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•A novel hydrogel was prepared via physical cross-linking of polydopamine and TOCNFs.•The hydrogel showed remarkable pH, NIR response, and long period drug release.•The hydrogel ...presented excellent wound healing and antibacterial abilities.
In this study, we reported a pH/near-infrared (NIR)-responsive hydrogel for on-demand drug delivery and wound healing. Cellulose nanofibrils (TOCNFs) were produced by 2, 2, 6, 6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation method. Polydopamine (PDA) was introduced into TOCNFs network to fabricate a PDA/TOCNFs hydrogel through ion-crosslinking with calcium ion as a crosslinker. Then, tetracycline hydrochloride (TH) which loaded on PDA could be released from the prepared hydrogels in an on-demand fashion under NIR exposure or at lower pH conditions. In addition, the in vivo skin defect experiments illustrated that the resultant composite hydrogel had a synergistic effect on promoting wound healing. Therefore, owing to the unique pH/NIR responsiveness, long time period drug releasing property, antibacterial and mechanical properties, together with their biodegradability and biocompatibility, the prepared PDA/TOCNFs hydrogel is highly promising as a new drug delivery vehicle, offering simple and safe alternatives to the conventional systems based on the petroleum-based polymers.
Interactions between nano/microplastics and suspended sediment (SS) in natural waters are important for the environmental fate of plastic particles. This study investigated the effect of ...heteroaggregation between nano/microplastics and SS on the settling of aggregates. In NaCl solutions (0.05–0.5 M), large SS (100–500 μm in diameter) significantly increased the settling ratio of polystyrene nanoplastics (PSNPs) with an average diameter of 100 nm due to the formation of PSNPs-SS aggregates. The settling ratio of the heteroaggregates increased significantly when the NaCl concentration increased from 50 to 200 mM. This was primarily because higher ionic strength reduced the electrostatic repulsion between large SS and PSNPs, and subsequently increased the heteroaggregation rate. No obvious differences in settling ratios were observed in 200 or 500 mM NaCl solutions because the heteroaggregation entered the diffusion-controlled regime. However, in HA solutions (10–50 mg L−1), the surface adsorption of HA on PSNPs and large SS reduced the heteroaggregation of PSNPs-SS and thus led to the low co-settling ratio due to the steric hindrance according to the DLVO theory. In contrast, polyethylene microplastics (PEMPs) with diameters of 1.0–1.2 mm were found to always float on water surface (up to 8 months), even after addition of 500 mg L−1 small SS (<10 μm in diameter). Clearly, the heteroaggregation of PEMPs and small SS had minor effect on the settling of PEMPs due to the overwhelming boyanccy. These results provided new insight into the fate and distribution of nano/microplastics in aquatic environment, which affect the bioavailability of plastic particles in natural waters.
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•Suspended sediment (SS) promotes polystyrene nanoplastics (PSNPs) settling in NaCl.•NaCl promotes co-settling of PSNPs and large SS in humic acid (HA) solution.•HA has minor effect on heteroaggregation and co-settling of PSNPs and large SS.•Polyethylene microplastics always float on water surface with or without small SS.
We obtain an exact Kerr-like black hole solution by solving the corresponding gravitational field equations in Einstein-bumblebee gravity model where Lorentz symmetry is spontaneously broken once a ...vector field acquires a vacuum expectation value. Results are presented for the purely radial Lorentz symmetry breaking. In order to study the effects of this breaking, we consider the black hole shadow and find that the radial of the unstable spherical orbit on the equatorial plane
r
c
decreases with the Lorentz breaking constant
ℓ
>
0
, and increases with
ℓ
<
0
. These shifts are similar to those of Einstein-aether black hole. The effect of the LV parameter on the black hole shadow is that it accelerates the appearance of shadow distortion, and could be detected by the new generation of gravitational antennas.
Monitoring and predicting tool wear is an important issue in dynamic process control under changing conditions, especially for machining large-sized difficult-to-cut materials used in airplanes. ...Existing tool wear monitoring and prediction methods are mainly based on given cutting conditions over a period of time. This paper presents a novel method for accurately predicting tool wear under varying cutting conditions based on a proposed new meta-learning model which can be easily trained, updated and adapted to new machining tasks of different cutting conditions. Experiments proved a substantial improvement in the accuracy of predicting tool wear compared with existing deep learning methods.
The use of cutting-edge technology has resulted in a significant enhancement in athletic training. Computer vision and motion tracking are very important for enhancing performance, reducing the risk ...of accidents, and training in general. Some computer vision algorithms investigate how a sportsperson moves when competing or practising. It is possible that coaches who continuously evaluate their players’ posture, muscle activation, and joint angles would have a better understanding of biomechanical efficiency. It is possible to generate performance measurements from the real-time surveillance of athletes while competing in sports. Through the use of computer vision, it is possible to identify acts that might be hazardous. Notifications are given to coaches if there is a deviation in the form of an athlete, which enables them to address the situation as soon as possible. The three variables that these sensors monitor are the direction, speed, and acceleration. Athletes can encounter realistic environments thanks to the integration of motion tracking with virtual reality. One may use the feedback loop to increase their spatial awareness and decision-making ability. Augmented reality allows for enhancing an athlete’s eyesight by providing them with real-time data while practising. Last but not least, the use of computer vision and motion tracking is bringing about a significant improvement in the sporting training process. Through collaborative efforts, researchers, athletes, and coaches can accelerate humans' performance to levels that have never been seen before.
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► We optimize printed PEDOT:PSS thin films through thermal and solvent annealing. ► Thermal annealing is ineffective for the improvement of the thin film properties. ► Solvent ...annealing makes the PEDOT:PSS solution more suitable for jetting. ► Conductivity and transmittance of the films can be improved by solvent annealing. ► Subsequent baking after solvent annealing can further improve conductivity.
PEDOT:PSS is a conductive polymer blend which is widely used as a thin functional film in the fabrication of electronic devices. Modification of PEDOT:PSS properties is usually required to enhance their performance which demands further research to gain a complete understanding. This paper is concerned with the optimization of PEDOT:PSS thin films produced by inkjet printing which is deemed as a very promising fabrication technology. Both thermal and solvent annealing were utilized to optimize the ink-jetted PEDOT:PSS thin films. It has been found that thermal annealing is relatively ineffective for the improvement of conductivity and transparency of the thin films. However, solvent annealing is introduced for inkjet printing combined with subsequent thermal annealing has induced a further increase of conductivity in the thin film.
Ecological materials are increasingly being applied in the loess slope protection, and the time-dependency deterioration of materials is an important criterion in evaluating their protective effects. ...Taking polypropylene fiber and guar gum as examples, the protection tests of these two ecological materials were carried out for a typical bare cut-slope on the Loess Plateau in this study. We quantified the erosion deterioration based on the approach of LiDAR, and the deterioration processes of both the ecological materials were then comprehensively evaluated. Results showed that both the materials could generate good protective effects on the test slopes, and the guar gum mixed soil (GGS) was slightly better than polypropylene fiber reinforced soil (PFS) at initial time. However, the two materials deteriorated diversely with the increasing service time. The scouring erosion was mainly observed in PFS, which is different from the surface spalling observed in GGS. The erosion mass of the two slopes also presented different stepwise growth along the slope downward. In addition, the protective advantage of GGS was decreasing and even disappearing over time. Revealed by the dry-wet cycle tests in laboratory, the rapid attenuation of disintegration resistance of PFS and shear strength parameters of GGS were the main reasons leading to the different deterioration of the two materials. The time-dependency deterioration model was furthermore established by combining the average intensity of effective rainfall as well as the disintegration rate and shear strength parameters of slope protection materials. The model indicated that the influences of disintegration rate, cohesion, and internal friction angle enhanced successively on the protective effects of slope protection materials. This study is of great significance for revealing the deterioration mechanism and promoting continuous improvement of slope protection materials.
•Spatio-temporal deterioration processes of slope protection materials were captured by LiDAR-based approach.•Factors are analyzed to reveal the deterioration differences in diverse protection materials.•A time-dependency model for evaluating the deterioration of protection materials is established.
We study the collision of two particles with the different rest masses moving in the equatorial plane of a Kerr–Taub–NUT spacetime and get the center-of-mass (CM) energy for the particles. We find ...that the CM energy depends not only on the rotation parameter, a, but also on the NUT charge of the Kerr–Taub–NUT spacetime, n. Especially, for the extremal Kerr–Taub–NUT spacetime, an unlimited CM energy can be approached if the parameter a is in the range 1,2, which is different from that of the Kerr and Kerr–Newman black holes.
Finishing determines the final dimension and geometric accuracy of parts, and the finishing process directly affects the stiffness and residual stress redistribution of the workpiece, so the ...optimisation of the finishing process plays a very important role in deformation control. At present, existing data-driven methods for deformation control need a large amount of labelled training data, which is always a challenge in the manufacturing area, especially for machining deformation. To address the above issues, this paper presents a meta-reinforcement learning model incorporated by simulation and real data, which is trained in a simulation environment with a piecewise sampling strategy for data collection, and can be updated in a real machining environment through a very small number of real monitoring data. The finishing process optimisation for deformation control can be realised using the proposed approach. Finally, the effectiveness of the proposed method is verified both in simulation environment and actual machining, and better results are obtained compared with other existing methods.
The corrosion resistance of Sn–Pb and several candidate lead free solders were investigated in 3.5
wt.% NaCl solution through potentiodynamic polarisation. Results showed that in NaCl solution lead ...free solders had better corrosion resistance than Sn–Pb solder and the corrosion resistance of lead free solders was similar, but the corrosion resistance of Sn–Ag solder was better than that of Sn–Ag–Cu and Sn–Cu solders. The corrosion products for Sn–Pb solder had a two-layered structure with Sn-rich phases at the outer layer and looser Pb-rich phases at the inner layer. The loose Pb-rich layer was detrimental to the corrosion property. The corrosion product on the surface of all these solders was tin oxide chloride hydroxide.
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