Abstract
Graphitic carbon nitride has long been considered incapable of splitting water molecules into hydrogen and oxygen without adding small molecule organics despite the fact that the ...visible-light response and proper band structure fulfills the proper energy requirements to evolve oxygen. Herein, through in-situ observations of a collective C = O bonding, we identify the long-hidden bottleneck of photocatalytic overall water splitting on a single-phased g-C
3
N
4
catalyst via fluorination. As carbon sites are occupied with surface fluorine atoms, intermediate C=O bonding is vastly minimized on the surface and an order-of-magnitude improved H
2
evolution rate compared to the pristine g-C
3
N
4
catalyst and continuous O
2
evolution is achieved. Density functional theory calculations suggest an optimized oxygen evolution reaction pathway on neighboring N atoms by C–F interaction, which effectively avoids the excessively strong C-O interaction or weak N-O interaction on the pristine g-C
3
N
4
.
Nitrate (NO3−) is a key signaling molecule in plant metabolism and development, in addition to its role as a nutrient. It has been shown previously in Arabidopsis that ANR1, a MADS‐box transcription ...factor, is a major component in the NO3−‐signaling pathway that triggers lateral root growth and that miR444, which is specific to monocots, targets four genes that are homologous to ANR1 in rice. Here, we show that miR444a plays multiple roles in the rice NO3−‐signaling pathway – not only in root development, but also involving nitrate accumulation and even Pᵢ‐starvation responses. miR444a overexpression resulted in reduced rice lateral root elongation, but promoted rice primary and adventitious root growth, in a nitrate‐dependent manner. In addition, overexpression of miR444a improved nitrate accumulation and expression of nitrate transporter genes under high nitrate concentration conditions, but reduced the remobilization of nitrate from old leaves to young leaves thus affecting the plant's ability to adapt to nitrogen‐limitating conditions. Intriguingly, we found that Pᵢ starvation strongly induced miR444 accumulation in rice roots and that overexpression of miR444a altered Pᵢ‐starvation‐induced root architecture and enhanced Pᵢ accumulation and expression of three Pᵢ transporter genes. We further provide evidence that miR444a is involved in the interaction between the NO3−‐signaling and Pᵢ‐signaling pathways in rice. Taken together, our observations demonstrated that miR444a plays multiple roles in the rice NO3−‐signaling pathway in nitrate‐dependent root growth, nitrate accumulation and phosphate‐starvation responses.
With the booming requirements for diabetes management, food quality control, and bioprocess inspection, monitoring of glucose in various matrices has drawn unprecedented interest of both academic and ...industrial researchers recently. As a relatively new class of glucose sensors, enzyme-free detection of the target is capable of providing several fascinating characters such as ultra-high sensitivity, excellent stability, and simple fabrication. Considering the rapid expansion of the glucose determination field without using any biological enzymes, here we focus our attention on updating the latest advances in non-enzymatic electrochemical glucose sensors based on non-noble transition metal materials achieved in the past few years. In this minireview, both the superiorities and the intrinsic drawbacks of detecting glucose by employing non-precious materials including Ni, Cu, Co, Mn, and Fe are intensively highlighted, followed by a systematic discussion on the important progress harvested for enzymeless glucose sensing. Finally, the potential opportunities of non-noble transition metal materials in fabricating high-performance enzyme-free glucose sensors are given, and the current challenges for their practical applications are also summarized.
We summarize the latest advances of non-enzymatic glucose detection using non-noble transition metal materials, highlighting their opportunities and challenges.
Two kinds of well-resolved wavelengths carbon dots (CDs) including red-emission CDs (rCDs) and blue-emission CDs (bCDs) were fabricated using osmanthus fragrans leaves as carbon source through ...solvent extraction methods. The prepared bCDs as reference signal and rCDs as response signal were constructed the ratiometric fluorescence MIPs@rCDs@bCDs@SiO2 sensor by the precipitation polymerization process for ultrasensitive and high selective TC determination.
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•The rCDs and bCDs were firstly fabricated using osmanthus fragrans leaves as carbon source by solvent extraction methods.•An environmental-friendly molecular imprinting ratiometric fluorescence sensor for detection of TC has been synthesized.•The MIPs@rCDs@bCDs@SiO2 was displayed ultrasensitive and excellent selective determination to tetracycline.
The molecular imprinting ratiometric fluorescence sensor has exhibited great potential in biological and environmental detection because of the combination between the excellent selectivity of molecular imprinting technique and outstanding robustness of ratiometric measurement methods On this basis, two kinds of different well-resolved wavelengths and high-fluorescent carbon dots (CDs) were prepared by various solvent extraction using osmanthus fragrans leaves as carbon source. Then the ratiometric fluorescence sensor (MIPs@rCDs/bCDs@SiO2) has been constructed by the obtained CDs which the red-emission CDs (rCDs) were used to responsive signal and the blue-emission CDs (bCDs) was served as reference signal and applied for highly selective and excellent sensitive detection of tetracycline (TC). Under optimum conditions, the ratiometric fluorescence MIPs@rCDs/bCDs@SiO2 sensor has also exhibited lower detection limit of 1.19nM and the linear range of 0–50nM. The ratiometric fluorescence sensor was further successfully employed to the determination of TC in water samples gathered from local river water and tap water, indicating its great worth toward water sample analysis in complicated environments.
Remote passive sonar detection is significant as it constitutes potential real-time monitoring of severe underwater threats. There is still a lack of an efficient approach to achieving weak ship ...signal detection with nonparametric and noninformation priors. We propose the relative multiscale change entropy (RMCE) method to tackle these problems that should be promising. It measures the similarity between the signal under test and the ambient noise by combining different time scale factors to perceive the small changes in the complexity of the ambient noise, which is led by the presence of the distant ship. The value of RMCE is demonstrated by simulation and applied to the actual recorded data. We analyze the distribution characteristics of relative multiscale entropy of the ambient noise data with and without ship noise, collected in the South China Sea. Then this article presents a Neyman-Pearson (N-P) criterion-based RMCE detector for ship signal detection in the marine environment. The results show that the RMCE method outperforms the narrowband energy detection (NBED) method considerably.
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•Renewable SLS and natural mineral (HNTs) were used for fabricating HPCs.•HNTs template and KOH activation had significant impacts on adsorption properties.•LTCA possessed ultrahigh ...adsorption capacity for TC (1297.0mg/g) and CAP (1067.2mg/g).•Sustainable and highly performance LTCA has promising potential in various areas.
In decade years, antibiotics residual has received considerable attention because of their detrimental effects on human health and the ecosystem, thereby resolution of this issue become a burning research project. Herein, we first prepared a novel sustainable hierarchical porous carbons (HPCs) (named LCTA) via the combination of halloysite nanotubes-template and in-situ KOH activation, using industrial by-product sodium lignin sulfonate (SLS) as biomass precursor. It was demonstrated that both HNTs template and KOH activation played a key role in the enhancements of the porosity and accessible surface. LTCA exhibited a high specific surface area of 2320m2/g and large pore volume of 1.342cm3/g. Moreover, LTCA showed an ultrahigh adsorption capacity for tetracycline (TC) of 1297.0mg/g and chloramphenicol (CAP) of 1067.2mg/g at 298K, which are far higher than those adsorbents previously reported. Additionally, fast adsorption kinetics, excellent environmental adaptability and good regeneration ability make this novel HPC as a promising material for antibiotics wastewater treatment practices.
At present, most of the analog circuit fault detection is aimed at component-level fault detection. In this paper, we propose a module-level soft fault detection method for the core module of a ...typical underwater acoustic sensing system. We use Simulink to implement function-level modeling of typical underwater acoustic sensing systems. The simulation data are obtained by establishing multiple measurement points, and the Short-Time Fourier Transform(STFT) is used to represent different fault modes so that the convolutional neural network can learn effectively. We design a deep learning model based on convolutional neural network, introduce an expansion bottleneck layer and an attention mechanism to improve the learning ability of the network. The model is then pre-trained by simulation data. Collecting experimental data for circuits that have been really applied to engineering practice, using less experimental data to fine-tune the model. Finally, the experimental results show that the proposed method can realize the soft fault detection of the core module of typical underwater acoustic sensing system under the premise of a small amount of real circuit data.
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•Aiming at the core module of the underwater acoustic perception system, we propose a fault detection method at the module level.•A deep learning network model is proposed to realize the soft fault detection of the core module of the underwater acoustic perception system.•We use simulated data to pre-train the deep learning model to reduce the dependence on real data.•The experimental data is come from underwater acoustic perception systems that have been used in practical engineering.
In this work, 0D/2D/2D Z-scheme AgVO3 /RGO/C3N4 blending porous PVDF photocatalytic self-cleaning membrane (AgVO3/RGO/C3N4-PVDF) were successfully fabricated. The AgVO3/RGO/C3N4-PVDF photocatalytic ...membranes have high efficiency for removing tetracycline and could synergistically separate and photocatalytic kill the E. coli.
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The enhancement of the self-cleaning ability of photocatalytic membranes and their degradation efficiency over tetracycline (TC) still remains a challenge. In this study, an alternative silver vanadate quantum dots (AgVO3 QDs) doped reduced graphene oxide (RGO) and graphitic carbon nitride (C3N4) nanocomposites modified polyvinylidene fluoride (PVDF) membrane (AgVO3/RGO/C3N4-PVDF) was successfully fabricated to enhance the photocatalytic activity. The AgVO3/RGO/C3N4 nanocomposites were functioned as the active component for the photocatalytic membrane. The unique Z-scheme heterostructure of AgVO3/RGO/C3N4 and the porous PVDF framework synergistically enhanced the separation and transport efficiency of photogenerated carriers and facilitated the interaction between the photocatalyst and the pollutant. As a result, the degradation efficiency of TC for the AgVO3/RGO/C3N4-PVDF reached 88.53% within 120 min, which was higher than those of the binary component membranes (64.8% for RGO/C3N4-PVDF and 79.18% AgVO3/C3N4-PVDF). In addition, AgVO3/RGO/C3N4-PVDF exhibited high permeability (1977 L·m−2·h−1·bar−1) and excellent antifouling activity. Under visible-light irradiation, the flux recovery rate (FRR) increased from 92.4% to 99.1%. Furthermore, AgVO3/RGO/C3N4-PVDF could reject 97.4% of Escherichia coli (E. coli) owning to its self-cleaning capacity, and eliminated the E. coli under visible-light irradiation trough the photogeneration of h+. This study highlights a highly efficient photocatalytic membrane based on a Z-scheme heterostructure, which may have a great potential application in practical wastewater treatment.
A bioinspired photocatalytic nanocomposite membrane was successfully prepared via polydopamine (pDA)-coated poly(vinylidene fluoride) (PVDF) membrane, as a secondary platform for vacuum-filtrated ...Au-TiO2 nanocomposites, with enhanced photocatalytic activity. The degradation efficiency of Au-TiO2/pDA/PVDF membranes reached 92% when exposed to visible light for 120 min, and the degradation efficiency of Au-TiO2/pDA/PVDF membranes increased by 26% compared to that of Au-TiO2 powder and increased by 51% compared to that of TiO2/pDA/PVDF nanocomposite membranes. The degradation efficiency remained about 90% after five cycle experiments, and the Au-TiO2/pDA/PVDF nanocomposite membranes showed good stability, regeneration performance, and easy recycling. The pDA coating not only served as a bioadhesion interface to improve the bonding force between the catalyst and the membrane substrate but also acted as a photosensitizer to broaden the wavelength response range of TiO2, and the structure of Au-TiO2/pDA/PVDF also improves the transfer rate of photogenerated electrons; the surface plasmon resonance effect of Au also played a positive role in improving the activity of the catalyst. Therefore, we believe that this study opens up a new strategy in preparing the bioinspired photocatalytic nanocomposite membrane for potential wastewater purification, catalysis, and as a membrane separation field.
BiOI uniform flowerlike hollow microspheres with a hole in its surface structures have been successfully synthesized through an EG-assisted solvothermal process in the presence of ionic liquid ...1-butyl-3-methylimidazolium iodine (BmimI). The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), nitrogen sorption, and diffuse reflectance spectroscopy (DRS). A possible formation mechanism for the growth of hollow microspheres was discussed. During the reactive process, ionic liquid not only acted as solvents and templates but also as an I source for the fabrication of BiOI hollow microspheres and was vital for the structure of hollow microspheres. Additionally, we evaluated the photocatalytic activities of BiOI on the degradation of methyl orange (MO) under visible light irradiation and found that as-prepared BiOI hollow microspheres exhibited higher photocatalytic activity than BiOI nanoplates and TiO2 (Degussa, P25) did. On the basis of such analysis, it can be assumed that the enhanced photocatalytic activities of BiOI hollow microspheres could be ascribed to its energy band structure, high BET surface area, high surface-to-volume ratios, and light absorbance.
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