Showing papers by "Zhong Chen published in 2020"
TL;DR: The mechanisms of how heavy metals are taken up, translocated, and detoxified in plants are described and the strategies applied to improve the efficiency of phytostabilization and phytoextraction are focused on, including the application of genetic engineering, microbe-assisted and chelate-assisted approaches.
Abstract: Heavy metal accumulation in soil has been rapidly increased due to various natural processes and anthropogenic (industrial) activities. As heavy metals are non-biodegradable, they persist in the environment, have potential to enter the food chain through crop plants, and eventually may accumulate in the human body through biomagnification. Owing to their toxic nature, heavy metal contamination has posed a serious threat to human health and the ecosystem. Therefore, remediation of land contamination is of paramount importance. Phytoremediation is an eco-friendly approach that could be a successful mitigation measure to revegetate heavy metal-polluted soil in a cost-effective way. To improve the efficiency of phytoremediation, a better understanding of the mechanisms underlying heavy metal accumulation and tolerance in plant is indispensable. In this review, we describe the mechanisms of how heavy metals are taken up, translocated, and detoxified in plants. We focus on the strategies applied to improve the efficiency of phytostabilization and phytoextraction, including the application of genetic engineering, microbe-assisted and chelate-assisted approaches.
564 citations
TL;DR: In this article, a hierarchical coating consisting of polydimethylsiloxane (PDMS) nanoparticles and PDMS microparticles (MPs) functional NPs through a combination of thermal treatment and spray treatment is proposed.
237 citations
TL;DR: In this paper, a review summarizes the latest preparation methods for MOF/graphene materials with a focus on applications in electrocatalysis and photocatalysis, and also the new comers to quickly catch up with the latest development in this field.
Abstract: Metal–organic frameworks (MOFs) are a special class of porous materials and have been widely explored for applications in supercapacitors, catalysts, and adsorbents, because of their large specific surface areas and tunable structure and composition. However, traditional MOFs suffer from poor conductivity and low stability, which limit their efficiency in catalysis and other applications that require good electrical conduction. To overcome this limitation, a composite made of electrically conducting graphene and MOFs is conceptually a viable solution. This review summarizes the latest preparation methods for MOF/graphene materials with a focus on applications in electrocatalysis and photocatalysis. We aim to assist existing researchers to obtain a fast and holistic overview of MOF and their derivatives with graphene composites in catalysis, and also the new comers to quickly catch up with the latest development in this field.
150 citations
TL;DR: A systematic summary of recent progress in air filtration covers the definition of PM, the characterization ofPM, the mechanism of PM capture, advanced purification materials, and special multifunctional performances.
Abstract: The PM (particulate matter)-induced haze problem has caused serious environmental and health concerns. It is still a huge challenge to control PM pollution because of the complex structure, diverse sources and intricate evolution mechanism of the particles. In recent years, there has been increasing efforts to develop advanced strategies for PM treatment. Herein, we wish to provide a systematic summary of recent progress in air filtration. The review covers the definition of PM, the characterization of PM, the mechanism of PM capture, advanced purification materials, and special multifunctional performances. As for characterizing PM particles, removal efficiency, pressure drop, flow rate, quality factor and optical transparency are the basic parameters. For the advanced filters with excellent filtration performance, some special properties such as thermal stability, antibacterial property, flame retardancy, recyclability and special wettability are in great need under certain extreme conditions. Finally, some future prospects for filtration materials, like material choice and structural design, are also discussed.
118 citations
TL;DR: In this article, a novel ionic conductor hydrogel consisting of interpenetrating sodium carboxymethylcellulose (CMC) microsheets and polyacrylamide (PAAm) network is presented.
110 citations
TL;DR: In this article, full-color micro light-emitting diodes (μ-LEDs) fabricated from semipolar wafers, with a quantum-dot photoresist color-conversion layer, were demonstrated.
Abstract: Red-green-blue (RGB) full-color micro light-emitting diodes (μ-LEDs) fabricated from semipolar (20-21) wafers, with a quantum-dot photoresist color-conversion layer, were demonstrated. The semipolar (20-21) InGaN/GaN μ-LEDs were fabricated on large (4 in.) patterned sapphire substrates by orientation-controlled epitaxy. The semipolar μ-LEDs showed a 3.2 nm peak wavelength shift and a 14.7% efficiency droop under 200 A/cm2 injected current density, indicating significant amelioration of the quantum-confined Stark effect. Because of the semipolar μ-LEDs’ emission-wavelength stability, the RGB pixel showed little color shift with current density and achieved a wide color gamut (114.4% NTSC space and 85.4% Rec. 2020).
99 citations
TL;DR: In this article, strong internal polarization fields in common c-plane LEDs, especially green, have been shown to be a promising candidate for visible light communication (VLC) in light-emitting diodes (LEDs).
Abstract: Light-emitting diodes (LEDs) have been regarded as promising candidates for visible light communication (VLC); however, strong internal polarization fields in common c-plane LEDs, especially green
86 citations
TL;DR: In this article, the authors presented a proof-of-concept of the application of deep learning and neural networks for high-quality, reliable, and very fast NMR spectra reconstruction from limited experimental data.
Abstract: Nuclear magnetic resonance (NMR) spectroscopy serves as an indispensable tool in chemistry and biology but often suffers from long experimental times. We present a proof-of-concept of the application of deep learning and neural networks for high-quality, reliable, and very fast NMR spectra reconstruction from limited experimental data. We show that the neural network training can be achieved using solely synthetic NMR signals, which lifts the prohibiting demand for a large volume of realistic training data usually required for a deep learning approach.
74 citations
TL;DR: In this paper, the authors conduct comprehensive experimental and theoretical investigations on the hydrogen evolution reaction (HER) preformation of FeP electrode in acidic and alkaline solutions and show that surface treatment in 37% HCl solution removes the oxide layer and significantly improves the HER performance, especially in alkaline solution.
Abstract: In this study, we conduct comprehensive experimental and theoretical investigations on the hydrogen evolution reaction (HER) preformation of FeP electrode in acidic and alkaline solutions. Theoretically, bulk Fe-O bond is unfavorable, but surface Fe-O bond is favorable and plays a negative role for HER. The presence of oxygen bonds (native or formed during reaction) is the root source of the reduced HER activity. Surface treatment in 37% HCl solution removes the oxide layer and significantly improves the HER performance, especially in alkaline solution. After etching, the overpotentials in 0.5 M H2SO4 are 79 and 95 mV at 10 and 20 mA cm−2, respectively. The ones in 1 M KOH are 95 and 102 mV at 10 and 20 mA cm−2, respectively. Long-term instability in alkaline solution is caused by the presence of oxygen in the electrolyte. Good stability can be realized by removing oxygen from the solution.
68 citations
TL;DR: In this paper, the all-solid-state Z-scheme CdS/QDs/ZnIn2S4 architectures with MoS2 quantum dots as solid-state electron mediator were successfully designed and constructed by optimally combining one-dimensional cdS nanorods, zero-dimensional MoS 2 quantum dots (QDs) and two-dimensional ZnIn 2S4 nanosheets.
64 citations
TL;DR: The current knowledge of signal transduction networks linking environmental stimulus to seed dormancy establishment, dormancy break and germination is summarized, underscoring the dominating roles of temperature, light, and nitric oxide.
Abstract: Seed dormancy and germination are two closely linked physiological traits that have great impacts on adaptation and survival of seed plants. Seed dormancy strengthen and germination potential are comprehensively influenced by a variety of internal factors and external environment cues. Environmental factors, such as water content, light condition, ambient temperature, and nitrogen availability, act as signal input to determine whether seeds keep in a dormant state or start to germinate. Light, temperature, and nitrogen availability are the most critical environmental factors that have profound impacts on seed dormancy and germination. However, the mechanisms underlying the regulation of seed dormancy and germination by environmental signals are still poorly understood. In this review, we summarize the current knowledge of signal transduction networks linking environmental stimulus to seed dormancy establishment, dormancy break and germination, underscoring the dominating roles of temperature, light, and nitric oxide. We review temperature, light, and nitric oxide signaling pathway separately as well as the integration of these signaling pathways with phytohormone abscisic acid (ABA) and gibberellins (GA) signaling pathway in the context of seed dormancy and germination.
TL;DR: In this article, a charged graphene aerogel filter (CGAF) was designed to capture the particulate matter (PMs) under the imposed electrostatic force to achieve high removal efficiency while maintaining a low pressure drop.
TL;DR: In this article, two types of Ni-Co alloys are generated on SiO2 including non-homogeneous or homogeneous form for CO methanation, and the formation of homogeneous NiCo alloy originates from the strong interaction between Ni and Co and a small amount of CoO.
Abstract: Designing and tailoring the fine structure of bimetallic nanoparticles is an essential and effective way to boost the catalytic properties. Herein, two types of Ni-Co alloys are generated on SiO2 including non-homogeneous or homogeneous form for CO methanation. The formation of homogeneous Ni-Co alloy originates from the strong interaction between Ni and Co and a small amount of CoO. Compared with non-homogeneous alloy, the homogeneous Ni-Co alloy exhibits superior CO conversion and CH4 selectivity below 380 °C, and is stable for 100 h long-term test at 400 °C in CO methanation. The electron enrichment of Ni and Co of homogeneous alloy contributes to CO dissociation, hydrogen spillover, and CO2 adsorption, which facilitates CH4 formation and the removal of deposited carbon species. This work provides a new clue for fabricating bimetallic catalysts and revealing the relationship between the fine structure of Ni-Co alloy and their catalytic performances.
TL;DR: In this article, molecular dynamics simulations of the pervaporation process are conducted to investigate the desalination performance of composite membranes composed of an HKUST-1 sheet and graphene oxide (GO) layers introduced to enhance its stability in water.
TL;DR: Based on an overall consideration, the BF-PMCs/H2O2 system has great potential for degradation of emerging organic pollutants (EOPs) in natural water systems.
TL;DR: In this paper, a new photocatalytic material sodium iron disulfide (NaFeS2) has been synthesized via a hydrothermal method for the degradation of methylene blue (MB) and indigo carmine (IC).
Abstract: A new photocatalytic material sodium iron disulfide (NaFeS2) has been synthesized via a hydrothermal method for the degradation of methylene blue (MB) and indigo carmine (IC). This material has been subjected to various analytical, electrochemical and photocatalytic studies to understand its morphology, crystallinity, band gap, oxidation-reduction potential and ability to catalyse the rate of dye degradation. The material exists as nanorods with a thickness of 30–100 nm and a monoclinic phase with an average crystallite size of 25–30 nm. The energy bandgap of the prepared photocatalyst has been calculated using the Kubelka-Munk function and is found to be 2.01 eV. Using a UV light source, the photocatalytic activity of NaFeS2 has been carried out, where the time of irradiation determined the ability of the catalyst to degrade the dye under investigation. With a degradation efficiency of 97% in 105 min for MB and 99% in 45 min for IC, NaFeS2 appears as an excellent photocatalytic material. The electrochemical studies also act as a testament for NaFeS2’sadmirable photocatalytic property. The photocatalytic and electrochemical activities of NaFeS2 offer an innovative platform for the treatment of various other environmental pollutants as well.
01 Sep 2020
TL;DR: In this article, a facile synthesis technique for the fabrication of super-hydrophobic antibacterial fabrics by employing fluorine-free silane coupling agents as cross-linkers for enhanced durability was reported.
Abstract: Multifunctional fabrics of high durability through a scalable and eco-friendly technique remains a great challenge hindering their commercialization. In this work, we report a facile synthesis technique for the fabrication of superhydrophobic antibacterial fabrics by employing fluorine-free silane coupling agents as cross-linkers for enhanced durability. Three silane cross-linkers, Aminoethylaminopropyltrimethoxysilane (AEAPTMS), Aminopropyltriethoxysilane (APTES), and Methacryloyloxypropyltrimethoxysilane (MPTMS), have been investigated. During the fabrication, a low surface energy polymer, polydimethylsiloxane (PDMS) was first deposited on cotton fabrics. Subsequently, antibacterial copper oxide (CuO) nanoparticles were anchored on the PDMS coated fabrics using the silane cross-linkers. The as-prepared fabrics displayed high superhydrophobicity and antibacterial performance with water contact angle (WCA) > 153°, water shedding angle (WSA)
TL;DR: The metal halide perovskite nanocrystal (MHP-NC), an easy-to-fabricate and low cost fluorescent material, is recognized to be among the promising candidates of the color conversion material in the micro light-emitting diode (micro-LED) display, providing that the stability can be further enhanced.
Abstract: The metal halide perovskite nanocrystal (MHP-NC), an easy-to-fabricate and low cost fluorescent material, is recognized to be among the promising candidates of the color conversion material in the micro light-emitting diode (micro-LED) display, providing that the stability can be further enhanced. It is found that the water steam, oxygen, thermal radiation and light irradiation—four typical external factors in the ambient environment related to micro-LED display—can gradually alter and destroy the crystal lattice. Despite the similar phenomena of photoluminescence quenching, the respective encroaching processes related to these four factors are found to be different from one another. The encroaching mechanisms are collected and introduced in separate categories with respect to each external factor. Thereafter, a combined effect of these four factors in an environment mimicking real working conditions of micro-LED display are also introduced. Finally, recent progress on the full-color application of MHP-NC is also reviewed in brief.
TL;DR: The results reveal a new mechanism for a release from PRC2-mediated gene repression through H3.15 deposition into chromatin, which is involved in reprogramming cell fate to produce pluripotent callus cells.
Abstract: Plants are capable of regenerating new organs after mechanical injury. The regeneration process involves genome-wide reprogramming of transcription, which usually requires dynamic changes in the chromatin landscape. We show that the histone 3 variant HISTONE THREE RELATED 15 (H3.15) plays an important role in cell fate reprogramming during plant regeneration in Arabidopsis H3.15 expression is rapidly induced upon wounding. Ectopic overexpression of H3.15 promotes cell proliferation to form a larger callus at the wound site, whereas htr15 mutation compromises callus formation. H3.15 is distinguished from other Arabidopsis histones by the absence of the lysine residue 27 that is trimethylated by the POLYCOMB REPRESSIVE COMPLEX 2 (PRC2) in constitutively expressed H3 variants. Overexpression of H3.15 promotes the removal of the transcriptional repressive mark H3K27me3 from chromatin, which results in transcriptional de-repression of downstream genes, such as WUSCHEL RELATED HOMEOBOX 11 (WOX11). Our results reveal a new mechanism for a release from PRC2-mediated gene repression through H3.15 deposition into chromatin, which is involved in reprogramming cell fate to produce pluripotent callus cells.
TL;DR: Self-recognizing and stimulus-responsive carrier-free metal-coordinated nanotheranostics that showed strongly synergistic potency for tumor photo-chemotherapy under the precise guidance of magnetic resonance/photoacoustic/fluorescence imaging, thereby achieving highly effective tumor curing efficiency.
Abstract: Carrier-free nanotheranostics directly assembled by using clinically used photosensitizers and chemotherapeutic drugs are a promising alternative to tumor theranostics. However, the weak interaction-driven assembly still suffers from low structural stability against disintegration, lack of targeting specificity, and poor stimulus-responsive property. Moreover, almost all exogenous ligands possess no therapeutic effect. Enlightened by the concept of metal-organic frameworks, we developed a novel self-recognizing metal-coordinated nanotheranostic agent by the coordination-driven co-assembly of photosensitizer indocyanine green (ICG) and chemo-drug methotrexate (MTX, also served as a specific "targeting ligand" towards folate receptors), in which ferric (FeIII) ions acted as a bridge to tightly associate ICG with MTX. Such carrier-free metal-coordinated nanotheranostics with high dual-drug payload (∼94 wt%) not only possessed excellent structural and physiological stability, but also exhibited prolonged blood circulation. In addition, the nanotheranostics could achieve the targeted on-demand drug release by both stimuli of internal lysosomal acidity and external near-infrared laser. More importantly, the nanotheranostics could self-recognize the cancer cells and selectively target the tumors, and therefore they decreased toxicity to normal tissues and organs. Consequently, the nanotheranostics showed strongly synergistic potency for tumor photo-chemotherapy under the precise guidance of magnetic resonance/photoacoustic/fluorescence imaging, thereby achieving highly effective tumor curing efficiency. Considering that ICG and bi-functional MTX are approved by the Food and Drug Administration, and FeIII ions have high biosafety, the self-recognizing and stimulus-responsive carrier-free metal-coordinated nanotheranostics may hold potential applications in tumor theranostics.
TL;DR: 3D printing and liquid metal filling techniques are utilized to fabricate integrative radio frequency probeheads for MR experiments and can accurately obtain complicated coil geometries at the micrometer scale, shortening the fabrication timescale and extending the application scenarios.
Abstract: Magnetic resonance (MR) technology has been widely employed in scientific research, clinical diagnosis and geological survey. However, the fabrication of MR radio frequency probeheads still face difficulties in integration, customization and miniaturization. Here, we utilized 3D printing and liquid metal filling techniques to fabricate integrative radio frequency probeheads for MR experiments. The 3D-printed probehead with micrometer precision generally consists of liquid metal coils, customized sample chambers and radio frequency circuit interfaces. We screened different 3D printing materials and optimized the liquid metals by incorporating metal microparticles. The 3D-printed probeheads are capable of performing both routine and nonconventional MR experiments, including in situ electrochemical analysis, in situ reaction monitoring with continues-flow paramagnetic particles and ions separation, and small-sample MR imaging. Due to the flexibility and accuracy of 3D printing techniques, we can accurately obtain complicated coil geometries at the micrometer scale, shortening the fabrication timescale and extending the application scenarios. Here, the authors combine 3D printing and liquid metal filling techniques to fabricate customised probeheads for magnetic resonance experiments. They demonstrate in situ electrochemical nuclear magnetic resonance analysis, reaction monitoring with continues-flow separation and small-sample imaging.
TL;DR: In this paper, a self-sacrifice template strategy was proposed for the synthesis of hollow Co-embedded in nitrogen-doped graphite (Co@CN) structure, which exhibits excellent catalytic efficiency in the oxidative esterification of 5-hydroxymethylfurfural to 2,5-furandicarboxylicacid dimethyl ester.
TL;DR: First-principles calculations based on density functional theory show that the formed Bi2O4/BiVO4 heterojunction can improve visible light utilization and promote transfer of photo-generated holes from BiVO4 to Bi2 O4.
Abstract: First-principles calculations based on density functional theory were carried out to explore the geometric structure, light absorption, charge separation, over-potential and stability of Bi2O4 (101)/BiVO4 (010) heterojunction. The results show that the formed heterojunction can improve visible light utilization and promote transfer of photo-generated holes from BiVO4 to Bi2O4. Furthermore, the Bi5+ site in the Bi2O4(101) surface is energetically more favorable as the photoanode for the oxygen evolution reaction (OER) than the Bi3+ sites in Bi2O4(101) and BiVO4(010). At the same time, it is also found that the Bi5+ in Bi2O4(101) are more stable than the Bi3+ due to the lower surface energy and stronger bond energy with neighbors. Therefore, forming the Bi2O4/BiVO4 heterojunction can effectively improve the activity and stability of BiVO4 for water splitting reactions.
TL;DR: The microstructure evolution of the prepared SiBCN ceramic aerogel/graphene composites and phase composition were studied by SEM, TEM and XRD, the pore structure of the preceramic composites pyrolyzed at 1200°C was tested by specific surface area and pore size analyzer.
TL;DR: In this article, a few-shot image segmentation mechanism using a deep convolutional network trained episodically is proposed. But, the method requires massive annotations in training to avoid overfitting and is difficult to acquire where biomedical expert knowledge is required.
TL;DR: The whole brain functional response to emotional infant faces in 20 new mothers and 22 nulliparous women during functional magnetic resonance imaging scans indicates that the experience of being a mother affects human brain responses in visual and social cognitive brain areas and in brain areas associated with theory-of-mind related and empathic processing.
Abstract: The experience of motherhood is one of the most salient events in a woman's life. Motherhood is associated with a series of neurophysiological, psychological, and behavioral changes that allow women to better adapt to their new role as mothers. Infants communicate their needs and physiological states mainly through salient emotional expressions, and maternal responses to infant signals are critical for infant survival and development. In this study, we investigated the whole brain functional response to emotional infant faces in 20 new mothers and 22 nulliparous women during functional magnetic resonance imaging scans. New mothers showed higher brain activation in regions involved in infant facial expression processing and empathic and mentalizing networks than nulliparous women. Furthermore, magnitudes of the activation of the left parahippocampal gyrus and the left fusiform gyrus, recruited during facial expression processing, were positively correlated with empathic concern (EC) scores in new mothers when viewing emotional (happy-sad) faces contrasted to neutral faces. Taken together, these results indicate that the experience of being a mother affects human brain responses in visual and social cognitive brain areas and in brain areas associated with theory-of-mind related and empathic processing.
TL;DR: In this article, a highly reproducible sol-gel process was developed to establish efficient and translucent WO3 photoanodes using a chemically stable ammonium metatungstate precursor.
Abstract: Although monoclinic WO3 is widely studied as a prototypical photoanode material for solar water splitting, limited success, hitherto, in fabricating WO3 photoanodes that simultaneously demonstrate high efficiency and reproducibility has been realized. The difficulty in controlling both the efficiency and reproducibility is derived from the ever-changing structures/compositions and chemical environments of the precursors, such as peroxytungstic acid and freshly prepared tungstic acid, which render the fabrication processes of the WO3 photoanodes particularly uncontrollable. Herein, a highly reproducible sol-gel process was developed to establish efficient and translucent WO3 photoanodes using a chemically stable ammonium metatungstate precursor. Under standard simulated sunlight of air mass 1.5 G, 100 mW cm−2, the WO3 photoanode delivered photocurrent densities of ca. 2.05 and 2.25 mA cm−2 at 1.23 V versus the reversible hydrogen electrode (RHE), when tested in 1 mol L−1 H2SO4 and CH3SO3H, respectively. Hence, the WO3 photoanodes fabricated herein are one of the WO3 photoanodes with the highest performance ever reported. The reproducibility of the fabrication scheme was evaluated by testing 50 randomly selected WO3 samples in 1 mol L−1 H2SO4, which yielded an average photocurrent density of 1.8 mA cm−2 at 1.23 VRHE with a small standard deviation. Additionally, the effectiveness of the ammonium metatungstate precursor solution was maintained for at least 3 weeks, when compared with the associated upper-limit values of peroxytungstic and tungstic acid based precursors after 3 d. This study presents a key step to the future development of WO3 photoanodes for efficient solar water splitting.
TL;DR: In this paper, the effect of the photoreaction temperature, initial concentration of ethylene and light intensity on photodegradation under ultraviolet-light emitting diode (UV-LED) light was investigated.
TL;DR: It is concluded that water hyacinth can be utilized as a phytoremediation agent to clean up heavy metal polluted water.
Abstract: Toxic heavy metal pollution of water is a major environmental problem and the current remediation approaches are not optimal as they are non-eco-friendly and lacking in efficiency. As such phytorem...