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•A transparent self-healing polyurethane based on disulfide bonds is reported.•The polyurethane has excellent self-healing properties and healing repeatability.•Shape memory effect ...acted as an auxiliary recover force for the closure of scratches.•The dynamic disulfide bonds triggered chain exchange and healed the scratches.
Polymers with self-healing ability have attracted great research efforts recently. A transparent self-healing polyurethane (PU) based on disulfide bonds is reported in this work. The crystalline structures, self-healing properties of the polyurethane were investigated by differential scanning calorimetry (DSC), X-ray diffraction measurements (XRD), dynamic mechanical analysis (DMA), stress relaxation and tensile tests. The as-prepared self-healing polyurethane was transparent due to low crystallinity and exhibited excellent self-healing properties, stretchability and healing repeatability. The healing efficiency and elongation at break at a moderate healing temperature were over 90% and 800%, respectively. Meanwhile, the self-healing polyurethane exhibited an excellent healing repeatability and service reliablility. The self-healing mechanism was analyzed through surface analysis of the scratches and shape memory effect. The system was composed of a polyurethane network, which was responsible for the autonomous crack closure due to its shape memory characteristic, and an intrinsic self-healing component through dynamic disulfide bond exchange. The self-healing polyurethane might have potential applications in the fields of flexible electronics, including artificial skins, soft robotics, etc.
Soft dielectric elastomer actuators (DEAs) exhibit interesting muscle-like behavior for the development of soft robots. However, it is challenging to model these soft actuators due to their material ...nonlinearity, nonlinear electromechanical coupling, and time-dependent viscoelastic behavior. Most recent studies on DEAs focus on issues of mechanics, physics, and material science, while much less importance is given to quantitative characterization of DEAs. In this paper, we present a detailed experimental investigation probing the voltage-induced electromechanical response of a soft DEA that is subjected to cyclic loading and propose a general constitutive modeling approach to characterize the time-dependent response, based on the principles of nonequilibrium thermodynamics. In this paper, some of the key observations are found as follows: 1) Creep exhibits the drift phenomenon, and is dominant during the first three cycles. The creep decreases over time and becomes less dominant after the first few cycles; 2) a significant amount of hysteresis is observed during all cycles and it becomes repeatable after the first few cycles; 3) the peak of the displacement is shifted from the peak of the voltage signal and occurs after it. To account for these viscoelastic phenomena, a constitutive model is developed by employing several dissipative nonequilibrium mechanisms. The quantitative comparisons of the experimental and simulation results demonstrate the effectiveness of the developed model. This modeling approach can be useful for control of a viscoelastic DEA and paves the way to emerging applications of soft robots.
The components of vocational education talents and the relationship between the development of handicraft and vocational education are examined in this study. Next, using the independent samples ...t-test, it examines the general state of vocational school students’ recognition of quality as well as the variations in craftsmanship levels between students with varying majors, genders, grades, and internship experiences. Then, using Pearson’s correlation coefficient method, the relationship between students’ craftsmanship and the theoretical curriculum teachers, practical activities, and other factors at the school was investigated. The multivariate linear regression model was used to analyze the factors that influence the cultivation effect of craftsmanship. The road map for developing craftsmanship in vocational education is finally developed. According to the study, there is a significant positive correlation between all the factors and students’ artisan spirit. The correlation coefficients between the campus environment, theoretical courses taught at the school, teachers, practical activities, personal career planning, and personal artisan literacy are, respectively, 0.55, 0.56, 0.57, 0.99, and 0.53, all of which are greater than 0. This study offers concrete and workable methods for fostering craftsmanship in today’s students, which is crucial for enhancing talent development and advancing the growth of the manufacturing sector.
Herein, we present a new strategy for the synthesis of 2D porous MoP/Mo2N heterojunction nanosheets based on the pyrolysis of 2D PMo12O403−‐melamine (PMo12‐MA) nanosheet precursor from a polyethylene ...glycol (PEG)‐mediated assembly route. The heterostructure nanosheets are ca. 20 nm thick and have plentiful pores (<5 nm). These structure features offer advantages to promote the HER activity, including the favorable water dissociation kinetics around heterojunction as confirmed by theoretical calculations, large accessible surface of 2D nanosheets, and enhanced mass‐transport ability by pores. Consequently, the 2D porous MoP/Mo2N heterojunction nanosheets exhibit excellent HER activity with low overpotentials of 89, 91 and 89 mV to achieve a current density of 10 mA cm−2 in alkaline, neutral and acidic electrolytes, respectively. The HER performance is superior to the commercial Pt/C at a current density >55 mA cm−2 in neutral medium and >190 mA cm−2 in alkaline medium.
2D porous MoP/Mo2N heterojunction nanosheets have been created based on a PEG‐mediated assembly strategy, which exhibit outstanding performance for HER over wide pH ranges even out‐performing the Pt/C benchmark at large current density. A series of tests and DFT calculations shows the synergy of the heterojunctions, pores and 2D nanosheets for promoting the HER performance.
In this study, Polyethyleneimine (PEI) was utilized to modulate the electronegativity of carbon nanotubes (CNTs) through a mild method to promote its electrocatalytic performance for electrosynthesis ...of H
2
O
2
. The characterization results indicate the co-doping of oxygen and nitrogen elements and the CNTs-80 (modification temperature was 80 °C) catalyst exhibited the highest content of nitrogen (4.05%) and O
II
functional groups (73.5%). Accordingly, the GF/CNTs-80/PTFE cathode exhibited the highest H
2
O
2
yield of 116.34 mg L
−1
at pH 7, suggesting that the introduction of nitrogen and oxygen-containing functional groups (carboxyl and ether groups) effectively enhances its 2e
−
ORR performance. Furthermore, a more positive surface potential and reduced diffusion resistance were conducive to the electrochemical generation of H
2
O
2
. This research contributes to the understanding of surface potential modulation and highlights the potential of PEI-modified CNTs cathodes for efficient H
2
O
2
electrogeneration.
Graphical abstract
Highlights
PEI-modified CNTs catalysts for electrochemical production of H
2
O
2
were synthesized.
The introduction of O-containing functional groups enhanced the catalytic activity of the composite cathode.
The positive surface potential enhanced the catalytic activity of the composite cathode.
The GF/CNTs-80/PTFE composite cathode achieved the highest H
2
O
2
yield of 116.34 mg·L
−1
at pH 7.
► Electrochemical remediation is a promising technology for remediation of soils. ► Enhancement techniques are required to enhance the technology. ► A comprehensive review of these enhancement ...techniques is given. ► Underlying principles of each enhancement technique are given in detail. ► A comprehensive and updated list of references is also provided.
Electrochemical remediation is a promising remediation technology for soils contaminated with inorganic, organic, and mixed contaminants. A direct-current electric field is imposed on the contaminated soil to extract the contaminants by the combined mechanisms of electroosmosis, electromigration, and/or electrophoresis. The technology is particularly effective in fine-grained soils of low hydraulic conductivity and large specific surface area. However, the effectiveness of the technology may be diminished by sorption of contaminants on soil particle surfaces and various effects induced by the hydrogen ions and hydroxide ions generated at the electrodes. Various enhancement techniques have been developed to tackle these diminishing effects. A comprehensive review of these techniques is given in this paper with a view to providing useful information to researchers and practitioners in this field.
Developing the efficient and low-cost electrocatalysts for overall water splitting is of the great importance for the production of H2. The popular bi-functional catalysts usually shown good activity ...for one half reaction at expense of the activity for another half-reaction, thus given a moderate performance for overall water splitting. In this paper, we have reported on integrating the active OER (Ni3N) and HER (NiMoN) components as Ni3N-NiMoN heterostructures for the effective overall water splitting. The heterostructures were constructed by the controllable nitridation of the Ni-Mo-O precursor anchored on carbon cloth (CC) under NH3 atmosphere. The micro-structures of the catalyst could be tuned by regulating the surface properties of CC and the calcination temperature. Under optimized condition, the Ni3N-NiMoN catalysts exhibited good catalytic activity for both OER and HER in alkaline electrolyte. The catalysts can achieve a current density of 10mAcm−2 at an overpotential of 31mV for HER, being close to Pt catalyst. Also, it only requiring an overpotential of 277mV to reach current density of 10mAcm−2 for OER. Moreover, the cell assembled by the identical Ni3N-NiMoN as both the cathode and anode needs only a cell voltage of 1.54V to achieve current density of 10mAcm−2. The superior performance of Ni3N-NiMoN heterostructures can be ascribed to the following points: 1) the simultaneous presence of active OER and HER components and the promoted action each other in the heterostructures, and 2) the exposure of the abundant active sites in the sheet-like structure assembled by the nanoparticles.
The OER-active Ni3N and HER-active NiMoN have been integrated as Ni3N-NiMoN heterostructures anchored on carbon cloth for the high-effective overall water splitting. The catalysts can achieve a current density of 10mAcm−2 at an overpotential of 31mV for HER and an overpotential of 277mV for OER. The cell assembled by Ni3N-NiMoN heterostructures as both the cathode and anode only needs a cell voltage of 1.54V to achieve 10mAcm−2 for overall water splitting. Display omitted
•The active OER and HER components are integrated as Ni3N-NiMoN heterostructures.•The heterostructures show good performance for both HER and OER.•The heterostructures exhibit superior performance for overall water splitting.•The origin of superior performance of the heterostructures is elucidated.
Considering the high in‐stent restenosis and stent thrombosis rate of stent implantation with balloon angioplasty, self‐expandable biodegradable vascular stent was prepared by 3D printing from shape ...memory polylactide (PLA). The printed stent could be compressed into a temporary shape with thinner diameter easy for implantation. The compressed stent had excellent shape fixity and could maintain its temporary shape at room temperature for storage. However, it could self‐expand to its initial shape after being implanted due to the heat triggering of shape memory polylactide. The longitudinal contraction or radical expansion under its working condition was carried out by finite element analysis. The combination of self‐expansion of biodegradable shape memory PLA with personalized designing of 3D printing provides the vascular stent a future solution for cardiovascular disease treatment.
Long noncoding RNAs (lncRNAs) are an important class of functional regulators involved in human cancers development, including gastric cancer (GC). Studying aberrantly expressed lncRNAs may provide ...us with new insights into the occurrence and development of gastric cancer by acting as oncogenes or tumor suppressors. In this study, we aim to examine the expression pattern of lncRNA HAGLROS in GC and its clinical significance as well as its biological role in tumor progression.
Bioinformatics analysis and qRT-PCR were performed to detect the relative expression of HAGLROS in GC tissues and cell lines. Gain or loss of function approaches were used to investigate the biological functions of HAGLROS. The effect of HAGLROS on proliferation was evaluated by MTT, colony formation assay and nude mouse xenograft model. Wound healing and Transwell assays were used to study the invasion and migration of GC cells. FISH, RIP, RNA-seq, Luciferase report assays, RNA pulldown and Western blot were fulfilled to measure molecular mechanisms. Results are shown as means ± S.D. and differences were tested for significance using Student's t-test (two-tailed).
We screened out HAGLROS, whose expression was significantly increased and correlated with outcomes of GC patients by publicly available lncRNAs expression profiling and integrating analyses. Exogenous down-regulation of HAGLROS expression significantly suppressed the cell proliferation, invasion and migration. Mechanistic investigations showed that HAGLROS was a direct target of transcriptional factor STAT3. Moreover, HAGLROS knockdown decreased mTOR expression and increased autophagy-related genes ATG9A and ATG9B expression. Further investigation showed that HAGLROS regulated mTOR signals in two manners. In the one hand, HAGLROS competitively sponged miR-100-5p to increase mTOR expression by antagonizing miR-100-5p-mediated mTOR mRNA inhibition. On the other hand, HAGLROS interacted with mTORC1 components to activate mTORC1 signaling pathway which was known to be an important negative signal of autophagy. Here activation of mTORC1 signaling pathway by HAGLROS inhibited autophagy, thereby promoted excessive proliferation and maintained the malignant phenotype of GC cells.
The present study demonstrates that HAGLROS overexpression contributes to GC development and poor prognosis and will be a target for GC therapy and further develop as a potential prognostic biomarker.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Building a complex structure such as the cell wall, with many individual parts that need to be assembled correctly from distinct sources within the cell, is a well-orchestrated process. Additional ...complexity is required to mediate dynamic responses to environmental and developmental cues. Enzymes, sugars, and other cell wall components are constantly and actively transported to and from the plasma membrane during diffuse growth. Cell wall components are transported in vesicles on cytoskeletal tracks composed of microtubules and actin filaments. Many of these components, and additional proteins, vesicles, and lipids are trafficked to and from the cell plate during cytokinesis. In this review, we first discuss how the cytoskeleton is initially organized to add new cell wall material or to build a new cell wall, focusing on similarities during these processes. Next, we discuss how polysaccharides and enzymes that build the cell wall are trafficked to the correct location by motor proteins and through other interactions with the cytoskeleton. Finally, we discuss some of the special features of newly formed cell walls generated during cytokinesis.
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