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Leaf senescence is a highly complex and coordinated process that involves ordered and continuous changes in the external environment and endogenous signaling pathways. Alternative oxidase (AOX), a key enzyme in the respiratory pathway, is involved in the regulation of plant senescence. Salicylic acid (SA) and reactive oxygen species (ROS), two significant inducers of plant senescence, also play an important role in plant senescence, but the relationship between AOX, ROS and SA is unclear. In this study, an RNA interference and overexpression transgenic strain of AOX was constructed using tomato as experimental material. It was found that AOX was able to reduce the accumulation of ROS during dark-induced plant senescence, and that AOX suppressed the synthetic gene SALICYLIC ACID INDUCTION DEFICIENT 2 (SID2) in the SA signaling pathway and salicylate receptor gene NONEXPRESSER OF PR GENES 1 (NPR1), decreasing endogenous SA content and blunting SA perception in plant leaf cells, thereby inhibiting SA-induced leaf senescence. Also, spraying the plants with ROS and ROS scavengers revealed that the synthesis of endogenous SA was affected and that AOX eliminated excess ROS, which in turn affected the SA content and delayed plant senescence. Based on these results, we propose that AOX mediates SA synthesis by balancing ROS content and plays a key role in leaf senescence.

Polygala tenuifolia is extensively used to treat amnesia in traditional Chinese medicine, and pharmacological studies have reported the beneficial effects of P. tenuifolia on intelligence and cognition. In the present study, the crude polysaccharide alkali-extracted from P. tenuifolia roots (PTB) inhibited lipopolysaccharide-induced microglia/astrocyte activation and significantly improved the learning and memory ability of Alzheimer's disease (AD) rats. To determine its bioactive components, a heteropolysaccharide (PTBP-1-3) was isolated from PTB. Structural analysis showed that PTBP-1-3 was composed of α-L-Araf-(1→, →3)-α-L-Araf-(1→, →5)-α-L-Araf-(1→, →3,5)-α-L-Araf-(1→, →2,5)-α-L-Araf-(1→, β-D-Xylp-(1→, →2,3,4)-β-D-Xylp-(1→, α-L-Rhap-(1→, β-D-Galp-(1→, →4)-α-D-Galp-(1→, →6)-α-D-Galp-(1→, →6)-α-D-Glcp-(1→, →3,6)-α-D-Glcp-(1→, →6)-α-D-Manp-(1→, and →2,4)-β-D-Manp-(1→ residues. PTBP-1-3 decreased the production of NO, TNF-α, and IL-1β in lipopolysaccharide-activated BV2 microglia cells in a manner similar to that of minocycline. In conclusion, PTBP-1-3 exhibited a potent inhibitory effect on neuroinflammation, and could be one of the bioactive ingredients in PTB for anti-neuroinflammation. PTB and PTBP-1-3 may be potential therapeutic agents for the treatment of AD.

This work investigated the chemical and electrochemical mechanisms of localised corrosion triggered by CaS·xMgO·yAl2O3·TiN complex inclusions in high strength low alloy steel (HSLAS) under a simulated marine environment. Special focus was given to the role of the TiN portion of the inclusion on the initiation and growth of the corrosion pits. The thermodynamic process of pitting initiation was investigated by Gibbs free energy, Pourbaix diagram and first principle calculation. Localised corrosion is mainly induced by inclusions and triggered by dissolution of adjacent distorted matrix. Chemical dissolution of CaS portion in CaS·xMgO·yAl2O3·TiN complex inclusion creates an acidic aggressive environment that accelerates the further dissolution of inclusion and matrix. Galvanic coupling effect between TiN inclusion and matrix is directly verified. TiN covered with a TiO2 film acts as the cathodic phase in galvanic corrosion, although it has a lower Volta potential than the matrix. This is an unusual correlation with the scanning Kelvin probe force microscopy result, which has been explained for this special system.

A novel self-healing coating with photothermal and pH dual-responsive properties has been designed to protect carbon steel against corrosion by loading the stimuli-responsive microcapsules into a shape memory epoxy coating. The sandwich-like microcapsules were based on reduced graphene oxide/mesoporous silica (rGO@MS) assembled with a pH-responsive poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) layer, and were loaded with benzotriazole (BTA) inhibitors (abbreviated as rGO@MS-P-BTA). Under near-infrared (NIR) light irradiation, the prominent photothermal effect of rGO could not only elevate the coating temperature to activate the shape memory effect and close the coating scratch, but also facilitate the release of corrosion inhibitors to suppress the corrosion activity. Moreover, the PDMAEMA as a pH-driven “gatekeeper” realized the controlled release of BTA from microcapsules at acid conditions. The surface morphology analysis, electrochemical impedance spectroscopy (EIS), and scanning electrochemical microscopy (SECM) were performed to evaluate the self-healing performance of the composite coatings. The results showed that the combination of NIR light and pH-responsive self-healing effects endowed the coating with short healing time and prominent healing efficiency.

In this study, a new self-healing strategy that can simultaneously recover the corrosion resistance and the adhesion strength of coatings was introduced. The coating was based on a shape memory epoxy resin containing ethylene vinyl acetate (EVA) microspheres loaded with Ce(NO3)3 inhibitors, and was cured at a relatively high temperature to facilitate the fusion of adjacent microspheres for a strengthened self-healing effect. The electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) results demonstrated that the shape memory effect of epoxy matrix, the filling of molten EVA microspheres as well as the release of Ce(NO3)3 inhibitors contributed synergistically to suppress the corrosion reaction at the coating damage. After healing, the low frequency impedance modulus of the coatings containing Ce(NO3)3-EVA microspheres was three orders of magnitude higher than that of the blank epoxy coating. The adhesion strength of the coatings containing Ce(NO3)3-EVA microspheres on the metal substrate was also largely repaired thanks to the strong bonding effect of the EVA microspheres.

Mn2+ doped LuAG phosphors with different contents of Si4+ ions were synthesized via the solid-state reaction method and the effects of Si4+ doping on the crystal structure and luminescence properties of phosphors were studied. XRD patterns of all phosphors exhibit a pure phase but with different extents of deviations. Owing to the 4T1→6A1 transition of Mn2+, the LuAG:Mn2+,Si4+ phosphors exhibit a broad emission band with an emission peak at 582 nm. Moreover, the introduction of Si4+ not only improves the emission intensity but also induces a red-shift with the emission peak from 582 to 612 nm and the spectra broadening with the full width at half maximum value from 64 to 74 nm, which results from the decrease of bond length between O2− anions and Mn2+ cations and the re-absorption of Mn2+-Mn2+ pairs. Suitable content of Si4+ replacement can weaken thermal quenching of Mn2+. Thus, via regulating the content of Si, the Mn2+, Si4+ co-doped LuAG phosphor with low correlated color temperature is a candidate for warm wLEDs.

In this paper, Ba0.75Al11O17.25 was selected as the host for the Eu2+ and Mn2+ co-dopants due to the Reidinger defects in its lattice. Upon the 365 nm excitation, the phosphors presented the cyan to green tunable emission by changing the doping concentration of Mn2+. Moreover, this phosphor possesses zero-thermal quenching up to 448 K due to the interaction between the traps and Eu2+/Mn2+. The completely densified ceramic guaranteed the high optical transmittance (∼72 % at 516 nm) and thermal conductivity (4.3 W·m−1·K−1 at room temperature). When combined with a 6 W commercial 365 nm emitting LED chip, the temperature of the ceramic eventually stabilized at 428 K and the luminous efficacy of the LED device was almost not influenced by the thermal quenching effect. This work may open a way for exploring new phosphor conversion materials for HP/HB PC solid state lighting.

A reliable yellow phosphor converter that can be efficiently excited by a 405 nm bluish violet laser is in high demand for laser illumination applications. A NaAlSiO4:Eu2+ phosphor with a quantum efficiency reaching 92% was obtained using LTA zeolite as the raw material. NaAlSiO4:Eu2+ ceramics with suitable porosities for laser illumination were prepared from the phosphor powders via spark plasma sintering. The ceramics lost only 2% of the quantum efficiency compared to the powders, maintained good thermal quenching properties (30% drop at 150 °C), and showed good thermal conductivity (2.02 W‧m−1‧K−1). The NaAlSiO4:Eu2+ ceramic with 405 nm bluish violet lasers, with the increase in laser power density to 9.15 W/mm2, exhibited an increasing luminous flux (23.83–70.26 lm) and maintained a stable luminous efficacy (47.7–46.8 lm/W), and the temperature distribution of the ceramic remained uniform and stable under long-time laser irradiation. This indicates that the nepheline-phase NaAlSiO4:Eu2+ ceramic is a promising material for laser illumination.

Production of reactive oxygen species (ROS) via the activity of respiratory burst oxidase homologs (RBOHs) plays a vital role in multiple layers of the plant immune system, including pathogen-associated molecular pattern-triggered immunity (PTI), damage-associated molecular pattern-triggered immunity (DTI), effector-triggered immunity (ETI), and systemic acquired resistance (SAR). It is generally established that RBOHD is activated by different receptor-like cytoplasmic kinases (RLCKs) in response to various immune elicitors. In this study, we showed that RPM1-INDUCED PROTEIN KINASE (RIPK), an RLCK VII subfamily member, contributes to ROS production in multiple layers of plant immune system. The ripk mutants showed reduced ROS production in response to treatment with all examined immune elicitors that trigger PTI, DTI, ETI, and SAR. We found that RIPK can directly phosphorylate the N-terminal region of RBOHD in vitro, and the levels of phosphorylated S343/S347 residues of RBOHD are sigfniciantly lower in ripk mutants compared with the wild type upon treatment with all tested immune elicitors. We further demonstrated that phosphorylation of RIPK is required for its function in regulating RBOHD-mediated ROS production. Similar to rbohd, ripk mutants showed reduced stomatal closure and impaired SAR, and were susceptible to the necrotrophic bacterium Pectobacterium carotovorum. Collectively, our results indicate that RIPK regulates broad-spectrum RBOHD-mediated ROS signaling during PTI, DTI, ETI, and SAR, leading to subsequent RBOHD-dependent immune responses.

Graph neural networks (GNNs) apply deep learning techniques to graph-structured data and have achieved promising performance in graph representation learning. However, existing GNNs rely heavily on labeled data or well-designed negative samples. To address these issues, we propose a new self-supervised graph representation method: deep graph bootstrapping (DGB). DGB consists of two neural networks: online and target networks, and the input of them are different augmented views of the initial graph. The online network is trained to predict the target network while the target network is updated with a slow-moving average of the online network, which means the online and target networks can learn from each other. As a result, the proposed DGB can learn graph representation without negative examples in an unsupervised manner. In addition, we summarize three kinds of augmentation methods for graph-structured data and apply them to the DGB. Experiments on the benchmark datasets show the DGB performs better than the current state-of-the-art methods and how the augmentation methods affect the performances.

Developing an effective and durable antibacterial surface is important for surgical tools and biomedical implants. In this work, a zwitterionic copolymer containing catechol groups as biomimetic anchoring segments was coated onto 316 L stainless steel via drop-casting. Energy-dispersive X-ray spectroscopy (EDS) and water contact angle (WCA) measurements indicated that the coatings made of the copolymers containing zwitterionic and dopamine segments at the molar ratios of 8:2 and 6:4 exhibited stronger stability and mechanical durability than the one at 9:1 after inducing tape-peeling and ultrasonication damage. The mechanically durable nanocoatings exhibited excellent antibacterial performance against Staphylococcus aureus and Escherichia coli in a period of 3 days. The nanocoatings with zwitterionic and dopamine segments at the molar ratio of 8:2 were further evaluated and demonstrated durable antibacterial performance after tape-peeling and ultrasonication treatments.

The thermal dispersion power depends on thermal conductivity and thickness of the thermal dispersion material that is a critical component of modern electronic devices due to the demands of high operating power in a miniaturized space. Films made of assembled graphene flakes have been becoming an emerging thermal dispersion material owing to their high thermal conductivity and tunable thickness up to millimeters, which outperform that of artificial graphite films made from polyimide. But the thermal conductivity typically decreases with the increase of film thickness. In our work, by pre-reducing the graphene oxide with Vitamin C and sequentially annealing the stacking films at 2950 °C, a 80 μm-thick graphene film (GF) with an in-plane thermal conductivity of above 1600 W/(m·K) is achieved. Detailed characterizations indicate that, the addition of Vitamin C is beneficial to the assembly ordering of graphene oxide platelets and the defect healing during the thermal annealing, which both contribute to the excellent thermal conductivity of the films. Our work provides an industrially scalable strategy towards high performance heat dissipation films for future electronic devices.

Pt-transition metal alloys are frequently used to improve the catalytic activity for methanol oxidation reaction. However, the severe dealloying strongly limits the applications of Pt-based alloy in fuel cells. Recently, Pt-rare earth metal alloys are considered to be the promising catalysts for electrocatalytic application in fuel cells. Metal oxide as the co-catalytic component of composite catalyst, is also applied to regulate the electronic structure and strengthen resistance to CO poisoning. In this work, we utilized hydrogen reduction method to prepare PtGd/Gd2O3 composite catalyst. X-ray diffraction result illustrates that both Gd2O3 and PtGd alloy co-exist in PtGd/Gd2O3 material. X-ray photoelectron spectroscopy data confirms that the main valence states of Pt and Gd are metal form in the PtGd/Gd2O3 catalyst and emerges obvious transfer of element binding energy. Transmission electron microscopy data presents that composite PtGd/Gd2O3 particles are uniformly dispersed on the carbon power with a typical core-shell structure. And upon the increase of Gd precursor in reduction process, the metal oxide layer becomes more thicker for PtGd/Gd2O3 composite material. Because of the synergistic contributions given by the Pt–Gd bimetals and alloy-metal oxide between PtGd alloy and Gd2O3 oxide, the PtGd/Gd2O3 composite catalysts exhibit superior catalytic performance toward methanol oxidation reaction. Specifically, the mass activity of Pt1Gd1/Gd2O3 is about 1.9 times that of commercial Pt/C; besides this, the optimal specific activity of Pt1Gd2/Gd2O3 is almost 4 times that of commercial Pt/C. More importantly, the Pt1Gd1/Gd2O3 emerged a 20.9% degradation after 8000 cycles test, while commercial Pt/C showed a 61.7% degradation. And this work provides an important insight for rare earth elements investigation on the electrocatalysis application in fuel cells.

Siamese networks have achieved great success in object tracking due to the balance of precision and speed. However, Siamese trackers usually utilize the local feature of the last layer, which may degrade tracking performance in some difficult scenarios. In this paper, we propose a novel Channel and Spatial Attention-guided Residual learning framework for Tracking, referred to as CSART, which can improve feature representation of Siamese networks by exploiting self-attention mechanism to capture powerful contextual information. Specifically, to be efficient and seamless integration, different kinds of self-attention are appended on the template and search branches of Siamese networks respectively, that model global semantic inter-dependencies in channel and spatial dimensions. To avoid representation degradation, we consider to adaptively aggregate basic feature and its attention-weighted features with residual learning. Furthermore, a joint loss consisting of classic logistic loss as well as focal softmax loss is designed to emphasize difficult samples and guide the learning process of the whole model. Benefiting from the above scheme, CSART alleviates the over-fitting problem to some extent and enhances the discriminability. Extensive experiments on six popular tracking datasets indicate that the proposed tracker achieves better performance with a speed of 65 fps than other state-of-the-art trackers.