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Developing active, durable, and inexpensive electrocatalysts for the oxygen evolution reaction (OER) is drawing increased interest. Here, a mild hydrothermal–electrodeposition two-step route is designed for the preparation of Ce-doped Ni–S@NiMoO4 micropillar composites on nickel foam (CeNiS@NiMoO4/NF). The as-constructed CeNiS@NiMoO4/NF electrode shows an ultralow overpotential, fast kinetics, superb intrinsic activity and excellent long-term stability for the OER. In 1 M KOH solution, 187 mV overpotential is required to deliver a current density of 10 mA cm−2 with a Tafel slope of 35.28 mV dec−1, and in a saline-alkaline solution of 1 M KOH and 0.5 M NaCl, only 260 mV overpotential is needed to reach 100 mA cm−2, demonstrating its excellent OER performance. The above outstanding electrocatalytic activity is attributed to the influence of CeNiS nanosheets on the surface microstructure of NiMoO4 micropillars, which not only improves the conductivity of the catalyst, but also increases the surface area, as well as accelerates the escape of gases produced. Compared with other non-precious metal OER electrocatalysts, the as-prepared CeNiS@NiMoO4/NF presents stronger or close electrocatalytic activity and better durability, which provides a new electrocatalyst selection in practical applications. [ABSTRACT FROM AUTHOR]

The present study describes application of computational approaches to identify robust and reliable three-dimensional quantitative structure activity relationship (3D-QSAR) models for hTAS2R1 ligands (23 peptides) through integrated ligand and structure based studies using bitter-tasting tetra-peptides. The 3D-QSAR analyses were performed using comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA) methods. A CoMFA model with good predictive ability was produced based on the training set (17 peptides) and also showed satisfactory external predictive ability with 6 peptides (R 2cv = 0.533, R2pred = 0.6601). To improve the performance of the derived model, a reliable CoMSIA model was obtained and gave enhanced statistical results (R 2cv = 0.612, R2pred = 0.7433). In addition, MD simulations validated the rationality of the derived models and predicted the detailed interactions between peptides and the hTAS2R1 receptor. Some key residues (Leu18, Phe72, Tyr73, Lys76, and Pro187) were also pointed out after binding free energy calculations. The contour plots developed on the basis of the best model combined with the binding information helped to identify the significant structural features required for improving activity so as to design and predict novel bitter-tasting peptides. [ABSTRACT FROM AUTHOR]

Exosomes are cell-derived membrane-enclosed biological nanoparticles that carry lots of parental molecular information, and are recognized as an ideal biomarker for non-invasive diagnosis. However, due to the low abundance of exosomes in plasma samples and the interferences from complex biological matrices, the sensitive and direct detection of exosomes still remains a challenge. Here, by combining the direct magnetic isolation with in situ fluorescence imaging, we developed a Single Microbead-based Fluorescent Aptasensor (SMFA) for specific enrichment and sensitive quantification of exosomes from plasma. In the SMFA, a single aptamer-modified microbead (MB) served as the reaction carrier so that the specific exosomes inserted with a fluorescent anchor will be highly enriched on the single MB. By in situ fluorescence imaging to monitor the fluorescence signals on the single MB, sensitive detection of exosomes can be realized without the requirement of any signal amplification routes, and as low as 4.9 × 104 particles per μL of exosomes could be simply detected. More importantly, the SMFA could be applied for direct detection of the exosomes from small amounts of clinical plasma samples without prior purification procedures, indicating its great potential applications in clinical diagnostics. [ABSTRACT FROM AUTHOR]

Urinary potassium is an important parameter in clinical health diagnosis. Rapid and convenient detection of potassium ions (K+) in urine is essential for personal healthcare and health management. Here, crown ether (4-aminodibenzo-18-crown-6, ADC) modified silver nanoparticles (ADC-Ag NPs) were successfully prepared for one-step rapid colorimetric detection of urinary potassium. The detection mechanism is as follows: due to the matching sizes of the diameter of K+ and the cavity in crown ether 6, K+ is encapsulated between the cavities of two crown ethers, resulting in the clumping of ADC-Ag NPs and the color of the solution being altered. The colorimetric detection method has a fast response and is completed within 20 minutes. It also shows good selectivity and interference immunity. The lowest detectable concentration is 20 μM with the naked eye and 2.16 μM for UV-vis absorption spectroscopy. A good linear relationship (R2 = 0.9931) between the absorption intensity ratio and K+ concentration (0–100 μM) indicates that this colorimetric probe can be used to detect K+. The method was also applied for quantitative analysis of K+ in real urine samples with recovery between 116 and 120%. [ABSTRACT FROM AUTHOR]

It is of great importance to construct non-precious metal bifunctional electrocatalysts with low cost and high efficiency for overall water splitting. In this work, a nickel foam (NF) supported hierarchical MnCo2O4 nanowire@NiFe layered double hydroxide (LDH) heterostructure (labeled as MCO@NiFe-LDH/NF) was constructed using a hydrothermal-annealing-hydrothermal route. Electrochemical tests showed that the as-constructed MCO@NiFe-LDH/NF could be used as an integral electrode for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 M KOH electrolyte. To get the current density of −10 mA cm−2 for HER or 100 mA cm−2 for OER, an overpotential of 129/283 mV was separately required. In a two-electrode system with MCO@NiFe-LDH/NF as both the anode and cathode, 1.55/1.705 V of cell voltage was needed to reach current density of 10/100 mA cm−2. More importantly, the as-constructed integral electrode could continuously catalyze for 200 h, full water splitting at the current density of 50 mA cm−2, demonstrating prominent long-term stability. [ABSTRACT FROM AUTHOR]

FeNi-layered double hydroxide (LDH) is thought to be an excellent electrocatalyst for oxygen evolution reaction (OER) but it always shows extremely poor electrocatalytic activity toward hydrogen evolution reaction (HER) in alkaline media. Hence, it is significant to improve its HER activity to make it a bifunctional electrocatalyst for the decomposition of water. Here, a simple galvanostatic electrodeposition method was designed for the successful construction of the bifunctional FeNi3@FeNi LDH electrocatalyst. The as-prepared catalyst displayed excellent electrocatalytic activity for HER/OER in 1.0 M KOH. To drive the current density of 10 mA cm−2 for HER/OER, an overpotential of 106/199 mV was needed, respectively. In a two-electrode system with the FeNi3@FeNi LDH/NF as the anode and the cathode simultaneously, the overpotential hardly changed after continuously working for 168 h at 10 mA cm−2. Compared with other FeNi-based catalysts, the present catalyst possessed close or better electrocatalytic activity. [ABSTRACT FROM AUTHOR]

Riboflavin (vitamin B2), a cis-diol-containing compound, is an essential vitamin for maintaining human health mainly in energy metabolism and is a critical component of enzyme cofactors and flavoproteins. Thus, the determination of riboflavin in food products is essential in riboflavin-fortified foods. However, analysis of riboflavin at natural levels in foods or biological samples is difficult because of its very low concentration level and the presence of undesirable matrix effects which could interfere with the measuring system. Thus, it is essential to develop efficient and selective enrichment approaches for riboflavin. Molecularly imprinted polymers can be well used for riboflavin extraction and pre-concentration from food samples. In this study, we present riboflavin-imprinted magnetic nanoparticles as an ideal sorbent for the selective enrichment of riboflavin followed by direct fluorometric determination. The riboflavin-imprinted magnetic nanoparticles were prepared according to a newly reported strategy, called boronate affinity-based surface initiated imprinting. Magnetic nanoparticles and vinylphenylboronic acid were used as supporting materials and a functional monomer, respectively. The prepared riboflavin-imprinted magnetic nanoparticles exhibited several significant advantages, such as excellent selectivity, high binding affinity and low binding pH toward riboflavin, which made the molecularly imprinted material become an ideal sorbent for the selective enrichment of riboflavin. The prepared riboflavin-imprinted magnetic nanoparticles were successfully applied to the analysis of riboflavin in milk. [ABSTRACT FROM AUTHOR]

Alternative messenger RNA (mRNA) splicing is a vital regulatory process during the gene expression of higher eukaryotes. The specific and sensitive quantification of disease-related mRNA splice variants in biological and clinical samples is becoming particularly important. Reverse transcription polymerase chain reaction (RT-PCR), the most classical strategy for the assay of mRNA splice variants, cannot avoid false positive signals, which poses a challenge to the specificity of mRNA splice variant detection. In this paper, by rationally designing two DNA probes with double recognition at the splice site and different lengths, different mRNA splice variants could generate amplification products of unique lengths. Combined with capillary electrophoresis (CE) separation, the product peak of the corresponding mRNA splice variant can be specifically detected, which can avoid false-positive signals caused by non-specific amplification of PCR, greatly improving the specificity of the mRNA splice variant assay. In addition, universal PCR amplification eliminates amplification bias caused by different primer sequences and improves quantitative accuracy. Furthermore, the proposed method can simultaneously detect multiple mRNA splice variants as low as 100 aM in a one-tube reaction and has been successfully applied to the assay of variants in cell samples, which will provide a new strategy for mRNA splice variant-based clinical diagnosis and research. [ABSTRACT FROM AUTHOR]

Antibiotic abuse is considered a serious problem affecting human health, necessitating that great attention be paid to explore robust, simple and sensitive methods for rapid evaluation. In this paper, we developed a fluorescent aptasensor for visual and real-time kanamycin detection by taking advantage of the label-free strategy based on H-aggregate disassembly of a chiral cyanine dye induced by a G-quadruplex aptamer. The good sensitivity and selectivity enabled this aptasensor to have a detection limit as low as 43 nM and have high specificity for kanamycin recognition. Furthermore, this assay was successfully applied for the detection of kanamycin in lake water and urine with excellent recoveries. [ABSTRACT FROM AUTHOR]

Gene fusions, produced by aberrant juxtapositions of two or more genes even in different chromosomes, play important roles in the primary oncogenic mechanism and have been demonstrated to be typically associated with many cancers. So the fused genes or the transcripts can be specific predictive biomarkers for cancer diagnosis and therapy. Herein, we develop a direct ligation- and ligase chain reaction (LCR)-based method for a fusion transcript assay. In virtue of the high selectivity of ligase and the exponential amplification capacity of LCR, the proposed method can detect as low as 1 fM fusion transcripts with high specificity and has been successfully applied to real samples. With the real-time fluorescence measurements, the fusion transcripts can be assayed in a simple way. Therefore, the proposed method can provide a simple and cost-effective platform for fusion transcript detection in routine laboratories and clinical diagnosis. [ABSTRACT FROM AUTHOR]

A triple sequential junction by rationally combining anatase/rutile nanoparticle TiO2 heterophase (Ans/R) and rutile/rutile TiO2 homophase (Rns/R) junctions was fabricated as a proof of concept. Such a continuous charge separation and transfer channel resulted in a remarkable enhancement in the separation of photogenerated carriers and the photocatalytic activity. [ABSTRACT FROM AUTHOR]

The non-conjugated inductive effect of trifluoromethyl (CF3) was found to be a new acceptor instead of other conjugated moieties. Two blue emissive compounds, 4CzCF3Ph and 5CzCF3Ph, were synthesized using a simple catalyst-free C–N coupling reaction. Solution-processed TADF devices based on the 5CzCF3Ph dopant exhibit significantly higher efficiency (11.8 cd A−1, 5.2%) than 4CzCF3Ph (1.03 cd A−1, 0.67%) due to the smaller ΔEST value for efficient RISC. [ABSTRACT FROM AUTHOR]

By using various fluoro-substituted pyridines and carbazole as starting materials, we have synthesized a series of carbazole–pyridine hybrid compounds through an efficient catalyst free C–N coupling reaction with high yields of 85–95%. The bi-, tri- and tetra-carbazole substituted pyridine derivatives exhibit increased thermal stabilities and comparatively high triplet energy levels of ∼3.0 eV. By using them as host materials for blue phosphorescent OLEDs, maximum current efficiencies are achieved ranging from 32–42 cd A−1. [ABSTRACT FROM AUTHOR]

The self-assembly of diphenylalanine peptides (l-Phe–l-Phe) into microtubes with “turn on” bright yellow green fluorescence was described, which was achieved using an aggregation-induced emission (AIE) molecule of 9,10-bis[4-(3-sulfonatopropoxyl)-styryl] anthracene (BSPSA) sodium. [ABSTRACT FROM AUTHOR]

An anionic fluorescent conjugated polymer (PFPaa), coupled with the metal ion-mediated fluorescence resonance energy transfer, has been used to design a versatile platform for homogeneous detection of protein kinase activity. [ABSTRACT FROM AUTHOR]