins and proteotypic peptides, in silico prediction of ubiquitylation sites is a potentially useful alternative strategy for whole proteome annotation. Because of various limitations, current ubiquitylation site prediction tools were not well designed to comprehensively assess proteomes.Results: We present a novel tool known as UbiProber, specifically designed for large-scale predictions of both general and species-specific ubiquitylation sites. We collected proteomics data for ubiquitylation from multiple species from several reliable sources and used them to train prediction models by a comprehensive machine-learning approach that integrates the information from key positions and key amino acid residues. Cross-validation tests reveal that UbiProber achieves some improvement over existing tools in predicting species-specific ubiquitylation sites. Moreover, independent tests show that UbiProber improves the areas under receiver operating characteristic curves by ∼15% by using the Combined model.Availability: The UbiProber server is freely available on the web at http://bioinfo.ncu.edu.cn/UbiProber.aspx. The software system of UbiProber can be downloaded at the same site.Contact: jdqiu@ncu.edu.cnSupplementary information: Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]

Abstract: Lysine acetylation and methylation are two major post-translational modifications of lysine residues. They play vital roles in both biological and pathological processes. Specific lysine residues in H3 histone protein tails appear to be targeted for either acetylation or methylation. Hence it is very challenging to distinguish between acetylated and methylated lysine residues using computational methods. This work presents a method that incorporates protein sequence information, secondary structure and amino acid properties to differentiate acetyl-lysine from methyl-lysine. We apply an encoding scheme based on grouped weight and position weight amino acid composition to extract sequence information and physicochemical properties around lysine sites. The proposed method achieves an accuracy of 93.3% using a jackknife test. Feature analysis demonstrates that the prediction model with multiple features can take full advantage of the supplementary information from different features to improve classification performance and prediction robustness. Analysis of the characteristics of lysine residues which can be either methylated or acetylated shows that they are more similar to methyl-lysine than to acetyl-lysine. [Copyright &y& Elsevier]

We demonstrate for the first time an interfacial polymerization method for the synthesis of high-quality polyaniline-modified graphene nanosheets (PANI/GNs), which represents a novel type of graphene/polymer heterostructure. The interfacial polymerization at a liquid-liquid interface allows PANI to grow uniformly on the surface of the GNs. An ultra-high loading of Pt nanoparticles was then controllably deposited on the surface of the PANI/GNs to form a Pt/PANI/GNs hybrid. The obtained composites were characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The Pt/PANI/GNs hybrid shows excellent electrocatalytic activity toward methanol oxidation and oxygen reduction. H2O2 and glucose were used as two representative analytes to demonstrate the sensing performance of a Pt/PANI/GNs-modified electrode. It is found that this sensing element shows high sensitivity and a low detection limit for H2O2 and glucose. The results demonstrate that the Pt/PANI/GNs hybrid may be an attractive and advanced electrode material with potential applications in the construction of electrochemical sensors and biosensors. [ABSTRACT FROM AUTHOR]

Abstract: A homogeneous chitosan–ferrocene/graphene oxide/glucose oxidase (CS–Fc/GO/GOx) nanocomposite film was successfully constructed as a novel platform for the fabrication of glucose biosensor. The morphologies and electrochemistry of the nanocomposite film were investigated by using scanning electron microscopy and electrochemical techniques including electrochemical impedance spectroscopy and cyclic voltammetry, respectively. Results demonstrated that the uniformly dispersed GO within the CS matrix could significantly improve the stability of GO and make it exhibit a positive charge, which was more favorable for the further immobilization of biomolecules, such as GOx, with higher loading. Further attaching redox mediator ferrocene group (Fc) to CS could not only effectively prevent the leakage of Fc from the matrix and retain its electrochemical activity, but also improve the electrical conductivity of CS and promote the electron-transfer between GOx and electrode. Biosensors based on this CS–Fc/GO/GOx film had advantages of fast response, excellent reproducibility, high stability, and showed a linear response to glucose in the concentration range from 0.02 to 6.78mM with a detection limit of 7.6μM at a signal-to-noise ratio of 3 and exhibited a higher sensitivity of 10μAmM−1 cm−2. The proposed strategy based on CS–Fc/GO nanocomposite for the immobilization of enzymes can be of practical relevance for the facile design of biosensors, as well as for the construction of new multifunctional bioelectrochemical systems. [Copyright &y& Elsevier]

Abstract: In vivo, some proteins exist as monomers (single polypeptide chains) and others as oligomers. Not like monomers, oligomers are composed of two or more chains (subunits) that are associated with each other through non-covalent interactions and, occasionally, through disulfide bonds. These proteins are the structural components of various biological functions, including cooperative effects, allosteric mechanisms and ion-channel gating. However, with the dramatic increase in the number of protein sequences submitted to the public data bank, it is important for both basic research and drug discovery research to acquire the possible knowledge about homo-oligomeric attributes of their interested proteins in a timely manner. In this paper, a high-throughput method, combined support vector machines with discrete wavelet transform, has been developed to predict the protein homo-oligomers. The total accuracy obtained by the re-substitution test, jackknife test and independent dataset test are 99.94%, 96.17% and 96.18%, respectively, showing that the proposed method of extracting feature from the protein sequences is effective and feasible for predicting homo-oligomers. The online service is available at http://bioinfo.ncu.edu.cn/Services.aspx. [Copyright &y& Elsevier]

Abstract: Many proteins exist in vivo as oligomers with different quaternary structural attributes rather than as individual chains. These proteins are the structural components of various biological functions, including cooperative effects, allosteric mechanisms and ion-channel gating. With the dramatic increase in the number of protein sequences submitted to the public databank, it is important for both basic research and drug discovery research to acquire the knowledge about possible quaternary structural attributes of their interested proteins in a timely manner. A high-throughput method (DWT_SVM), fusing discrete wavelet transform (DWT) and support vector machine (SVM) classifier algorithm with various physicochemical features, has been developed to predict protein quaternary structure. The accuracy in distinguishing candidate proteins as homo-oligomer or hetero-oligomer using the dataset R2720 was 85.95% and 85.49% respectively by jackknife, showing that DWT_SVM is guide promising in predicting protein quaternary structures. The online service is available at http://bioinfo.ncu.edu.cn/Services.aspx. Protein sequences in FASTA format can be directly fed to the system OligoPred. The processed results will be presented in a diagram that includes the information of feature extraction and the classification error rate. [Copyright &y& Elsevier]

n amperometric immunosensor has been developed for sensitive determination of hepatitis B surface antigen as a model protein. A glassy carbon electrode was modified with an assembly of positively charged poly(allylamine)-branched ferrocene (PAA-Fc) and negatively charged gold nanoparticles (Au NPs). The formation of PAA-Fc effectively avoids the leakage of Fc, retains its electrochemical activity, and enhances the conductivity of the composite. The adsorption of Au NPs onto the PAA-Fc matrix provides sites for the immobilization of the antigen and a favorable micro-environment to maintain its activity. The morphologies and electrochemistry of the sensing film were investigated via scanning electron microscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. Factors influencing the performance of the immunosensor were studied in detail. The concentration of the antigen can be quantitated (by measuring the decrease of the amperometric response resulting from the specific binding between antigen and antibody) in the range between 0.1 and 150 ng mL, with a detection limit of 40 pg mL (S/N = 3). The method is economical, efficient, and potentially attractive for clinical immunoassays. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: It is very challenging and complicated to predict protein locations at the sub-subcellular level. The key to enhancing the prediction quality for protein sub-subcellular locations is to grasp the core features of a protein that can discriminate among proteins with different subcompartment locations. In this study, a different formulation of pseudoamino acid composition by the approach of discrete wavelet transform feature extraction was developed to predict submitochondria and subchloroplast locations. As a result of jackknife cross-validation, with our method, it can efficiently distinguish mitochondrial proteins from chloroplast proteins with total accuracy of 98.8% and obtained a promising total accuracy of 93.38% for predicting submitochondria locations. Especially the predictive accuracy for mitochondrial outer membrane and chloroplast thylakoid lumen were 82.93% and 82.22%, respectively, showing an improvement of 4.88% and 27.22% when other existing methods were compared. The results indicated that the proposed method might be employed as a useful assistant technique for identifying sub-subcellular locations. We have implemented our algorithm as an online service called SubIdent (http://bioinfo.ncu.edu.cn/services.aspx). [Copyright &y& Elsevier]

Abstract: In this work, the magnetic core–shell Fe3O4@Au nanoparticles attached to the surface of a magnetic glassy carbon electrode (MGCE) were applied to the immobilization/adsorption of myoglobin (Mb) for fabricating Mb/Fe3O4@Au biofilm. The morphology, structure, and electrochemistry of the nanocomposite were characterized by transmission electron microscope, UV–vis spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry, respectively. The resultant Fe3O4@Au NPs not only have the magnetism of Fe3O4 NPs that make them easily manipulated by an external magnetic field, but also have the good conductivity and excellent biocompatibility of Au layer which can maintain the bioactivity and facilitate the direct electrochemistry of Mb in the biofilm. The modified electrode based on this Mb/Fe3O4@Au biofilm displayed good electrocatalytic activity to the reduction of H2O2 with a linear range from 1.28 to 283μM. The proposed method simplified the immobilization methodology of proteins and showed potential application for fabricating novel biosensors and bioelectronic devices. [Copyright &y& Elsevier]

Abstract: A novel experimental methodology based on the unique characteristics of chitosan-branched ferrocene (CS-Fc) and gold nanoparticles (Au NPs) was developed to design a label-free amperometric immunosensor for the sensitive detection of hepatitis B surface antigen (HBsAg) as a model protein. The controllable electrodeposition of CS-Fc solution formed a three-dimensional robust film with good biocompatibility and large surface area for the assembly of Au NPs and further immobilization of hepatitis B surface antibody (HBsAb) on an electrode. The morphologies and electrochemistry of the formed nanocomposite biofilm were investigated by using scanning electron microscopy and electrochemical techniques including cyclic voltammetry and electrochemical impedance spectroscopy, respectively. The HBsAg concentration was measured through the decrease of amperometric responses in the corresponding specific binding of antigen and antibody. The decreased differential pulse voltametric values were proportional to the HBsAg concentration in the range of 0.05–305ngmL−1 with a detection limit 0.016ng. This would provide an approach for the application of mediator in immunoassays. [Copyright &y& Elsevier]

Abstract: Being the largest family of cell surface receptors, G-protein-coupled receptors (GPCRs) are among the most frequent targets. The functions of many GPCRs are unknown, and it is both time-consuming and expensive to determine their ligands and signaling pathways by experimental methods. It is of great practical significance to develop an automated and reliable method for classification of GPCRs. In this study, a novel method based on the concept of Chou’s pseudo amino acid composition has been developed for predicting and recognizing GPCRs. The discrete wavelet transform was used to extract feature vectors from the hydrophobicity scales of amino acid to construct pseudo amino acid (PseAA) composition for training support vector machine. The prediction accuracies by the current method among the major families of GPCRs, subfamilies of class A, and types of amine receptors were 99.72%, 97.64%, and 99.20%, respectively, showing 9.4% to 18.0% improvement over other existing methods and indicating that the proposed method is a useful automated tool in identifying GPCRs. [Copyright &y& Elsevier]

Abstract: A simple and controllable electrodeposition method is described to fabricate a homogeneous chitosan-ferrocene/Au nanoparticles/glucose oxidase (CS-Fc/Au NPs/GOx) nanocomposite film. The morphologies and electrochemistry of the nanocomposite film were investigated by using scanning electron microscopy (SEM) and electrochemical techniques including electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), respectively. The ferrocene group (Fc) covalently bounded chitosan hybrid (CS-Fc) can effectively avoid the leakage of Fc and retain its electrochemical activity. Further immobilization of Au NPs into the CS-Fc matrix enhances both the charge-transport properties of the composite and bioaffinity to enzyme. Biosensor based on this CS-Fc/Au NPs/GOx film has advantages of fast response, excellent reproducibility and high stability. This biosensor shows a linear response to glucose in the concentration range from 0.02 to 8.66mM with a detection limit of 5.6μM at a signal-to-noise ratio of 3. The present method offers a facile way to fabricate biosensors and bioelectronic devices. [Copyright &y& Elsevier]

Abstract: A novel dopamine sensor was fabricated by forming the 6-ferrocenylhexanethiol (HS(CH2)6Fc) functionalized Fe3O4@Au nanoparticles (NPs) films on the surface of a carbon paste electrode with the aid of a permanent magnet. HS(CH2)6Fc, which acted as the redox mediator, was self-assembled to Fe3O4@Au NPs via Au–S bond. Transmission electron microscopy, UV–visible absorption spectroscopy, Fourier transform infrared spectra, and cyclic voltammetry were used to characterize the properties of the Fe3O4@Au NPs/HS(CH2)6Fc nanocomposite. It is shown that the prepared ferrocene-functionalized Fe3O4@Au NPs composite shuttled electrons between analyte and electrode, increased the mediator loading, and more importantly prevented the leakage of the mediator during measurements, which resulted in the substantially enhanced stability and reproducibility of the modified electrode. The electrooxidation of dopamine could be catalyzed by Fc/Fc+ couple as a mediator and had a higher electrochemical response due to the unique performance of Fe3O4@Au NPs. The nanocomposite modified electrode exhibited fast response (3s) and the linear range was from 2.0×10−6 to 9.2×10−4 M with a detection limit of 0.64μM. This immobilization approach effectively improved the stability of the electron transfer mediator and is promising for construction of other sensors and bioelectronic devices. [Copyright &y& Elsevier]

Abstract: The enzymatic attributes of newly found protein sequences are usually determined either by biochemical analysis of eukaryotic and prokaryotic genomes or by microarray chips. These experimental methods are both time-consuming and costly. With the explosion of protein sequences registered in the databanks, it is highly desirable to develop an automated method to identify whether a given new sequence belongs to enzyme or non-enzyme. The discrete wavelet transform (DWT) and support vector machine (SVM) have been used in this study for distinguishing enzyme structures from non-enzymes. The networks have been trained and tested on two datasets of proteins with different wavelet basis functions, decomposition scales and hydrophobicity data types. Maximum accuracy has been obtained using SVM with a wavelet function of Bior2.4, a decomposition scale j=5, and Kyte–Doolittle hydrophobicity scales. The results obtained by the self-consistency test, jackknife test and independent dataset test are encouraging, which indicates that the proposed method can be employed as a useful assistant technique for distinguishing enzymes from non-enzymes. [Copyright &y& Elsevier]

Abstract: A kind of nanocomposite with good dispersion in water was prepared through covalent adsorption of ferrocenecarboxaldehyde on multiwalled carbon nanotubes (MWNTs) for electrical communication between glucose oxidase (GOD) and electrode. The ferrocene-modified multiwalled carbon nanotube nanocomposites (MWNTs-Fc) could be conveniently cast on electrode surfaces. With the aid of chitosan, GOD was then immobilized on the nanostructure film to form a reagentless amperometric sensor for glucose determination. FTIR spectra and cyclic voltammetry were used to characterize the nanocomposites. The presence of both ferrocene as mediator of electron transfer and MWNTs as conductor enhanced greatly the enzymatic response to the oxidation of glucose. The novel biosensor exhibited a fast response toward glucose with a detection limit of 3.0×10−6 mol/L and the linear range extended up to 3.8×10−3 mol/L. [Copyright &y& Elsevier]

Abstract: A novel amperometric sensor for glucose was constructed by entrapping glucose oxidase (GOD) in a new chitosan composite doped with ferrocene monocarboxylic acid-modified 3-(aminopropyl) triethoxysilane enwrapping multiwalled carbon nanotubes (FMC-AMWNTs). The approach was very simple, timesaving and effectively prevented the leakage of the ferrocene monocarboxylic acid mediator during measurements. The entrapped FMC-AMWNTs composite performed excellent redox electrochemistry and acted as an electron transfer mediator. This matrix showed a biocompatible microenvironment for retaining the native activity of the entrapped GOD and a very low mass transport barrier to the substrate. Under optimal conditions, this biosensor was able to detect glucose in the linear range of 0.01–4.2mM with a detection limit of 3.4μM (S/N=3), the value of was 6.3mM. This immobilization approach effectively improved the stability of the electron transfer mediator and is promising for construction of biosensor and bioelectronic devices. [Copyright &y& Elsevier]

Facing the complex coexistence of various metal ions in wastewater and mineral resources, metal–organic frameworks (MOFs) with diverse functionalities and tunable pores are poised to serve as distinctive solutions for efficiently recognizing and selectively separating radioactive thorium (Th(IV)). Herein, a fluorescent MOF (DBT‐DHTA‐Cd) with unique thorium nanocavity traps is rationally designed by using two rigid ligands, including azole and hydroxyl groups, respectively. Notably, the synergistic effect of the appropriate pore size and dense hydroxyl···N nanocavity traps in DBT‐DHTA‐Cd results in selective capture of Th(IV), arising from the high charge density of nano‐trap and extremely low binding energy (Eads = −602.7 KJ mol−1). The fast adsorption kinetics (30 min) and rapid fluorescence response (1 min) of DBT‐DHTA‐Cd toward Th(IV) are attributed to the stronger electron holding capacity of the d and f orbitals belonged to Th(IV), making it more prone to accepting electrons transferred from the N/O active sites in the nano‐trap. As a verification test, tailing breakthrough experiments confirm that DBT‐DHTA‐Cd can efficiently purify Th(IV) from monazite mining solid waste in one step. This work provides profound insights into relationship between structure and property of MOFs and has valuable guidance for designing materials in the radioactive purification field. [ABSTRACT FROM AUTHOR]

Using unmodified Au nanorods with enzyme-linkage reaction, a label-free colorimetric method for simple and convenient assay of DNA methylation is presented. [ABSTRACT FROM AUTHOR]

An imidazolyl hydrogen-bonded organic framework (HOF-T) with outstanding thermal and water stability was constructed by C–H⋯N hydrogen bonding and C–H⋯π interactions. UO22+ can be selectively captured by the imidazole group of HOF-T and rapidly reduced to UO2 under visible light irradiation, realizing exceptional uranium removal with high capacity and fast kinetics. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Herein, a novel fluorescent ionic covalent organic framework (BTTA–BDNP) based on a linked carbazole unit was constructed for the synchronous monitoring and capture of TcO4−/ReO4−. BTTA–BDNP has a fast fluorescence response time with a low detection limit (66.7 nM) for ReO4− (a non-radioactive substitute for TcO4−). Meanwhile, the high charge density and hydrophobic skeleton of BTTA–BDNP enable it to exhibit rapid and selective trapping of ReO4− in complex environments. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cu-based metal covalent organic framework (Cu-TMT) was prepared for the extraction of uranium. • Cu-TMT has unsaturated Cu centers that serve as chemical reduction sites. • Cu-TMT has excellent visible light conversion efficiency and low band gap. • Cu-TMT reduced uranium by chemical reduction and photocatalytic reduction reached 1438.8 mg g−1. The reduction of hexavalent uranium to tetravalent uranium is an effective strategy for controlling uranium contamination in wastewater. Herein, a C C bonded metal-covalent organic framework (Cu-TMT) was synthesized via the Aldol condensation reaction by using the metal cluster Cu 3 (PyCA) 3 and 2,4,6-trimethyl-1,3,5-triazine (TMT) for the chemical and photocatalytic synergistic reduction of uranium. In the Cu-TMT, the low-valent Cu in the metal clusters provides the framework with numerous distributed redox sites being capable of chemically reducing UVI. Meanwhile, the encapsulating Cu clusters in long-range ordered frameworks can provide fast transport channels for intramolecular charge transfer and effectively inhibit electron/hole complexation, making Cu-TMT suitable for photocatalytic reduction of uranium. The chemical reduction of uranium by Cu-TMT was verified under light-avoidance conditions, reaching 659.5 mg g−1. After exposure of Cu-TMT to light, the amount of reduced uranium further increases to 1438.8 mg g−1 with 98.1 % removal rate of actual uranium containing wastewater. This study not only expands the range of applications of variable valence metal covalent organic frameworks, but also provides unique insights into the effective combination of chemical and photocatalytic reduction strategies for removing UVI in a single material. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cocrystals based on I-, Br-based halogen-bond donors and N-based halogen-bond acceptor were constructed. • Strength and density of σ-hole could affect degree of electron-hole separation and charge carrier transport. • Tuning photoelectric response of halogen-bonded cocrystals can be achieved employing the σ-hole effect. • Halogen-bonded cocrystals are enable to effectively photocatalytic reduce U(VI) of uranium contamination. The mechanism of how the internal composition of halogen-bonded cocrystals affecting photoelectric properties is ambiguous. Herein, we report a series of stable halogen-bonded cocrystals containing I-, Br-based halogen bond donors and N-based halogen bond acceptor. The halogen bonds served an intrinsic hub, and the two parts (donor and acceptor) were spliced into a highly ordered periodic network with a tight electronic configuration. The charge transfer within lattice induced by the σ-hole effect activates disparate photoelectric phenomena. The results uncover that the degree of photoelectric response of cocrystals can be adjusted rationally by manipulating the intensity and density of σ-holes with an atomic precision at the molecular level. The experimental and theoretical studies of the σ-hole effect pave the way to simplify the design principle of functional cocrystals. Eventually, benefiting from the fascinating photoelectric activity, halogen-bonded cocrystals exhibited excellent photocatalytic reduction ability of radionuclide uranium. [ABSTRACT FROM AUTHOR]

[Display omitted] • Phosphate functionalized COF/rGO was synthesized using post-synthetic modification. • Tb-BD-P/rGO exhibited excellent physicochemical stability and rapid uranyl mass transfer ability. • TB-BD-P/rGO enabled photoelectrothermal synergistic photocatalytic reduction of uranium. • Tb-BD-P/rGO performed excellent removal rates (>95 %) in actual strong acid nuclear wastewater. Photocatalytic reduction is becoming an effective method to remove UVI from uranium mine wastewater. Herein, 1,3,5-benzotrialdehyde (Tb) and 4,4′-diaminobiphenyl (BD) used as monomers of covalent organic framework (COF) are in situ growth on graphene oxide (GO) surfaces to obtain Tb-BD/rGO. Then, Tb-BD/rGO is converted into Tb-BD-P/rGO by asymmetric hydrogen phosphorylation, which is served as a new material for photocatalytic reduction of uranium via photoelectrothermal synergy. Benefiting from the transformation of dynamic imine bonds into irreversible carbon–nitrogen single bonds, Tb-BD-P/rGO expresses remarkable chemical and thermal stability. The introduction of phosphate groups improve the electronegativity and hydrophilicity of Tb-BD-P/rGO, which contribute to rapid transportation of uranium. In addition, the introduction of rGO achieves excellent photothermal conversion, accelerating the adsorption kinetics of uranium. Meanwhile, the π-π interaction between Tb-BD-P and rGO promotes inter-interfacial electron transfer and reduces the complexation of electron-hole pairs during the photocatalytic process, further improving photocatalytic performance. Therefore, Tb-BD-P/rGO demonstrates exceptional removal uranium rates (>95 %) in uranium mine wastewater by synergistically photoelectrothermal integration, offering a pathway for developing multifunctional and integrated photocatalysts. [ABSTRACT FROM AUTHOR]

The increasing uranium containing wastes generated during uranium mining and finishing pose a huge threat to the environment and human health, and thus robust strategies for on-site monitoring of uranium pollutant are of great significance for environmental protection around uranium tailings. Herein, a facile "turn-on" colorimetric platform that can achieve uranium detection by spectrometry and naked eyes was developed based on the uranium-enhanced nanozyme activity of covalent organic framework (JUC-505). Thanks to the extended π-conjugated skeleton and donor-acceptor (D-A) structure, JUC-505 exhibited superior photo-activated nanozyme activity, which would be prohibited when the cyano group in JUC-505 skeleton was transformed to the amidoxime group. Further results elucidated that the coordination of uranium with amidoxime groups led to the electron transfer between uranium and the JUC-505-AO skeleton, and thus significantly restored the nanozymatic activity of JUC-505-AO with the subsequent remarkable color changes. Moreover, the uranium concentrations in uranium tailing wastewater detected by the present "turn-on" colorimetric method were well agreed with those by ICP-MS, demonstrating a high accuracy of the present method in real samples. The D-A structured JUC-505 with superior photocatalytic property and nanozymatic activity was applied to facilitate colorimetric detection of uranium, which displays the advantages of low detection limit, excellent selectivity, fast response and simple operation for uranium detection in real samples, and shows a great potential in on-site monitoring of uranium pollutant around uranium tailings as well as nuclear power plant. [Display omitted] • A facile "turn-on" colorimetric platform was developed for on-site uranium detection by the nanozymatic activity of JUC-505. [ABSTRACT FROM AUTHOR]

Phosphorylation of viral proteins plays important roles in enhancing replication and inhibition of normal host-cell functions. Given its importance in biology, a unique opportunity has arisen to identify viral protein phosphorylation sites. However, experimental methods for identifying phosphorylation sites are resource intensive. Hence, there is significant interest in developing computational methods for reliable prediction of viral phosphorylation sites from amino acid sequences. In this study, a new method based on support vector machine is proposed to identify protein phosphorylation sites in viruses. We apply an encoding scheme based on attribute grouping and position weight amino acid composition to extract physicochemical properties and sequence information of viral proteins around phosphorylation sites. By 10-fold cross-validation, the prediction accuracies for phosphoserine, phosphothreonine and phosphotyrosine with window size of 23 are 88.8%, 95.2% and 97.1%, respectively. Furthermore, compared with the existing methods of Musite and MDD-clustered HMMs, the high sensitivity and accuracy of our presented method demonstrate the predictive effectiveness of the identified phosphorylation sites for viral proteins. [ABSTRACT FROM AUTHOR]

Photoreduction of highly toxic U(VI) to less toxic U(IV) is crucial for mitigating radioactive contamination. Herein, a CoWO 4 /TpDD p-n heterojunction is synthesized, with TpDD serving as the n-type semiconductor substrate and CoWO 4 as the p-type semiconductor grown in situ on its surface. The Fermi energy difference between TpDD and CoWO 4 provides the electrochemical potential for charge-hole separation. Moreover, the Coulombic forces from the distinct carrier types between the two materials synergistically facilitate the transfer of electrons and holes. Hence, an internal electric field directed from TpDD to CoWO 4 is established. Under photoexcitation conditions, charges and holes migrate efficiently along the curved band and internal electric field, further enhancing charge-hole separation. As a result, the removal capacity of CoWO 4 /TpDD increases from 515.2 mg/g in the dark to 1754.6 mg/g under light conditions. Thus, constructing a p-n heterojunction proves to be an effective strategy for remediating uranium-contaminated environments. [Display omitted] • CoWO 4 /TpDD heterojunction was formed by CoWO 4 in situ grown on the TpDD surface. • The differences in energy levels and carrier types facilitate carrier separation. • The electric field and energy band facilitate the photogenerated carrier separation. • Photogenerated electrons moving to TpDD contribute to the photoreduction of U(VI). • DFT and in-situ XPS confirm the mechanism of carrier transfer in heterojunction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ti-MOF@DATp was developed by using Ti-MOF as core and in-situ growing DATp shells on its surface. • A Z-Scheme heterojunction was created through covalent bonds between Ti-MOF and DATp. • The Ti-MOF@DATp enables tetracycline passing through the DATp shell while selectively capturing U(VI). • Ti-MOF serves as the site for photooxidation tetracycline, while DATp serves as the site for photoreduction U(VI). Uranium and antibiotics coexisting in natural water bodies pose a significant threat to the environment and human health. Herein, Ti-MOF@DATp was developed by using a metal–organic framework (Ti-MOF) as the core and in-situ growing covalent organic framework (DATp) shells on its surface for simultaneous photocatalytic reduction U(VI) and oxidation tetracycline. The staggered energy levels between Ti-MOF and DATp create a Z-Scheme heterojunction through covalent bonds between them, promoting the charge and holes transfer with enhancing the photocatalytic performance. The Ti-MOF@DATp enables tetracycline passing through the DATp shell while selectively capturing U(VI), then Ti-MOF functions as the site for photooxidation tetracycline, while DATp serves as the site for photoreduction U(VI). The oxidation and reduction of sites can be effectively separated, improving the utilization efficiency of photogenerated electrons and holes. Hence, Ti-MOF@DATp can effectively accomplish the simultaneous photocatalytic removal of 96% U(VI) and 90% tetracycline of their mixture. In comparison to the removal efficiency of 89% for U(VI) and 77% for tetracycline when removal alone, a notable enhancement in performance is observed. Particularly, the removal rate constant of the U(VI) and tetracycline mixture is 55 times higher than that of U(VI) alone and 4 times higher than that of tetracycline alone. Therefore, bifunctional photocatalysts offer an effective approach to tackling complex environmental challenges. [ABSTRACT FROM AUTHOR]

Untreated radioactive iodine (129I and 131I) released from nuclear power plants poses a significant threat to humans and the environment, so the development of materials to capture iodine from water media and steam is critical. Here, we report a charge transfer complex (TCNQ-MA CTC) with abundant nitrogen atoms and π-conjugated system for adsorption of I 2 vapor and I 3 - from aqueous solutions. Due to the synergistic binding mechanism of benzene/triazine rings and N-containing groups with iodine, special I-π and charge transfer interaction can be formed between the guest and the host, and thus efficient removal of I 2 and I 3 - can be realized by TCNQ-MA CTC with the adsorption capacity up to 2.42 g/g and 800 mg/g, respectively. TCNQ-MA CTC can capture 92% of I 3 - within 2.5 min, showing extremely fast kinetics, excellent selectivity and high affinity (K d = 5.68 × 106 mL/g). Finally, the TCNQ-MA CTC was successfully applied in the removal of iodine from seawater with the efficiency of 93.71%. This work provides new insights in the construction of charge transfer complexes and lays the foundation for its environmental applications. [Display omitted] • A π-conjugated and hydrogen-bonded charge transfer complex (TCNQ-MA CTC) was prepared. • The TCNQ-MA CTC has a high affinity for iodine due to the aboundant binding sites. • The TCNQ-MA CTC can adsorb I 2 and I 3 - with large capacity and good selectivity. • The TCNQ-MA CTC shows fast adsorption kinetics with the removal rate of 92% in 2.5 min [ABSTRACT FROM AUTHOR]

The radioactive ion U(VI) and organophosphorus pollutants in sewage do great harm to the ecological environment and human health. Bifunctional photocatalyst MOF525@BDMTp was prepared by in-situ covalent bridging method, and U(VI) and chlorpyrifos (CP) were removed by one-to-two strategy. MOF525@BDMTp had high carrier migration performance and conformed to the type-II heterojunction. Under light conditions, electrons were transferred from MOF525 to BDMTp due to the action of the built-in electric field, increasing the electron density of BDMTp and thus activating the U(VI) binding sites. BDMTp interacted with S and N atoms in CP to promote its hydrolysis and oxidation by h+ and ·O 2 -. Thus, MOF525@BDMTp guaranteed the simultaneous reduction of U(VI) on BDMTp and the oxidation of CP on MOF525. Therefore, designing functional integrated composites is an effective means to improve the photocatalytic performance of composite materials in complex environments. [Display omitted] • MOF525@BDMTp was prepared by in-situ covalent bond bridging method. • MOF525@BDMTp can adsorb both U (VI) and chlorpyrifos. • Type-II heterojunction in MOF525@BDMTp improved electron-hole separation. • The presence of U(VI) and CP improved the removal performance of each other. [ABSTRACT FROM AUTHOR]

• TFHH-POM was developed by using amino-modified polyoxometalates embedded in covalent organic framework pores. • The covalent bond connection between TFHH and POM improves the stability of POM. • Covalent bonding and internal confined improve the mass transfer from TFHH to POM. • TFHH-POM exhibits a notably elevated photoreduction capacity of U(VI). To achieve sustainable nuclear energy and environmental protection, capturing uranium from mining wastewater is imperative. Herein, as an extraction composite of U(VI), TFHH-POM was developed by using a highly conjugated polyaromatic ether-based covalent organic framework (TFHH) as the carrier with amino-modified polyoxometalates (POM) embedded in its pores through amide bonds. The highly conjugated structure of TFHH facilitates charge transport, and in combination with the charge density contrast between POM and TFHH, along with the constraining effect of POM within TFHH channels, jointly enhances charge separation efficiency. As a result, the photoreduction efficiency of U(VI) is substantially increased. Simultaneously, the oxygen-containing groups in POM and carboxyl groups in TFHH could selectively adsorb U(VI), while Mo(V) in POM effectively reduces U(VI) to U(IV), synergistically promoting U(VI) capture. Hence, TFHH-POM exhibits remarkable U(VI) extraction efficiency through enhanced mass transfer, improved diffusion, and introduced chemical reduction. The U(VI) extraction capacity of TFHH-POM reaches 489.2 mg/g, surpassing those of POM and TFHH by 3.2 and 1.6 times, respectively. The reduced U(IV) remains stable after 30 days of storage with no reoxidation observed. Moreover, TFHH-POM demonstrates selective U(VI) capture from mining wastewater, highlighting its vast potential for environmentally sustainable uranium mining. [ABSTRACT FROM AUTHOR]

Abstract: As an extremely important and ubiquitous post-translational lipid modification, palmitoylation plays a significant role in a variety of biological and physiological processes. Unlike other lipid modifications, protein palmitoylation and depalmitoylation are highly dynamic and can regulate both protein function and localization. The dynamic nature of palmitoylation is poorly understood because of the limitations in current assay methods. The in vivo or in vitro experimental identification of palmitoylation sites is both time consuming and expensive. Due to the large volume of protein sequences generated in the post-genomic era, it is extraordinarily important in both basic research and drug discovery to rapidly identify the attributes of a new protein''s palmitoylation sites. In this work, a new computational method, WAP-Palm, combining multiple feature extraction, has been developed to predict the palmitoylation sites of proteins. The performance of the WAP-Palm model is measured herein and was found to have a sensitivity of 81.53%, a specificity of 90.45%, an accuracy of 85.99% and a Matthews correlation coefficient of 72.26% in 10-fold cross-validation test. The results obtained from both the cross-validation and independent tests suggest that the WAP-Palm model might facilitate the identification and annotation of protein palmitoylation locations. The online service is available at http://bioinfo.ncu.edu.cn/WAP-Palm.aspx. [Copyright &y& Elsevier]

Abstract: Tyrosine sulfation is a ubiquitous posttranslational modification that regulates extracellular protein–protein interactions, intracellular protein transportation modulation, and protein proteolytic process. However, identifying tyrosine sulfation sites remains a challenge due to the lability of sulfation sequences. In this study, we developed a method called PredSulSite that incorporates protein secondary structure, physicochemical properties of amino acids, and residue sequence order information based on support vector machine to predict sulfotyrosine sites. Three types of encoding algorithms—secondary structure, grouped weight, and autocorrelation function—were applied to mine features from tyrosine sulfation proteins. The prediction model with multiple features achieved an accuracy of 92.89% in 10-fold cross-validation. Feature analysis showed that the coil structure, acidic amino acids, and residue interactions around the tyrosine sulfation sites all contributed to the sulfation site determination. The detailed feature analysis in this work can help us to understand the sulfation mechanism and provide guidance for the related experimental validation. PredSulSite is available as a community resource at http://www.bioinfo.ncu.edu.cn/inquiries_PredSulSite.aspx. [Copyright &y& Elsevier]

Abstract: In this study, magnetic core–shell Fe3O4@Al2O3 nanoparticles (NPs) attached to the surface of a magnetic glassy carbon electrode (MGCE) were used as a functional interface to immobilize several heme proteins including hemoglobin (Hb), myoglobin (Mb) and horseradish peroxidase (HRP) for fabricating protein/Fe3O4@Al2O3 film. Transmission electron microscope, UV–vis spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry were used to characterize the films. With the advantages of the magnetism and the excellent biocompatibility of the Fe3O4@Al2O3 NPs, the protein/Fe3O4@Al2O3 film could be easily fabricated in the present of external magnetic field, and well retained the bioactivity of the immobilized proteins, hence dramatically facilitated direct electron transfer of heme proteins and excellent electrocatalytic behaviors towards H2O2 were demonstrated. The presented system avoids the complex synthesis for protecting Fe3O4 NPs, supplies a facile, low cost and universal way to immobilize proteins, and is promising for construction of third-generation biosensors and other bio-magnetic induction devices. [ABSTRACT FROM AUTHOR]

Reversible post-translational modification (PTM) orchestrates various biological processes by changing the properties of proteins. Since many proteins are multiply modified by PTMs, identification of PTM crosstalk site has emerged to be an intriguing topic and attracted much attention. In this study, we systematically deciphered the in situ crosstalk of ubiquitylation and SUMOylation that co-occurs on the same lysine residue. We first collected 3363 ub iquitylation- S UMOylation (UBS) crosstalk site on 1302 proteins and then investigated the prime sequence motifs, the local evolutionary degree and the distribution of structural annotations at the residue and sequence levels between the UBS crosstalk and the single modification sites. Given the properties of UBS crosstalk sites, we thus developed the mUSP classifier to predict UBS crosstalk site by integrating different types of features with two-step feature optimization by recursive feature elimination approach. By using various cross-validations, the mUSP model achieved an average area under the curve (AUC) value of 0.8416, indicating its promising accuracy and robustness. By comparison, the mUSP has significantly better performance with the improvement of 38.41 and 51.48% AUC values compared to the cross-results by the previous single predictor. The mUSP was implemented as a web server available at http://bioinfo.ncu.edu.cn/mUSP/index.html to facilitate the query of our high-accuracy UBS crosstalk results for experimental design and validation. [ABSTRACT FROM AUTHOR]

The decline of fossil fuels is fostering research on carbon–neutral fuels such as nuclear energy, yet uranium supply is limited by actual techniques of uranium extraction from seawater. In particular, biofouling by marine bacteria and adsorbent instability are major drawbacks. Here we synthesized a novel amidoxime-functionalized antibacterial covalent organic framework that displays high stability and inhibits more than 90% the growth of marine bacteria, thus resulting in an enhanced uranium recovery capacity of 6.64 mg/g. Meanwhile, due to its exceptional fluorescence properties, the adsorbent can also be applied to highly sensitive on-site and real-time monitoring of UO22+. [ABSTRACT FROM AUTHOR]

[Display omitted] • A bi-functional COF based heterostructure (NH 2 -Ti 3 C 2 T x @COF) was developed in situ. • The Schottky interface realizes efficient carrier separation and solar utilization. • NH 2 -Ti 3 C 2 T x @COF has excellent photocatalytic activity without sacrificial agents. • NH 2 -Ti 3 C 2 T x @COF exhibits multiple-in-one advantage for photoreduction U(VI). Reduction of soluble U(VI) to insoluble U(IV) is considered as a promising strategy to avoid uranium contamination. Herein, a bi-functional covalent organic framework based heterojunction (NH 2 -Ti 3 C 2 T x @COF) was constructed on the amino-modified Ti 3 C 2 T x MXene for efficient photoreduction U(VI) without additional sacrificial agents. Schottky interface with electronic unidirectional channel is established by the formation of local electrophilic/nucleophilic region due to the introduction of reductive COF with alkynyl group, resulting in efficient photogenerated carrier separation and solar energy utilization. More importantly, NH 2 -Ti 3 C 2 T x with negative charge served as electron collector and transfer channel can effectively surmount the low photocatalytic activity caused by high polarization of imine-linked COFs. Thus, the tailored-made design of NH 2 -Ti 3 C 2 T x @COF exhibits excellent photocatalytic activity, fast reaction kinetics (removal of 97.8 % in 60 min) and high adsorptive capability (1557.2 mg/g) under the light condition. This multiple-in-one advantage makes well-designed NH 2 -Ti 3 C 2 T x @COF as a promising capture platform. This work will provide some new insight and inspiration to COF based heterojunctions for enhancing U(VI) capture. [ABSTRACT FROM AUTHOR]

[Display omitted] • A covalent organic framework (DANT-BTT) with a D-A structure was synthesized based on naphthalimide. • DANT-BTT exhibits excellent chemical stability and photocatalytic properties. • Protonated DANT-BTT with superior photocatalytic capability and higher selectivity for uranium. • DANT-BTT has excellent removal efficiency for uranium at pH 1. Efficient removal of UO 2 2+ from radioactive wastewater under strong acid conditions remains a significant challenge due to the competition of excess H+ for adsorption and reduction sites. Here, covalent organic framework with complete charge separation and protonation properties (DANT-BTT) was synthesized for efficient removal of UO 2 2+ under strong acids. The DANT-BTT with strong electron-deficient naphthalimide significantly extended light absorption and enhanced intramolecular charge transfer, which significantly improve the separation efficiency of electrons and holes. Additionally, the auxiliary coordination of hydroxyl groups after protonation provides unparalleled selectivity for UO 2 2+ in strong acids, effectively preventing the competition of H+ for adsorption sites. Protonation of nitrogen atoms and ketones also extends light absorption and store electrons, further enhancing the photocatalytic performance of DANT-BTT. Consequently, DANT-BTT can achieve 71 % photoreduction UO 2 2+ efficiency (pH 1) after 60 min irradiation, where dark adsorption accounts for 43 %. This work provides a strategy for the efficient reduction of U(VI) under strong acids. [ABSTRACT FROM AUTHOR]

In the present work, we have introduced a series of stable radical-doped coordination compounds composed of donor–acceptor structures and shown to produce organic radicals in situ as a result of unconventional lone pair–π interactions in ambient conditions. Inconspicuous lone pair–π and C–H⋯π interactions were shown to play a key role in self-assembly as well as the charge transfer process, resulting in a long-lived charge-separated state able to generate organic radicals. The resultant species displayed broad-spectrum antimicrobial activity, including against multi-drug-resistant bacteria. This study unveiled the promise of reactive organic radical-doped materials as a new platform for developing antimicrobial agents that can overcome antibiotic resistance. [ABSTRACT FROM AUTHOR]

Uranium is a key resource for the development of the nuclear industry, and extracting uranium from the natural seawater is one of the most promising ways to address the shortage of uranium resources. Herein, a semiconducting covalent organic framework (named NDA‐TN‐AO) with excellent photocatalytic and photoelectric activities was synthesized. The excellent photocatalytic effect endowed NDA‐TN‐AO with a high anti‐biofouling activity by generating biotoxic reactive oxygen species and promoting photoelectrons to reduce the adsorbed UVI to insoluble UIV, thereby increasing the uranium extraction capacity. Owing to the photoinduced effect, the adsorption capacity of NDA‐TN‐AO to uranium in seawater reaches 6.07 mg g−1, which is 1.33 times of that in dark. The NDA‐TN‐AO with enhanced adsorption capacity is a promising material for extracting uranium from the natural seawater. [ABSTRACT FROM AUTHOR]

Uranium is a key resource for the development of the nuclear industry, and extracting uranium from the natural seawater is one of the most promising ways to address the shortage of uranium resources. Herein, a semiconducting covalent organic framework (named NDA‐TN‐AO) with excellent photocatalytic and photoelectric activities was synthesized. The excellent photocatalytic effect endowed NDA‐TN‐AO with a high anti‐biofouling activity by generating biotoxic reactive oxygen species and promoting photoelectrons to reduce the adsorbed UVI to insoluble UIV, thereby increasing the uranium extraction capacity. Owing to the photoinduced effect, the adsorption capacity of NDA‐TN‐AO to uranium in seawater reaches 6.07 mg g−1, which is 1.33 times of that in dark. The NDA‐TN‐AO with enhanced adsorption capacity is a promising material for extracting uranium from the natural seawater. [ABSTRACT FROM AUTHOR]

Stimulus-responsive double-ligand luminol-Eu-IPA infinite coordination polymer nanoparticles (luminol-Eu-IPA CPNPs) were prepared as a ratiometric fluorescence probe for highly selective detecting Hg2+. The CPNPs were constituted of Eu3+ as the nuclear metal coordinated by isophthalic acid (IPA) together with luminol as an auxiliary ligand. The photoinduced electron transfer (PET) occurring from IPA to luminol prevented the antenna effect between IPA and Eu3+, leading to the quench fluorescence of Eu3+ under light excitation. As Hg2+ has a high affinity to N atom of luminol and the spin-orbit coupling effect, spectroscopically and magnetically silent properties, the fluorescence intensity of luminol was quenched. Meanwhile, the PET effect between luminol and IPA was interrupted under the presence of Hg2+. This process resulted in a significant decrease in the fluorescence intensity of luminol and a significant increase in the fluorescence intensity of Eu3+. Therefore, the fluorescence ratiometric detection of Hg2+ was performed by monitoring the ratio of the fluorescence at 617 nm of Eu3+ to that at 430 nm of luminol. The linear range was from 0.05 to 20 μM with a detection limit as low as 13.2 nM Hg2+ (S/N = 3). Due to the fluorescence of luminol be quenched and the effect of PET be disrupted simultaneously, the probe exhibiting excellent detection selectively can avoid false positive signals, which was demonstrated for monitoring mercury ions in real water samples. Precision in positioning ligands in CPNPs is an advantage to achieve high specificity in comparison to traditional organic dendrimers or precious metal nanomaterials. Image 1 • An effective lanthanide ratiometric fluorescent probe for Hg2+ based on luminol-Eu-IPA CPNPs has been demonstrated. • The photoinduced electron transfer occurring from luminol to IPA prevents the antenna effect between IPA and Eu3+. • The fluorescence of luminol is quenched and the effect of PET is disrupted simultaneously under the presence of Hg2+. • The ratiometric probe exhibiting excellent detection selectively can avoid false positive signals. [ABSTRACT FROM AUTHOR]

Electrochemical nitrogen fixation techniques have emerged as a promisingly sustainable approach to face the challenge associated with nitrogen activation of ammonia synthesis by the Haber–Bosch process under ambient conditions. Herein, the performance of electrocatalytic nitrogen reduction for the production of α‐Fe2O3 nanospindles coated with mesoporous TiO2 with different crystallinity [denoted as α‐Fe2O3@mTiO2‐X (X=300, 400, and 500 °C)] were investigated. The as‐prepared α‐Fe2O3@mTiO2‐400 composite exhibits a large NH3 yield (27.2 μg h−1 mgcat.−1) at −0. 5 V vs. the reversible hydrogen electrode and a high Faradaic efficiency (13.3 %) in 0.1 m Na2SO4, with excellent electrochemical durability. This work presents a novel avenue for the rational design of efficient unique hetero‐phase nanocatalysts toward sustainable electrocatalytic N2 fixation. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) decorated carbon nitride nanosheets (Au–g-C3N4 NSs) could work as an excellent on-electrode cathodic coreactant for Ru(bpy)32+. Based on the regulation effect of AuNPs and mercury (Hg2+) for the dual-potential electrochemiluminescence (ECL) of Ru(bpy)32+, a simple, sensitive and selective ECL system was created for the ratiometric sensing of Hg2+. [ABSTRACT FROM AUTHOR]

The traditional detection of telomerase activity is mainly based on the polymerase chain reaction (PCR), which has the disadvantages of being time-consuming and susceptible to interferences; thus, here, we propose a facile method for the fabrication of fluorescent tungsten oxide quantum dots (WOx QDs) and employ them for telomerase activity sensing. It is found that the fluorescence of WOx QDs can be significantly quenched by hemin based on the inner filter effect (IFE). However, in the presence of telomerase, the primer-DNA can be extended to generate repeating units of TTAGGG to form G-quadruplex and thus, hemin can be encapsulated to reduce its absorbance, resulting in decreased IFE and efficient fluorescence recovery of WOx QDs. Based on the fluorescence changes of IFE between hemin and WOx QDs, the telomerase activity within the range of 50–30 000 HeLa cells can be detected and the lowest detection amount can reach 17 cells. The method exhibits good versatility that can also be applied to telomerase detection in A549 and L929 cells. In addition, because of the good biocompatibility of the sensor, it can be used for the real-time monitoring of telomerase activity in living cells, thus showing great potential in tumor diagnosis and inhibitor drug screening. [ABSTRACT FROM AUTHOR]

Telomerase, as a potential biomarker for early cancer diagnostics and therapies, has attracted considerable interests concerning its detection and monitoring. Herein, we develop a novel method for sensitive detection of telomerase activity by designing a gold nanoparticles/graphene oxide (AuNPs/GO) probe. The AuNPs were functionalized with a telomerase substrate (TS) primer and a 6-carboxy-fluorescein (FAM)-modified complementary DNA (P1). In the absence of telomerase, P1 exists in the random-coiled conformation, and the fluorescence resonance energy transfer (FRET) from FAM to AuNPs and GO results in efficient fluorescence quenching. In the presence of telomerase, the multiple hybridization between TS extension products and P1 leads to the conformation transition of P1 from single-stranded DNA to double-stranded rigid structure, and thus the FRET process can be prevented with the efficient fluorescence recovery. The metal enhanced fluorescence (MEF) effect between FAM and AuNPs can further effectively enhance the fluorescence of FAM, and thus the sensitivity and specificity of telomerase detection can be remarkably improved. It is worth mentioning that the proposed strategy does not need to design complex hairpin structure and allows the measurement of telomerase activity in three crude cell extracts equivalent to 7 HeLa cells, 8 A549 cells and 8 L929 cells in 1 h. In addition, the present sensing platform can be applied to inhibitor screening, in situ telomerase imaging, and intracellular drug delivery. Image 1 • The metal enhanced fluorescence effect can be regulated to generate significant fluorescence enhancement. • Weak background fluorescence can be realized via efficient fluorescence resonance energy transfer. • Telomerase activity down to 7 HeLa cells can be sensitively detected. • The method facilitates cellular imaging, inhibitor screening and drug delivery. [ABSTRACT FROM AUTHOR]

A fluorometric method is described for the determination of thrombin. Polymer nanoparticles containing the luminol-terbium(III) complex (luminol-Tb) were prepared where luminol acts as the bridging ligand, and Tb(III) acts as the central metal ion. Thrombin possesses a large number of electrons donating groups that coordinate with luminol-Tb. Following coordination, the rigidity of the linker is increased, and this decreases the non-radiative decay rate and induces an increase in fluorescence intensity at 430 nm. Hence, thrombin can be fluorometrically determined. The detection limit of thrombin is as low as 3.5 pM (at an SNR of 3). This is about 10 times lower than assays using an aptamer. The method was applied in the determination of thrombin in human serum via the standard addition method and gave satisfying results. [ABSTRACT FROM AUTHOR]

The measurement of arsenic has received considerable attention due to its contaminant to environment and harm on human safety. This paper provides an overview of optical methods on the measurement of inorganic arsenic (arsenite and arsenate). We present and discuss the colorimetric, scattering, and fluorimetric strategies for inorganic arsenic detection based on the organic/biological molecules and their coupling with inorganic nanomaterials. The detection mechanism for arsenite and arsenate is summarized and the advantages/limitations are highlighted in the present review. In addition, prospects and future developments of optical sensors for arsenic analysis are also proposed. • Different optical methods for arsenics were reviewed. • The detection mechanism of optical methods was summarized. • The sensors with organic/biological molecules and nanomaterials were described. • The challenges and prospects in arsenic analysis were discussed. [ABSTRACT FROM AUTHOR]