Dynamic Covalent Bonded Gradient Structured Actuators with Mechanical Robustness and Self-Healing Ability.

Flexible actuators with excellent adaptability and interaction safety have a wide range of application prospects in many fields. However, current flexible actuators have problems such as fragility and poor actuating ability. Here, inspired by the features of nacre structure, a gradient structured flexible actuator is proposed with mechanical robustness and self-healing ability. By introducing dynamic boronic ester bonds at the interface between MXene nanosheets and epoxy natural rubber matrix, the resulting nanocomposites with ordered micro-nano structures exhibit excellent tensile strength (25.03 MPa) and satisfactory repair efficiency (81.2%). In addition, the gradient distribution structure of MXene nanosheets endows the actuator with stable photothermal conversion capability, which can quickly respond to near-infrared light stimulation. The interlayer dynamic covalent bond crosslinking enables good response speed after multiple bending and is capable of functional self-healing after damage. This work introduces gradient structure and dynamic covalent bonding into flexible actuators, which provides a reference for the fabrication of self-healing soft robots, wearable, and other healable functional materials.

An RRM domain protein SOE suppresses transgene silencing in rice.

Gene expression is regulated at multiple levels, including RNA processing and DNA methylation/demethylation. How these regulations are controlled remains unclear. Here, through analysis of a suppressor for the OsEIN2 over-expressor, we identified an RNA recognition motif protein SUPPRESSOR OF EIN2 (SOE). SOE is localized in nuclear speckles and interacts with several components of the spliceosome. We find SOE associates with hundreds of targets and directly binds to a DNA glycosylase gene DNG701 pre-mRNA for efficient splicing and stabilization, allowing for subsequent DNG701-mediated DNA demethylation of the transgene promoter for proper gene expression. The V81M substitution in the suppressor mutant protein mSOE impaired its protein stability and binding activity to DNG701 pre-mRNA, leading to transgene silencing. SOE mutation enhances grain size and yield. Haplotype analysis in c. 3000 rice accessions reveals that the haplotype 1 (Hap 1) promoter is associated with high 1000-grain weight, and most of the japonica accessions, but not indica ones, have the Hap 1 elite allele. Our study discovers a novel mechanism for the regulation of gene expression and provides an elite allele for the promotion of yield potentials in rice.

The GDSL Lipase MHZ11 Modulates Ethylene Signaling in Rice Roots.

Ethylene plays important roles in plant growth and development, but the regulation of ethylene signaling is largely unclear, especially in crops such as rice (Oryza sativa). Here, by analysis of the ethylene-insensitive mutant mao huzi 11 (mhz11), we identified the GDSL lipase MHZ11, which modulates ethylene signaling in rice roots. MHZ11 localized to the endoplasmic reticulum membrane and has acyl-hydrolyzing activity. This activity affects the homeostasis of sterols in rice roots and is required for root ethylene response. MHZ11 overexpression caused constitutive ethylene response in roots. Genetically, MHZ11 acts with the ethylene receptor ETHYLENE RESPONSE SENSOR2 (OsERS2) upstream of CONSTITUTIVE TRIPLE RESPONSE2 (OsCTR2) and ETHYLENE INSENSITIVE2 (OsEIN2). The mhz11 mutant maintains more OsCTR2 in the phosphorylated form whereas MHZ11 overexpression promotes ethylene-mediated inhibition of OsCTR2 phosphorylation. MHZ11 colocalized with the ethylene receptor OsERS2, and its effect on OsCTR2 phosphorylation requires ethylene perception and initiation of ethylene signaling. The mhz11 mutant overaccumulated sterols and blocking sterol biosynthesis partially rescued the mhz11 ethylene response, likely by reducing receptor-OsCTR2 interaction and OsCTR2 phosphorylation. We propose that MHZ11 reduces sterol levels to impair receptor-OsCTR2 interactions and OsCTR2 phosphorylation for triggering ethylene signaling. Our study reveals a mechanism by which MHZ11 participates in ethylene signaling for regulation of root growth in rice.

Pinholes in Al/MgF2.

Pinholes in A l/M g F 2 were first inferred by the transmittance enhancement in Larruquert group's research. However, no direct proof was reported to verify the existence of the pinholes in A l/M g F 2. In the past 80 years, pinholes were first observed by dark-field microscopy and bright-field microscopy in the transmission mode. They were small and on the order of several hundred nanometers to several micrometers. Essentially, the pinhole was not a real hole, partially because of the lack of the Al element. Increasing the thickness of Al cannot reduce the size of the pinholes. The occurrence of the pinholes was dependent on the deposition rate of the Al film and the substrate heating temperature, and it was independent of the substrate materials. This research eliminates an otherwise easily ignored scattering source, and it will benefit the development of ultra-precise optics, including mirrors for gyro-lasers, the detection of gravitational waves, and coronagraph detection.

Far ultraviolet mirrors for aurora imaging: design and fabrication.

The emission lines of 140-180 nm are auroral bands of N 2 Lyman-Birge-Hopfield, and they have been imaging targets of many satellites that need reflective mirrors. To obtain good imaging quality, the mirrors also should have excellent out-of-band reflection suppression as well as high reflectance at working wavelengths. We designed and fabricated non-periodic multilayer L a F 3/M g F 2 mirrors with working wave bands of 140-160 nm and 160-180 nm, respectively. We used a match design method and deep search method to design the multilayer. Our work has been utilized in the new wide-field auroral imager of China, and the application of these notch mirrors with excellent out-of-band suppression reduces the utilization of corresponding transmissive filters in the optical system of space payload. Furthermore, our work provides new routes for the design of other reflective mirrors in the far ultraviolet region.

Polymerizable Deep Eutectic Solvent-Based Skin-Like Elastomers with Dynamic Schemochrome and Self-Healing Ability.

Animal skin is a huge source of inspiration when it comes to multifunctional sensing materials. Bioinspired sensors integrated with the intriguing performance of skin-like steady wide-range strain detection, real-time dynamic visual cues, and self-healing ability hold great promise for next-generation electronic skin materials. Here, inspired by the skins of a chameleon, cellulose nanocrystals (CNCs) liquid crystal skeleton is embedded into polymerizable deep eutectic solvent (PDES) via in situ polymerization to develop a skin-like elastomer. Benefiting from the elastic ionic conductive PDES matrix and dynamic interfacial hydrogen bonding, this strategy has broken through the limitations that CNCs-based cholesteric structure is fragile and its helical pitch is non-adjustable, endowing the resulting elastomer with strain-induced wide-range (0-500%) dynamic structural colors and excellent self-healing ability (78.9-90.7%). Furthermore, the resulting materials exhibit high stretch-ability (1163.7%), strain-sensing and self-adhesive abilities, which make them well-suitable for developing widely applicable and highly reliable flexible sensors. The proposed approach of constructing biomimetic skin-like materials with wide-range dynamic schemochrome is expected to extend new possibilities in diverse applications including anti-counterfeit labels, soft foldable displays, and wearable optical devices.

Near-infrared ITO-based photonic hypercrystals with large angle-insensitive bandgaps.

The angle-sensitive photonic bandgap (PBG) is one of the typical features of one-dimensional photonic crystals. Based on the phase-variation compensation effect between the dielectric and hyperbolic metamaterials (HMMs), angle-insensitive PBGs can be realized in photonic hypercrystals. However, since hypercrystals are usually constructed using metal components, these angle-insensitive PBGs are mostly limited to narrow bandwidths in visible range. Here, we replace metal with indium tin oxide (ITO) to construct HMMs in the near-infrared range. In these ITO-based HMMs, we experimentally demonstrate the negative refraction of light in transverse magnetic polarization. With this HMM component, we realize a photonic hypercrystal with an angle-insensitive PBG in the wavelength range of 1.15-2.02 µm. These ITO-based hypercrystals with large angle-insensitive PBGs can find applications in near-infrared reflectors or filters.

Estimation precision for a normalized response matrix in linear polarization calibration.

The purpose of polarization calibration is to obtain the response matrix of an instrument such that the subsequent observation data can be corrected. The calibration precision, however, is partially restricted by the noise of the detector. We investigate the precision of the normalized response matrix in the presence of signal-independent additive noise or signal-dependent Poisson shot noise. The influences of the source intensity, type of noise, and calibration configuration on the precision are analyzed. We compare the theoretical model and the experimental measurements of the polarization calibration to show that the relative difference between the two is less than 16%. From this result, we can use the model to determine the minimum source intensity and choose the optimal configurations that provide the required precision.

PROSPECT-PMP+: Simultaneous Retrievals of Chlorophyll a and b, Carotenoids and Anthocyanins in the Leaf Optical Properties Model.

The PROSPECT leaf optical radiative transfer models, including PROSPECT-MP, have addressed the contributions of multiple photosynthetic pigments (chlorophyll a and b, and carotenoids) to leaf optical properties, but photo-protective pigment (anthocyanins), another important indicator of vegetation physiological and ecological functions, has not been simultaneously combined within a leaf optical model. Here, we present a new calibration and validation of PROSPECT-MP+ that separates the contributions of multiple photosynthetic and photo-protective pigments to leaf spectrum in the 400-800 nm range using a new empirical dataset that contains multiple photosynthetic and photo-protective pigments (LOPEX_ZJU dataset). We first provide multiple distinct in vivo individual photosynthetic and photo-protective pigment absorption coefficients and leaf average refractive index of the leaf interior using the LOPEX_ZJU dataset. Then, we evaluate the capabilities of PROSPECT-MP+ for forward modelling of leaf directional hemispherical reflectance and transmittance spectra and for retrieval of pigment concentrations by model inversion. The main result of this study is that the absorption coefficients of chlorophyll a and b, carotenoids, and anthocyanins display the physical principles of absorption spectra. Moreover, the validation result of this study demonstrates the potential of PROSPECT-MP+ for improving capabilities in remote sensing of leaf photosynthetic pigments (chlorophyll a and b, and carotenoids) and photo-protective pigment (anthocyanins).

Nonreciprocal Tamm plasmon absorber based on lossy epsilon-near-zero materials.

Contrary to conventional Tamm plasmon (TP) absorbers of which narrow absorptance peaks will shift toward short wavelengths (blueshift) as the incident angle increases for both transverse magnetic (TM) and transverse electric (TE) polarizations, here we theoretically and experimentally achieve nonreciprocal absorption in a planar photonic heterostructure composed of an isotropic epsilon-near-zero (ENZ) slab and a truncated photonic crystal for TM polarization. This exotic phenomenon results from the interplay between ENZ and material loss. And the boundary condition across the ENZ interface and the confinement effect provided by the TP can enhance the absorption in the ENZ slab greatly. As a result, a strong and nonreciprocal absorptance peak is observed experimentally with a maximum absorptance value of 93% in an angle range of 60∼70°. Moreover, this TP absorber shows strong angle-independence and polarization-dependence. As the characteristics above are not at a cost of extra nanopatterning, this structure is promising to offer a practical design in narrowband thermal emitter, highly sensitive biosensing, and nonreciprocal nonlinear optical devices.

C-N Coupling Reactions on Graphene with Aromatic Macromolecules and the Spatial Conformation of Grafted Macromolecules.

The fabrication of advanced graphene-based nanocomposites with high-performance polymers requires covalent modification of graphene with aromatic macromolecules. Herein, C-N coupling reactions between fluorinated graphene (FG) and aromatic polyamides containing the benzimidazole moiety are successfully achieved. The optimized conditions are presented based on the nucleophilic behavior of the C-N coupling reaction on graphene. Different from the C-N coupling reaction between two small aromatic molecules, the conformation of grafted aromatic polyamide after reaction changes from torsional to paralleled alignment on graphene with the molecular length increment. Non-covalent interactions between graphene and aromatic polyamides result in this conformational change owing to the extended π systems of graphene and aromatic polyamides, and the synergistic effect of covalent and non-covalent interactions is put forward. As a consequence, graphene dispersibility is greatly enhanced in the solution of aromatic polyamide.

Optimal configurations for different incident polarization states in linear polarization calibration.

The purpose of polarization calibration is to measure the response matrix of an instrument and the deviation of noise to correct for subsequent flight measurements. The precision, however, is relative to the states of incident light. We investigate the influence of partially polarized light, in the presence of signal-independent additive noise or signal-dependent Poisson shot noise. We obtain the estimation precision for different numbers of the polarization state generators and analyzers in linear Stokes measurements. To reduce the influence of incident light, we suggest that the numbers of the polarization state generators and analyzers should be greater than or equal to 4. In particular, for an instrument including three polarizers oriented at 0°, 60°, and 120°, estimation precision is found to be dependent on the response matrix and incident polarization states.

Graph neural network recommendation algorithm based on improved dual tower model.

In this era of information explosion, recommendation systems play a key role in helping users to uncover content of interest among massive amounts of information. Pursuing a breadth of recall while maintaining accuracy is a core challenge for current recommendation systems. In this paper, we propose a new recommendation algorithm model, the interactive higher-order dual tower (IHDT), which improves current models by adding interactivity and higher-order feature learning between the dual tower neural networks. A heterogeneous graph is constructed containing different types of nodes, such as users, items, and attributes, extracting richer feature representations through meta-paths. To achieve feature interaction, an interactive learning mechanism is introduced to inject relevant features between the user and project towers. Additionally, this method utilizes graph convolutional networks for higher-order feature learning, pooling the node embeddings of the twin towers to obtain enhanced end-user and item representations. IHDT was evaluated on the MovieLens dataset and outperformed multiple baseline methods. Ablation experiments verified the contribution of interactive learning and high-order GCN components.

Mineral oil emulsion species and concentration prediction using multi-output neural network based on fluorescence spectra in the solar-blind UV band.

The accurate monitoring of oil spills is crucial for effective oil spill recovery, volume determination, and cleanup. Oil slicks become emulsified under the effects of wind and waves, which increases the consistency of the oil spills. This phenomenon makes oil spills more challenging to handle and exacerbates environmental pollution. In this study, the variation of the solar-blind ultraviolet (UV) fluorescence spectra obtained from simulated oil spills with different oil types and oil-water ratios was investigated. By designing and constructing a multi-angle excitation and detection system, an apparent fluorescence peak of the oil emulsions was observed at around 290 nm under 220 nm excitation. By utilizing competitive adaptive reweighted sampling (CARS) and multi-output neural network algorithms, both the types and concentrations of the emulsified oils were obtained simultaneously. The classification accuracy for identifying the oil type exceeds 98%, and the mean absolute percentage error (MAPE) for concentration regression is around 2%. The results indicate that active solar-blind UV fluorescence could become a supplementary method for on-site oil spill detection to achieve comprehensive monitoring of oil spills. This study provides potential applications for UV-induced fluorescence spectrometry in oil spill on-site monitoring during the daytime.

Multi-Modal Melt-Processing of Birefringent Cellulosic Materials for Eco-Friendly Anti-Counterfeiting.

Ubiquitous anti-counterfeiting materials with a rapidly rising annual consumption (over 1010 m2) can pose a serious environmental burden. Biobased cellulosic materials with birefringence offer attractive sustainable alternatives, but their scalable solvent-free processing remain challenging. Here, a dynamic chemical modification strategy is proposed for multi-modal melt-processing of birefringent cellulosic materials for eco-friendly anti-counterfeiting. Relying on the thermal-activated dynamic covalent-locking of the spatial topological structure of preferred oriented cellulose, the strategy balances the contradiction between the strong confinement of long-range ordered structures and the molecular motility required for entropically-driven reconstruction. Equipped with customizable processing forms including mold-pressing, spinning, direct-ink-writing, and blade-coating, the materials exhibit a wide color gamut, self-healing efficiency (94.5%), recyclability, and biodegradability. Moreover, the diversified flexible elements facilitate scalable fabrication and compatibility with universal processing techniques, thereby enabling versatile and programmable anti-counterfeiting. The strategy is expected to provide references for multi-modal melt-processing of cellulose and promote sustainable innovation in the anti-counterfeiting industry.

In-plane compressive responses and failure behaviors of composite sandwich plates with resin reinforced foam core.

The paper presented an experimental study on the effect of the resin reinforced core configuration and core thickness on in-plane compressive responses and failure behaviors of composite sandwich specimens. Two resin reinforced core machining configurations were designed with three core thickness along. In-plane compressive load, displacement, strains on both sides, and failure morphology were closely monitored during the loading process. Meanwhile, the theoretical method also was supplementary to forecast the failures of sandwich structures. It was found that the enhancement of grooved, perforated holes and contour cut (GPC) core was better than double-side grooved and perforated hole (DGP) core to improve the in-plane compressive capacity of sandwich specimens for all thick cores. The core fracture or skin/core debonding failure of sandwich specimens resulted in an instant drop of in-plane compressive load, and the global buckling led to a slower reduction. The failure mode changed from global buckling to skin/core debonding at both sides as the core thickness increased for the Plain core sandwich specimen; switched from global buckling to a combined failure of core fracture and skin/core debonding at both sides, and then to skin/core debonding at both sides for the DGP core sandwich specimen; the skin/core debonding at the shallow side occurred for all GPC core specimens. The slight buckling trace of strains before the peak load probably triggered the skin/core debonding of sandwich specimens. The theoretical method could well forecast failure loads and corresponding failure modes of sandwich specimens with the 15 mm thick core, and reasonably predict failure loads for sandwich specimens with 30 mm and 45 mm thick cores.

Membrane protein MHZ3 regulates the on-off switch of ethylene signaling in rice.

Ethylene regulates plant growth, development, and stress adaptation. However, the early signaling events following ethylene perception, particularly in the regulation of ethylene receptor/CTRs (CONSTITUTIVE TRIPLE RESPONSE) complex, remains less understood. Here, utilizing the rapid phospho-shift of rice OsCTR2 in response to ethylene as a sensitive readout for signal activation, we revealed that MHZ3, previously identified as a stabilizer of ETHYLENE INSENSITIVE 2 (OsEIN2), is crucial for maintaining OsCTR2 phosphorylation. Genetically, both functional MHZ3 and ethylene receptors prove essential for OsCTR2 phosphorylation. MHZ3 physically interacts with both subfamily I and II ethylene receptors, e.g., OsERS2 and OsETR2 respectively, stabilizing their association with OsCTR2 and thereby maintaining OsCTR2 activity. Ethylene treatment disrupts the interactions within the protein complex MHZ3/receptors/OsCTR2, reducing OsCTR2 phosphorylation and initiating downstream signaling. Our study unveils the dual role of MHZ3 in fine-tuning ethylene signaling activation, providing insights into the initial stages of the ethylene signaling cascade.

Ultraviolet-induced fluorescence of oil spill recognition using a semi-supervised algorithm based on thickness and mixing proportion-emission matrices.

In recent years, marine oil spill accidents have been occurring frequently during extraction and transportation, and seriously damage the ecological balance. Accurate monitoring of oil spills plays a vital role in estimating oil spill volume, determination of liability, and clean-up. The oil that leaks into natural environments is not a single type of oil, but a mixture of various oil products, and the oil film thickness on the sea surface is uneven under the influence of wind and waves. Increasing the mixed oil film thickness dimension and the mix proportion dimension has been proposed to weaken the effect of the detection environment on the fluorescence measurement results. To preserve the relationships between the data of oil films with different thicknesses and the relationships between the data of oil films with different mixing proportions, the three-dimensional fluorescence spectral data of mixed oil films on a seawater surface were measured in the laboratory, producing a thickness-fluorescence matrix and a proportion-fluorescence matrix. The nonlinear variation of the fluorescence spectra was investigated according to the fluorescence lidar equation. This work pre-processes the data by sum normalization and two-dimensional principal component analysis (2DPCA) and uses the dimensionality reduction results as two feature-point views. Then, semi-supervised classification of collaborative training (co-training) with K-nearest neighbors (KNN) and a decision tree (DT) is used to identify the samples. The results show that the average overall accuracy of this coupling model can reach 100%, which is 20.49% higher than that of the thickness-only view. Using unlabeled data can reduce the cost of data acquisition, improve the classification accuracy and generalization ability, and provide theoretical significance and application prospects for discrimination of spectrally similar oil species in natural marine environments.

Biobased Intelligent Food-Packaging Materials with Sustained-Release Antibacterial and Real-Time Monitoring Ability.

It has been widely accepted that sustainable polymers derived from renewable resources are able to replace the short-turnover petroleum-based materials and reduce environmental impact in the future. However, their hydrophilic chemical structures rich with oxygen groups could lead to easy growth of bacteria, which greatly limit their applications in packaging materials. Here, we present an intelligent food-packaging material with sustained-release antibacterial and real-time monitoring ability based on totally biobased contents. In detail, sodium alginate with Artemisia argyi emission oil (encapsulated in gelatin-Arabic gum microcapsules) and citric acid-sourced pH-responsive carbon quantum dots (CQDs) are coated on bamboo cellulose papers. The obtained biobased composite material (almost 100% biocarbon content) with antibacterial ability is able to extend the shelf life of fresh shrimps and can be biodegraded. Moreover, owing to the introduction of CQDs, the composite can rapidly (within 1 s) detect slight pH variations (response pH ∼5, 10-9 mol/L of OH-) through an obvious color change (hue value from 305 to 355°). The developed strategy may open up new opportunities in the design of multifunctional biobased composites for intelligent applications.

Detection of the intraoperative bile leakage in laparoscopic cholecystectomy using indocyanine green fluorescence imaging: A case report.

Herein, we report two cases of successful application of indocyanine green (ICG) fluorescence imaging for detecting intraoperative bile leakage during laparoscopic cholecystectomy (LC). Bile leakage was detected rapidly and accurately using fluorescence guidance. Based on our findings, we recommend using ICG fluorescence imaging during LC because it is effective and feasible for detecting intraoperative bile leakage.