Heterostructured Graphene@Silica@Iron Phenylphosphinate for Fire-Retardant, Strong, Thermally Conductive Yet Electrically Insulated Epoxy Nanocomposites.

The portfolio of extraordinary fire retardancy, mechanical properties, dielectric/electric insulating performances, and thermal conductivity (λ) is essential for the practical applications of epoxy resin (EP) in high-end industries. To date, it remains a great challenge to achieve such a performanceportfolio in EP due to their different and even mutually exclusive governing mechanisms. Herein, a multifunctional additive (G@SiO2@FeHP) is fabricated by in situ immobilization of silica (SiO2) and iron phenylphosphinate (FeHP) onto the graphene (G) surface. Benefiting from the synergistic effect of G, SiO2 and FeHP, the addition of 1.0 wt% G@SiO2@FeHP enables EP to achieve a vertical burning (UL-94) V-0 rating and a limiting oxygen index (LOI) of 30.5%. Besides, both heat release and smoke generation of as-prepared EP nanocomposite are significantly suppressed due to the condensed-phase function of G@SiO2@FeHP. Adding 1.0 wt% G@SiO2@FeHP also brings about 44.5%, 61.1%, and 42.3% enhancements in the tensile strength, tensile modulus, and impact strength of EP nanocomposite. Moreover, the EP nanocomposite exhibits well-preserved dielectric and electric insulating properties and significantly enhanced λ. This work provides an integrated strategy for the development of multifunctional EP materials, thus facilitating their high-performance applications.

Percutaneous transhepatic cholangioscopy-assisted biliary polypectomy for local palliative treatment of intraductal papillary neoplasm of the bile duct.

BACKGROUND: Intraductal papillary neoplasm of the bile duct (IPNB) is a premalignant biliary-type epithelial neoplasm with intraductal papillary or villous growth. Currently reported local palliative therapeutic modalities, including endoscopic nasobiliary drainage, stenting and biliary curettage, endoscopic biliary polypectomy, percutaneous biliary drainage, laser ablation, argon plasma coagulation, photodynamic therapy, and radiofrequency ablation to relieve mechanical obstruction are limited with weaknesses and disadvantages. We have applied percutaneous transhepatic cholangioscopy (PTCS)-assisted biliary polypectomy (PTCS-BP) technique for the management of IPNB including mucin-hypersecreting cast-like and polypoid type tumors since 2010. AIM: To assess the technical feasibility, efficacy, and safety of PTCS-BP for local palliative treatment of IPNB. METHODS: Patients with mucin-hypersecreting cast-like or polypoid type IPNB and receiving PTCS-BP between September 2010 and December 2019 were included. PTCS-BP was performed by using a half-moon type snare with a soft stainless-steel wire, and the tumor was snared and resected with electrocautery. The primary outcome was its feasibility, indicated by technical success. The secondary outcomes were efficacy, including therapeutic success, curative resection, and clinical success, and safety. RESULTS: Five patients (four with mucin-hypersecreting cast-like type and one with polypoid type IPNB) were included. Low- and high-grade intraepithelial neoplasia (HGIN) and recurrent IPNB with invasive carcinoma were observed in one, two, and two patients, respectively. Repeated cholangitis and/or obstructive jaundice were presented in all four patients with mucin-hypersecreting cast-like type IPNB. All five patients achieved technical success of PTCS-BP. Four patients (three with mucin-hypersecreting cast-like type and one with polypoid type IPNB) obtained therapeutic success; one with mucin-hypersecreting cast-like type tumors in the intrahepatic small bile duct and HGIN had residual tumors. All four patients with mucin-hypersecreting IPNB achieved clinical success. The patient with polypoid type IPNB achieved curative resection. There were no PTCS-BP-related serious adverse events. CONCLUSION: PTCS-BP appears to be feasible, efficacious, and safe for local palliative treatment of both mucin-hypersecreting cast-like and polypoid type IPNB.

Stem cell gene Girdin: a potential early liver metastasis predictor of colorectal cancer.

The objective of this study is to investigate the liver's metastasis-related genes and the relationship between Girdin protein expression and clinical and pathological characteristics and prognosis in colorectal cancer. The differential expression of genes between tumor cells from cases with liver metastasis and those from cases without liver metastasis were detected using an RT(2) Profiler™ PCR Array. The expression of the stem cell gene Girdin was analyzed using immunohistochemistry staining. Subsequently, the relationship between Girdin and clinicopathological parameters of colorectal cancer was determined. The Girdin protein was verified as a gene related to liver metastasis and was expressed positively in 161 (37.01 %) of the 435 cases examined. The expression of Girdin protein was related to histological grade and distant metastasis (P = 0.007 and 0.007, respectively). After analyzing survival rates, cases with highly expressed Girdin protein were shown to attain a significantly higher rate of liver metastasis and poorer postoperative, disease-specific survival than those with no or low expressed Girdin protein (P = 0.001). In the Cox regression test, the depth of tumor invasion, histological grade, duke's stage, distant metastasis, and the Girdin protein were detected as an independent prognostic factor (0.020, 0.032, 0.001, 0.001, and 0.010, respectively). The Girdin protein may be a potential new early liver metastasis biomarker of colorectal cancer.

The Influence of Public Mental Health Based on Artificial Intelligence Technology on the Teaching Effect of Business Administration Major.

As an emerging technology, public mental health based on artificial intelligence engineering has broad application and development prospects in improving teaching effects, realizing high efficiency and intelligence, and improving refined education. The application of public mental health based on artificial intelligence engineering in the practice of the teaching effect of business administration has a very positive significance for accurately discovering the mental health and teaching effect of business administration students. For the sake of improving the teaching effect of business administration major, we come up with a method for the influence of public mental health on the teaching effect of business administration profession based on artificial intelligence engineering. Firstly, we collect the video and audio of the teaching of business administration, conducts data screening and cleaning, and sorts out the video and audio synchronization clips as training data. Secondly, we propose a multimodal feature extraction network and a multimodal fusion network for the extraction and fusion of video and audio clips, respectively. Then, the fully connected network structure is used to evaluate and classify the effect of business administration professional teaching, and use mental health factors for evaluation to avoid human intervention and improve the prediction effect. Finally, through intensive experimental results, we prove that the method raised by us can use artificial intelligence engineering to evaluate the teaching effect of business administration majors from the perspective of public mental health and achieve good experimental results.

CeO2 quantum dots for highly selective and ultrasensitive fluorescence detection of 4-nitrophenol via the fluorescence resonance energy transfer mechanism.

A rapid and simple fluorescence probe based on CeO2 quantum dots (QDs) was developed for highly selective and ultrasensitive direct determination of 4-nitrophenol (4-NP). CeO2 QDs were prepared using the sol-gelmethod with the precursor of Ce(NO3)3·6H2O as a cerium source. The products were characterized through high-resolution electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. The fluorescent probe based on CeO2 QDs exhibited a broad linear response to the concentration of 4-NP in the range of 0.005-75.00 µM and provided a low detection limit of 1.50 nM. The fluorescence of CeO2 QDs was quenched by 4-NP through the fluorescence resonance energy transfer mechanism owing to the well overlaps between the fluorescence emission spectrum of CeO2 QDs with the ultraviolet absorption spectrum of 4-NP. This result was confirmed by the time-resolved fluorescence spectra and the evaluation of the interaction distance between CeO2 QDs and 4-NP. The prepared CeO2 QDs are successfully applied to the determination of 4-NP in real water samples, where the spiked recoveries range from 98.2% to 102.4%.

A label-free DNAzyme sensor for lead(II) detection by quantitative polymerase chain reaction.

A label-free sensor was developed for sensitive detection of lead(II), combining high selectivity of a Pb(2+)-dependent DNAzyme with enormous signal amplification of quantitative polymerase chain reaction (QPCR). Specifically, a substrate strand was designed to have two primer-hybridization sequences at either terminus. The presence of lead ion (Pb(2+)) catalyzed cleavage of the substrate strands. This resulted in a concentration decrease of the substrate strand that could be detected by QPCR. Compared with existing DNAzyme-based protocols for Pb(2+) assay, this strategy circumvented the use of various optical or electrical labels that might be difficult to be synthesized. Also, the incorporation of QPCR furnished our approach with high sensitivity and superb reproducibility. In addition, QPCR allowed an immediate quantification of the cleavage efficiency that could be useful for evaluation of the DNAzyme activity. The results obtained revealed that our approach exhibited a dynamic response toward Pb(2+) within a three-decade concentration range from 10 nM to 5 microM with a detection limit of 1 nM. This approach also demonstrated good selectivity against other metal ions that commonly coexisted with Pb(2+).

Stem-loop clutch probes for sequence-specific dsDNA analysis with improved single-mismatch selectivity.

A stem-loop clutch probe (SLCP)-based strategy has been explored to guide sequence-specific double stranded DNA (dsDNA) analysis with enhanced single-base mismatch selectivity. This assay method can also modulate the dynamic range by employing natural processes relying on distal-site mutation inhibition and allosteric activation.

Colorimetric Method for Sensitive Detection of Microcystin-LR Using Surface Copper Nanoparticles of Polydopamine Nanosphere as Turn-On Probe.

A novel, facile sensor was further developed for microcystin-LR (MC-LR) determination by visible spectroscopy. Antibody-functionalized SiO2-coated magnetic nanoparticles (Fe3O4@SiO2) and aptamer-functionalized polydopamine nanospheres decorated with Cu nanoparticles (PDA/CuNPs) recognized specific sites in MC-LR and then the sandwich-type composites were separated magnetically. The Cu in the separated composites was converted to Cu2+ ions in solution and turn-on visible absorption was achieved after reaction with bis(cyclohexanone)oxaldihydrazone (BCO) (λmax = 600 nm). There was a quantitative relationship between the spectral intensity and MC-LR concentration. In addition, under the optimum conditions, the sensor turns out to be a linear relationship from 0.05 to 25 nM, with a limit of detection of 0.05 nM (0.05 µg/L) (S/N = 3) for MC-LR. The sensitivity was dependent on the low background absorption from the off-to-on spectrum and label amplification by the polydopamine (PDA) surface. The sensor had high selectivity, which shows the importance of dual-site recognition by the aptamer and antibody and the highly specific color formed by BCO with Cu2+. The bioassay was complete within 150 min, which enabled quick determination. The sensor was successfully used with real spiked samples. These results suggest it has potential applications in visible detection and could be used to detect other microcystin analogs.

An Electrochemical Sensor for Diphenylamine Detection Based on Reduced Graphene Oxide/Fe3O4-Molecularly Imprinted Polymer with 1,4-Butanediyl-3,3'-bis-l-vinylimidazolium Dihexafluorophosphate Ionic Liquid as Cross-Linker.

In this paper, we report a new composite of reduced graphene oxide/Fe3O4-ionic liquid based molecularly imprinted polymer (RGO/Fe3O4-IL-MIP) fabricated for diphenylamine (DPA) detection. RGO/Fe3O4-IL-MIP was prepared with RGO/Fe3O4 as supporter, ionic liquid 1-vinyl-3-butylimidazolium hexafluorophosphate ([VC4mim][PF6]) as functional monomer, ionic liquid 1,4-butanediyl-3,3'-bis-l-vinylimidazolium dihexafluorophosphate ([V2C4(mim)2][(PF6)2]) as cross-linker, and diphenylamine (DPA) as template molecule. Fourier transform infrared spectroscopy, thermal gravimetric analysis, scanning electron microscopy, and vibrating sample magnetometer were employed to characterize the RGO/Fe3O4-IL-MIP composite. RGO/Fe3O4-IL-MIP was then drop-cast onto a glassy carbon electrode to construct an electrochemical sensor for DPA. The differential pulse voltammetry (DPV) peak current response for 20 µM DPA of RGO/Fe3O4-IL-MIP modified glassy carbon electrode (GCE) was 3.24 and 1.68 times that of RGO/Fe3O4-IL-NIP and RGO/Fe3O4-EGDMA-MIP modified GCEs, respectively, indicating the advantage of RGO/Fe3O4-IL-MIP based on ionic liquid (IL) as a cross-linker. The RGO/Fe3O4-IL-MIP sensor demonstrated good recognition for DPA. Under the optimized conditions, the RGO/Fe3O4-IL-MIP sensor exhibited a DPA detection limit of 0.05 µM (S/N = 3) with a linear range of 0.1⁻30 µM. Moreover, the new RGO/Fe3O4-IL-MIP based sensor detected DPA in real samples with satisfactory results.

Highly sensitive and selective sensor for sunset yellow based on molecularly imprinted polydopamine-coated multi-walled carbon nanotubes.

Polydopamine (PDA) can be formed by monomeric self-polymerization in water. This convenient behavior was exploited to prepare a molecularly imprinted polymer (MIP) layer on the surface of multi-walled carbon nanotubes (MWCNTs) with sunset yellow (SY) as a template molecule. The prepared nanocomposites were characterized, and their electrochemical behavior towards SY was investigated. Under the optimized conditions, a glassy carbon electrode modified with the imprinted nanocomposite showed a highly selective and ultrasensitive electrochemical response to SY compared with the performance of control electrodes and previously reported electrochemical sensors for SY. The improved behavior of the developed sensor can be attributed to its superficial highly matched imprinted cavities on the excellent electrocatalytic matrix of MWCNTs and the electronic barrier of the non-imprinted PDA to outside molecules. The fabricated sensor expressed a linear relationship to SY concentrations from 2.2nM to 4.64µM with a detection limit of 1.4nM (S/N = 3). The sensor also exhibited excellent selectivity for SY over its structural analogs, good stability, and adequate reproducibility. The prepared sensor was successfully used to detect SY in real spiked samples. This methodology has potential application value and may be readily adapted to design other PDA-based MIP sensors.

[Characteristics and contribution of the strengthening units of composite constructed wetland for treating urban sewage].

There are some defects in constructed wetland, including the uneven distribution of flow, easily blocked, lack of oxygen supply systems and the unsatisfactory phosphorus adsorption capacity of the substrates, etc. The research mainly studied the function and contribution of the pool of hydrolysis acidification, the natural reoxygenation/sinking device and strengthen slot for reducing nitrogen and phosphorus. The results showed the removal efficiency of COD and SS in hydrolysis-acidification pool accounted for 38.05% and 34.82% of the total removal efficiency of system. The SS removal efficiency of the natural reoxygenation/sinking device accounted for 22.01% of the total removal efficiency of system, and the concentration of DO kept above 2.5 mg.L-1. The two strengthen slots can ensure the TP, TN, COD up to the standard of the level 1 of GB 18918-2002.