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This research combines simulation technology, a surrogate model, and a dung beetle optimizer (DBO) to propose a structural optimization design method for lightweight adhesive modules. The structure of the wall-climbing robot is introduced, and its adhesion stability is analyzed. Through simulation comparison of four typical Halbach array magnetic circuit modes, it was determined that the adhesion generated by the three-magnetic circuit structure mode is more advantageous. Determine the parameters that need to be optimized through sensitivity analysis. The Chebyshev model of adhesion force and parameters was established. An optimization model aimed at lightweight and the constraints of adhesion stability and structural parameters was set. The penalty function combined with DBO was used to solve the optimization model. Compared with before optimization, the weight of the adhesive module is reduced by 11.7 %. The experiments verified the adhesive module's adhesion force and the robot's load capacity. [ABSTRACT FROM AUTHOR]

Human organoid models potentially offer a physiologically relevant platform to replace traditional monolayer cultures and animal models. In particular, the rapid development of engineered strategies including microfluidics, hydrogel, 3D printing and others, which have enormous advantages in comparison to conventional methods, is expected to further advance organoid technology. Up to now, many studies have demonstrated the engineered organoid models with complex cell composition, controlled structure, enhanced maturation, reduced heterogeneity, and so on. These engineered organoids are high promising for studies in development, disease, tissue repair, precision medicine and drug screening. In this review, a comprehensive summary of the engineered organoid model systems is provided based on microfluidics, hydrogel, 3D printing and so on. Then, the biomedical applications of these models are highlighted, which have displayed the great power in organoid field. Finally, the key bottlenecks and future development of organoid models are discussed about from an engineering perspective. [ABSTRACT FROM AUTHOR]

Hydrogel patches have outstanding values in wound treatment; challenges in this field are concentrated on developing functional and intelligent hydrogel patches with new antibacterial strategies for improving healing process. Herein, a novel melanin‐integrated structural color hybrid hydrogel patches for wound healing is presented. Such hybrid hydrogel patches are fabricated by infusing asiatic acid (AA)‐loaded low melting‐point agarose (AG) pregel into the melanin nanoparticles (MNPs)‐integrated fish gelatin inverse opal film. In this system, MNPs not only impart the hybrid hydrogels with properties of photothermal antibacterial and antioxidant, but also improve the visibility of structural colors by providing an inherent dark background. Besides, the photothermal effect of MNPs under near‐infrared irradiation can also trigger liquid transformation of AG component in hybrid patch, resulting in the controllable release of its loaded proangiogenic AA. Attracting, this drug release induced refractive index variations in the patch can be detected as visible structural color shifting, which can be used to monitor their delivery processes. Benefiting from these features, the hybrid hydrogel patches are demonstrated to achieve excellent therapeutic effects for in vivo wound treatment. Thus, it is believed that the proposed melanin‐integrated structural color hybrid hydrogels are valuable as multifunctional patches for clinical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] Heart-on-chips have emerged as a powerful tool to promote the paradigm innovation in cardiac pathological research and drug development. Attempts are focused on improving microphysiological visuals, enhancing bionic characteristics, as well as expanding their biomedical applications. Herein, inspired by the bright feathers of peacock, we present a novel optical and electrical dual-responsive heart-on-a-chip based on cardiomyocytes hybrid bright MXene structural color hydrogels for hormone toxicity evaluation. Such hydrogels with inverse opal nanostructure are generated by using pregel to replicate MXene-decorated colloidal photonic crystal (PhC) array templates. The attendant MXene in the hydrogels could not only enhance the saturation of structural color, but also ensure the composite hydrogel with excellent electroconductivity to facilitate the synergetic beating of their surface cultured cardiomyocytes. In this case, the hydrogels would undergo a synchronous deformation and generate shift in corresponding photonic band gap and structural color, which could be employed as visual signal for self-reporting of the cardiomyocyte mechanics. Based on these features, we demonstrated the practical value of the optical and electrical dual-responsive structural color MXene hydrogels constructed heart-on-a-chip in hormone toxicity testing. These results indicated that the proposed heart-on-a-chip might find broad prospects in drug screening, biological research, and so on. [ABSTRACT FROM AUTHOR]

Erythrocytes are the most abundant cells in the blood. As the results of long‐term natural selection, their specific biconcave discoid morphology and cellular composition are responsible for gaining excellent biological performance. Inspired by the intrinsic features of erythrocytes, various artificial biomaterials emerge and find broad prospects in biomedical applications such as therapeutic delivery, bioimaging, and tissue engineering. Here, a comprehensive review from the fabrication to the applications of erythrocyte‐inspired functional materials is given. After summarizing the biomaterials mimicking the biological functions of erythrocytes, the synthesis strategies of particles with erythrocyte‐inspired morphologies are presented. The emphasis is on practical biomedical applications of these bioinspired functional materials. The perspectives for the future possibilities of the advanced erythrocyte‐inspired biomaterials are also discussed. It is hoped that the summary of existing studies can inspire researchers to develop novel biomaterials; thus, accelerating the progress of these biomaterials toward clinical biomedical applications. [ABSTRACT FROM AUTHOR]

Avian coccidiosis causes huge economic losses to the poultry industry worldwide and currently lacks effective live vector vaccines. Achieving efficient antigen delivery to mucosa-associated lymphoid tissue (MALT) is critical for improving the effectiveness of vaccines. Here, chicken claudin-3 (CLDN3), a tight junction protein expressed in MALT, was identified as a target, and the C-terminal region of Clostridium perfringens enterotoxin (C-CPE) was proven to bind to chicken CLDN3. Then, a CLDN3-targeting Lactobacillus plantarum NC8-expressing C-CPE surface display system (NC8/GFP-C-CPE) was constructed to successfully express the heterologous protein on the surface of L. plantarum. The colonization level of NC8/GFP-C-CPE was significantly increased compared to the non-targeting strain and could persist in the intestine for at least 72 h. An oral vaccine strain expressing five EGF domains of Eimeria tenella microneme protein 8 (EtMIC8-EGF) (NC8/EtMIC8-EGF-C-CPE) was constructed to evaluate the protective efficacy against E. tenella infection. The results revealed that CLDN3-targeting L. plantarum induced stronger mucosal immunity in gut-associated lymphoid tissues (GALT) as well as humoral responses and conferred better protection in terms of parasite replication and pathology than the non-targeting strain. Overall, we successfully constructed a CLDN3-targeting L. plantarum NC8 surface display system characterized by MALT-targeting, which is an efficient antigen delivery system to confer enhanced protective efficacy in chickens against E. tenella infection. [ABSTRACT FROM AUTHOR]

Void defects in the matrix and between fibers inevitably occur during fabricating of fiber reinforced composites. Although the effects of matrix voids or interfiber voids on the properties of composites have been studied recently, the failure mechanisms and the damage evolution of composites with matrix voids and interfiber voids are still challenging to explore. The coupling effect between matrix voids and interfiber voids is also unclear. This work established three-dimensional parametric microstructure models simultaneously containing matrix voids and interfiber voids. The effects of void types and void volume fractions on the strength of composites are investigated quantitatively by the computational model. The damage evolution process is visualized, and the failure mechanisms and the coupling effect between various voids are explained on the microscale. Additionally, the failure envelopes of composites with different void volume fractions are provided in τ 13 - σ 22 stress space, which has good agreements with both the Hashin–Rotem and Puck failure criteria. The verified computational model composed of the microstructure model and the failure envelopes can help designers accurately and conventionally predict the properties of composite materials in engineering. [ABSTRACT FROM AUTHOR]

Light scattering and absorption during underwater propagation lead to colour distortion and fogging in underwater images, lacking reference for undegraded images, posing challenges in directly applying the underwater images to real-world scenes. We provide a novel approach for generating underwater images by utilizing a conditional diffusion model to address this issue. Besides, we present a novel approach called Ghost-UNet to address the issue of substantial memory and computational demands in implementations of deep convolutional neural networks. Compared with previous methods, our method exceeds 3.8% and 1.7% in the peak signal-to-noise ratio and underwater colour image quality evaluation respectively. Additionally, our method leads to a 0.016-second gain in test speed. The parameters of Ghost-UNet is 1/39 of a transformer model. Ghost-UNet is highly suitable for real-time underwater image enhancement network implementation. [ABSTRACT FROM AUTHOR]

[Display omitted] • An efficient/accurate model for predicting interface fatigue performance is proposed. • A multi-fidelity RSM for MPH structures with micro-structure interlock is developed. • The non-synergistic mechanisms on MPH static and fatigue performances are elucidated. • The developed methodology for predicting MPH's performance is validated in industry. Metal-polymer hybrid (MPH) structures, featuring a micro-structure interlocking design, combine the high strength of metal with the exceptional formability of polymer-based composites and have gained significant attention in automotive load-bearing components. Challenges persist in accurately predicting MPH structure fatigue life using small samples with diverse interlock parameters and swiftly generating static strength and fatigue life response surfaces for automated optimization. We introduce a simplified model for predicting fatigue at the interfaces of MPH structures. Our multi-fidelity prediction method integrates this model with limited high-fidelity data samples to assess both the static strength and fatigue life effectively. This method predicts the deviation with less than 3% error compared to FSR-FEM, achieving a reduction in prediction time of over 60%. Additionally, we elucidate the non-synergistic mechanisms of key interfacial locking parameters between static strength and fatigue life at the micro-scale. Finally, we propose and apply a multi-objective synergistic optimization strategy to the MPH thrust rods in vehicles. By utilizing our optimization method, we achieve a 27.9% weight reduction compared to steel counterparts, while enhancing overall tensile strength by 11.8% and significantly improving fatigue life by 46.7% compared to MPH torque rods lacking an interlock interface. [ABSTRACT FROM AUTHOR]

Heart‐on‐a‐chip plays an important role in revealing the biological mechanism and developing new drugs for cardiomyopathy. Tremendous efforts have been devoted to developing heart‐on‐a‐chip systems featuring simplified fabrication, accurate imitation and microphysiological visuality. In this paper, the authors present a novel electroconductive and anisotropic structural color hydrogel by simply polymerizing non‐close‐packed colloidal arrays on super aligned carbon nanotube sheets (SACNTs) for visualized and accurate heart‐on‐a‐chip construction. The generated anisotropic hydrogel consists of a colloidal array‐locked hydrogel layer with brilliant structural color on one surface and a conductive methacrylated gelatin (GelMA)/SACNTs film on the other surface. It is demonstrated that the anisotropic morphology of the SACNTs could effectively induce the alignment of cardiomyocytes, and the conductivity of SACNTs could contribute to the synchronous beating of cardiomyocytes. Such consistent beating rhythm caused the deformation of the hydrogel substrates and dynamic shifts in structural color and reflection spectra of the whole hybrid hydrogels. More attractively, with the integration of such cardiomyocyte‐driven living structural color hydrogels and microfluidics, a visualized heart‐on‐a‐chip system with more consistent beating frequency has been established for dynamic cardiomyocyte sensing and drug screening. The results indicate that the electroconductive and anisotropic structural color hydrogels are potential for various biomedical applications. [ABSTRACT FROM AUTHOR]

Structural health monitoring technology based on ultrasonic guided waves (UGW) is a potential application for damage detection in plate-like composite structures. This paper introduces a novel physics-augmented spatial–temporal graph convolutional network (P-STGCN) for the damage detection task in composite plate. Firstly, the graph topology containing edge weight attributes is constructed based on the spatial correlation of the sensors and the UGW scattering principle, which strengthens the expression of the data spatial information of the data. Then, a spatial feature extractor and a temporal feature extractor are constructed based on graph convolutional network and convolutional neural network, respectively. Further, the spatial–temporal fusion method is proposed for the first time in the field of UGW damage detection, which enables the perception of multi-level damage information. In addition, a sample compensation attention module based on wavefield scattering energy is designed to compensate for the samples' spatial distribution. Finally, a dataset was constructed in a composite plate containing only four sensors to evaluate the model's performance. The results show that the average localization error is 10.36 mm. Compared with other deep learning localization methods, the P-STGCN model is superior in both localization accuracy and computational resources. [ABSTRACT FROM AUTHOR]

Lamb wave-based technology for damage diagnosis in composite structures has emerged as a promising tool for structural health monitoring (SHM). However, traditional SHM faces challenges in multi-sensor localization, including complex data processing, high costs, and cumbersome maintenance management. The current trend is to employ data-driven approaches, but achieving precise damage localization across the entire structure with fewer sensors still presents difficulties. To address this issue, a damage localization method based on Lamb wave envelope characteristics and modular artificial neural network (M-ANN) is developed. In this approach, the envelope characteristics are employed to characterize the damage information and reduce the data dimension. Subsequently, the M-ANN model is innovatively designed with dropout layers in each hidden layer, significantly enhancing performance on random datasets. In the composite laminate experiment using only four sensors, the proposed method achieves an average relative error of 2.96 % for random damage samples, with 95 % falling within 6.17 %, outperforming other advanced damage localization approaches. Additionally, the method is utilized to investigate the requirements for the relative density of data acquisition under different damage localization needs in composite structures. [Display omitted] • Damage localization method based on envelope characteristics and M-ANN model with modular structure is proposed. • Global high-precision damage localization with only four PZTs is achieved. • The adaptability of the method is verified by experiments of different damage sizes. • Data acquisition requirements for various damage localization needs are explored. [ABSTRACT FROM AUTHOR]

Information security occupies an important position in the era of big data. Attempts to improve the security performance tend to impart them with more additional encryption strategies. Herein, inspired by the wettability feature of Stenocara beetle elytra and signal model of traffic light, a novel array of perovskite nanocrystals (PNs)‐integrated PhC microsphere for information security is presented. The photoluminescent PNs are encapsulated in angle‐independent PhC microspheres to impart them with binary optical signals as coding information. Through the multimask superposition approach, PNs‐integrated PhC microspheres with different codes are placed into fluorosilane‐treated PDMS substrate to form different arrays. These arrays could converge moisture on PhC microspheres in wet environment, which avoids the ions loss of the PNs and effectively prevented mutual contamination. In addition, the fluorescence of the PNs inside PhC microspheres could reversibly quench or recover in response to the environmental moisture. Based on these features, it is demonstrated that the PNs‐integrated PhC microsphere arrays could realize various information encryption modes, which indicate their excellent values in information security fields. [ABSTRACT FROM AUTHOR]

A multistage adaptive lateral deformation tracked robot is proposed based on module design. The mechanical structures of lateral and tracked deformations are established by analyzing the constraints of space barriers and the elastic potential energy change mechanism of internal storage. The interaction of the operating environment and the mechanism is analyzed during the deformation process, and the internal potential energy change mechanism is optimized using the NSGA-II algorithm. The dynamic model is established in RecurDyn software, and the main modules and their coupling relationships are analyzed. Finally, the robot prototype is fabricated, and the obstacle surmounting performance and deformation mode are verified through experimental tests. For small robots, it has the advantages of large load, long driving distance, strong obstacle surmounting ability, and stable steering on the slope, and for robots with the same size, it can increase or decrease its width, has stronger terrain passability and environmental adaptability, so that it can operate in different scenarios within the same mission. [ABSTRACT FROM AUTHOR]

As a fundamental feature of solid surfaces, wettability is playing an increasingly important role in our daily life. Benefitting from the inspiration of biological paradigms and the development in manufacturing technology, numerous wettability materials with elaborately designed surface topology and chemical compositions have been fabricated. Based on these advances, wettability materials have found broad technological implications in various fields ranging from academy, industry, agriculture to biomedical engineering. Among them, the practical applications of wettability materials in biomedical‐related fields are receiving remarkable researches during the past decades because of the increasing attention to healthcare. In this review, the research progress of materials with specific wettability is discussed. After briefly introducing the underlying mechanisms, the fabrication strategies of artificial materials with specific wettability are described. The emphasis is put on the application progress of wettability biomaterials in biomedical engineering. The prospects for the future trend of wettability materials are also presented. [ABSTRACT FROM AUTHOR]

Background: Nurses represent China's largest healthcare workforce. Nurse practitioners (NPs) play an essential role in providing cost-effective quality healthcare and bridging the healthcare gaps. However, NPs are relatively new in China, and limited evidence exists on senior nurses' knowledge of and attitudes toward NPs. Aims: This study aimed to describe senior nurses' knowledge, attitudes, and perceived facilitators and barriers of NPs in China using a self-designed, culturally adaptive questionnaire. Methods: A cross-sectional online survey was conducted among 412 senior nurses in Hunan Province from December 2021 to January 2022. The Knowledge and Attitudes towards Nurse Practitioners Questionnaire (KANPQ) was developed based on the Delphi method, which included 30 items under three dimensions: knowledge (22 items), attitude (2 items), and perceived facilitators and barriers (6 items). Multivariate linear regression was conducted to explore factors associated with senior nurses' attitudes toward NPs. Results: The average KANPQ knowledge score was 68.56 ± 22.69, with 55.09%,10.20%, and 34.71% of participants showing good, moderate, and poor levels of knowledge, respectively. The average KANPQ attitude score was 7.79 ± 1.72, with 65.3% thinking NPs were necessary and 69.9% expressing willingness to become NPs. Nurses with higher professional titles and better knowledge of NPs had more positive attitudes toward NPs. The three most frequently mentioned barriers to NP implementation were patient trust, laws, and education. Conclusions: Approximately one-third of senior nurses have poor knowledge and negative attitudes toward NPs, indicating much room for improvement. Strengthening the education and training of NPs, especially among those with lower professional titles and lower knowledge of NPs, may help improve their knowledge and attitudes toward NPs. In addition, continuous political, social, economic, and individual efforts are needed to facilitate the successful development of NPs in China. [ABSTRACT FROM AUTHOR]

Polymer‐matrix composites are widely used in various industries due to their high specific strength and specific stiffness. However, the void formation is inevitable as a by‐product during manufacturing processes, which may have negative effects on its mechanical properties. The purposes of this paper are to quantitatively evaluate the influence of voids on the anisotropic elastic properties of composites and to provide corresponding theoretical prediction models. Firstly, three‐dimensional representative volume elements (RVE) of fiber‐reinforced composite materials with different fiber contents (36.37%, 45.47%, 50.92%) and different void contents (1%, 3%, 5%, 7%) are established. To obtain the elastic properties in different directions, various periodic boundary conditions are applied to the RVE models and corresponding subroutines are developed by ABAQUS‐PYTHON. Secondly, a series of theoretical models are proposed to quickly predict the anisotropic elastic properties of unidirectional fiber/epoxy composites containing random‐sized void defects, which agree well with the finite element simulation results. Especially, the proposed models have concise expressions, which require only a few parameters to be input, and hence they are convenient for engineering application. Both theoretical and numerical results show that void defects have an obvious influence on the transverse modulus, major Poisson's ratio, and the out‐of‐plane shear modulus. When the void volume reaches 7%, all of the properties mentioned above decrease by more than 10% for the FRPs studied. [ABSTRACT FROM AUTHOR]

The five epidermal growth factor-like domains (EGF) of Eimeria tenella microneme protein 8 (EtMIC8) (EtMIC8-EGF) plays a vital role in host cell attachment and invasion. These processes require interactions between parasite proteins and receptors on the surface of host cells. In this study, five chicken membrane proteins potentially interacting with EtMIC8-EGF were identified using the GST pull-down assay and mass spectrometry analysis, and only chicken (Gallus gallus) epithelial cell adhesion molecule (EPCAM) could bind to EtMIC8-EGF. EPCAM-specific antibody and recombinant EPCAM protein (rEPCAM) inhibited the EtMIC8-EGF binding to host cells in a concentration-dependent manner. Furthermore, the rEPCAM protein showed a binding activity to sporozoites in vitro , and a significant reduction of E. tenella invasion in DF-1 cells was further observed after pre-incubation of sporozoites with rEPCAM. The specific anti-EPCAM antibody further significantly decreased weight loss, lesion score and oocyst output during E. tenella infection, displaying partial inhibition of E. tenella infection. These results indicate that chicken EPCAM is an important EtMIC8-interacting host protein involved in E. tenella -host cell adhesion and invasion. The findings will contribute to a better understanding of the role of adhesion-associated microneme proteins in E. tenella. • EtMIC8-EGF binds to chicken epithelial cell adhesion molecule (EPCAM). • EPCAM is involved in E. tenella -host cell adhesion and invasion. • The specific anti-EPCAM antibody shows partial inhibition of E. tenella infection. • Contributing to a better understanding of the role of adhesion-associated MICs in E. tenella. [ABSTRACT FROM AUTHOR]

The existing commercial software can only predict the fatigue life of homogeneous materials/structures under constant amplitude loading. This work developed a software tool that could predict the fatigue life of the adhesive interface under variable amplitude loading by embedding a modified fatigue cohesive zone model and amplitude variation function. Central to this innovation is the load sequence effect factor (γ), designed to consider nuanced influences like the shock effect of stepped amplitude changes on the fatigue properties. The effects of the block loading sequence on the fatigue life and crack growth rate of the adhesive interface were investigated numerically, and the influence of stepped amplitude on the evolution of a damage zone ahead of the main crack front was observed. It was found that the loading sequence from Low to High (L-H) accelerated the crack growth rate and reduced the fatigue life, and vice versa. Under the same fatigue life, a constant amplitude fatigue equivalence (CAFE) strategy is proposed, which could convert a variable amplitude road spectrum into a constant amplitude load more suitable for the testing bench. The proposed tool and method are also suitable for bi-material interface failure prediction under variable amplitude fatigue loading. [Display omitted] • A fatigue prediction method under variable amplitude fatigue loading is proposed. • A software tool is developed and the fatigue simulation accuracy for adhesive interface is within 15 %. • The influence of load sequence on crack growth rate of adhesive interface is investigated quantitatively. • An equivalence strategy replacing VAF load by CAF one is proposed for tests and simulation. [ABSTRACT FROM AUTHOR]

To improve the adaptive motion performance of traditional wall-climbing robots on variable-curvature facades, a crawler-type wall-climbing robot suitable for ship wall features is proposed by utilizing the advantages of passive mechanisms in realizing autonomous robots. The robot consists of two passive adaptive crawler mechanisms and a connecting module. Each track structure contains multiple permanent magnets that can passively adapt to concave and convex facades of different curvatures. A static failure model is established according to the characteristics of the triangular distributed load, and the minimum adsorption force required for the robot to achieve safe motion is determined. The Halbach Array magnetic circuit design method was used to construct a gap-type permanent magnet adsorption model for lightweight design. The influence of wall thickness and air gap distance on the adsorption force is analyzed by parametric simulation. The prototype platform test shows that the robot can realize adaptive variable curvature motion through passive adjustment of the mobile mechanism attitude and has a certain load capacity. [ABSTRACT FROM AUTHOR]

Monitoring the damage of adhesive joining could avoid potential accidents in multimaterial lightweight vehicles. Different from the additional sensors, a kind of functional adhesives with hybrid fillers of carbon nanotubes (CNTs) and carbon black (CB) was developed, and verified by in-situ sensing of adhesion damage in single-lap shear joints (SLAJ) of composite-to-metal. The influences of the total weight percent of fillers and relative ratio of CNT-to-CB on the mechanical, piezoresistive and the microwave absorption performance of SLAJ were investigated experimentally. The addition of both CNTs and CB increases the cohesive shear strength but decreases the failure strain at the same time. For the formula of total 2wt.% fillers and CNT:CB = 1:3, the shear strength of SLAJ is nearly 37.50% higher than that of pure adhesives. Both CNT and CB lead to the reduction of electrical resistivity. When approaching the failure strain, the electric resistances for all CNT-to-CB ratios increase sharply. For this formula, the relative electric resistance ratio is 29% at strain 0.038, close to the failure strain. The adhesives with this formula also show a better microwave absorption. This research shows a potential application of adhesives with hybrid nanoparticles in lightweight and low-cost structural health monitoring. [ABSTRACT FROM AUTHOR]

This paper presents an extensive investigation on the low-energy impact damage and post-impact fatigue of composite/steel and composite/composite adhesive joints experimentally and numerically. Using carbon-fiber and glass-fiber reinforced plastics (CFRP and GFRP) as well as high-strength steel (HSS), four kinds of adhesive joints were fabricated, i.e., CFRP/CFRP, CFRP/HSS, GFRP/GFRP and GFRP/HSS single-lap joints (SLJ). The impact damage of the joints under different energy impacts was analyzed and introduced into the fatigue simulation. A multi-step coupling numerical method was proposed and validated to predict the post-impact fatigue life of the adhesive joints cost-effectively and conveniently. The effects of the impact energy density and the adherend/adhesive stiffness ratio were studied. The results show that the post-impact fatigue life decreases with the increasing impact energy density. The life decrease percentage of 1275 mJ/g impact condition is approximately more than seven times that of 425 mJ/g impact condition. The post-impact fatigue life of composite/steel joints is more susceptible to low-energy impact damage than that of the composite/composite joints. Reducing the flexural stiffness difference between two adherends as well as the adhesive can improve the post-impact fatigue life of the adhesive joints in composites. [ABSTRACT FROM AUTHOR]

Low velocity impact behavior of carbon fiber reinforced thermoplastic laminates are analyzed in this article. Governing equations are derived based on the first‐order shear deformation theory and Hamilton's principle. The impact contact force history between the impactor and laminate is formulated by the Hertzian contact law. A Ritz‐based solution in space domain for various boundary conditions is developed. Solutions of the system equations in time domain are solved by the Newmark's time integration scheme. Impact parameters such as impact force history, indentation history, and contact time are considered. The accuracy of this method is validated by comparing the obtained results with those from the ABAQUS/Explicit software simulation. The effects of impact velocity, plate geometrical parameters, stacking sequence, and temperature on the dynamic response of laminates under clamped boundary condition and support boundary condition were discussed. [ABSTRACT FROM AUTHOR]

As simulators of organisms in Nature, soft robots have been developed over the past few decades. In particular, biohybrid robots constructed by integrating living cells with soft materials demonstrate the unique advantage of simulating the construction and functions of human tissues or organs, thus attracting extensive attention and research interest. Here, we present up-to-date studies concerning biohybrid robots with various biological actuators such as contractile cells and microorganisms. After presenting the basic components including biological components and synthetic materials, the controlling methods and locomotion modalities of biohybrid robots are clarified and summarized. We then focus on the applications, especially the biomedical applications, of the biohybrid robots including drug delivery, bioimaging, and tissue engineering. The challenges and prospects for the future development of biohybrid robots are also presented. [ABSTRACT FROM AUTHOR]

Biological soft robots have attracted extensive attention and research because of their superiority in executing designed biomedical missions compared with conventional robots. Here, inspired by the crawling mechanism of snakes and caterpillars, a novel biological soft robot composed of asymmetric claws, a carbon nanotube (CNT)‐induced myocardial tissue layer, and a structural color indicator is presented. The asymmetric claws can assist the whole soft robot to accomplish directional movement during the cardiomyocytes' contraction process. The oriented conduct of the CNT layer can regulate the cardiomyocytes' arrangement and improve their beating capability and the contraction performance. However, the structural color indicator provides a visualized monitoring approach to dynamically and immediately reflect the motion status of the biological soft robots. With these three functional layers, the cardiomyocyte‐driven soft robot can greatly simulate the crawling behavior of a caterpillar. It is demonstrated that by integrating these soft robots in a microfluidic organ‐on‐a‐chip system with multitrack construction, they can run along the tracks and exhibit different running speed based on the stimulus concentrations in the tracks. These features indicate the potential values of the cardiomyocyte‐driven soft robots for providing an effective screening platform for clinical diseases. [ABSTRACT FROM AUTHOR]

The precise and stable detection of damage in carbon fiber composite material structures holds immense significance in ensuring the continuous, secure functioning of equipment used for long-term services and averted calamities. This paper proposes a novel damage localization method for composite materials structures named global-local feature cross-fusion network (GLFCFN), which utilizes advanced deep learning methodologies, namely convolutional neural network (CNN), gated multi-layer perceptron (gMLP), and multi-head attention mechanism, coupled with ultrasonic guided wave (UGW) based structural health monitoring (SHM) technique, in order to improve the damage localization performance. Firstly, a novel feature extraction method is proposed, which constructs local feature extractor and global perception feature extractor based on CNNs and MLPs, respectively, to extract more comprehensive damage indices. Secondly, a feature fusion method based on the multi-head attention mechanism is developed to allow interactive fusion of local features and global perception features to automatically summarize the important feature representations of damage information, thereby effectively improving the accuracy and stability of damage localization. Finally, the performance of the method is evaluated using simulated damage experiments on a composite material laminate with only four transducers. The results indicate that the proposed method achieves a mean relative error of 3.54 % on the 100 unseen samples, with a standard deviation of localization errors at 5.83 mm, compared with other deep learning-based damage localization methods, the proposed GLFCFN method has superior performance. [Display omitted] • GLFCFN method is proposed to achieve precise and stable damage localization in composite structures with only four sensors. • The local and global feature extractors was developed, enabling GLFCFN to extract rich damage info from complex signals. • A global-local feature fusion method is developed, enabling GLFCFN to more efficiently learn important damage features. • The method automatically extracts high-level features from UGW signals, eliminating complex feature engineering. [ABSTRACT FROM AUTHOR]

To predict the strength of plain weave fabric composites (PWFCs) quickly, an analytical model was developed by simplifying it as a three‐layer orthogonal laminate (0°/90°/0°). The undulation effects of fibers were taken into account based on stiffness and strength degradation theory. Moreover, less memory space is occupied due to the symmetry in ply stacking of the simplified laminate model. A PWFC was taken as an example to obtain the undetermined coefficients in the proposed analytical model. In comparison with the available experiment results the prediction accuracy of our method was checked. It demonstrates that the prediction errors for tensile strength of PWFCs are less than 10%, while the total modeling and computing time is no more than 30 s. Therefore, the proposed model is very suitable for quick conceptual design in engineering applications of PWFCs. Moreover, it is easy to extend this model to predict strength of PWFCs with other woven patterns, for example, triaxial woven composites. POLYM. COMPOS., 40:2391–2399, 2019. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

As a new class of two-dimensional (2D) materials, molybdenum disulfide (MoS 2) has huge potential in biomedical area; while its applications in multiplex bioassays are still a challenge. Here, we present novel MoS 2 -integrated silica colloidal crystal barcode (SCCB) for multiplex microRNA (miRNA) screening. MoS 2 was adsorbed on SCCBs by electrostatic interaction, and quantum dots (QDs) decorated hairpin probes were coupled on MoS 2 by covalent linkage. As the MoS 2 could quench the QDs of the hairpin probes, they together formed a molecular beacon (MB) structure before the detection. When used in assays, target miRNA could form a double strand with the probe and made QDs keep away from MoS 2 sheets to recovery their fluorescence. Because the released QDs were positively correlated with the concentration of the hybridized nucleic acid, the target miRNAs could be quantified by measuring the fluorescence signal of the QDs on the SCCBs. In addition, by utilizing different MoS 2 -integrated structural color encoded SCCBs, multiplexed miRNA quantification could also be realized. Based on this strategy, we have demonstrated that several pancreatic cancer-related miRNAs could be selectivity and sensitivity detected with a detection limit of 4.2 ± 0.3 nM. These features make the MoS 2 -integrated SCCB ideal for many potential applications. • A novel MoS 2 -integrated silica colloidal crystal barcodes (SCCBs) for multiplex miRNA screening. • MoS 2 sheets on SCCBs and the QD-decorated hairpin probes formed a molecular beacon (MB) structure for target detection. • MiRNAs could be quantified by measuring the fluorescent signal which positively correlated with their concentration. • The label-free strategy demonstrated good accuracy and high sensitivity multiplexed miRNA quantification. [ABSTRACT FROM AUTHOR]

Abstract Thermoplastic elastomer (TPE) incorporates the large deformation capability of rubber with the formability and recyclability of thermoplastics. When mixed with conductive carbon allotropes, it has potential application for sensors. Herein, various weight ratios of one-dimensional carbon nanotubes (CNTs) to zero-dimensional carbon black (CB) are introduced to the biocompatible TPE poly(styrene-ethylene-butylene-styrene) (SEBS) system to modulate its sensing behaviors, including electrical, mechanical hysteresis and piezoresistive sensitivity properties. The lowest percolation threshold is achieved experimentally when this ratio is 1:3. Energy loss due to the mechanical hysteresis decreases when CNTs are replaced with CB, which indicates a good recoverability for sensors under repeated stretching and releasing loads. Respecting to piezoresistive sensibility, theoretical models are proposed to explain the sensing mechanism. Especially, the highest gauge factor (GF = 9.872) meaning the highest sensitivity is obtained for this formula. SEM is used to illustrate the correlated mechanisms. This paper presents a promising tunable technology for large deformation sensors. Highlights • SEBS nanocomposites filled by CNTs and CB are prepared and their electrical conductivities are investigated experimentally. • The mechanisms of the decrease of mechanical hysteresis energy losses due to the replacement of CNTs with CB are explained. • The replacement of CNTs with CB brings a higher and more stable piezoresistive sensitivity and the mechanisms are explained. • Mathematical models of sensing mechanisms are proposed and all parameters are identified to explore the sensing mechanisms. • This study provides a guideline for tailoring the sensing behaviors using hybrid nanofillers for large deformation sensors. [ABSTRACT FROM AUTHOR]

Abstract Metal polymer hybrid technology is a promising way of automotive weight reduction and safety improvement. In this study, high strength steel and glass-fiber reinforced PA66 composite were integrated by direct injection molding process. The mechanical properties and failure behavior of steel/composite hybrids under tension, bending, mode I and II fracture loads were investigated experimentally, theoretically and numerically. The properties of the interface between steel and composite were measured using double cantilever beam and end-notched flexure tests for the first time. The analytical model and finite element simulation considering the interface mechanical behavior were proposed and validated. They can be utilized to predict the mechanical properties and progressive failure process of hybrid material cost-effectively and accurately. It is found that the cracks initiate at the interface, and then propagate through composite until the hybrid material loses load-carrying capacity completely. The steel dominates the load-bearing capacity, and the interface dominates the failure process. The results obtained in this study offer a scientific guidance and theoretical basis for the engineering application of metal polymer hybrid materials. [ABSTRACT FROM AUTHOR]

Abstract Glass fiber aluminium laminate (GLARE) is a kind of fiber metal laminates widely applied in aircraft structures, frequently subjected to low-velocity impact incidents. The purpose of this paper is to investigate the dynamic response and damage mechanism characterization of GLARE under single and repeated low-velocity impacts. Firstly, a progressive degradation finite element (FE) model was developed and validated. Three different failure criteria were compared to analyze the damage behavior of composites of GLARE in terms of accuracy and efficiency, wherein a user defined material subroutine VUMAT was introduced. Then, the validated model was used to study the influence of the impact angle. Four different impact angles including 30°, 45°, 60° and 90° were analyzed in terms of plastic deformation, impact contact force, energy absorption and internal damage. Finally, the simulation of GLARE subjected to repeated impacts was carried out, in which the cumulative damage effects were considered. The detailed dynamic response and damage evolution of aluminium layers and composite layers as well as their interfaces with the number of impacts increasing were revealed. [ABSTRACT FROM AUTHOR]

Abstract Multi-material hybrid application is an effective way of automotive weight reduction. This paper proposes and validates a direct injection-molding adhesion process for polymer composite–metal hybrid (PMH) materials to overcome several limitations of existing PMH technologies. The fundamental tension and bending properties of PMH materials are investigated by experiments. The force–displacement curves of PMH coupons present a multi-stage feature, which is the cumulative results of two constituent materials, and a typical stepwise progressive failure process was observed. Furthermore, scanning electron microscopy and digital image correlation observations reveal the failure mechanisms of PMH materials at micro-scale, including polymer composite–metal interface debonding, brittle fracture of thermoplastic matrix, glass fiber breakage or pull-out from matrix, and ductile failure of steel. The convex–concave interlocking mechanism plays an important role in PMH interface bonding. Under tension and bending loads, the rule of mixture prediction method for modulus and strength of PMH coupons have a high precise compared with the test results. These basic material characteristics may serve as a foundation for the future engineering applications of PMH load-bearing components. [ABSTRACT FROM AUTHOR]

Highlights • Low-velocity impact investigations were conducted on steel/short glass-fiber reinforced thermoplastic hybrid plates fabricated by a direct injection molding process. • A finite element model is developed successfully to predict the low-velocity response of direct injection molding hybrid plates. • The interface between steel and thermoplastic composite is a weak position in the hybrid material systems and sensitive to low-velocity impact loading. • Plastic deformation of steel layer, fracture of injection composite layer and the interface delamination are three main failure modes. • The incident angle significantly affects the dynamic response of direct injection molding hybrid plates under low-velocity impact loading. Abstract Low-velocity impact tests were carried out on steel/short glass-fiber reinforced thermoplastic hybrid plates fabricated by a direct injection molding process. The impact response such as absorbed energy, peak force, dent depth and damage area was studied. A finite element model based on the data obtained from the dynamic and static tests of the constituent materials has been proposed to predict the response and failure behavior of hybrid plates under low-velocity impact loading, which is validated by comparing experimental results. Using the validated model, the damage process of the thin interface between steel and composite was analyzed conveniently and cost-effectively. It is found that the plastic deformation of steel, the fracture of composite and the interface delamination are three main failure modes. After the minor plastic deformation of constituent materials, the interface delamination occurred and propagated rapidly. In addition, the finite element model is developed successfully to investigate the effects of the impact velocity, the incident angle as well as the constituent material thickness on the impact behavior of hybrid plates. The results obtained in this study can support the design and optimization of load-bearing metal-polymer hybrid (MPH) structures. [ABSTRACT FROM AUTHOR]

In this work, we present a simple droplet microfluidic approach for generating graphene oxide (GO) hydrogel composite particles for oil decontamination. By stepwise solvent exchanges, the resulted hydrophilic GO hydrogel composite particles were transferred into organic media without any chemical modifications. As the GOs were locked tightly in hydrogel network, they were hardly changed during the processes of solvent exchanges. Thus, their polar surfaces remained in direct contact with the exchanged organic media, which indicated that the transferred GO particles were capable of effectively adsorbing polar impurities. Attractively, by encapsulating hollow cores and additional magnetic nanoparticles into the emulsion templates during the fabrication, the GO hydrogel composite particles were imparted with hierarchical porous structures and controllable movement capability, both of which could improve their efficiency of impurities adsorbing. These features make the GO hydrogel composite particles described here ideal for oil decontamination. [ABSTRACT FROM AUTHOR]

Difficulties of in vitro culture and genetic manipulation of Eimeria tenella have hindered the screening of virulence factors in this parasite. In this study, the E. tenella rhoptry protein 30 (EtROP30) was expressed in Toxoplasma gondii (RH∆Ku80-EtROP30), and its effect on the proliferation and virulence of parasites was investigated. The results revealed that the expression of EtROP30 had no impact on the invasion and egress processes. However, the RH∆Ku80-EtROP30 strain formed larger plaques compared to the RH∆Ku80, indicating that the EtROP30 expression promotes T. gondii proliferation. Furthermore, the RH∆Ku80-EtROP30 strain exhibited greater pathogenicity, resulting in earlier mortality and shorter overall survival time compared to RH∆Ku80. These results imply that EtROP30 expression facilitates parasite intracellular proliferation and virulence in mice, suggesting that EtROP30 might be a candidate virulence factor of E. tenella. [ABSTRACT FROM AUTHOR]

Abstract Organic sheet overmolding injection (OSOI) is an integrated manufacturing process in which thermoplastics or composites are injected directly on the back of thermoformed organic sheets. It is one of the most promising processes to obtain lightweight structures with excellent mechanical properties and complex geometry. Microstructures, mechanical properties and bonding mechanisms of the interface between injection and thermoformed composites were investigated using SEM analysis, nano-indentation tests and molecular dynamics simulation, because the interface may be the weakest layer due to the pores, inclusions and thermal-expansion coefficient mismatch. SEM results show that the interface microstructures can be categorized into three kinds of features, that are wavy, bubble, and diffusion configurations, respectively, and they are greatly influenced by the preheating temperature of laminates. By appropriate preheating, the equivalent interface elastic modulus increases approximately 2.3 times. Moreover, the bonding mechanisms of the interface of preheated specimen include micro/nano scale mechanical interlocks, diffusion reaction, Van der Waals force and electrostatic interaction. This research could serve as a foundation for the application of hybrid fiber reinforced thermoplastic polymer. Highlights • Microstructures and properties of hybrid fiber reinforced thermoplastic were studied using SEM and nano-indentation tests. • Three typical kinds of interfacial microstructures, namely, wavy, bubble and diffusion configurations are found. • The contribution of preheating thermo-stamped polymer composites to interface bonding strength was revealed. • A molecular dynamics method to predict interface modulus of hybrid fiber reinforced thermoplastic is proposed and validated. • The interface bonding included micro-mechanical interlocks, diffusion reaction, Van der Waals and electrostatic interaction. [ABSTRACT FROM AUTHOR]

The key issue for polymer-steel direct-adhesion (PSDA) technology is to find an effective and efficient way to enhance the adhesion strength. A high-power precision laser processing method was utilized to form a periodic microstructure on the metal surface before PSDA joining. The corresponding theoretical model was proposed to optimize the processing parameters and establish the relationship between microstructures and adhesion fracture energy. Additionally, single-lap tensile shear tests of PSDA samples with various mircostructures were carried out. The experimental results show that the proposed method could increase the ultimate tensile load by nearly 1.5 times higher than the traditional chemical surface pretreatment. Due to the processing of periodic microstructure could be controlled accurately by machines, the dimensional precision was improved. The investigation also discovered that the packing arrangement of interfacial microstructures affects the adhesion strength and fracture energy, but independent of the roughness. The present method is demonstrated to be an effective, efficient, and economic interface treatment for polymer-steel hybrid structures. [ABSTRACT FROM AUTHOR]

[Display omitted] • A mesoscale model is established to predict the failure of IOAC structure. • The effect of interface waviness on tensile and shear properties is investigated. • The IOAC interface failure mechanism at different waviness is revealed. • The failure process and modes of IOAC structure are predicted visually. The injection overmolding after compression (IOAC) is a promising hybrid process that manufactures the load-bearing parts by assembling the fiber-reinforced thermoplastic (FRTP) laminate with FRTP ribs. However, the size effects of interfacial mechanical interlocking on failure evolution are unclear. A mesoscale model of representative volume element, including the fibers, matrix, matrix-fiber interface as well as the IOAC interface, is established to predict its failure process and failure modes. The influence of IOAC interface waviness (height, width, and thickness) on shear and tensile strength is investigated. The results show that the increased height and thickness positively affect the shear and tensile strength, while the increased width has a negative effect. The crack originates from the wave trough of waveform interface at tensile loading, while it originates between the wave trough and the wave crest under shear loading. The primary failure modes of IOAC structure include interface fracture, matrix damage, and matrix-fiber interface debonding. The results in this work can guide the interface design by changing its waviness through the surface pretreatment and IOAC process control. Visualizing the failure process of IOAC structure can provide some information difficult to capture in tests, which is useful in predicting the failure degree and location of IOAC structure in engineering application. [ABSTRACT FROM AUTHOR]

• The bi-material specimens are fabricated by the IMAC process. • The bi-material interfacial properties are characterized comprehensively. • The influence of surface pretreatment methods on interfacial properties is analyzed. • Mechanisms affecting interface properties are revealed. • The matching design principle of material-process-geometry-property is proposed. Injection molding after compression (IMAC) is used for manufacturing the bi-material structure. However, the bi-material interface may be the weakest region restricting overall structural performance. Various specimens with discontinuous GF30/PA66 or GF30/PA6 over-molded injection on a continuous CF/PA6 sheet are prepared using the IMAC process. The interfacial shear and cross-tension tensile strength, mode-I/II fracture energy, and overall bending strength are then systematically characterized. The influence interlock features derived from sandpaper grinding, sandblasting, and nano-coating have on the properties are then investigated. It is found that decreasing interface roughness can improve interfacial tensile strength and mode-I fracture energy while weakening shear strength and mode-II fracture energy. These surface pretreatments are also effective for the promotion of overall bending strength. A design matching principle between the material, process, geometry, and properties is ultimately proposed. This work provides the fundamental interfacial properties of IMAC structures for engineering applications. [ABSTRACT FROM AUTHOR]

• A multifunctional microneedle patch with aligned CNT sheet basement is presented. • The microneedle patch has photo-thermal and electro-thermal conversion capacity. • The microneedle patch could induce the orientation of fibroblasts. • The multifunctional patch loaded with VEGF could promote wound healing. Wound healing has become a health concern and economic burden worldwide for its high incidence and complexity. Attempts to improve wound treatment tend to develop biomedical patches with delicate structure design and functionality. In this paper, we present novel multifunctional microneedle patches with aligned carbon nanotube (CNT) sheet basement for promoting wound healing. Because of the outstanding biocompatibility, biodegradability and non-immunogenicity, hyaluronic acid (HA) is utilized to construct the CNT-integrated microneedle patch with vascular endothelial growth factor (VEGF) encapsulation. It was found that the aligned CNT layer basement could not only impart the composite microneedle patch with orientation morphology, but also endow the patch with controllable release performance, due to its photo-thermal or electro-thermal conversion capacity. Based on these features, we have demonstrated that the highly ordered microstructure of CNT could effectively induce the orientation of fibroblasts; while VEGF release could facilitate tubular formation of endothelial cells. Thus, the aligned CNT and VEGF-loaded multifunctional patch is beneficial to the wound repair process in a typical animal experiment. These results indicate that the proposed microneedle patch is potentially promising for regeneration medicine. [ABSTRACT FROM AUTHOR]

• The interfacial tensile and shear strength of PMH structures is characterized experimentally. • A series of CZMs for PMH interface with various mechanical interlocks are established. • The mapping relationship between micro parameters and macro performance is developed. • The failure propagation mechanisms of PMH interface at micro/macro-scale are revealed. This paper studies the polymer-metal hybrid (PMH) structures, formed by direct injection over-molding the glass fiber-reinforced polymer (GFRP) composite on the surface of high-strength steel (HSS), which integrate the advantage of HSS and GFRP, and have been applied in the lightweight design of vehicles. However, the existence of an interface between GFRP and HSS weakens the ultimate carrying capacity of the overall PMH structures, and hence, the interface needs further improvement. First, five kinds of PMH specimens with different micro-interlock features were designed and fabricated, and the corresponding interfacial tensile and shear strength (σ I c and σ II c) and fracture toughness (G I C and G II c) were characterized experimentally. An interface constitutive model suitable for describing different mechanical interlocks was established, and the general program for parameter identification was developed in a finite element code. Using this model, the crack evolution mechanisms of PMH structures under tensile and bending loading were revealed. Finally, the micro–macro mapping rule between the interlock features and the ultimate loading of overall PMH structures is proposed. These results are conducive to the lightweight design and performance prediction of PMH structures. [ABSTRACT FROM AUTHOR]

Lead is not only one of heavy metals imposing environment and health risk, but also critical resource to maintain sustainable development of many industries. Recently, due to the shortage of fossil fuels, clean energy vehicles, including electric bicycle, have emerged and are widely adopted soon in the world. China became the world’s largest producer of primary lead and a very significant consumer in the past decade, which has strained the supplies of China’s lead deposits from lithosphere and boost the anthropogenic consumption of metallic lead and lead products. Here we summarize that China’s lead demand will continually increase due to the rapid growth of electric vehicle, resulting in a short carrying duration of lead even with full lead recycling. With these applications increasing at an annual rate of 2%, the carrying duration of lead resource until 2030 will oblige that recycling rate should be not less than 90%. To sustain lead utilization in China, one approach would be to improve the utilization technology, collection system and recycling technology towards closed-loop supply chain. Other future endeavors should include optimizing lead industrial structure and development of new energy. [ABSTRACT FROM AUTHOR]

To avoid the additional damage caused by conductive films embedded between layers of composites and to decrease the complexity of sensing structure manufacturing, a novel conductive smart coating for structural health monitoring is developed. This coating can be applied onto the surface of composite products. Also, a design principle for conductive coatings is proposed to provide design guidelines for sensor materials. A conductive coating with multiwall carbon nanotubes and carbon black is fabricated to verify the design principles. Besides, coating-related properties such as resistance change, conductivity, and failure strain are characterized through experiments. The damage to composite laminates with various thicknesses at tensile and different impact loads is analyzed to verify the monitoring effect of the coating. Additionally, to determine the damage location, a damage localization prototype is proposed. The results of this paper provide a reference and a design method for the engineering application of coated sensors and damage monitoring. • An object-oriented design principle of conductive coatings is proposed. • A MWCNTs/CB waterborne conductive smart coating is fabricated. • The properties of coatings with various formulas are characterized. • The monitoring effect of different CFRTP objectives are investigated. • A damage localization prototype is proposed. [ABSTRACT FROM AUTHOR]

Lactobacillus strains exhibit preferable properties that make them attractive candidates for vaccine delivery systems because of their ability to regulate intestinal mucosal immunity in the body. To date, live Lactobacillus delivery vaccines reported for the defense against Eimeria tenella have been inducer-dependent systems whose applications are significantly limited due to their unattainable induction conditions in vivo. Here, a constitutive expression of Lactobacillus plantarum NC8 surface display system was constructed. Then, this system was used to prepare a live oral vaccine to constitutively express the E. tenella U6L5H2 (EtU6) protein on the NC8 surface and to evaluate its protective efficacy against E. tenella challenge in chickens. The results showed that the heterologous protein (EGFP or EtU6) was successfully expressed on the surface of L. plantarum NC8 without any inducer. The immunoprotection of EtU6 with constitutive expression in L. plantarum NC8 system (NC8/Pc-EtU6) was significantly stronger than that of EtU6 with induced expression of L. plantarum NC8 system (NC8/Pi-EtU6) (ACI: 168.28 vs. 152.74) as evidenced by increased body weight, decreased oocyst output and lesion scores. Furthermore, the constitutive system NC8/Pc-EtU6 produced higher levels of specific cecal SIgA, serum IgG, transcription of cytokines IFN-γ and IL-2, and lymphocyte proliferation than the induced system NC8/Pi-EtU6. These results indicate that, compared to the inducible system, the constitutive surface display system of L. plantarum has the advantages of continuously expressing antigens in vivo and stimulating the host immune system. It could be an ideal platform for vaccine expression. The live vector vaccine for coccidiosis constructed by this constitutive system greatly improves the application potential in chicken production and provides a novel platform for the prevention of coccidiosis in chickens. • First report to use constitutive L. plantarum surface display system against chicken coccidiosis. • It continuously expresses antigens in vivo and stimulates the host immune system. • It could be an ideal platform for vaccine expression. [ABSTRACT FROM AUTHOR]

• A modified phase field model is established to predict the interface failure. • The influence of key parameters on interface fracture behavior is analyzed. • The variation rule of interfacial fracture patterns is acquired. • The mechanism of interfacial void defects on fracture behavior is revealed. When it comes to load transmission of multiple materials in hybrid structures, the interface is crucial. In this paper, the driving force in the established phase field model for predicting the interface fracture behavior is the contribution of mode-I and II fracture energy based on an approximate method. The model can be used to investigate the mixed mode failure by adding the compression strain energy along with the tension strain energy. The correctness of the model is verified experimentally, and the effectiveness is compared with other phase field models. This model investigates the effects of interfacial cohesion, internal friction angle, and fracture energy on failure behaviors. As per the findings, the increasing interfacial adhesion, mode-I fracture energy reduce the interface strength, while the internal friction angle affects it differently. However, the increase of mode-I fracture energy has no effect on compressive-shear fracture patterns of cracks, which is primarily determined by mode-II fracture energy. The interfacial fracture patterns change from normal shear to lateral fractures with the decrease of mode-II fracture energy. Furthermore, the mechanism of interface void defects on fracture behaviors of the multi-material structures has been explained. [ABSTRACT FROM AUTHOR]

Thioredoxin (Trx) is a widespread protein regulator of redox reactions in all organisms. It operates together with NADPH and thioredoxin reductase as a general protein disulfide catalytic system. Recently, Trx has been found to be related to the process by which apicomplexan protozoa invade host cells. In this study, Eimeria tenella thioredoxin (EtTrx1) was identified and its gene structural features, expression levels at different developmental stages, localization in sporozoites, roles in adhesion and invasion, and immunogenicity were investigated. Sequence analysis indicated that EtTrx1 contains a Trx domain with a WCGPC motif in 29–33 aa and a typical Trx fold, and belongs to thioredoxin family. EtTrx1 was detected on the surface of sporozoites using anti-EtTrx1 polyclonal antibodies under non-permeabilized conditions by indirect immunofluorescence assay (IFA) and also in a secretion form. EtTrx1 protein was highly transcribed and expressed in merozoites and sporozoites by quantitative PCR and western blot. The attachment assay showed that the adherence rates of yeast cells expressing EtTrx1 on the surface to host cells were 3.1-fold higher than those of the blank control. Specific anti-EtTrx1 antibodies inhibited the invasion of sporozoites into DF-1 cells. The highest inhibition rate was up to 36.75% compared to the control group. Immunization with recombinant EtTrx1 peptides also showed significant protection against lethal infections in chickens. It could offer moderate protective efficacy (Anticoccidial Index [ACI]: 163.70), induce humoral responses, and be an effective candidate for the development of new vaccines. • EtTrx1 protein locates on the surface of E. tenella sporozoites and is a secreted protein. • EtTrx1 may play a role in host adhesion and invasion. • EtTrx1 protein is immunogenic. [ABSTRACT FROM AUTHOR]

To predict the residual life of structure under repeated impacts, the crack behavior of standard specimens with and without notch were studied experimentally and numerically. The history of crack propagation and energy absorption was recorded, and the fracture surface appearance was observed experimentally. A energy-based life prediction method for repeated impacts was proposed and validated by experiments, which includes the effects of strain rate and cumulative damage. It is found that structures under repeated impacts are extremely sensitive to notch or crack. With the increasing number of impacts, both the ratio of plastic energy to elastic energy raises and finally approaches to infinite at fracture. [ABSTRACT FROM AUTHOR]

With the wide application of carbon fiber reinforced polymer (CFRP) composites, dynamic loading cases are increasingly considered in structural design and analysis. Hence, it is necessary to investigate their dynamic mechanical properties. In this paper, the carbon/epoxy laminates with different stacking sequences prepared by vacuum assisted resin infusion process were studied by quasi-static tension and split Hopkinson tension bar experiments. The loading strain rate is ranged from 2.2 × 10−4 s−1 to 2200 s−1. The results indicate that the composites are strain rate dependent. Four stacking sequence laminates show different strain rate sensitivities, and their mechanical performance differences depend on the strain rate. As the strain rate increases, tensile strength and elastic modulus increase, but failure strain decreases. Therein, the elastic modulus is highly sensitive. The elastic modulus difference of unidirection/cross-ply or unidirection/quasi-isotropic decreases but that of unidirection/angle-ply increases with increasing strain rate. The failure strain difference of unidirection/angle-ply decreases significantly with increasing strain rate. These experimental data and research results could provide some insight for epoxy matrix CFRPs. [ABSTRACT FROM AUTHOR]

The density of polymethyl methacrylate (PMMA) is about half that of inorganic glass. Hence, PMMA is expected to replace inorganic glass in vehicles such as automobiles to reduce weight. High and low temperature environments and dynamic loading need to be considered during its service. In this paper, an experimental investigation on the strain rate and temperature dependent mechanical behavior of PMMA was performed over the environmental temperature range of 243 K to 373 K and the strain rate range of 10−3 s−1 to 103 s−1. CM207 PMMA and PFE50 PMMA were used, and three kinds of specimens were fabricated by injection molding. The results show that two PMMAs have obvious strain rate and temperature sensitivity. The compressive modulus and yield strength increase with increasing strain rate. The strain rate sensitivity factor (SRSF) decreases as the temperature increases, indicating that high temperature can reduce the strain rate effect. PFE50 PMMA is more sensitive to the temperature, but CM207 PMMA is more sensitive to the strain rate. A modified ZWT constitutive model can be used to describe the strain rate and temperature dependent nonlinear mechanical behavior of PMMA. [ABSTRACT FROM AUTHOR]