All-weather-available down carbon fiber hydrogel with enhanced mechanical properties for simultaneous efficient clean water generation and dye adsorption from dye wastewater.

Solar-driven photothermal conversion can produce clean water from dye wastewater while leaving the dye in the evaporation medium. Herein, a biomass-based composite hydrogel via down-fiber carbon (DFC) aerogel modified with chitosan-polyvinyl alcohol (CS-PVA) hydrogel was designed to address the aforementioned problem. The CS-PVA@DFC hydrogel integrated the capacity of simultaneous clean water production/dye adsorption during the day and continuous dye adsorption during the night. Furthermore, the modification of the CS-PVA hydrogel endowed the composite hydrogel with enhanced compression stress of 190.07 kPa (76.03 times that of DFC aerogel of 2.50 kPa) and impressive resilient recovery. Moreover, the CS-PVA@DFC hydrogel possessed solar light absorption of 99.56 % and strengthened water replenishment capacity due to the high porosity and CS-PVA hydrophilic network structure. The CS-PVA@DFC hydrogel demonstrated a stable, high evaporation rate of 2.34 kg·m-2·h-1 and simultaneous dye adsorption capacity of 70.39 % for treating methyl orange dye solution within 5 h. Additionally, the 24-h outdoor test showed that the CS-PVA@DFC hydrogel possessed excellent clean water production capacity during the daytime (reaching 4.17 kg·m-2·h-1 at 1:00p.m.) and continuous satisfactory dye adsorption capacity all day (89.68 %). These findings will inspire researchers seeking opportunities to improve the mechanical properties of aerogel and its application for treating wastewater, especially wastewater with harmful dyes.

Performance and Interfacial Microstructure of Al/Steel Joints Welded by Resistance Element Welding.

In this study, an upper sheet of an A6061 aluminum alloy and a lower sheet of Q235 steel were welded by resistance element welding with a steel rivet. The temperature field during welding was calculated using ABAQUS numerical simulation software, and the interfacial microstructure was observed. A nugget was formed between the rivet shank and the lower sheet. With increases in welding current and welding time, the tensile shear load of the joint increased first and then decreased slightly. When the welding current was 14 kA and the welding time was 300 ms, the tensile shear load of the joint reached a maximum of 7.93 kN. The smaller the distance from the position to the lower sheet along the interface between the rivet shank and upper sheet, the longer the high-temperature duration and the higher the peak temperature during welding. At the junction of the rivet shank, upper sheet, and lower sheet in the joint, the high-temperature duration was the longest, at about 392 ms, and the peak temperature was the highest, at about 1237 °C. The results show that the smaller the distance from the position to the lower sheet along the interface between the rivet shank and the upper sheet in the joint, the thicker the reaction layer generated there, and that the thickness of the reaction layer was about 2.0 µm at the junction of the rivet shank, upper sheet, and lower sheet in the joint.

Natural down fiber-reinforced and polypyrrole-modified silk fibroin composite aerogel for efficient solar steam generation toward seawater desalination and wastewater treatment.

Poor mechanical properties and low photothermal efficiency of silk fibroin (SF)-based aerogels are current challenges that need to be addressed. Herein, SF composite aerogel was developed to enhance the mechanical properties through physical interpenetration of natural down fiber (Df) and hydrogen bonds formed among SF, Df, and polypyrrole (PPy) and to improve the evaporation performance via in-situ polymerization of PPy. The resultant Df/PPy@SF aerogel showed significant improvement of compressive stress (194.29 kPa), which was 6.96 times than that of SF aerogel (27.91 kPa), and also good compression resiliency. Furthermore, due to uniform distribution of PPy and high porosity of 95.27 %, Df/PPy@SF aerogel possessed high light absorbance of 99.87 % and low thermal conductivity (0.043 W·m-1·K-1). Thus, the Df/PPy@SF aerogel evaporator demonstrated high evaporation rates of 2.12 kg·m-2·h-1 for 3.5 wt% saline water, 2.04-2.15 kg·m-2·h-1 for various dye water, and 2.10 kg·m-2·h-1 for actual dye wastewater. Moreover, the developed aerogel exhibited evaporation stability and outstanding salt-resistance when treating seawater due to continuous water supply by superhydrophilic porous aerogel. Therefore, these findings demonstrate the excellent performance of Df/PPy@SF aerogel and will inspire further research on developing natural fiber-reinforced aerogels for use in the fields of solar water evaporation, energy, and other related applications.

The Mg doping ZIF-8 loaded with Icariin and its antibacterial and osteogenic performances.

In this study, ICA@Mg-ZIF-8 was synthesized by Mg doping in ZIF-8 and loaded with icariin (ICA). The morphologies and phases were observed and analyzed by SEM, XRD, and the release behaviors of Mg, Zn ions and ICA were tested. Its antibacterial and mineralization performances were evaluated. The results showed that ICA@Mg-ZIF-8 has the same morphology and crystal structure as ZIF-8. ICA@Mg-ZIF-8 showed enhanced antibacterial activity against Escherichia coli and Staphylococcus aureus, and the antibacterial rate was increased to 87.7 % and 64.0 %, respectively. The results of in vitro mineralization showed that ICA@Mg-ZIF-8 presented better osteogenic performance promoting the uniform deposition of more calcium and phosphorus in simulated body fluids compared to ZIF-8.

Dendrite-Free Lithium Anodes Enabled by a Commonly Used Copper Antirusting Agent.

Li metal is considered the most promising anode for high energy density secondary batteries due to its high theoretical capacity and low redox potential. However, lithium is prone to form dendrites which will not only cause internal short-circuits but also bring accumulation of "dead Li" and result in fast capacity decay, thus its large-scale application is challenging. In this work, we demonstrate that the commonly used metal corrosion inhibitor, benzotriazole (BTA), can be used to modify the Cu foil surface and guide homogeneous Li+ plating/stripping due to the lithiophilic nature of the N atom in the BTA molecule. As a result, the lithium plated on the BTA modified Cu (BTA-Cu) substrate is free of dendrites, and a Coulombic efficiency (CE) as high as 99.0% was achieved for Li+ plating/stripping on the BTA-Cu substrate at a current density of 1 mA/cm2. Furthermore, the BTA-Cu foil can be used as an anode to assemble an anode-free cell (BTA-Cu∥LFP), and ∼73.3% of the initial capacity can be obtained after 50 cycles. Last but not the least, a BTA-Cu@Li electrode prepared by plating of Li+ on the BTA-Cu substrate can serve as a stable Li anode in a BTA-Cu@Li∥LFP cell and display an average cycled CE of 98.5% at a depth of discharge (DOD) of 33%. This simple method of Li+ plating/stripping behavior regulation could inspire researchers on the development of highly stable lithium metal anodes for high energy density batteries.

Needle-disk Electrospinning: Mechanism Elucidation, Parameter Optimization and Productivity Improvement.

BACKGROUND: Nanofiber's productivity plagues nanofibrous membranes' applications in many areas. Herein, we present the needle-disk electrospinning to improve throughput. In this method, multiple high-curvature mentals are used as the spinning electrode. METHODS: Three aspects were investigated: 1) mechanism elucidation of the needle-disk electrospinning; 2) parameter optimization of the needle-disk electrospinning; 3) productivity improvement of the needle-disk electrospinning. RESULTS: Results show that high-curvature electrode evokes high electric field intensity, making lower voltage supply in spinning process. The needle number, needle length and needle curvature synergistically affect the spinning process and nanofiber morphology. Additionally, higher disk rotation velocity and higher voltage supply can also result in higher nanofiber's productivity. CONCLUSION: Compared with previous patents related to this topic, the needle-disk electrospinning is featured with the merits of high throughput, low voltage supply, controllable spinning process and nanofiber morphology, benefiting the nanofiber practical industrial employment and further applications of nanofiber-based materials.

MicroRNA-222-3p participates in the development of oral squamous cell carcinoma by targeting CDKN1B.

OBJECTIVE: The aim of this study was to explore the potential role and regulatory mechanism of microRNA (miR)-222-3p in oral squamous cell carcinoma (OSCC). METHODS: The expression level and prognostic significance of miR-222-3p was detected in OSCC tissues. CCK-8, transwell, and flow cytometry assays were used to explore the effect of miR-222-3p on cell proliferation, migration, invasion, and apoptosis. The influence of miR-222-3p on cyclin-dependent kinase inhibitor 1B (CDKN1B) expression was evaluated by luciferase assays, real-time polymerase chain reaction, and Western blot. RESULTS: We found that miR-222-3p was overexpressed in OSCC tissues, comparing with normal tissues. Kaplan-Meier curves showed that OSCC patients with high expression of miR-222-3p (P = .003) showed worse overall survival than those patients with low expression of miR-222-3p. Multivariate analysis showed that miR-222-3p (P = .037) expression was an independent prognostic factor of OSCC patients. miR-222-3p promoted cell proliferation, migration and invasion and induced the apoptosis of SCC-15 and Tca-83 cells. Furthermore, luciferase reporter assays indicated that CDKN1B is targeted by miR-222-3p in OSCC cells. Overexpression of CDKN1B inhibited OSCC cell proliferation, migration, and invasion and promoted cell apoptosis rate. CONCLUSIONS: miR-222-3p affects OSCC cell proliferation, migration, invasion, and apoptosis through targeting CDKN1B, and may be a potential prognostic biomarker for OSCC patients.

Efficient Oil/Water Separation Membrane Derived from Super-Flexible and Superhydrophilic Core-Shell Organic/Inorganic Nanofibrous Architectures.

To address the worldwide oil and water separation issue, a novel approach was inspired by natural phenomena to synthesize superhydrophilic and underwater superoleophobic organic/inorganic nanofibrous membranes via a scale up fabrication approach. The synthesized membranes possess a delicate organic core of PVDF-HFP and an inorganic shell of a CuO nanosheet structure, which endows super-flexible properties owing to the merits of PVDF-HFP backbones, and superhydrophilic functions contributed by the extremely rough surface of a CuO nanosheet anchored on flexible PVDF-HFP. Such an organic core and inorganic shell architecture not only functionalizes membrane performance in terms of antifouling, high flux, and low energy consumption, but also extends the lifespan by enhancing its mechanical strength and alkaline resistance to broaden its applicability. The resultant membrane exhibits good oil/water separation efficiency higher than 99.7%, as well as excellent anti-fouling properties for various oil/water mixtures. Considering the intrinsic structural innovation and its integrated advantages, this core-shell nanofibrous membrane is believed to be promising for oil/water separation, and this facile approach is also easy for scaled up manufacturing of functional organic/inorganic nanofibrous membranes with insightful benefits for industrial wastewater treatment, sensors, energy production, and many other related areas.

Self-Assembled Monolayer Enables Slurry-Coating of Li Anode.

Li metal has long been considered as the ultimate anodic material for high-energy-density batteries. Protection of Li metal in electrochemical cycling and in the manufacturing environment is critical for practical applications. Here, we present the passivation of the Li metal-carbon nanotube (CNT) composite with molecular self-assembly of a long-chain aliphatic phosphonic acid. The dynamics of the self-assembly process is investigated with sum-frequency generation spectroscopy (SFG). The aliphatic phosphonic acid molecules self-assemble on the Li metal surface via the lithium phosphate bonding, while the well-aligned long chains of the molecules help to prevent corrosion of lithium by oxygen and water in the air. As a result, the self-assembled monolayer (SAM) passivated Li-CNT composite displays excellent stability in dry or even humid air, and could be slurry-coated with organic solvents. The resulting slurry-coated Li anode exhibits a high Coulombic efficiency of 98.8% under a 33% depth of discharge (DOD) at a 1C rate in full battery cycling. The concept of molecular self-assembly on Li metal and the stability of the resulting SAM layer open vast possibilities of designed reagents for surface passivation of Li, which may eventually pave the way for practical application of Li metal in secondary batteries.

Recent Progress of the Needleless Electrospinning for High Throughput of Nanofibers.

BACKGROUND: In recent decades, nanofiber-based materials have been considered as one of the top interesting fundamental materials for academic studies and practical applications. However, the electrospinning, as the most popular method for manufacturing nanofibers, is plagued by its low productivity. The first patent about electrospinning was emerged in 1934 and the needleless electrospinning is regarded as one of the most promising methods to realize the high throughput of nanofibers. METHODS: This review compares the recent needleless spinning technologies from limited liquid surfaces to free liquid surfaces for improvement of nanofiber throughput. The aim of this review is to reveal the merits and drawbacks of recent methods in practical employment. The view focuses also on the future concern of the needleless electrospinning. RESULTS: The current needleless electrospinning is featured with the properties: 1) high throughput; 2) lower voltage supply for the stable spinning process; 3) narrow fiber diameter distribution, followed by the drawbacks of poor long-term spinning process and limitation of a good bonding of low voltage supply. CONCLUSION: This review provides an update on needleless electrospinning methods for high throughput of nanofibers for industrial applications.

Nanostructured Bimetallic Iron Molybdenum Nitride as a Non-Precious Cathode Catalyst for Li­O2 Batteries.

Herein we report the facile fabrication and electrocatalytic activity of nanostructured bimetallic iron molybdenum nitride (Fe3Mo3N), which was prepared by an ammonolysis process directly towards the solid state mixture of Mo precursor and Fe precursor. The prepared nanostructured Fe3Mo3N presented remarkable electrocatalytic activities towards both oxygen reduction reaction and oxygen evolution reaction in nonaqueous phase, due to the modulation of electronic configuration of catalyst by Fe element and porous structure. Then, lithium-O2 batteries with nanostructured Fe3Mo3N as cathode catalysts were assembled, which show alleviated polarization and enhanced cyclability.