Uptake, translocation, detoxification, and sequestration of heavy metals (HMs) are key processes in plants to deal with excess amounts of HM. Under natural conditions, plant roots often establish ...ecto‐ and/or arbuscular‐mycorrhizae with their fungal partners, thereby altering HM accumulation in host plants. This review considers the progress in understanding the physiological and molecular mechanisms involved in HM accumulation in nonmycorrhizal versus mycorrhizal plants. In nonmycorrhizal plants, HM ions in the cells can be detoxified with the aid of several chelators. Furthermore, HMs can be sequestered in cell walls, vacuoles, and the Golgi apparatus of plants. The uptake and translocation of HMs are mediated by members of ZIPs, NRAMPs, and HMAs, and HM detoxification and sequestration are mainly modulated by members of ABCs and MTPs in nonmycorrhizal plants. Mycorrhizal‐induced changes in HM accumulation in plants are mainly due to HM sequestration by fungal partners and improvements in the nutritional and antioxidative status of host plants. Furthermore, mycorrhizal fungi can trigger the differential expression of genes involved in HM accumulation in both partners. Understanding the molecular mechanisms that underlie HM accumulation in mycorrhizal plants is crucial for the utilization of fungi and their host plants to remediate HM‐contaminated soils.
Heave metal (HM) accumulation is often altered in mycorrhizal plants, but the physiological and molecular mechanisms underlying changes in HM accumulation are elusive. This review summarizes the progress in understanding the physiological and molecular mechanisms involved in HM accumulation in nonmycorrhizal versus mycorrhizal plants. Mycorrhizal‐induced changes in HM accumulation are mainly due to HM sequestration in fungal partners, improvements in the nutritional and antioxidative status of host plants, and fungi‐triggered differential expression of genes involved in HM accumulation in both partners.
Overexpression of bacterial γ‐glutamylcysteine synthetase in the cytosol of Populus tremula × P. alba produces higher glutathione (GSH) concentrations in leaves, thereby indicating the potential for ...cadmium (Cd) phytoremediation. However, the net Cd²⁺influx in association with H⁺/Ca²⁺, Cd tolerance, and the underlying molecular and physiological mechanisms are uncharacterized in these poplars. We assessed net Cd²⁺influx, Cd tolerance and the transcriptional regulation of several genes involved in Cd²⁺transport and detoxification in wild‐type and transgenic poplars. Poplars exhibited highest net Cd²⁺influxes into roots at pH 5.5 and 0.1 mM Ca²⁺. Transgenics had higher Cd²⁺uptake rates and elevated transcript levels of several genes involved in Cd²⁺transport and detoxification compared with wild‐type poplars. Transgenics exhibited greater Cd accumulation in the aerial parts than wild‐type plants in response to Cd²⁺exposure. Moreover, transgenic poplars had lower concentrations of O₂˙⁻and H₂O₂; higher concentrations of total thiols, GSH and oxidized GSH in roots and/or leaves; and stimulated foliar GSH reductase activity compared with wild‐type plants. These results indicate that transgenics are more tolerant of 100 μM Cd²⁺than wild‐type plants, probably due to the GSH‐mediated induction of the transcription of genes involved in Cd²⁺transport and detoxification.
Constructing a heterojunction and introducing an interfacial interaction by designing ideal structures have the inherent advantages of optimizing electronic structures and macroscopic mechanical ...properties. An exquisite hierarchical heterogeneous structure of bimetal sulfide Sb2S3@FeS2 hollow nanorods embedded into a nitrogen-doped carbon matrix is fabricated by a concise two-step solvothermal method. The FeS2 interlayer expands in situ grow on the interface of hollow Sb2S3 nanorods within the nitrogen-doped graphene matrix, forming a delicate heterostructure. Such a well-designed architecture affords rapid Na+ diffusion and improves charge transfer at the heterointerfaces. Meanwhile, the strongly synergistic coupling interaction among the interior Sb2S3, interlayer FeS2, and external nitrogen-doped carbon matrix creates a stable nanostructure, which extremely accelerates the electronic/ion transport and effectively alleviates the volume expansion upon long cyclic performance. As a result, the composite, as an anode material for sodium-ion batteries, exhibits a superior rate capability of 537.9 mAh g–1 at 10 A g–1 and excellent cyclic stability with 85.7% capacity retention after 1000 cycles at 5 A g–1. Based on the DFT calculation, the existing constructing heterojunction in this composite can not only optimize the electronic structure to enhance the conductivity but also favor the Na2S adsorption energy to accelerate the reaction kinetics. The outstanding electrochemical performance sheds light on the strategy by the rational design of hierarchical heterogeneous nanostructures for energy storage applications.
Though fluorescence‐tag‐based anti‐counterfeiting technology has distinguished itself with cost‐effective features and huge information loading capacity, the clonable decryption process of ...spatial‐resolved anti‐counterfeiting cannot meet the requirements for high‐security‐level anti‐counterfeiting. Herein, we demonstrate a spatial‐time‐dual‐resolved anti‐counterfeiting system based on new organic–inorganic hybrid halides BAPPZn2(ClyBr1−y)8 (BAPP=1,4‐bis(3‐ammoniopropyl)piperazinium, y=0–1) with ultra‐long room‐temperature phosphorescence (RTP). Remarkably, the afterglow lifetime can be facilely tuned by regulating the halide‐induced heavy‐atom effect and can be identified by the naked eyes or with the help of a simple machine vision system. Therefore, the short‐lived unicolor fluorescence and lasting‐time‐tunable RTP provide the prerequisites for unicolor‐time‐resolved anti‐counterfeiting, which lowers the decryption‐device requirements and further provides the design strategy of advanced portable anti‐counterfeiting technology.
A new zero‐dimensional Zn‐based metal halide with ultra‐long room‐temperature phosphorescence (RTP) is reported. The RTP lifetimes can be facilely regulated via halide engineering, paving the way for designing spatial‐time‐dual‐resolved anti‐counterfeiting materials.
Glass is a group of materials with appealing qualities, including simplicity in fabrication, durability, and high transparency, and they play a crucial role in the optics field. In this paper, a new ...organic–inorganic metal halide luminescent glass exhibiting >78 % transmittance at 506–800 nm range together with a high photoluminescence quantum yield (PLQY) of 28.5 % is reported through a low‐temperature melt‐quenching approach of pre‐synthesized (HTPP)2MnBr4 (HTPP=hexyltriphenylphosphonium) single crystal. Temperature‐dependent X‐ray diffraction, polarizing microscopy, and molecular dynamics simulations were combined to investigate the glass‐crystal interconversion process, revealing the disordered nature of the glassy state. Benefiting from the transparent nature, (HTPP)2MnBr4 glass yields an outstanding spatial resolution of 10 lp mm−1 for X‐ray imaging. The superb optical properties and facility of large‐scale fabrication distinguish the organic–inorganic metal halide glass as a highly promising class of materials for optical devices.
A novel zero‐dimensional manganese‐based metal halide capable of forming a stable melt is reported. Large‐area luminescent metal halide glasses can be conveniently synthesized by the melt‐quenching method and used as scintillators for radiation detection.
Effective role shaping of cultural education in colleges and universities is of tremendous and far-reaching strategic significance to the development of socialist modernization. This paper ...establishes 3DBP-TBR method based on the 3D CLBP method with higher granularity to identify and analyze the role behavioral characteristics of teachers in higher education. It uses the elbow method to determine the optimal number of clusters in the clustering analysis, extracting and identifying the characteristics of teachers’ role behavior. By analyzing the role shaping of teachers, it was found that Teachers have the highest teaching support role index of 0.9548 points, and there is a significant difference in the dimension of teaching support characteristics of teachers teaching different courses (P=0.047<0.05). The analysis results in this paper lay a foundation for the study of role modeling and characteristics of college teachers, and the proposed role modeling suggestions also provide a reference for the future improvement of cultural education in colleges and universities.
Heavy metal (HM)-accumulating herbaceous and woody plants are employed for phytoremediation. To develop improved strategies for enhancing phytoremediation efficiency, knowledge of the ...microstructural, physiological and molecular responses underlying HM-accumulation is required. Here we review the progress in understanding the structural, physiological and molecular mechanisms underlying HM uptake, transport, sequestration and detoxification, as well as the regulation of these processes by signal transduction in response to HM exposure. The significance of genetic engineering for enhancing phytoremediation efficiency is also discussed. In herbaceous plants, HMs are taken up by roots and transported into the root cells via transmembrane carriers for nutritional ions. The HMs absorbed by root cells can be further translocated to the xylem vessels and unloaded into the xylem sap, thereby reaching the aerial parts of plants. HMs can be sequestered in the cell walls, vacuoles and the Golgi apparatuses. Plant roots initially perceive HM stress and trigger the signal transduction, thereby mediating changes at the molecular, physiological, and microstructural level. Signaling molecules such as phytohormones, reactive oxygen species (ROS) and nitric oxide (NO), modulate plant responses to HMs via differentially expressed genes, activation of the antioxidative system and coordinated cross talk among different signaling molecules. A number of genes participated in HM uptake, transport, sequestration and detoxification have been functionally characterized and transformed to target plants for enhancing phytoremediation efficiency. Fast growing woody plants hold an advantage over herbaceous plants for phytoremediation in terms of accumulation of high HM-amounts in their large biomass. Presumably, woody plants accumulate HMs using similar mechanisms as herbaceous counterparts, but the processes of HM accumulation and signal transduction can be more complex in woody plants.
Background and Aims
There is growing evidence that single‐stranded, circular RNA (circRNA) plays a key role in the development of certain cancers, including hepatocellular carcinoma (HCC). It is less ...clear, however, what role circRNA plays in HCC metastasis.
Approach and Results
In this study, through circRNA sequencing, we identified a circRNA: circASAP1 (a circRNA derived from exons 2 and 3 of the ASAP1 gene, hsa_circ_0085616), which is associated with pulmonary metastasis after curative resection in patients with HCC. CircASAP1 was overexpressed in HCC cell lines with high metastatic potential and in metastatic HCCs. In vitro, circASAP1 promoted cell proliferation, colony formation, migration, and invasion, and in vivo, it enhanced tumor growth and pulmonary metastasis. Mechanism studies showed that circASAP1 acts as a competing endogenous RNA for microRNA 326 (miR‐326) and microRNA 532‐5p (miR‐532‐5p), both of which are tumor suppressors in HCC. We found that mitogen‐activated protein kinase (MAPK) 1 and colony stimulating factor (CSF)‐1 were direct common targets for microRNA 326 (miR‐326) and microRNA 532‐5p (miR‐532‐5p), which were regulated by circASAP1. CircASAP1 promotes HCC cell proliferation and invasion by regulating miR‐326/miR‐532‐5p‐MAPK1 signaling and, furthermore, mediates tumor‐associated macrophage infiltration by regulating the miR‐326/miR‐532‐5p‐CSF‐1 pathway. Clinical HCC samples exhibited a positive correlation between circASAP1 expression and levels of CSF‐1, MAPK1, and CD68+ tumor‐associated macrophages, all of which were predictive of patient outcomes.
Conclusion
We identified circASAP1 as a key regulator of HCC metastasis that acts on miR‐326/miR‐532‐5p‐MAPK1/CSF‐1 signaling and serves as a prognostic predictor in patients with HCC.
Meteorological parameters are the important factors influencing the infectious diseases such as severe acute respiratory syndrome (SARS) and influenza. This study aims to explore the association ...between Corona Virus Disease 2019 (COVID-19) deaths and weather parameters. In this study, we collected the daily death numbers of COVID-19, meteorological parameters and air pollutant data from 20 January 2020 to 29 February 2020 in Wuhan, China. Generalized additive model was applied to explore the effect of temperature, humidity and diurnal temperature range on the daily death counts of COVID-19. There were 2299 COVID-19 death counts in Wuhan during the study period. A positive association with COVID-19 daily death counts was observed for diurnal temperature range (r = 0.44), but negative association for relative humidity (r = −0.32). In addition, one unit increase in diurnal temperature range was only associated with a 2.92% (95% CI: 0.61%, 5.28%) increase in COVID-19 deaths in lag 3. However, both 1 unit increase of temperature and absolute humidity were related to the decreased COVID-19 death in lag 3 and lag 5, with the greatest decrease both in lag 3 −7.50% (95% CI: −10.99%, −3.88%) and −11.41% (95% CI: −19.68%, −2.29%). In summary, this study suggests the temperature variation and humidity may also be important factors affecting the COVID-19 mortality.
Display omitted
•First study to explore the effects of meteorological factors on COVID-19 mortality•A positive association is found between daily death counts of COVID-19 and DTR.•Absolute humidity is negatively associated with daily death counts of COVID-19.
Stress state has significant influence on the initiation of suffusion, whereas the effect of deviator stress has not been investigated thoroughly. This paper presented a series of hydro-mechanical ...coupling suffusion tests on four internally unstable cohesionless soils to investigate the effect of deviator stress on the initiation of suffusion. A dimensionless parameter, shear stress ratio, which is the ratio of deviator stress to mean effective stress, was introduced to denote the variation of deviator stress under the same confining pressure. The results indicate that the deviator stress or shear stress ratio has significant influence on the initiation of suffusion. The relationship between shear stress ratio and critical hydraulic gradient initiating suffusion is piecewise linear, and there is a critical shear stress ratio for different internally unstable soils. The critical hydraulic gradient first linearly increases with the increase in shear stress ratio, and it reaches the maximum value at the critical shear stress ratio, then it decreases suddenly and significantly, finally it increases linearly again with the increase in shear stress ratio. The critical shear stress ratio is not the division between volumetric contraction and dilation, but it can be determined by a consolidated drained triaxial compression test. Based on the characteristic of the relationship between shear stress ratio and critical hydraulic gradient, an empirical method determining the critical hydraulic gradients under complex stress states was developed.
PDF
