Microplastics become one of the serious persistent pollutants in terrestrial environments, and thus may represent a threat to the quality of soil and inhabiting organisms. It is imperative to ...understand occurrence and distribution of microplastics in soils. In this study, a large-scale field survey encompassing 85 locations along the lower reaches of Yangtze River and estuary was performed to investigate the microplastics abundance in agricultural soils. Microplastics were isolated from all the samples and all depths (0–80 cm). The microplastics abundance in soils ranged from 4.94 items/kg to 252.70 items/kg, with an average of 37.32 items/kg. The most common microplastic type detected was Polypropylene (PP) occurring as white fragments with sizes ranging from 0.1 mm to 0.5 mm. Abiotic parameters such as soil pH and texture were the general factors being associated with microplastic abundance. Meantime, traffic was indicated as one important factor to affect the microplastic abundance. Overall, the road input seems to be the main source of microplastic pollution in agricultural areas along the Yangtze River and estuary. Further studies should elucidate the original of the plastic fragments in order to establish a baseline for regulative initiatives securing environmental protection.
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•No significant difference of microplastics abundance were found in different soils.•Microplastics abundance in neutral soil was higher than that in acid soil.•Soil particle grad was an essential factor affecting the abundance of microplastics.•Road input was one important source of soil microplastics in the Yangtze River area.
Due to high absorbance of UV light and low solid loading, the stereolithography-based additive manufacturing of gray-colored and dense Si3N4 ceramic is of significant difficulty and challenge. The ...effects of geometric properties of ceramic powders on the curing performance were investigated by studying the absorption difference of the Si3N4 ceramic particles with different colors and particle sizes and ultraviolet light. The results show that the transmission of ultraviolet light and curing performance of the darker Si3N4 ceramic slurry are much poor. Under the same particle size, the Si3N4 ceramic slurry using lighter particles presents the smaller scattering coefficient. The scattering coefficient (∼202) of the gray powder with ∼0.8 μm average particle size is the smallest. Under the same color, the larger the particle size, the smaller the scattering coefficient. The smallest scattering coefficient of the white powder with ∼2.0 μm average particle size is ∼110.
Atmospheric deposition is an essential pathway of heavy metals (HMs) from the atmosphere to soils, while few studies assess the effects and contributions of atmospheric deposition on HMs ...accumulations in agricultural soils from the field and regional scales. In this study, eleven representative field monitoring sites from industrial areas, agricultural areas, and reference site in a typical rapid industrial development region were selected to determine the effects of atmospheric deposition on soil HMs accumulation. Industrial activities significantly increased the deposited particles flux from atmospheric deposition, with annual particles fluxes in industrial areas being 1.83 and 1.90 times higher than in agricultural areas and reference site, respectively. Although the HMs deposition fluxes had decreased significantly with time by literature comparison, the deposition fluxes of Cd and Pb were still at high levels in this study area. Precipitation was the key factor affecting seasonal variations of atmospheric HMs deposition. Lead isotope analysis indicated that atmospheric Pb originated from coal combustion, and atmospheric deposition was the primary source of Pb contamination in agricultural soil adjacent to industries. This study provided insight into the effects of atmospheric deposition on agricultural soil HMs accumulations at the regional scale and an important theoretical basis for source-preventing soil HMs contamination in industrial developed and other similar areas.
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•Heavy metals determination in atmospheric deposition-soil systems at regional scale.•Industrial emission significantly increases atmospheric heavy metals deposition.•Precipitation influences seasonal variation of atmospheric heavy metals deposition.•Coal combustion increases atmospheric Pb and leads to soil Pb accumulation.
Hydroxyapatite (HA) was selected as dopant and synthesized by a sonochemical method in this study. PVA-HA-KOH-H2O composite alkaline solid polymer electrolyte (ASPE) was prepared by solution casting ...method. Two different doping routes, i.e., the physical mixing (PM) and in situ synthesis (ISS) were considered. The influences of the ASPE composition such as HA content, KOH content and water content on the conductivity were investigated. The ASPE prepared by ISS route has a porous structure which is important for ion transfer. Accordingly, the conductivity of the ASPE prepared by ISS is higher than that of by PM. A highest conductivity of about 0.1 S/cm is reached for ASPE prepared by ISS route at 70% water content for m(PVA):m(KOH):m(HA) = 10:14:10 system, higher than that of by PM route, 0.08 S/cm. The nickel/zinc cell shows better electrochemical properties assembled with the ASPE prepared by ISS approach than by PM approach.
Photocurable gray-colored Si3N4 ceramic slurry with high solid loading, suitable viscosity and high curing depth is critical to fabricate dense ceramic parts with complex shape and high surface ...precision by stereolithography technology. In the present study, Si3N4 ceramic slurry with suitable viscosity, high solid loading (45 vol %) and curing depth of 50 μm was prepared successfully when surface modifier KH560 (1 wt%) and dispersant Darvan (1 wt%) were used. The slurry exhibits the shear thinning behavior. Based on the Beer-Lambert formula, Dp(the attenuation length) and Ec (the critical energy dose) of Si3N4 ceramic slurry with solid loading of 45 vol % were derived as 0.032 mm and 0.177 mJ/mm2, respectively. Si3N4 ceramic green parts with complex shape and high surface precision were successfully fabricated by stereolithography technology. After optimizing the debinding and sintering process for green parts, dense Si3N4 ceramics with 3.28 g/cm3 sintering density were fabricated. The microhardness and fracture toughness of as-sintered Si3N4 ceramics are ~14.63 GPa and ~5.82 MPa m1/2, respectively, which are comparable to those of the samples by traditional dry-pressed and pressureless sintering technology. These results show that ceramic stereolithography technology could be promising to fabricate high performance ceramics, especially for gray-colored monolithic Si3N4 ceramics.
Silicon nitride (Si3N4) ceramic slurry with high-solid loading, low-viscosity and high curing depth was prepared by using a surface modifier (silane coupling agent) directly as the dispersant. The ...effect of the interaction between modified Si3N4 powders and prepolymer on rheological property, kinetic stability, wettability and curing property of the slurry was investigated. The stereolithography forming mechanism of the modified Si3N4 ceramic slurry was elucidated. It is revealed that the epoxy group of KH560 can easily form an ether covalent bond with the hydroxyl group of bisphenol A epoxy acrylate (EA). This makes submicron sized Si3N4 powder well-dispersed in the premixed liquid and leads to improved rheological properties and kinetic stability of the ceramic slurry. In particular, the ether covalent bond formed between surface modified Si3N4 powder and EA reduces the surface tension of the slurry and enhances the wettability of the cured slurry layer. KH560 acts as a molecular bridge linking EA to Si3N4 powder surface and forms an EA shell structure. Therefore, the refractive index difference between the Si3N4 powder and prepolymer reduces significantly by two orders of magnitude, leading to an increase in the curing depth. These findings could be crucial for the stereolithographic fabrication of high refractive index ceramics parts with high precision and complex geometries.
The titanium dioxide nanotube array (TiO2-NTA) is prepared by a two-step anodic oxidation method and annealed at 450 ∘C subsequently. The Al-inserted TiO2-NTA is prepared by polarizing the TiO2-NTAs ...electrode at 0.4mA for 2min in 1mol/L AlCl3. The results show that the Al-inserted sample still remains pure anatase TiO2 phase (by XRD) and keeps intact nanotube array structure (by FE-SEM). The X-ray photoelectron spectroscopy (XPS) analysis indicates that the insertion of Al3+ into TiO2-NTAs facilitates in the reduction of Ti4+ to Ti3+. Electrochemical investigation on the Al3+ insertion process reveals that presence of Cl− ions plays vital role for the effective insertion and de-insertion of Al3+ into/from the TiO2-NTA.
•The pomegranate-like Si@C microspheres were successfully prepared with inexpensive AlSi alloy by surface modification, coating with resin, carbonization, and acid etching processes.•The distinctive ...pomegranate-like Si@C structure stabilizes the porous structure of Si particle and improves the electrochemical property.•As high as 84.98% ICE and 100% Coulombic efficiency were obtained for the sample (Si40@C3), which provide a helpful guide to synthesize the Si/C anode with high ICE and Coulombic efficiency and stable cycling.
Si/C materials are considered as the most promising anodes for the next generation lithium ion batteries. However, the Si/C anodes with high Coulombic efficiency are still a challenge. Here, pomegranate-like Si@C microspheres are successfully prepared with inexpensive AlSi alloy by surface modification, coating with resin, carbonization and acid etching processes. As high as 84.98% initial Coulombic efficiency (ICE) and 100% Coulombic efficiency are obtained for the sample (Si40@C3), and the specific capacity still maintained over 620 mAh g−1 with capacity retention of 70.4% over 250 cycles. The excellent electrochemical performance could be attributed to the distinctive pomegranate-like Si@C structure, which either stabilizes the porous structure of Si particle by inhibiting the volume expansion and pulverization or improves the electrochemical property by the appropriate carbon coating layer. This would provide a helpful guide to synthesize the Si/C anode with high ICE and Coulombic efficiency and stable cycling.
Herein, we prepared a novel nickel iron-layered double hydroxide/reduced graphene oxide/nickel foam (NiFe-LDH/RGO/NF) electrodes by two step electrodeposition processes for oxygen evolution reaction ...(OER). The modification of NF by RGO increased the interface conductivity and electrochemical active surface areas (ECSA) of the electrode. The NiFe-LDH/RGO/NF electrode has shown higher catalytic activity with a lower overpotential of 150 mV at the current density of 10 mA cm−2. The NiFe-LDH/RGO/NF electrode has also shown a small Tafel slope of 35 mV per decade due to the synergy effect between the larger ECSA and the conductive RGO interface. Furthermore, the electrodes exhibits almost 10 h stability under a general current density of 10 mA cm−2.
•The RGO/NF interface is prepared by a simple electrodeposition method.•The RGO/NF interface significantly increased the electrochemical activity of NiFe-LDH.•NiFe-LDH/RGO/NF electrode far outperforms IrO2 catalyst in activity and kinetics.
Exosomal microRNAs (miRNAs) have great potentials as a novel biomarker to predict lung cancer. We applied a miRNA microarray to identify aberrantly expressed serum exosomal miRNAs as candidate ...biomarkers for patients with lung adenocarcinoma (LUAD). Compared with the normal control, 31 exosomal miRNAs were found to be upregulated and 29 exosomal miRNAs were downregulated in the serum of LUAD respectively. Then, 10 dysregulated exosomal miRNAs expression levels in serum were further validated via qRT‐polymerase chain reaction. Notably, exosomal miR‐7977 was highest expressed and miR‐98‐3p was lowest expressed in the patients with LUAD, and exosomal miR‐7977 showed significant correlation with the N stage and TNM stage with patients with LUAD (P < .05). Receiver operating characteristic curve showed that the abundant level of exosomal miR‐7977 may predict LUAD with an area of under the curve (AUC) of 0.787. In comparison with exosomal miR‐7977, exosomal miR‐98‐3p had a smaller area (0.719). The combination of exosomal miR‐7977 and miR‐98‐3p improved the AUC to 0.816. Furthermore, in vitro experiments revealed that inhibition of miR‐7977 enhanced the proliferation, invasion, and inhibited apoptosis in A549 cells, the opposite results were performed by miR‐7977 mimics. In conclusion, exosomal miR‐7977 was identified as a novel biomarker for patients with LUAD and may play as a tumor suppressor in lung cancer.
We were the first time to provides evidence that serum exosomes‐derived miR‐7977 is a novel promising diagnostic biomarker for lung adenocarcinoma and may play a tumor suppressor in lung cancer.
