Droplet Bottom Expansion and Its Wettability Control Mechanism Based on Macroscopic Defects.

Biomimetic surfaces with special wettability have received much attention due to their promising prospects in droplet manipulation. Although some progress has been made, the manipulation of droplets by macroscopic defects of the millimeter structure and the wetting-state transition mechanism have rarely been reported. Herein, inspired by lotus leaves and desert beetles, biomimetic surfaces with macroscopic defects are prepared by laser processing and chemical modification. Various functions of droplet manipulation are achieved by controlling the millimeter-scale macroscopic defects, such as droplet capture, motion trajectory changing, and liquid well. And a droplet bottom expansion phenomenon is proposed: wetting-state transition in superhydrophobic regions around defects. The "edge failure effect" is proposed to explain the force analysis of droplet capture and the droplet bottom expansion to distinguish it from the adhesion phenomenon presented by the droplet sliding. 53.28° is defined as the expanded saturated angle of the as-prepared surface, which is used to distinguish whether the defect could cause the droplet bottom expansion. An enhanced edge failure effect experiment is designed to make the droplet bottom expansion more intuitive. This work provides a mechanistic explanation of the surfaces that utilize macroscopic defects for droplet manipulation. It can be applied to the monitoring of droplet storage limits, providing a perspective on the design and optimization of superhydrophobic surfaces with droplet manipulation.

Multi-biomimetic Double Interlaced Wetting Janus Surface for Efficient Fog Collection.

Various methods to solve water scarcity have attracted increasing attention. However, most existing water harvesting schemes have a high demand for preparation methods and costs. Here, a multi-biomimetic double interlaced wetting Janus surface (DIWJS) was prepared by laser for effective fog collection. The as-prepared surfaces are composed of superhydrophilic points/hydrophobic substrates on the A-side and superhydrophilic stripes/hydrophobic substrates on the B-side. The interlaced wettability and superhydrophilic points on the A side are conducive to capture and permeation of droplets. The superhydrophilic stripes and interlaced wettability on the B-side are conducive to transportation and shedding of droplets. Therefore, the overall fog collection process is accelerated. The proposal of smart farm model validates broad application prospects of DIWJS. This work provides an advanced and multi-biomimetic surface and provides important insights for green, low-cost, and versatile strategies to solve water scarcity issues.

Additive Manufacturing Provides Infinite Possibilities for Self-Sensing Technology.

Integrating sensors and other functional parts in one device can enable a new generation of integrated intelligent devices that can perform self-sensing and monitoring autonomously. Applications include buildings that detect and repair damage, robots that monitor conditions and perform real-time correction and reconstruction, aircraft capable of real-time perception of the internal and external environment, and medical devices and prosthetics with a realistic sense of touch. Although integrating sensors and other functional parts into self-sensing intelligent devices has become increasingly common, additive manufacturing has only been marginally explored. This review focuses on additive manufacturing integrated design, printing equipment, and printable materials and stuctures. The importance of the material, structure, and function of integrated manufacturing are highlighted. The study summarizes current challenges to be addressed and provides suggestions for future development directions.

Synthesis of MOF-5/polyethersulfone (PES) mixed matrix membranes for enhancing membrane filtration performance in polyphenol purification.

The various apple products industries produce a large amount of apple residue, which is easily fermented, causes environmental pollution, and its disposal cost is high, but is rich in nutrients, such as polyphenols. Polyphenols can be purified to realize high-value deep processing of apple pomace and to promote energy reuse of food waste. In this study, the highly selective purification of polyphenols was achieved by membrane filtration using prepared Metal-organic framework (MOF)-5/PES mixed matrix membranes with apple peels as raw material. The polyethersulfone mixed matrix membrane was loaded with MOF-5 by the phase inversion method, and their structural and physicochemical properties were characterized by scanning electron microscopy (SEM), and X-ray diffraction (XRD). Zeta potential and specific surface area of MOF-5 particles were measured, as well as the water contact angle and anti-fouling properties of the mixed matrix membrane were analyzed. It was confirmed that the membrane loaded with MOF-5 showed better hydrophilicity and mechanical properties compared with the pristine polyether sulfone membrane. Under practical conditions, the increased hydrophilicity could enhance the anti-fouling properties of membranes, which would improve the flux recovery ratio of membranes. In addition, the prepared MOF-5/PES mixed matrix membrane was applied to the purification of polyphenols, showing excellent purification performance of polyphenols. In particular, the purity of polyphenol after membrane filtration could reach 70.45% when the additional amount of MOF-5 was 10%. This research provides a method to prepare MOF-5/PES mixed matrix membranes, which effectively solves the problem of unstable and unsatisfactory purification effect of commercially available membranes, promotes the development of new materials in membrane science, and realizes high-value deep processing and comprehensive resource development of food waste using membrane filtration.

Multi-Level Structural Enhancement Mechanism of the Excellent Mechanical Properties of Dung Beetle Leg Joint.

The multi-level structure is a strategy to enhance the mechanical properties of dung beetle leg joints. Under external loads, the microstructure facilitates energy dissipation and prevents crack extension. The macrostructure aids in transferring the load to more reliable parts. The connection established by the two hemispheres is present in the dung beetle leg joint. The micron-layered and nanoscale crystal structures further constitute the leg joint with excellent mechanical properties. The maximum compression fracture force is ≈101000 times the weight of the leg. Here, the structural design within the dung beetle leg joints and reveal the resulting mechanical response and enhancement mechanisms is determined. A series of beetle leg joints where the macrostructure and microstructure of the dung beetle leg provide mechanical strength at critical strains while avoiding catastrophic failure by transferring the load from the joint to the exoskeleton of the femur is highlighted. Nanocrystalline structures and fiber layers contribute to crack propagation of the exoskeleton. Based on this, the bionic joint with multi-level structures using resin and conducted a series of tests to verify their effectiveness is prepared. This study provides a new idea for designing and optimizing high-load joints in engineering.

Flexible Multimodal Sensing System Based on a Vertical Stacking Strategy for Efficiently Decoupling Multiple Signals.

Multisensory integration enables the simultaneous perception of multiple environmental stimuli while minimizing size and energy consumption. However, conventional multifunctional integration in flexible electronics typically requires large-scale horizontal sensing arrays (such as flexible printed circuit boards), posing decoupling complexities, tensile strain limitation, and spatial constraints. Herein, a fully flexible multimodal sensing system (FMSS) is developed by coupling biomimetic stretchable conductive films (BSCFs) and strain-insensitive communication interfaces using a vertical stacking integration strategy. The FMSS achieves vertical integration without additional adhesives, and it can incorporate individual sensing layers and stretchable interconnects without any essential constraint on their deformations. Accordingly, the temperature and pressure are precisely decoupled simultaneously, and tensile stress can be accurately discerned in different directions. This vertical stacking integration strategy is expected to offer a new approach to significantly streamline the design and fabrication of multimodal sensing systems and enhance their decoupling capabilities.

Bio-inspired, sensitivity-enhanced, bi-directional airflow sensor for turbulence detection.

Detecting airflow turbulence precursors promptly is crucial for ensuring flight safety and control. The initial stages of turbulence involve small reverse flows with random velocities and directions, which are not easily detected by existing airflow sensors. In this study, we designed a bionic, sensitivity-enhanced, bi-directional airflow sensor (BSBA) by incorporating bio-inspired circular tip slits and enlarging the central part of the cruciform beam structure. The BSBA exhibits a rapid response time (24.1 ms), high sensitivity (1.36 mV m-1 s-1), consistent detection of forward and backward airflow (correlation coefficient of 0.9854), and a low airflow detection threshold (1 ml). With these features, the proposed sensor can rapidly and accurately measure slight variations in the oscillating airflow, flow field, and contact force. The BSBA also achieves transparent obstacle detection on a quadrotor, even in visually challenging environments, by capturing minute changes in the flow fields produced by the quadrotor when encountering obstacles. The sensor's high sensitivity, consistent bi-directional detection, and fast response give it significant potential for enhancing safety in aircraft control systems.

High-Fidelity, Low-Hysteresis Bionic Flexible Strain Sensors for Soft Machines.

Stretchable flexible strain sensors based on conductive elastomers are rapidly emerging as a highly promising candidate for popular wearable flexible electronic and soft-mechanical sensing devices. However, due to the intrinsic limitations of low fidelity and high hysteresis, existing flexible strain sensors are unable to exploit their full application potential. Herein, a design strategy for a successive three-dimensional crack conductive network is proposed to cope with the uncoordinated variation of the output resistance signal arising from the conductive elastomer. The electrical characteristics of the sensor are dominated by the successive crack conductive network through a greater resistance variation and a concise sensing mechanism. As a result, the developed elastomer bionic strain sensors exhibit excellent sensing performance in terms of a smaller overshoot response, a lower hysteresis (∼2.9%), and an ultralow detection limit (0.00179%). What's more, the proposed strategy is universal and applicable to many conductive elastomers with different conductive fillers (including 0-D, 1-D, and 2-D conductive fillers). This approach improves the sensing signal accuracy and reliability of conductive elastomer strain sensors and holds promising potential for various applications in the fields of e-skin and soft robotic systems.

Bio-inspired copper ion-chelated chitosan coating modified UHMWPE fibers for enhanced interfacial properties of composites.

Ultra-high molecular weight polyethylene (UHMWPE) fibers are broadly applied in lightweight and high-strength composite fiber materials. However, the development of UHMWPE fibers is limited by their smooth and chemically inert surfaces. To address the issues, a modified UHMWPE fibers material has been fabricated through the chelation reaction between Cu2+ and chitosan coatings within the surface of fibers after plasma treatment, which is inspired by the hardening mechanism, a crosslinked network between metal ions and proteins/polysaccharides of the tips and edges in arthropod-specific cuticular tools. The coatings improve the surface wettability and interfacial bonding ability, which are beneficial in extending the application range of UHMWPE fibers. More importantly, compared to the unmodified UHMWPE fiber cloths, the tensile property of the modified fiber cloths is increased by 18.89% without damaging the strength, which is infrequent in modified UHMWPE fibers. Furthermore, the interlaminar shear strength and fracture toughness of the modified fibers laminate are increased by 37.72% and 135.90%, respectively. These improvements can be attributed to the synergistic effects between the surface activity and the tiny bumps of the modified UHMWPE fibers. Hence, this work provides a more straightforward and less damaging idea of fiber modification for manufacturing desirable protective and medical materials.

The intelligent prediction of membrane fouling during membrane filtration by mathematical models and artificial intelligence models.

Recently, membrane separation technology has been widely utilized in filtration process intensification due to its efficient performance and unique advantages, but membrane fouling limits its development and application. Therefore, the research on membrane fouling prediction and control technology is crucial to effectively reduce membrane fouling and improve separation performance. This review first introduces the main factors (operating condition, material characteristics, and membrane structure properties) and the corresponding principles that affect membrane fouling. In addition, mathematical models (Hermia model and Tandem resistance model), artificial intelligence (AI) models (Artificial neural networks model and fuzzy control model), and AI optimization methods (genetic algorithm and particle swarm algorithm), which are widely used for the prediction of membrane fouling, are summarized and analyzed for comparison. The AI models are usually significantly better than the mathematical models in terms of prediction accuracy and applicability of membrane fouling and can monitor membrane fouling in real-time by working in concert with image processing technology, which is crucial for membrane fouling prediction and mechanism studies. Meanwhile, AI models for membrane fouling prediction in the separation process have shown good potential and are expected to be further applied in large-scale industrial applications for separation and filtration process intensification. This review will help researchers understand the challenges and future research directions in membrane fouling prediction, which is expected to provide an effective method to reduce or even solve the bottleneck problem of membrane fouling, and to promote the further application of AI modeling in environmental and food fields.

Magnetoactive Soft Materials with Programmable Magnetic Domains for Multifunctional Actuators.

Despite considerable progress having been made in the research of soft actuators, there remains a grand challenge in creating a facile manufacturing process that offers both extensive programmability and exceptional actuation capabilities. Taking inspiration from uncomplicated small organisms, this work aims to develop soft actuators that can be mobilized through straightforward design and control, similar to caterpillars or inchworms. They execute intricate actions and functions to meet survival needs in the most efficient manner possible. Here, a novel soft actuator with uniformly dispersed ferromagnetic microparticles but programmatic magnetic profile distribution is proposed by a convenient magnetization process. Benefiting from its high magnetic sensitivity and good matrix flexibility, the actuator can simultaneously achieve reversible, remote, and fast programmable shape transformation and controllable movement even in a magnetic field as low as 14 Gs. Complemented by intrinsic material properties and structural configuration, actuation employing spatial magnetization profiles can facilitate multiple modes of locomotion when subjected to magnetic fields, allowing for an efficient manipulation task of both solid and liquid media. More importantly, a finite element model is developed to assist in the design of the interaction between the alternating magnetic field and the magnetic torques. This advanced soft actuator would strongly push forward major breakthroughs in key applications such as intelligent sensors, disaster rescue, and wearable devices.

Identification of a Necroptosis-Related Prognostic Signature and Associated Regulatory Axis in Lung Adenocarcinoma.

Background: Lung cancer is considered to be the second most aggressive and rapidly fatal cancer after breast cancer. Necroptosis, a novel discovered pattern of cell death, is mediated by Receptor-interacting serine/threonine-protein kinase 1 (RIPK1), Receptor-interacting serine/threonine-protein kinase 3 (RIPK3), and Mixed Lineage Kinase Domain Like Pseudokinase (MLKL). Methods: For the purpose of developing a prognostic model, Least absolute shrinkage and selection operator (LASSO) Cox regression analysis was conducted. Using Pearson's correlation analysis, we evaluated the correlation between necroptosis-related markers and tumor immune infiltration. A bioinformatics analysis was conducted to construct a necroptosis-related regulatory axis. Results: There was a downregulation of most of necroptosis-related genes in lung adenocarcinoma (LUAD) versus lung tissues but an increase in PGAM5, HMGB1, TRAF2, EZH2 levels. We also summarized the Single Nucleotide Variant (SNV) and copy number variation (CNV) of necroptosis-related genes in LUAD. Consensus clustering identified two clusters in LUAD with distinct immune cell infiltration and ESTIMATEScore. Genes related to necroptosis were associated with necroptosis, Tumor necrosis factor (TNF) signaling pathway, and apoptosis according to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Four prognostic genes (ALDH2, HMGB1, NDRG2, TLR2) were combined to develop a prognostic gene signature for LUAD patients, which was highly accurate in predicting prognosis. Univariate and multivariate analysis identified HMGB1, pT stage, and pN stage as independent factors impacting on LUAD patients' prognosis. A significant correlation was found between the level of TLR2 and NDRG2 and clinical stage, immunity infiltration, and drug resistance. Additionally, the progression of LUAD might be regulated by lncRNA C5orf64/miR-582-5p/NDRG2/TLR2. Conclusion: The current bioinformatics analysis identified a necroptosis-related prognostic signature for LUAD and their relation to immunity infiltration. This result requires further investigation.

A Selective-Response Hypersensitive Bio-Inspired Strain Sensor Enabled by Hysteresis Effect and Parallel Through-Slits Structures.

Flexible strain sensors are promising in sensing minuscule mechanical signals, and thereby widely used in various advanced fields. However, the effective integration of hypersensitivity and highly selective response into one flexible strain sensor remains a huge challenge. Herein, inspired by the hysteresis strategy of the scorpion slit receptor, a bio-inspired flexible strain sensor (BFSS) with parallel through-slit arrays is designed and fabricated. Specifically, BFSS consists of conductive monolayer graphene and viscoelastic styrene-isoprene-styrene block copolymer. Under the synergistic effect of the bio-inspired slit structures and flexible viscoelastic materials, BFSS can achieve both hypersensitivity and highly selective frequency response. Remarkably, the BFSS exhibits a high gage factor of 657.36, and a precise identification of vibration frequencies at a resolution of 0.2 Hz through undergoing different morphological changes to high-frequency vibration and low-frequency vibration. Moreover, the BFSS possesses a wide frequency detection range (103 Hz) and stable durability (1000 cycles). It can sense and recognize vibration signals with different characteristics, including the frequency, amplitude, and waveform. This work, which turns the hysteresis effect into a "treasure," can provide new design ideas for sensors for potential applications including human-computer interaction and health monitoring of mechanical equipment.

Synthesis, catalysts and enhancement technologies of biodiesel from oil feedstock - A review.

Biodiesel is considered as one of the most promising alternative fuels due to the depletion of fossil fuels and the need to cope with potential energy shortages in the future. This article provides a thorough analysis of biodiesel synthesis, covering a variety of topics including oil feedstock, synthesis methods, catalysts, and enhancement technologies. Different oil feedstock for the synthesis of biodiesel is compared in the review, including edible plant oil, non-edible plant oil, waste cooking oil, animal fat, microbial oil, and algae oil. In addition, different methods for the synthesis of biodiesel are discussed, including direct use, blending, thermal cracking, microemulsions, and transesterification processes, highlighting their respective advantages and disadvantages. Among them, the transesterification method is the most commonly used and a thorough examination is given of the benefits and drawbacks of utilizing enzymatic, heterogeneous, and homogeneous catalysts in this process. Moreover, this article provides an overview of emerging intensification technologies, such as ultrasonic and microwave-assisted, electrolysis, reactive distillation, and microreactors. The benefits and limitations of these emerging technologies are also reviewed. The contribution of this article is offering a thorough and detailed review of biodiesel production technologies, focusing mainly on recent advances in enhanced chemical reaction processes. This provides a resource for researchers to assess and compare the latest advancements in their investigations. It also opens up the potential for enhancing the value of oil feedstocks efficiently, contributing to the development of new energy sources.

Modeling and motion control of helical microrobots using the dual quaternion framework and adaptive sliding mode strategy.

This study investigates the tracking control problem of helical microrobots (HMRs) in complicated blood environments. The integrated relative motion model of HMRs is established by resorting to the dual quaternion method, which can describe the coupling effect between the rotational and translational motions. Subsequently, an original apparent weight compensator (AWC) is designed to alleviate the adverse effects of the HMR sinking and drifting owing to its own weight and buoyancy. An adaptive sliding mode control based on the developed AWC (AWC-ASMC) is constructed to guarantee the fast convergence of the relative motion tracking errors in the presence of model uncertainties and unknown perturbations. The chattering phenomenon of the classical SMC is significantly reduced using the developed control strategy. Furthermore, the stability of the closed-loop system under the constructed control framework is demonstrated by the Lyapunov theory. Finally, numerical simulations are performed to demonstrate the validity and superiority of the developed control scheme.

Bioinspired Near-Full Transmittance MgF2 Window for Infrared Detection in Extremely Complex Environments.

Due to the extreme complexity of the anti-reflective subwavelength structure (ASS) parameters and the drastic limitation of Gaussian beam manufacturing accuracy, it remains a great challenge to manufacture ASS with ultrahigh transmittance on the surface of infrared window materials (such as magnesium fluoride (MgF2)) directly by femtosecond laser. Here, a design, manufacturing, and characterization method that can produce an ultrahigh-performance infrared window by femtosecond laser Bessel beam is proposed. Inspired by the excellent anti-reflective and hydrophobic properties of the special structure of dragonfly wings, a similar structural pattern with grid-distributed truncated cones is designed and optimized for its corresponding parameters to achieve near-full transmittance. The desired submicron structures are successfully fabricated by a Bessel beam after effectively shaping the beam. As a practical application, the bioinspired ASS is manufactured on the surface of MgF2, achieving an ultrahigh transmittance of 99.896% in the broadband of 3-5 µm, ultrawide angle of incidence (over 70% at 75° incidence), and good hydrophobicity with a water contact angle of 99.805°. Results from infrared thermal imaging experiments show that the ultrahigh-transmittance MgF2 window has superior image acquisition and anti-interference performance (3.9-8.6% image contrast enhancement and more accurate image edge recognition) in an environment with multiple interfering factors, which may play a significant role in facilitating applications of infrared thermal imaging technologies in extremely complex environments.

Multifunctional Biomimetic Composite Coating with Antireflection, Self-Cleaning and Mechanical Stability.

Antireflective and self-cleaning coatings have attracted increasing attention in the last few years due to their promising and wider applications such as stealth, display devices, sensing, and other fields. However, existing antireflective and self-cleaning functional material are facing problems such as difficult performance optimization, poor mechanical stability, and poor environmental adaptability. Limitations in design strategies have severely restricted coatings' further development and application. Fabrication of high-performance antireflection and self-cleaning coatings with satisfactory mechanical stability remain a key challenge. Inspired by the self-cleaning performance of nano-/micro-composite structure on natural lotus leaves, SiO2/PDMS/matte polyurethane biomimetic composite coating (BCC) was prepared by nano-polymerization spraying technology. The BCC reduced the average reflectivity of the aluminum alloy substrate surface from 60% to 10%, and the water contact angle (CA) was 156.32 ± 0.58°, illustrating the antireflective and self-cleaning performance of the surface was significantly improved. At the same time, the coating was able to withstand 44 abrasion tests, 230 tape stripping tests, and 210 scraping tests. After the test, the coating still showed satisfactory antireflective and self-cleaning properties, indicating its remarkable mechanical stability. In addition, the coating also displayed excellent acid resistance, which has important value in aerospace, optoelectronics, industrial anti-corrosion, etc.

Lightweight Structural Biomaterials with Excellent Mechanical Performance: A Review.

The rational design of desirable lightweight structural materials usually needs to meet the strict requirements of mechanical properties. Seeking optimal integration strategies for lightweight structures and high mechanical performance is always of great research significance in the rapidly developing composites field, which also draws significant attention from materials scientists and engineers. However, the intrinsic incompatibility of low mass and high strength is still an open challenge for achieving satisfied engineering composites. Fortunately, creatures in nature tend to possess excellent lightweight properties and mechanical performance to improve their survival ability. Thus, by ingenious structure configuration, lightweight structural biomaterials with simple components can achieve high mechanical performance. This review comprehensively summarizes recent advances in three typical structures in natural biomaterials: cellular structures, fibrous structures, and sandwich structures. For each structure, typical organisms are selected for comparison, and their compositions, structures, and properties are discussed in detail, respectively. In addition, bioinspired design approaches of each structure are briefly introduced. At last, the outlook on the design and fabrication of bioinspired composites is also presented to guide the development of advanced composites in future practical engineering applications.

Review of Synthesis and Separation Application of Metal-Organic Framework-Based Mixed-Matrix Membranes.

Metal-organic frameworks (MOFs) are porous crystalline materials assembled from organic ligands and metallic secondary building blocks. Their special structural composition gives them the advantages of high porosity, high specific surface area, adjustable pore size, and good stability. MOF membranes and MOF-based mixed-matrix membranes prepared from MOF crystals have ultra-high porosity, uniform pore size, excellent adsorption properties, high selectivity, and high throughput, which contribute to their being widely used in separation fields. This review summarizes the synthesis methods of MOF membranes, including in situ growth, secondary growth, and electrochemical methods. Mixed-matrix membranes composed of Zeolite Imidazolate Frameworks (ZIF), University of Oslo (UIO), and Materials of Institute Lavoisier (MIL) frameworks are introduced. In addition, the main applications of MOF membranes in lithium-sulfur battery separators, wastewater purification, seawater desalination, and gas separation are reviewed. Finally, we review the development prospects of MOF membranes for the large-scale application of MOF membranes in factories.

A review of the polyphenols purification from apple products.

Apple polyphenols are one of the major bioactive compounds in apple products and have strong anti-inflammatory effects and the ability to prevent chronic diseases with health benefits. The development of apple polyphenol products is dependent on the extraction, purification and identification of apple polyphenols. The extracted polyphenols need to be further purified to improve the concentration of the extracted polyphenols. This review, therefore, presents the studies on the conventional and novel methods for polyphenols purification from apple products. The different chromatography methods, as one of the most widely used conventional purification methods, for polyphenol purification from various apple products are introduced. In addition, the perspective of the adsorption-desorption process and membrane filtration technique in enhancing the purification of polyphenols from apple products are presented in this review. The advantages and disadvantages of these purification techniques are also discussed and compared in depth. However, each of the reviewed technologies has some disadvantages that need to be overcome, and some mechanisms need to be further identified. Therefore, more competitive polyphenols purification techniques need to emerge in the future. It is hoped that this review can provide a research basis for the efficient purification of apple polyphenols, which can facilitate their application in various fields.