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Uracil DNA glycosylase (UDG) and human alkyladenine DNA glycosylase (hAAG) are the important DNA glycosylases for initiating the repair of DNA damage, and the aberrant expression of DNA glycosylases is closely associated with various diseases, such as Parkinson's disease, several cancers, and human immunodeficiency. The simultaneous detection of UDG and hAAG is helpful for the study of early clinical diagnosis. However, the reported methods for multiple DNA glycosylase assay suffer from the application of an expensive single-molecule instrument, labor-tedious magnetic separation, and complicated design. Herein, we develop a simple fluorescence method with only three necessary DNA strands for the selective and sensitive detection of multiple DNA glycosylase activity based on the generation of 3'-OH terminal-triggered encoding of multicolor fluorescence. The method can achieve the detection limits of 5.5 × 10

Genomic deoxyribonucleic acid (DNA) is selected as the ideal carrier for preserving and transmitting the genetic information over the course of evolution. However, the genomic DNA is constantly exposed to various endogenous and environmental threats, causing a diversity of damaged bases, lesions, mismatches and base-pair modifications in the genome, eventually leading to genomic instability and cancers. Base excision repair (BER) is the most important repair mechanism, repairing a variety of DNA damages arising from oxidation, alkylation, methylation, deamination, and hydrolysis reactions. DNA glycosylases are responsible for initiating the first step of the BER pathway through cleaving the N-glycosidic bond between the damaged base and the DNA backbone. However, abnormal DNA glycosylases are associated with a variety of diseases such as cancer, cardiovascular disease, neurological disease and inflammation, suggesting the important role of DNA glycosylases in cancer diagnosis and treatment. Therefore, it is highly desirable to monitor the activity of DNA glycosylases, gaining a deep understanding of the restoration process of damaged DNA and clinical diagnosis. Recently, a series of novel DNA glycosylases detection methods with excellent performance have been developed. In this minireview, we summarize the recent advances in DNA glycosylase assays including amplification-free assay and amplification-assisted assay. Firstly, a brief introduction of amplification-free assay for DNA glycosylase is given. Then, amplification-assisted assays for DNA glycosylases are discussed in detail. Ultimately, the conclusions and prospects of the directions of DNA glycosylase assays are provided.

Herein, a novel chiral covalent organic framework, DA-TD COF, with good chemical/thermal stability was synthesized and used as a chiral stationary phase for open-tubular capillary electrochromatography enantioseparation. The DA-TD COF coated capillary exhibited excellent enantioseparation efficiency and its separation efficiency did not show an obvious decrease over 200 runs. Furthermore, the enantioseparation mechanism was studied.

A new D–A emitter with HLCT and AIE characteristics has been designed based on BTT acceptor and TPA donor, and non-doped and doped solution-processed devices show deep-red emission.

A series of lanthanide-containing water-resistant nitrates, namely RE(OH)

Poly(3-hexylthiophene) (P3HT) is regarded as one of the most promising polymer donors for organic solar cells (OSCs) owing to its own merits of low-cost and controllable synthesis, and large-area and roll-to-roll printing device fabrication. However, the mutual restriction and imbalance of the open-circuit voltage (VOC) and short-circuit current density (JSC) greatly limits further breakthrough of power conversion efficiency (PCE) for P3HT-based OSCs. Herein, a new A-π-D-π-A type acceptor (JC14) with the same conjugated skeleton as that of our previous acceptor (JC2) has been designed through removing an electron-withdrawing ester group from a thiophene-fused benzotriazole (BTAZT) unit as a “π-bridge”. In comparison, JC14 retains the BTAZT unit that can still stabilize the quinoid structure of the conjugated backbone to favor JSC. Remarkably, the fine structural regulation of the “π-bridge” significantly raises the LUMO energy level of JC14, which is more conducive to the enhancement of VOC. Thus, the P3HT:JC14-based OSC device achieves very balanced and high JSC (JSC = 16.04 mA cm−2) and VOC (VOC = 0.759 V) that leads to a high PCE of 7.72%, while the P3HT:JC2-based device shows a relatively lower PCE of 6.12% with JSC of 14.53 mA cm−2 and VOC of 0.685 V.

Background: Type 2 diabetes mellitus (T2DM) is a multifaceted disorder affecting epidemic proportion at global scope. Defective insulin secretion by pancreatic β-cells and the inability of insulin-sensitive tissues to respond effectively to insulin are the underlying biology of T2DM. However, circulating biomarkers indicative of early diabetic onset at the asymptomatic stage have not been well described. We hypothesized that global and targeted mass spectrometry (MS) based metabolomic discovery can identify novel serological metabolic biomarkers specifically associated with T2DM. We further hypothesized that these markers can have a unique pattern associated with latent or early asymptomatic stage, promising an effective liquid biopsy approach for population T2DM risk stratification and screening.Methods: Four independent cohorts were assembled for the study. The T2DM cohort included sera from 25 patients with T2DM and 25 healthy individuals for the biomarker discovery and sera from 15 patients with T2DM and 15 healthy controls for the testing. The Pre-T2DM cohort included sera from 76 with prediabetes and 62 healthy controls for the model training and sera from 35 patients with prediabetes and 27 healthy controls for the model testing. Both global and targeted (amino acid, acylcarnitine, and fatty acid) approaches were used to deep phenotype the serological metabolome by high performance liquid chromatography-high resolution mass spectrometry. Different machine learning approaches (Random Forest, XGBoost, and ElasticNet) were applied to model the unique T2DM/Pre-T2DM metabolic patterns and contrasted with their effectiness to differentiate T2DM/Pre-T2DM from controls.Results: The univariate analysis identified unique panel of metabolites (n = 22) significantly associated with T2DM. Global metabolomics and subsequent structure determination led to the identification of 8 T2DM biomarkers while targeted LCMS profiling discovered 14 T2DM biomarkers. Our panel can effectively differentiate T2DM (ROC AUC = 1.00) or Pre-T2DM (ROC AUC = 0.84) from the controls in the respective testing cohort.Conclusion: Our serological metabolite panel can be utilized to identifiy asymptomatic population at risk of T2DM, which may provide utility in identifying population at risk at an early stage of diabetic development to allow for clinical intervention. This early detection would guide ehanced levels of care and accelerate development of clinical strategies to prevent T2DM.

This case-control study aimed to analyze the clinical features and determine the expression of type I interferon-induced genes in systemic lupus erythematosus (SLE) patients harboring the CD11b rs1143679 single-nucleotide polymorphism (SNP) and elucidate whether it is involved in the relapses of SLE. One hundred twenty-five relatively inactive SLE patients with SLEDAI scores < 6, including 102 CD11b rs1143679 G allele patients as controls and 23 rs1143679 A allele carriers as cases, were enrolled from the SLE patient specimen bank in the Department of Rheumatology and Immunology. The sample set was retrospectively analyzed for differences in clinical features, and quantitative PCR and Western blot analyses were performed to evaluate the relative expression of type I interferon (IFN)-inducible genes. The 24-h urinary protein levels in the case group were significantly elevated, and serum C3 levels were significantly reduced compared with those in the control group (P = 0.019 and P = 0.021, respectively). The relative mRNA levels of IFN-inducible genes IFIT1, IFIT4, and ISG15 in the case group were higher than that in the control group (P = 0.0257, 0.0344, and 0.0311, respectively) and matched with the Western blot results. The relative expression of type I IFN-inducible genes in inactive SLE patients harboring the CD11b rs1143679 polymorphism was higher than that in other lupus patients. These findings suggest that the rs1143679 SNP can precipitate relapses in inactive SLE patients. • The rs1143679 GA genotype was associated with SLE clinical features. • The rs1143679 GA genotype showed higher interferon-inducible gene expression relative to the GG genotype.

A smart fluorescent probe DPAS-Cys has been rationally designed based on a typical AIEgen DPAS and an acrylate moiety. The probe DPAS-Cys not only can be used for the detection of cysteine (Cys) selectively with large Stokes shift (200 nm) and relatively low detection limit (2.4 μM), but also shows lipid droplets (LDs) targeting property. The response mechanism for Cys was carefully verified. Importantly, due to the aggregation-induced emission characteristic, the introduction of considerable percentage of traditional organic solvent is avoidable, which makes it suitable for bioimaging in physiological systems. In addition, the confocal fluorescence imaging demonstrates that DPAS-Cys is able to detect Cys in LDs of different cell lines with universality. Our study opens a new avenue to understand the importance of LDs in biosystem, for which the gap between the essential biothiol Cys and the energy storage organelle LDs was bridged for the first time.

Covalent organic frameworks (COFs), as one of the most significant members of the porous organic frameworks, have been well used in the photocatalysis owing to their outspread π-conjugated framework, high crystallinity and regular pore structure. Herein, after reducing the labile imine-linked COF-300 to the more stable amine-linked COF-300-AR, we for the first time demonstrated that COF-300-AR was the light-responsive oxidase mimic. COF-300-AR exhibited excellent oxidase-mimicking activity under purple light stimulation (λ = 400 nm), which can catalyze the oxidation of classical substrates such as 3,3',5,5'-tetramethylbenzydine (TMB) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) by the formation of •OH and O2•- free radicals in the presence of dissolved oxygen. The COF-300-AR oxidase mimic has outstanding advantages of easy light control, high stability, good reusability, and highly catalytic oxidation capacity and has been applied to detect glutathione (GSH) levels in HL60 cells with good selectivity and high sensitivity. This study will broaden the sensing applications of COFs and offer a promising build block for the construction of artificial enzymes.

Molecular structural modifications are utilized to improve the short-circuit current (J

Covalent organic frameworks (COFs) are divided into two-dimensional (2D) and three-dimensional (3D) structures according to the connection dimension of covalent bonds. 3D COFs have smaller pore size and larger surface area, which would facilitate the separation of small organic molecules with similar structures and properties in capillary electrochromatographic (CEC) separation. However, the application of 3D COFs in CEC is still in its early stages. Thus, 3D COFs (3D-IL-COF-1 and 3D-IL-COF-2) were synthesis by a new synthesis method in this work. The related characterization results confirmed that spherical 3D-IL-COFs formed by the accumulation of small polyhedral particles were successfully synthesized. Then, 3D-IL-COFs were introduced into the inner wall of capillary by in-situ growth method to prepare the 3D COFs coated capillaries for the first time. The electrochromatographic separation performance of the 3D-IL-COFs coated capillaries was investigated using the 3D-IL-COF-1 coated capillary as the model. The results indicate that the 3D-IL-COF-1 coated capillary with uniform coating exhibits a broad-spectrum separation capacity not only for acidic, basic and neutral analytes but also for neutral isomers, which shows that 3D-IL-COFs becomes an attractive potential stationary phase for electrochromatographic separation.

Recently, covalent organic frameworks (COFs), owning to their excellent and unique properties, are attracting the attention of numerous researchers in some areas, especially the domain of chromatographic separation. However, the application of hydrazine linkages COFs in open-tubular capillary electrochromatography (OT-CEC) lies in the early stage at present. Herein, a well-crystallized hydrazine-linked COF (Tf-DHzOH) was synthesized successfully from 2,5-dihydroxyterephtalohydrazide and 1,3,5-triformyl-benzene. Tf-DHzOH was firstly regarded as a stationary phase material to prepare the Tf-DHzOH coated capillaries with different coating thickness by covalent bonding in this work. The characterization results showed that Tf-DHzOH was successfully synthesized. The separation performance and stability of the Tf-DHzOH coated capillary were evaluated by considering amino acids, sulfonamides, tetracyclines and benzene compounds as analytes. The relative standard deviations (RSDs) of separation time in the intra-day (n=9), inter-day (n=6), column-to-column (n=3) and batch-to-batch (n=3) were 0.76-4.97%, 1.59-5.94%1.78-8.72% and 1.66%-8.23%, respectively, the RSDs of peak areas were 1.90-5.16%, 1.73-5.24%, 1.26-7.33% and 3.77%-11.24%, respectively. It was confirmed that there was no visible change of separation efficiency after the Tf-DHzOH-coated capillary was used more than 200 runs. The results make clear that 2D hydrazine-linked COF (Tf-DHzOH) has superior potential as the stationary phase in OT-CEC for chromatographic separation.

Environmental quality data sets are typically imbalanced, because environmental pollution events are rarely observed in daily life. Prediction of imbalanced data sets is a major challenge in machine learning. Our recent work has shown deep cascade forest (DCF), as a base learning model, is promising to be recommended for environmental quality prediction. Although some traditional models were improved by introducing the cost matrix, little is known about whether cost matrix could enhance the prediction performance of DCF. Additionally, feature extraction is also an important way to potentially improve the model's ability to predict the imbalanced data. Here, we developed two novelty learning models based on DCF: cost-sensitive DCF (CS-DCF) and DCF that combines unsupervised learning models and greedy methods (USM-DCF-G). Subsequently, CS-DCF and USM-DCF-G were successfully verified by an imbalanced drinking water quality data set. Our data presented both CS-DCF and USM-DCF-G show better prediction performance than that of DCF alone did. In particular, USM-DCF-G shows the best performance with the highest F1-score (95.12 ± 2.56%), after feature extraction and selection by using unsupervised learning models and greedy methods. Thus, the two learning models, especially USM-DCF-G, were promising learning models to address environmental imbalanced issues and accurately predict environmental quality.

As a class of new porous crystalline materials, covalent organic frameworks (COFs) are attracting the attention of a large number of scientists. Because of their large specific surface area, low density, high stability, and tunable pore size, COFs have been widely applied in many fields, including analytical chemistry. Open-tubular capillary electrochromatography (OT-CEC) is a mode of capillary electrochromatography. In recent years, a variety of materials such as porous organic frameworks have been used as the stationary phase for OT-CEC to overcome the disadvantages of low phase ratio and column capacity, thereby improving the separation efficiency. However, there are a few reports on the use of COFs as the stationary phase to improve the separation efficiency of OT-CEC. Environmental endocrine disruptors (EEDs) are a large class of exogenous chemicals that can disturb the effect of the normal endocrine substances and adversely affect the endocrine and reproductive systems of human beings. Considering the widespread existence of EEDs and the disadvantages of existing detection methods (e. g., gas chromatography-mass spectrometry and high performance liquid chromatography-mass spectrometry), such as complicated operation and large sample consumption, it is necessary to develop new methods for the separation and determination of EEDs in complex samples. OT-CEC is a good choice in this regard because of its low sample dosage, simple operation, and high analytical speed. Accordingly, a two-dimensional azine-linked covalent organic framework (ACOF-1) with a large surface area and small pore size was synthesized according to the reference method. Then, an ACOF-1-coated capillary was fabricated using ACOF-1 as the stationary phase, via covalent bonding, and used as the separation channel to establish a new OT-CEC method for the separation and detection of nitrophenol EEDs. X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) were used to characterize the synthesized ACOF-1 and the ACOF-1-coated capillary. The peak pattern in the XRD spectrum confirmed the successful synthesis of ACOF-1. The absorption peaks in the FT-IR spectrum and the morphology of the inner wall seen in the SEM images also demonstrated that the ACOF-1-coated capillary was fabricated successfully. A series of experiments were carried out to investigate the effects of the organic additive (methanol) content, pH, and concentration of the borate buffer on the resolution, migration time, and peak shape. Based on the results, the optimal separation conditions for the four nitrophenol analytes were 15 mmol/L borate (pH 9.20) with 10% (v/v) methanol. Under the optimum conditions, 2-nitrophenol (2-NP), 4-nitrophenol (4-NP), 2,4-dinitrophenol (DNP), and 2,4,6-trinitrophenol (TNP) could be baseline separated within 20 min by the established OT-CEC method. The linear range for 2-NP and 4-NP was 10-500 mg/L, while that for DNP and TNP was 20-1000 mg/L. The determination coefficients (

Three 6-fluoro-thieno[2′,3′:4,5]benzo[1,2-d][1,2,3]triazole (fBTAZT) containing copolymers, named as PfBTAZT-H, PfBTAZT-F, and PfBTAZT-Cl, were employed to pair with a benzo[1,2-d][1,2,3]triazole (...

As a promising signaling transduction approach, fluorescence polarization (FP)/fluorescence anisotropy (FA), provides a powerful quantitative tool for the rotational motion of fluorescently labeled molecules in chemical or biological homogeneous systems. Unlike fluorescence intensity, FP/FA is almost independent the concentration or quantum of fluorophores, but they are highly dependent on the size or molecular weight of the molecules or materials attached to fluorophores. Recently, significant progress in FP/FA was made, due to the introduction of some nanomaterials as FP/FA enhancers. The detection sensitivity is thus greatly improved by using nanomaterials as FP/FA enhancers, and nanomaterial-based FP/FA is currently used successfully in immunoassay, and analysis of protein, nucleic acid, small molecule and metal ion. Nanomaterial-based FP/FA provides a new kind of strategy to design fluorescent sensors and establishes innovative analytical methods. In this review, we summarize the scientific publications in the field of FP/FA sensor in recent five years, and first introduce the recent progress of FP/FA sensor based on nanomaterial. Subsequently, the various analytical applications of FP/FA based on nanomaterial are discussed. Finally, we provide perspectives on the current challenges and future prospects in this promising field.

The addition of potassium ferrocyanide (K4[Fe(CN)6]) in table salt as anti-caking agent has a crucial role in preventing the formation of lumps. However, the excess of K4[Fe(CN)6] and its decomposers are harmful to both human health and environment. To date, there are still lack of suitable methods for simple and rapid analysis of K4[Fe(CN)6] in table salt and salted food. Herein, a novel fluorescent Si QDs probe for sensitive, selective and rapid detection of K4[Fe(CN)6] was synthesized by facile one-step strategy. Notably, the fluorescence of Si QDs could be remarkably quenched by K4[Fe(CN)6] via electrostatic interaction. Based on this phenomenon, a new method of determination of K4[Fe(CN)6] was established. A wide linear range was obtained from 0.05 to 8.0 µg/mL with a detection limit of 30 ng/mL. The established fluorescent new method was suitable for detecting K4[Fe(CN)6] in table salt and salted food samples with satisfactory results.

Poly(3-hexylthiophene) (P3HT)-based organic solar cells (OSCs) have been extensively studied due to unique advantages of P3HT such as roll-to-roll and large-area printing fabrication, but a poor sh...

The exploration of novel nanocomposite about two-dimensional (2D) nanoporous graphene (NPG) is of great significance for the further investigation of their outstanding properties and potential applications. Thus, an exceptionally facile and rapid strategy named combustion-reduction synthesis is reported. 2D NPG/cuprous oxide (NPG/Cu2O) nanocomposite can be obtained via combustion of graphene oxide (GO) and copper chloride in an oven at 450 °C for only one minute. By simply washing away Cu2O with acid, NPG was obtained. By burning away graphene, Cu2O nanoparticles were also obtained. As a new kind of hybrid materials, NPG/Cu2O nanocomposite presented much more excellent catalytic activity than the reduced GO/Cu2O nanocomposite, free GO, NPG and Cu2O nanoparticles. The outstanding catalytic property can be ascribed to the hybridization of Cu2O and 2D NPG architectures. With this new hybrid material, a chemiluminescence sensing platform was firstly constructed for fast, excellently sensitive and highly selective determination of nicotinamide adenine dinucleotide (NADH) with a detection limit of 3.5 nM. The as-established approach was successfully applied for quantitative determination of NADH in human serum and cell lysates. This strategy may open up a valuable avenue to fabricate a diversity range of nanocomposites containing nanoporous graphene and metal oxides with various potential applications.

In this work, two new donor-acceptor (D-A) copolymers (P32 and P33) for non-fullerene polymer solar cells (PSCs) have been synthesized based on a thiophene-fused benzotriazole (BTAZT) unit and thiophene substituted benzodithiophene (BDTT) unit, in which two different electron-withdrawing groups (i.e., fluorine and ester groups) have been introduced at the side of BTAZT unit, respectively. It is found that P32 with a long alkyl chain ester group shows a more redshifted intramolecular charge transfer absorption, and also exhibits a better complementary absorption spectrum with a small molecular acceptor based on the dithienocyclopentathieno[3,2-b]thiophene core end-capped with 1,1-dicyanomethylene-3-indanone unit (IHIC) than P33. Moreover, P32:IHIC blended film shows higher and more balanced hole/electron charge mobilities as well as better morphologies with more suitable phase separation scale for efficient charge separation and transport than P33:IHIC blended film. Thus, the P32:IHIC based PSC device exhibits the higher power conversion efficiency of 8.35% with higher short-circuit current density (JSC = 16.77 mA cm−2) and fill factor (FF = 64.89%) compared with the P32:IHIC based PSC device, indicating that the different electron-withdrawing side groups at BTAZT unit exerts a significant influence on the properties of the polymers as well as the photovoltaic performances of the PSCs.

Cloud of Things (CoT) is a significant paradigm for bridging cloud resource and mobile terminals. Mobile edge computing (MEC) is a supporting architecture for CoT. The objectives of this paper are to describe and evaluate a method to handle the computation offloading problem during user mobility which minimizes the offloading failure rate in heterogeneous network. Furthermore, users’ mobility and their choices for offloading lead to the everchanging condition of wireless network and opportunistic resource available. By modeling such dynamic mobile edge environment, quantizing the user cost, failure penalty and diversified QoS requirements, computation offloading problem is converted into an online decision-making problem in a stochastic process. We divide the decision-making into two phases: offloading planning phase and offloading running phase. In both phases the learning agent can continuously improve the control policy. We also conduct a failure recovery policy to tackle different types of failure and is included in the decision-making process. The numerical results show that the proposed online learning offloading method for mobile users can derive the optimal offloading scheme compared with the baseline algorithms.

Co3O4 nanoparticles-graphene oxide (Co3O4 NPs-GO) nanocomposites with good solubility were successfully synthesized and well characterized. As a nanocatalyst with oxidase-mimicking activity, the nanocomposites can catalyze the oxidation of 3′,5,5′-tetramethylbenzidine (TMB) with high efficiency. The catalyzing reaction was rapid and no extra H2O2 was needed compared with other similar TMB oxidation reactions. The catalyzing reaction mechanism of the system was investigated in detail. And it was demonstrated that the oxygen involved in the reaction came from the oxygen absorbed on the nanocomposites which oxidized TMB. Based on this reaction, a colorimetric system for vitamin C detection in vegetable and fruits was established. Under the optimum conditions, the detection can be achieved within 10 min and a linear relationship in concentration range of 2.5 × 10−6 to 1.8 × 10−5 M and 3.4 × 10−5 to 1.7 × 10−4 M was obtained with a detection limit of 7.0 × 10−7 M. The colorimetric system exhibited good selectivity, sensitivity and satisfactory recoveries ranged from 93.1% to 101.1%.

Infrared (IR) nonlinear optical (NLO) materials are of current interest owing to their technological applications in many military and civil fields. Metal halides are among the most favorable candidates for IR laser frequency conversion owing to their relatively large NLO effects, wide IR transparency and high laser damage thresholds (LDT). However, the comprehensive review for metal halides NLO materials is absent. Herein, we focus on the relationship between the structural features and NLO performances in the reported metal halide NLO materials. In particular, metal halides are classified according to the NLO-active [MXk] anionic units and NLO-active cations, i.e., they are sorted into traditional metal halides containing linear units, triangle pyramidal units, tetrahedral units, rectangular pyramidal units, five-coordinated pseudo-octahedra, six- and more-coordinated polyhedral units, organic-inorganic and supramolecular metal halides. The determination rules of these microscopic structures on NLO properties in metal halides are summarized and analyzed on the basis of the combination of available experimental data and first-principles results. From the deduced structure-property relationship, the development prospects for NLO metal halides are discussed.

DNA methyltransferase (MTase) is an important epigenetic modification enzyme responsible for DNA methylation, and the dysregulation of DNA MTase activity is associated with various diseases in humans. Herein, we take advantage of the DNA lesion repair mechanism in vivo to develop a new fluorescence approach for the specific and sensitive detection of DNA methyltransferase (DNA MTase) on the basis of the DNA lesion repair-directed cascade isothermal amplification. Due to the high amplification efficiency of the uracil repair-mediated exponential isothermal amplification reaction (EXPAR), the efficient cleavage of endonuclease IV (Endo IV)-induced cyclic catalysis, and the low background signal caused by single uracil repair-mediated inhibition of nonspecific amplification, this approach exhibits high sensitivity with a detection limit of 0.014 U mL-1 for pure Dam MTase and 0.61 × 10-6 mg mL-1 for Dam MTase in E. coli cells and it can be further applied for the screening of DNA MTase inhibitors. More importantly, this approach can be applied to detect other DNA MTases by designing appropriate substrates, showing great potential in biomedical research and clinical diagnosis.

The importance of measuring the content of silver ions (Ag+) in aqueous solutions and biological samples has increased in recent years due to their very high toxicity to the environment and the human body. Orange-emissive carbon dots (CDs) were simply synthesized through the hydrothermal treatment of p-aminobenzoic acid and p-aminophenol. The obtained CDs display orange fluorescence and stability, including favorable photostability, salt tolerance and water solubility. Significantly, the fluorescence intensity of the CDs was quenched by the addition of Ag+via static quenching to form a nonfluorescent complex; thus a highly selective fluorescent method for the determination of Ag+ was developed. The present method showed a rapid response and excellent selectivity for Ag+ over other metal ions, and the relevant linear range and limit of detection were 5–100 μM and 1.4 μM, respectively. Furthermore, the practicability of this method was validated by the successful determination of Ag+ in water samples and a human serum sample. Compared with previous reports, this method showed rapid response and excellent selectivity, which present it as a valuable strategy in environmental protection and biological assays.

DNA glycosylase (DG) plays a significant role in repairing DNA lesions, and the dysregulation of DG activity is associated with a variety of human pathologies. Thus, the detection of DG activity is essential for biomedical research and clinical diagnosis. Herein, we develop a facile fluorometric method based on the base excision repair (BER) mediated cascading triple-signal amplification for the sensitive detection of DG. The presence of human alkyladenine DNA glycosylase (hAAG) can initiate the cleavage of the substrate at the mismatched deoxyinosine site by endonuclease IV (Endo IV), resulting in the breaking of the DNA substrate. The cleaved DNA substrate functions as both a primer and a template to initiate strand displacement amplification (SDA) to release primers. The released primers can further bind to a circular template to induce an exponential primer generation rolling circle amplification (PG-RCA) reaction, producing a large number of primers. The primers that resulted from the SDA and PG-RCA reaction can induce the subsequent recycling cleavage of signal probes, leading to the generation of a fluorescence signal. Taking advantage of the high amplification efficiency of triple-signal amplification and the low background signal resulting from single uracil repair-mediated inhibition of nonspecific amplification, this method exhibits a low detection limit of 0.026 U mL−1 and a large dynamic range of 4 orders of magnitude for hAAG. Moreover, this method has distinct advantages of simplicity and low cost, and it can further quantify the hAAG activity from HeLa cell extracts, holding great potential in clinical diagnosis and biomedical research.

In order to understand related pathogenesis of some diseases and design new intracellular drug delivery systems, investigation of pH change in living cells in real time is important. In this paper, a new style of fluorescent silicon nanoparticles (SiNPs) as a pH-sensitive probe and for the visualization of the pH changes in cells was designed and prepared using 4-aminophenol as a reducing agent and N-aminoethyl-γ-aminopropyltrimethyl as a silicon source by a one-pot hydrothermal method. It was particularly noteworthy that the fluorescence intensity emitted from the SiNPs positively correlated with the pH value of solutions, making the SiNPs a viable probe used for sensitive sensing of pH. At the same time, a response of the probe to the pH was found in 5.0-10.0, and the SiNPs have an excellent biocompatibility (e.g., ∼74% of cell viability was remained after treatment for 24 h at 500 μg/mL of the SiNPs). The proposed method that could display the change in pH of live cells provided an effective means for visually diagnosing diseases related to intracellular pH.

A new 3D noncentrosymmetric mixed-metal sulfate iodate, AgBi(SO

The two-photon absorption properties of a set of linear copolymers based on the regular alternation of a 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine electron-accepting unit with different electron-donating groups attached to two of the thiophen ends were investigated. Comparison of these data with those of the analogous octupolar monomers and hyperbranched polymers allows us to understand the role of the triazine-thiophen core and its molecular architecture in the nonlinear optical properties of these polymeric materials. It is concluded that the arrangement of the push–pull unit into a unidimensional array, as it is the case of the linear copolymer, favours the two-photon absorption cross-section. Hybrid nanoparticles dispersed in water were prepared from selected polymers with two-photon excited fluorescence emission comparable with those of the best performing quantum dots.

In recent years, classification with big data sets has become one of the latest research topic in machine learning. Distributed classification have received much attention from industry and academia. Recently, the Alternating Direction Method of Multipliers (ADMM) is a widely-used method to solve learning problems in a distributed manner due to its simplicity and scalability. However, distributed ADMM usually converges slowly and thus suffers from expensive time cost in practice. To overcome this limitation, we propose a novel distributed stochastic ADMM (DS-ADMM) algorithm for big data classification based on the MPI framework. By formulating the original problem as a series of sub-problems through a cluster of multiple computers (nodes). In particular, we exploit a stochastic method for sub-problem optimization in parallel to further improve time efficiency. The experimental results show that our proposed distributed algorithm is suitable to enhance the performance of ADMM, and can be effectively applied for big data classification.

Levodopa (L-DOPA) is promising as chiral stationary phase for open tubular capillary electrochromatography (OT-CEC) enantioseparation owing to its self-polymerization adhesive property and chiral recognition potential. In this work, CuSO4/H2O2 was used as a trigger agent to accelerate the polymerization process of L-DOPA and the poly-levodopa (poly-(L-DOPA)) coated column was successfully prepared for the first time by depositing it on the inner wall of fused silica capillary via the rapid and in-situ approach at room temperature. The performance of the poly-(L-DOPA) coated capillary was validated by the separation of different chiral analytes, including chiral amine drugs, neurotransmitters and amino acids, and the good enantioseparation efficiencies were achieved. For five consecutive runs, the relative standard deviations (RSDs) for the migration time of the analytes for intra-day, inter-day and column-to-column were in the range of 0.19-1.33%, 0.96-4.47%, and 2.21-7.79%, respectively. Additionally, the poly-(L-DOPA) coated capillary column could be successively used over 250 runs without observable change in the separation efficiency.

An ingenious and viable method for preparing heterogeneous Co3O4 dodecahedrons that contain carbon and encapsulated Au nanoparticles (Au@C-Co3O4) was proposed via pyrolysis of Au nanoparticle-encapsulated zeolitic imidazolate framework-67 (Au@ZIF-67). The obtained Au@C-Co3O4 possessed hierarchically porous structure, abundant active sites, excellent conductivity, and durability, all of which can significantly improve the analysis performance of the biosensor. Meanwhile, the fabricated electrode based on the porous Au@C-Co3O4 showed remarkable electrocatalytic performance towards H2O2 with a limit of detection of 19 nM and ultra-high sensitivity of 7553 μA mM−1 cm−2, even when the Au content in the composite was as low as 0.85 wt%. This novel biosensor was successfully used to monitor H2O2 concentration released from living cells, and the results can be used to identify cancer cells, thus advancing the use of transition metal oxides in the field of biosensing.

Silicon nanoparticles (SiNPs) have attracted increasing attentions due to their unique properties and related applications. However, previously reported SiNPs generally showed emission band only in the blue- or green-light regions, which limited their applications in biochemical samples. So far, synthesis of longer wavelength emissive SiNPs remains a challenge. In this paper, the yellow-emitting fluorescent SiNPs were prepared via a facile room temperature procedure, which avoided heating and pressurizing operation, multistep and time-consuming post-modified procedures. The obtained SiNPs displayed excellent water-solubility, pH-stability, salt-tolerance, and photo-stability. Significantly, the fluorescence of SiNPs could be remarkably quenched by crystal violet (CV) via synergistic effect of inner filter effect (IFE) and fluorescence resonance energy transfer (FRET). Based on this phenomenon, a method for the determination of CV was established. Under the optimum conditions, the method showed a wide linearity range from 0.075 to 15.0 μg/mL with a limit of detection of 25 ng/mL. Furthermore, the method was successfully applied to the analysis of CV in fish tissues samples.

In this work, a kind of “donor–acceptor (D–A) combined π-bridge” based on the regioselective reactivity of monofluoro-substituted benzothiadiazole (FBT) to link a thiophene ring has been designed to construct a new A−π–D−π–A-type small molecular acceptor (IDT-FBTR) with indacenodithiophene (IDT) as a central core (D) and 3-octyl-2-(1,1-dicyanomethylene)rhodanine as an electron-withdrawing terminal group (A). Because of the strong intramolecular push–pull electron effect, the IDT-FBTR shows a strong and broad intramolecular charge-transfer absorption band in the range of 500–750 nm. Especially, as an electron-deficient FBT unit (A′) and an electron-rich thiophene ring (D′) in “D–A combined π-bridge” exert an “offset effect” to regulate the highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) energy levels of the molecule, a relatively high LUMO energy level can be maintained for IDT-FBTR that is helpful to enhance the open-circuit voltage (Voc) for highly efficient organic s...