Bounded Confidence and Cohesion-Moderated Pressure: A General Model for the Large-Scale Dynamics of Ordered Opinion.

Due to the development of social media, the mechanisms underlying consensus and chaos in opinion dynamics have become open questions and have been extensively researched in disciplines such as sociology, statistical physics, and nonlinear mathematics. In this regard, our paper establishes a general model of opinion evolution based on micro-mechanisms such as bounded confidence, out-group pressure, and in-group cohesion. Several core conclusions are derived through theorems and simulation results in the model: (1) assimilation and high reachability in social networks lead to global consensus; (2) assimilation and low reachability result in local consensus; (3) exclusion and high reachability cause chaos; and (4) a strong "cocoon room effect" can sustain the existence of local consensus. These conclusions collectively form the "ideal synchronization theory", which also includes findings related to convergence rates, consensus bifurcation, and other exploratory conclusions. Additionally, to address questions about consensus and chaos, we develop a series of mathematical and statistical methods, including the "energy decrease method", the "cross-d search method", and the statistical test method for the dynamical models, contributing to a broader understanding of stochastic dynamics.

An electrochemical biosensor for detecting DNA methylation based on AuNPs/rGO/g-C3N4 nanocomposite.

DNA methylation as a ubiquitously regulation is closely associated with cell proliferation and differentiation. Growing data shows that aberrant methylation contributes to disease incidence, especially in tumorigenesis. The approach for identifying DNA methylation usually depends on treatment of sodium bisulfite, which is time-consuming and conversion-insufficient. Here, with a special biosensor, we establish an alternative approach for detecting DNA methylation. The biosensor is consisted of two parts, which are gold electrode and nanocomposite (AuNPs/rGO/g-C3N4). Nanocomposite was fabricated by three components, which are gold nanoparticles (AuNPs), reduced graphene oxide (rGO) and graphite carbon nitride (g-C3N4). For methylated DNA detection, the target DNA was captured by probe DNA immobilized on the gold electrode surface through thiolating process and subjected to hybrid with anti-methylated cytosine conjugated to nanocomposite. When the methylated cytosines in target DNA were recognized by anti-methylated cytosine, a change of electrochemical signals will be observed. With different size of target DNAs, the concentration and methylation level were tested. It is shown that in short size methylated DNA fragment, the linear range and LOD of concentration is 10-7M-10-15M and 0.74 fM respectively; in longer size methylated DNA, the linear range of methylation proportion and LOD of copy number is 3%-84% and 103 respectively. Also, this approach has a high sensitivity and specificity as well as anti-disturbing ability.

An electrochemiluminescence biosensor based on Graphitic carbon nitride luminescence quenching for detection of AFB1.

Based on graphite-like carbon nitride (g-CN) nanocomposites coupled with aptamer, a regenerable electrochemiluminescence (ECL) biosensor is developed for the quantitative detection of aflatoxin B1 (AFB1). In the existence of AFB1, the structure of the aptamer changed into a loop, and the original ECL intensity was reduced owing to the enhancement of luminescence quenching between the ferrocene modified at the end of the aptamer and the luminescent substrate g-CN. Moreover, AFB1 with oxidation state could also react with high energy state g-CN, leading to further reduction of the electrochemiluminescence signal. At optimum conditions, ECL intensity was decreased in linearity with an AFB1 concentration range from 0.005 ng/mL to 10 ng/mL, and the minimum detectable concentration was down to 0.005 ng/mL, which realized trace detection demand with high sensitivity. It was selective for AFB1 and its performance had been verified on rice samples, which indicated a promising applying prospect of non-enzymatic electrochemiluminescence AFB1 detection.

Triazine-Porphyrin-Based Hyperconjugated Covalent Organic Framework for High-Performance Photocatalysis.

Covalent organic frameworks (COFs) with porphyrins as structural units are a new kind of porous organic polymers, which have a regular and ordered structure, abundant porosity, and good stability. In the past, the construction of porphyrin COFs was generally synthesized by routes such as a Schiff base reaction. Here, we report a new COF structure by linking the porphyrin with the triazine ring. Using a cyano group-terminated porphyrin as a structural unit precursor, a new triazine-porphyrin hyperconjugated COF (TA-Por-sp2-COF) was constructed through the cyano group's self-polymerization. The extension of porphyrin units in two directions that stemmed from the cyano group at para-positions accounts for the establishment of a highly ordered two-dimensional topological structure. Attributing to the collaboration of electron-donating and withdrawing blocks for photo-induced carrier separation and adequate porosity for mass diffusion, this hyperconjugated system showed high photocatalytic performance in organic reactions such as the aerobic coupling reaction of benzylamine and thioanisole selective oxidation.

3D macroporous CUPC/g-C3N4 heterostructured composites for highly efficient multifunctional solar evaporation.

Solar-driven interfacial evaporation is a promising technology for water recycling and purification. A sustainable solar evaporation material should have not only high photothermal conversion efficiency, but also an ecofriendly fabrication process as well as pollutant degradation and sterilization properties. We present in this work a solar evaporator based on graphitic carbon nitride (g-C3N4) and copper phthalocyanine (CUPC) composites with typical type-I heterojunctions. Superhydrophilic three-dimensional macroporous g-C3N4 was obtained by self-assembly of precursors in aqueous solution followed by thermal polycondensation. By adding various weight ratios (0.15%, 1.5% and 7.5%) of CUPC, the composites exhibited a strong absorption in the region of red and infrared light. The CUPC-CN 7.5% composite achieved a photothermal conversion efficiency of 98.5% in nanofluids with an interfacial solar evaporation efficiency of 93.6% for artificial sea water and 98.7% for deionized water, which are among the highest reported to date. Besides, the composite materials demonstrated superior water purification capabilities by decomposing dye molecules and E. coli bacteria in aqueous solution. Our work established a novel approach for the development of multifunctional interfacial evaporators based on macroporous organic semiconductor heterostructures.

Exploring the evolution patterns of melem from thermal synthesis of melamine to graphitic carbon nitride.

In the exploration of synthesizing graphitic carbon nitride (g-C3N4), the existence of secondary anime bridging units shows the incompleteness of related theories. Thus, taking the thermal synthesis of melamine as an example, this work finds a possible reaction path with Density Functional Theory (DFT) for forming melem during the thermal synthesis of g-C3N4. Combined with transition state theory (TST), it indicates that the formation of melem results from the condensation of melamine and isomerization of melam. Meanwhile, the weak signal near 2135 cm-1 in the Fourier Transform Infrared Spectra (FTIR) corresponds to the vibration of carbodi-imines (-N[double bond, length as m-dash]C[double bond, length as m-dash]N-), which further proves the proposed reaction path. Thus, this work can explain the formation of g-C3N4 and its monomer, which may contribute to the successful formation of ideal g-C3N4 in the future.

Efficient Schottky Junction Construction in Metal-Organic Frameworks for Boosting H2 Production Activity.

Manipulation of the co-catalyst plays a vital role in charge separation and reactant activation to enhance the activity of metal-organic framework-based photocatalysts. However, clarifying and controlling co-catalyst related charge transfer process and parameters are still challenging. Herein, three parameters are proposed, V transfer (the electron transfer rate from MOF to co-catalyst), D transfer (the electron transfer distance from MOF to co-catalyst), and V consume (the electron consume rate from co-catalyst to the reactant), related to Pt on UiO-66-NH2 in a photocatalytic process. These parameters can be controlled by rational manipulation of the co-catalyst via three steps: i) Compositional design by partial substitution of Pt with Pd to form PtPd alloy, ii) location control by encapsulating the PtPd alloy into UiO-66-NH2 crystals, and iii) facet selection by exposing the encapsulated PtPd alloy (100) facets. As revealed by ultrafast transient absorption spectroscopy and first-principles simulations, the new Schottky junction (PtPd (100)@UiO-66-NH2) with higher V transfer and V consume exhibits enhanced electron-hole separation and H2O activation than the traditional Pt/UiO-66-NH2 junction, thereby leading to a significant enhancement in the photoactivity.

Harnessing Photocatalytic and Photothermal Effects of C-Doped Graphitic Carbon Nitride for Efficient Bacterial Disinfection.

In this work, the photocatalytic and photothermal effects of carbon-ring-doped graphitic carbon nitride materials against bacteria were systematically studied in a dispersed solution and on a membrane. C-doped graphitic carbon nitride materials C-CN 0.15, 1.5, and 7.5 were synthesized by mixing urea precursor with 0.15, 1.5, and 7.5 wt % glucose. With the increase in the doping level, the photothermal effect was clearly enhanced while the generation of reactive oxygen species (ROS) was slightly inhibited. With exposure to irradiation under a 100 mW cm-2 Xeon lamp with a cutoff filter (λ ≥ 420 nm), the ROS concentration of C-CN 1.5 increased 30% in the dispersed solution and its temperature increased about 10 °C in the dispersed solution and on the membrane compared to that of pristine carbon nitride. As a result, the bactericidal activity of C-CN 1.5 was improved by an order of magnitude in the dispersed solution and more than 2 orders of magnitude on the membrane immersed in a solution at 40 °C. To investigate the fundamental light absorption process on the membrane, an optical model using the finite-difference time-domain method was developed based on the topography of the membrane. The simulation results may explain that although C-CN produces more ROS in a solution; however, with a larger extinction coefficient, the power absorption is lower near the surface of the membrane. The ROS production is therefore inhibited and the bactericidal activity is dominated by the photothermal effect. Our experimental and simulation results provide a basis for designing high-performance photoactive disinfection materials and surfaces.

The synergistic effect of Co/Ni in ultrathin metal-organic framework nanosheets for the prominent optimization of non-enzymatic electrochemical glucose detection.

Hybrid metal compounds have been paid increasing attention for the development of electroanalysis materials due to the specific collaboration interaction and synergy effect of metal elements. Herein, a series of ultrathin Ni/Co bimetallic metal-organic-framework nanosheets (UMOFNs) with different metal ratios were investigated as high-performance electroanalysis materials for non-enzymatic glucose electrochemical sensing. The synergistic effect between Ni/Co endowed UMOFNs with not only the unique electrochemical behavior that prompts the sensing-related electrochemical oxidation at a low applied potential, but also the enhanced affinity to glucose; also, they facilitated the electron transfer involving the analyte. The UMOFN composite with an elaborately adjusted Co/Ni ratio exhibits an extremely outstanding glucose sensing performance, including high sensitivity (2086.7 µA mM-1 cm-2), wide linear range (0.1 µM-1.4 mM), low detection limit (0.047 µM), and excellent selectivity. It can also be used for the detection of glucose in actual human serum samples with an accuracy of 90.1%, demonstrating a good application prospect of the non-enzymatic electrochemical glucose detection.

Electrophoresis-Deposited Mesoporous Graphitic Carbon Nitride Surfaces with Efficient Bactericidal Properties.

With the rise of bacterial infections and antimicrobial resistance, it is important to develop environmentally friendly functional materials and surfaces with efficient bactericidal activity. In this work, nanostructured graphitic carbon nitride (g-C3N4) surfaces were fabricated by electrophoresis deposition of mesoporous g-C3N4 materials. Efficient bactericidal performance was achieved through the synergistic biophysical interaction of bacterial cells with the nanotopographies and visible light active photocatalytic properties. The nanotopographies of g-C3N4 surfaces demonstrated a "contact-killing" efficiency of >90% against Pseudomonas aeruginosa and >80% against Staphylococcus aureus cells. The number of surviving bacteria on the surfaces further decreased remarkably upon illumination using visible light generated by a light-emitting diode lamp with an irradiation intensity of 12.4 mW cm-2. In total, the number of viable bacteria was reduced by approximately 3 orders of magnitude for P. aeruginosa and 2 orders of magnitude for S. aureus. Our experimental findings provide potential prospects for developing highly efficient photocatalytic bactericidal surfaces.

FgRad50 Regulates Fungal Development, Pathogenicity, Cell Wall Integrity and the DNA Damage Response in Fusarium graminearum.

Rad50 is a member of the double strand break repair epistasis group of proteins that play important roles in regulating DNA damage checkpoint signaling, telomere maintenance, homologous recombination and non-homologous end-joining in eukaryotes. However, the function of Rad50 in fungal plant pathogens remains unknown. In this study, we report the functional investigation of FgRad50 in the wheat head blight pathogen Fusarium graminearum. FgRad50 is an ortholog of Saccharomyces cerevisiae Rad50 that could restore the sensitivity of the yeast Rad50 mutant to DNA damage agents. The FgRad50 deletion mutant (ΔFgRad50) exhibited defective vegetative growth, asexual/sexual development and virulence, as well as disrupted deoxynivalenol biosynthesis. Moreover, deletion of FgRad50 resulted in hypersensitivity to DNA damage agents. Unexpectedly, FgRad50 plays a key role in responses to cell wall-damaging agents by negatively regulating phosphorylation of FgMgv1, a MAP kinase in the cell wall integrity (CWI) pathway. Taken together, these results suggest that FgRad50 plays critical roles in fungal development, virulence and secondary metabolism in F. graminearum, as well as CWI and the DNA damage response.

The transcription factor FgCrz1A is essential for fungal development, virulence, deoxynivalenol biosynthesis and stress responses in Fusarium graminearum.

The zinc finger transcription factor Crz1 is an important downstream regulator of calcium-dependent signal transduction pathways in many organisms. The function of Crz1 in the wheat-head blight pathogen Fusarium graminearum remains unclear. In this study, we identified and functionally characterised FgCrz1A, a potential ortholog of yeast Crz1. The deletion mutant ΔFgCrz1A exhibited slower hyphal growth on basic medium, and conidia formation and sexual reproduction were completely blocked. ΔFgCrz1A also displayed increased sensitivity to metal cations Ca2+, Mg2+, Mn2+ and Li+, but decreased sensitivity to Zn2+. Unexpectedly, the deletion mutant was more resistant to osmotic stress and cell wall-damaging agents than the wild-type fungus. Pathogenicity assays showed that virulence of the mutant was dramatically decreased on flowering wheat heads and corn silks, consistent with the observed reduction in deoxynivalenol production. Moreover, GFP-fused FgCrz1A was mainly localised in the nucleus, and was required for transcriptional induction of abaA and wetA that are involved in conidiogenesis, as well as genes of the MAT locus during sexual reproduction, and TRI genes responsible for deoxynivalenol biosynthesis. Taken together, the results indicate that FgCrz1A plays critical roles not only in regulating fungal development, secondary metabolism and virulence in F. graminearum, but also in multiple stress responses.

Electrochemical method for the quantitative determination of Escherichia coli based on gold functionalized FTO substrate.

This work presents a novel rapid and sensitive label-free electrochemical method for the detection of bacteria on surface nanostructures. A simple electrochemical deposition and calcination method is employed to prepare different gold nanostructures on FTO substrate. The sensor based on nanostructure gold exhibits excellent linear relation between E. coli DH5α bacteria and the changes of ΔRct, especially FTO-GEDC-D30, with a correction coefficient R2 = 0.998. Both the spectrophotometric (OD600 methods) and fluorescence-staining methods also verified the reliability of electrochemical impedance spectroscopy (EIS) methods for evaluating the antibacterial activity of the gold nanostructure.

Surface Engineering for Extremely Enhanced Charge Separation and Photocatalytic Hydrogen Evolution on g-C3 N4.

Reinforcing the carrier separation is the key issue to maximize the photocatalytic hydrogen evolution (PHE) efficiency of graphitic carbon nitride (g-C3 N4 ). By a surface engineering of gradual doping of graphited carbon rings within g-C3 N4 , suitable energy band structures and built-in electric fields are established. Photoinduced electrons and holes are impelled into diverse directions, leading to a 21-fold improvement in the PHE rate.

A Strategy to Boost H2 Generation Ability of Metal-Organic Frameworks: Inside-Outside Decoration for the Separation of Electrons and Holes.

Inhibiting the recombination of electron and holes plays an essential role in photocatalytic process, particularly for metal-organic frameworks (MOFs), which had long been anticipated as high-efficient photocatalysts. Herein, we introduce a new strategy to make efficient separation of electrons and holes for the MOF-based photocatalyst, UiO-66-NH2 . At first, encapsulation of Pt nanoparticles (NPs) into UiO-66-NH2 (Pt@U6N) to shorten the electrons transport distance inside of MOF crystals, then using graphene oxide to wrap the external surface of Pt@U6N to facilitate the electrons transfer on the surface. The designed structure was found to possess superior H2 -generation ability compared to only inside or outside decorated samples, highlighting that the enhanced property strongly correlates with the inhibited recombination of electrons and holes by the inside/outside modification strategy. These findings suggest a synergistic effect of Pt NPs and graphene oxide on UiO-66-NH2 and reveal a new modification strategy to enhance the catalytic activity of the photocatalysts.

Highly sensitive nonenzymatic glucose sensor based on nickel nanoparticle-attapulgite-reduced graphene oxide-modified glassy carbon electrode.

In this article, a fast and sensitive nonenzymatic glucose sensor is reported utilizing a glassy carbon electrode modified by synthesizing nanocomposites of nickel nanoparticle-attapulgite-reduced graphene oxide (Ni NPs/ATP/RGO). A facile one-step electrochemical co-deposition approach is adopted to synthesize Ni NPs-ATP-RGO nanocomposites via electrochemical reduction of mixed precursor solution containing graphene oxide (GO), attapulgite (ATP) and nickel cations (Ni(2+)) at the cathode potentials. This strategy results in simultaneous depositions of ATP, cathodic reduction of Ni(2+) into nickel nanoparticles under acidic conditions, and in situ reduction of GO. The as-prepared NiNPs/ATP/RGO-based glucose sensor exhibits outstanding performance for enzymeless glucose sensing with sensitivity (1414.4 µAmM(-1)cm(-2)), linear range (1-710µM) and detection limit (0.37µM). What is more, the sensor has excellent stability and selectivity against common interferences in real sample.

A facile one-step folic acid modified partially oxidized graphene for high sensitivity tumor cell sensing.

A highly sensitive and selective tumor cell sensor based on partially oxidized graphene (POG) and folate acid (FA) composite was constructed. The POG was prepared through a modified Hummers method and characterized by means of Raman spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammetry, atomic force microscopy and transmission electron microscopy. The as-prepared POG exhibited the advantages of high electrochemical activity and a good capacity of linking amine derivatives. Using a facile one step reaction, the FA-modified POG was endowed with a more sensitive response to folate-expressing tumor cells than those sensors constructed by the two-step reaction, as well as high selectivity, good reproducibility and long-term stability.

Vanadium nanobelts coated nickel foam 3D bifunctional electrode with excellent catalytic activity and stability for water electrolysis.

Pursuit of highly active, stable and low-cost electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is the key point for large-scale water splitting. A vanadium nanobelts coating on a nickel foam (V/NF) is proposed as an excellent 3D bifunctional electrode for water electrolysis here, which exhibits high activities with overpotentials of 292 and 176 mV at 10 mA cm(-2) for OER and HER, respectively. When employed as a bifunctional electrocatalyst in an alkaline water electrolyzer, a cell voltage of 1.80 V was required to achieve 20 mA cm(-2) with a slight increase during a 24 h durability test. The existence of the appropriate amount of nitrogen and oxygen elements in the surface region of vanadium nanobelts is regarded to be responsible for the electrocatalytic activity.

Amorphous Phosphorus/Nitrogen-Doped Graphene Paper for Ultrastable Sodium-Ion Batteries.

As the most promising anode material for sodium-ion batteries (SIBs), elemental phosphorus (P) has recently gained a lot of interest due to its extraordinary theoretical capacity of 2596 mAh/g. The main drawback of a P anode is its low conductivity and rapid structural degradation caused by the enormous volume expansion (>490%) during cycling. Here, we redesigned the anode structure by using an innovative methodology to fabricate flexible paper made of nitrogen-doped graphene and amorphous phosphorus that effectively tackles this problem. The restructured anode exhibits an ultrastable cyclic performance and excellent rate capability (809 mAh/g at 1500 mA/g). The excellent structural integrity of the novel anode was further visualized during cycling by using in situ experiments inside a high-resolution transmission electron microscope (HRTEM), and the associated sodiation/desodiation mechanism was also thoroughly investigated. Finally, density functional theory (DFT) calculations confirmed that the N-doped graphene not only contributes to an increase in capacity for sodium storage but also is beneficial in regards to improved rate performance of the anode.

An electrochemical DNA sensor based on polyaniline/graphene: high sensitivity to DNA sequences in a wide range.

A label-free electrochemical DNA sensor was fabricated by deposition of polyaniline and pristine graphene nanosheet (P/G(ratios)) composites in different mass ratios, DNA probe and bovine serum albumin (BSA) layer by layer on the surface of a glassy carbon electrode (GCE). Electrochemical impedance spectroscopy (EIS) was employed to monitor every step of fabrication of P/G(ratio)-based DNA sensors and to evaluate the detection results in terms of the hybridization of complementary DNA, mutant DNA and non-complementary DNA. The results illustrate that the P/G(ratio)-based DNA sensor could highly efficiently detect complementary DNA from 0.01 pm to 1 µm and discriminate single-nucleotide polymorphisms (SNPs). In the process of detection, double-stranded DNA (dsDNA), resulting from hybridization of a DNA probe, escaping from or remaining on the sensor surface, was monitored by changing the ratio of polyaniline (PANI) to graphene, which was decided by the competition between the electrostatic interaction and Brownian motion.