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Pathogenic bacteria are severe threats to public health. Existing bacterial detection methods are often time-consuming and costly. Impedance-based electrochemical sensors using carbon electrodes have been explored for bacterial detection. However, the pristine carbon surface is inefficient in attracting bacterial cells. Here, we demonstrate an interfacial engineering method for graphenic carbon (GC) electrodes by using a common antibacterial material to achieve ultrasensitive bacterial detection. Polyhexamethylene guanidine hydrochloride (PHMG) is a broad-spectrum antimicrobial material. We first conjugated perylene bisimide (PBI) with PHMG to form a new PBI-PHMG compound. PBI-PHMG with an optimal PBI content can retain PHMG's intrinsic antibacterial activity while PBI anchors PBI-PHMG on the GC surface via strong pi-pi interactions. The resulting PBI-PHMG modified GC electrodes have positively charged surfaces, which effectively attract and inactivate bacterial cells. Cytoplasm materials released from damaged cells change the impedance of GC electrodes significantly, leading to considerably enhanced bacterial detection sensitivity down to 2 CFU mL−1 for both E. coli and S. aureus within 30 min of incubation time. The facile preparation, short detection time and high sensitivity of the impedance sensors based on the modified GC electrodes are promising for practical applications such as portable devices for point-of-use bacterial detection. Image 1 [ABSTRACT FROM AUTHOR]

• The method of analyzing rheological parameters by Box-Behnken Design was established. • The rheological properties of cemented coal gangue backfill was studied. • The regression models of rheological parameters were established. • The weight of effect factors on rheological parameters was characterized. In order to study the different mix proportions on rheological properties of cemented coal gangue backfill (CGB). Firstly, by single-factor test, the appropriate dosage ranges of mass concentration, fly ash content and fine gangue ratio were determined. Then on this basis, by response surface methodology, the quadratic polynomial regression models of yield stress and plastic viscosity were constructed respectively. The results show that the rheological model of fresh CGB accorded with rheological behavior of the Bingham fluid. With the increase of mass concentration, the yield stress of fresh CGB increases significantly. With the increase of fly ash content, the plastic viscosity of fresh CGB increase significantly. With the increase of the fine gangue ratio, the yield stress of fresh CGB decreases first and then increases, and the plastic viscosity increases slowly. This study will provide theoretical support for practitioners to predict the rheological properties of fresh CGB with different material compositions, and optimize the pumping performance in order to guide the engineering application more accurately. [ABSTRACT FROM AUTHOR]

Aurivillius phase CaBi 4 Ti 4- x (Ta 2/3 Mn 1/3) x O 15 (x = 0–0.1) high-temperature piezoelectric ceramics were fabricated using the conventional solid-state reaction process. The effects of the Ta–Mn co-doping level on the structure, piezoelectric properties and electrical conduction behaviours of the as-prepared CBT (CaBi 4 Ti 4 O 15) ceramics were explored in detail. It was revealed that the Ta–Mn co-doping efficaciously enhanced the electrical performances of the CaBi 4 Ti 4 O 15 ceramic, which may be due to optimisation of the crystal structure and a reduction in the oxygen vacancy concentration. The composition with x = 0.04 presented superior electrical properties with an outstanding piezoelectric constant (d 33) of 24 pC/N accompanied by a high Curie temperature (T C) of 793 °C, an optimised dielectric loss (tanδ) of 1.5%, and an improved resistivity (ρ) of 4.96 × 108 Ω cm at 400 °C. Moreover, the ceramic exhibited impressive thermal stability with the d 33 value maintaining 91.7% of its initial value at room temperature (25 °C) after being annealed at 600 °C for 2 h. The improved performance indicates that the Ta–Mn co-doped CaBi 4 Ti 4 O 15 ceramic might be a promising candidate for piezoelectric device applications at elevated temperatures. [ABSTRACT FROM AUTHOR]

• Morphological characteristics of coarse aggregate were quantified. • The effect of coarse aggregate morphological on rheological properties was studied. • The effect of coarse aggregate morphological on mechanical properties was studied. • The influence weight of coarse aggregate quantization parameters was characterized. • The model with coarse aggregate morphological parameters as variables was established. In order to clarify the influence of coarse aggregate morphology on the rheological property and mechanical property of fresh concrete, the morphological characteristics of coarse aggregate were quantitatively characterized, the core parameters of coarse aggregate morphology were screened, the standard parameters for quantitative characterization of coarse aggregate morphology were established, and the influence of coarse aggregate morphology on the rheological property and mechanical property of fresh concrete was explored. The results show that among the 8 parameters that represent the morphological characteristics of coarse aggregate, the flatness, angularity and roughness of aggregate have the greatest influence on the rheological properties and mechanical properties of fresh concrete. The weight of flatness on plastic viscosity is 50.54%, the weight of angularity on 28 days compressive strength is 48.95%, the weight of roughness on yield stress and flexural strength is 52.69% and 64.12%. When only the morphological composition of coarse aggregate is changed, the yield stress and plastic viscosity show the opposite variation law, the greater the yield stress, the smaller the plastic viscosity, and vice versa. When coarse aggregate with flatness less than 0.2 and roughness more than 0.4 are excluded, the yield stress is reduced by 28.58%, the plastic viscosity is increased by 23.15%, and the compressive strength is still over 60 MPa. The quantitative characterization of the coarse aggregate based on the characteristic parameters can provide a more effective method for researchers to predict the influence of coarse aggregate on the rheological properties and mechanical properties of concrete. [ABSTRACT FROM AUTHOR]

The commercial WS 2 is introduced in mZVI based Fenton-like reaction for accelerating the Fe3+/Fe2+ cycle and foreclosing the passivation of mZVI for the first time. Compared with mZVI/H 2 O 2 -based Fenton-like reaction, the mZVI/WS 2 /H 2 O 2 involved system exhibits much higher stability in the remediation of organic pollutants. Importantly, the poisoned mZVI can regain reduction ability to remove heavy metal ions (Cr6+, Cu2+ and Ni2+) efficiently through a continuous oxidation reaction, under the help of WS 2. The enhanced activity and stability can be ascribed to the double active sites on the WS 2 and mZVI surfaces. This research provides a new approach for the development of efficient mZVI-based Fenton-like system with high activity and stability in the environmental applications. • WS 2 cocatalytic mZVI/H 2 O 2 Fenton-like reaction was employed for the remediation of pollutants. • WS 2 can greatly facilitate the Fe(II)/Fe(III) cycle reaction by the exposed W4+ active sites. • The OH and O 2 − are the primary reactive oxygen species for the oxidation. • The passivated mZVI surface can be regeneration by the WS 2 cocatalytic effect. One of the biggest problems of microsized iron powder (mZVI) is that with the occurrence of redox reactions, a compact iron oxide shell can be formed on the surface of mZVI, which eventually leads to the catalyst poisoning and inactivation. Here, commercial WS 2 is employed for accelerating Fe3+/Fe2+ cycle and foreclosing passivation of mZVI to achieve the regeneration of mZVI for the first time. After 10 cycles oxidation, WS 2 cocatalytic effect can make the mZVI/H 2 O 2 maintain the degradation rate of 99% for the remediation of organic pollutants. Moreover, it is found that WS 2 can realize the regeneration of mZVI after the reduction of heavy metal ions (Cr6+, Cu2+ and Ni2+), especially, the removal rate of Ni2+ can be recovered from 9.2% back to 30.8%. The enhanced activity and stability can be ascribed to the double active sites on WS 2 and mZVI surfaces. The exposed active W4+ sites on WS 2 surface can accelerate the Fe3+/Fe2+ cycling reaction, and the active Fe0 active sites can increase the circulation of iron and tungsten ions simultaneously. This research provides a new approach for the regeneration of mZVI during the redox reaction in environmental application, which makes it possible to use mZVI to treat sewage on a large scale. [ABSTRACT FROM AUTHOR]

• Sixty-five GDSL-type esterase/lipase genes were identified and analyzed in watermelon, some of which were shown to be involved in plant defense against gummy stem blight inoculation. The GDSL esterase and lipase families play important roles in abiotic stress, pathogen defense, seed development and lipid metabolism. Identifying the lipase activity of a putative GDSL lipase is necessary to determine its function. Systematic analysis of the GDSL gene family is still lacking for Citrullus lanatus. In this study, we identified 65 watermelon GDSL-type esterase/lipase genes and divided these genes into 6 clades based on phylogeny. The phylogenetic relationship of watermelon GDSL genes and Arabidopsis thaliana GDSL esterase/lipase genes was also determined, and these genes were divided into four groups related to morphological development, abiotic stress response, pathogen defense, and secondary metabolism. The chromosomal location of these genes revealed that they are distributed unevenly across all eleven watermelon chromosomes. Analysis of duplication events suggested that segmental duplication and tandem duplication were the major driving forces of GDSL family evolution. Synteny analysis indicated that GDSL genes in watermelon were highly homologous to those in A. thaliana , melon and cucumber. Transcriptome analyses showed the organ-specific and common expression of the GDSL genes in the root, stem and leaf organs and revealed that some of the GDSL genes are responsive to gummy stem blight inoculation, suggesting the possible involvement of these genes in disease stress–response pathways. Our results provide a basis for selecting candidate watermelon GDSL genes for further studies to determine the biological functions of the GDSL genes in watermelon. [ABSTRACT FROM AUTHOR]

• Analytical solution to Couette inverse problem of Herschel-Bulkley fluid was derived. • The transformation equation was validated by both computer synthesized and experimental data. • Comparison between the analytical equation and the approximation equation was conducted. The Herschel-Bulkley model is one of the most commonly used rheological models for Non-Newtonian fluids, and it has been applied to describe the non-linear rheological behavior of fresh concrete. However, because it is difficult to transform the measured rotating speed and torque data into fundamental rheological units for coaxial cylinder rheometers, only an approximate approach has been proposed for this model. In order to improve the accuracy of the solution, a new integral equation describing the torque-rotation speed of Herschel-Bulkley model was derived in this paper, and 40 sets of simulated data were used for the comparison between the two methods. The equation introduced in this study was further validated by the experimental data of SCC. The results indicated that the established solution yielded more accurate results than the approximate one. [ABSTRACT FROM AUTHOR]

The rheological properties of fresh concrete can be characterized by the function between shear rate and shear stress. However, neither shear rate nor shear stress can be measured directly, but transformed from the rotation speed and torque logged by the rheometer. Therefore, the relationship between the rheological model and the torque-rotation speed function needs to be established. In order to describe the nonlinear rheological behavior of fresh concrete, the Robertson-Stiff model was proposed in this paper, and the relationship between rotation speed-torque and rheological parameters measured by the coaxial cylindrical rheometer was derived. Eight concrete mixtures were made, and its rheological properties were tested with ConTec 5 viscometer. Then raw data was utilized to validate the model. The results showed that the Robertson-Stiff model could be used to describe the rheological behavior of fresh concrete. [ABSTRACT FROM AUTHOR]