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The biomedical application of self-healing materials in wet or (under)water environments is quite challenging because the insulation and dissociation effects of water molecules significantly reduce the reconstruction of material–interface interactions. Rapid closure with uniform tension of high-tension wounds is often difficult, leading to further deterioration and scarring. Herein, a new type of thermosetting water-resistant self-healing bioelastomer (WRSHE) was designed by synergistically incorporating a stable polyglycerol sebacate (PGS) covalent crosslinking network and triple hybrid dynamic networks consisting of reversible disulfide metathesis (SS), and dimethylglyoxime urethane (Dou) and hydrogen bonds. And a resveratrol-loaded WRSHE (Res@WRSHE) was developed by a swelling, absorption, and crosslinked network locking strategy. WRSHEs exhibited skin-like mechanical properties in terms of nonlinear modulus behavior, biomimetic softness, high stretchability, and good elasticity, and they also achieved ultrafast and highly efficient self-healing in various liquid environments. For wound-healing applications of high-tension full-thickness skin defects, the convenient surface assembly by self-healing of WRSHEs provides uniform contraction stress to facilitate tight closure. Moreover, Res@WRSHEs gradually release resveratrol, which helps inflammatory response reduction, promotes blood vessel regeneration, and accelerates wound repair.

Dynamic covalent thermosets have emerged as a next-generation sustainable plastic that combines the advantages of traditional thermosets and thermoplastics. However, dynamic covalent thermosets generally suffer from the trade-off between strength/stiffness and ductility/toughness. Herein, a strategy to simultaneously strengthen and toughen dynamic covalent thermosets, incorporation of hydrogen-bonded (H-bonded) cross-links into the dynamic covalent networks, is reported. We designed a polyimine network cross-linked by both the dynamic imine bonds and H-bonds, resulting in a remalleable and recyclable polyimine thermoset with high yield strength (ca. 55.2 MPa) and Young’s modulus (ca. 1.7 GPa) as well as high ductility (ca. 72%) and toughness (ca. 32.7 MJ m–3). When the H-bonded cross-links are removed from the polyimine network or replaced by the imine bonds, the mechanical strength or toughness of the polyimines is significantly declined, respectively. Therefore, this work provides an effective design principle for strong and tough dynamic covalent thermosets with modularity and recyclability.

The COVID-19 pandemic has resulted in huge amounts of face masks worldwide. However, there is a lack of awareness on the additives and their potential risk to aquatic ecosystems of face masks. To address this issue, the additives and their toxicity in 13 face masks (e.g., polypropylene, polyethylene, and polylactic acid) were determined using nontarget analysis and bioassays. A total of 826 organic additives including intermediates (14.8%), surfactants (9.3%), plasticizers (8.2%), and antioxidants (6.1%) were tentatively identified, with 213 compounds being assigned confidence levels of 1 and 2. Interestingly, polylactic acid masks contained more additives than most polypropylene or polyethylene masks. Among these additives, the concentration of tris(2-ethylhexyl) phosphate in masks was 9.4–978.2 ng/g with a 100% detection frequency. Furthermore, 13 metals such as zinc (up to 202.0 μg/g), copper (32.5 μg/g), and chromium (up to 5.7 μg/g) were detected in the face masks. The methanol extracts of the masks showed the developmental toxicity, swimming behavior, and/or endocrine disruption in embryos/larvae of Oryzias melastigma. The findings demonstrate that face masks contain various toxic additives to marine medaka, which deserves close attention to pollution by face masks.

NARROW LEAF1(NAL1) exerts a multifaceted influence on leaf morphology and crop yield. Recent crystal study proposed that histidine 233 (H233) is part of the catalytic triad. Here we report that unlike suggested previously, H234 instead of H233 is a component of the catalytic triad alongside residues D291 and S385 in NAL1. Remarkably, residue 233 unexpectedly plays a pivotal role in regulating NAL1’s proteolytic activity. These findings establish a strong foundation for utilizing NAL1 in breeding programs aimed at improving crop yield.

In engineering applications, concrete crack monitoring is very important. Traditional methods are of low efficiency, low accuracy, have poor timeliness, and are applicable in only a limited number of scenarios. Therefore, more comprehensive detection of concrete damage under different scenarios is of high value for practical engineering applications. Digital image correlation (DIC) technology can provide a large amount of experimental data, and neural network (NN) can process very rich data. Therefore, NN, including convolutional neural networks (CNN) and back propagation neural networks (BP), can be combined with DIC technology to analyze experimental data of three-point bending of plain concrete and four-point bending of reinforced concrete. In addition, strain parameters can be used for training, and displacement parameters can be added for comprehensive consideration. The data obtained by DIC technology are grouped for training, and the recognition results of NN show that the combination of strain and displacement parameters, i.e., the response of specimen surface and whole body, can make results more objective and comprehensive. The identification results obtained by CNN and BP show that these technologies can accurately identify cracks. The identification results for reinforced concrete specimens are less affected by noise than those of plain concrete specimens. CNN is more convenient because it can identify some features directly from images, recognizing the cracks formed by macro development. BP can issue early warning of the microscopic cracks, but it requires a large amount of data and computation. It can be seen that CNN is more intuitive and efficient in image processing, and is suitable when low accuracy is adequate, while BP is suitable for occasions with greater accuracy requirements. The two tools have advantages in different situations, and together they can play an important role in engineering monitoring.

Ketamine, a popular anesthetic, is often abused by people for its hallucinogenic effect. Thus, the safety of ketamine in pediatric populations has been called into question for potential neurotoxic effects. However, ketamine also has neuroprotective effects in many brain injury models. The differentiation of neural stem cells (NSCs) was influenced significantly by ketamine, but the molecular mechanism is still unclear. NSCs were extracted from the hippocampi of postnatal day 1 rats and treated with ketamine to induce NSCs differentiation. Our results found that ketamine promoted neuronal differentiation of NSCs dose-dependently in a small dose range (P < 0.001). The main types of neurons from NSCs were cholinergic (51 ± 4 %; 95 % CI: 41–61 %) and glutamatergic neurons (34 ± 3 %; 95 % CI: 27–42 %). Furthermore, we performed RNA sequencing to promise a more comprehensive understanding of the molecules regulated by ketamine. Finally, we combined bioimaging and multiple molecular biology techniques to clarify that ketamine influences NSC differentiation by regulating transient receptor potential canonical 3 (TRPC3) expressions. Ketamine dramatically repressed TRPC3 expression (MD [95 % CI]=0.67 [0.40–0.95], P < 0.001) with a significant increase of phosphorylated glycogen synthase kinase 3β (p-GSK3β; MD [95 % CI]=1.00 [0.74–1.27], P < 0.001) and a decrease of β-catenin protein expression (MD [95 % CI]=0.60 [0.32–0.89], P = 0.001), thereby promoting the differentiation of NSCs into neurons and inhibiting their differentiation into astrocytes. These results suggest that TRPC3 is necessary for ketamine to modulate NSC differentiation, which occurs partly via regulation of the GSK3β/β-catenin pathway.

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Soft robotics locomotion at the liquid–air interface has become more and more important for an intelligent society. However, existing locomotion of soft robotics is limited to two dimensions. It remains a formidable challenge to realize three-dimensional locomotion (X, Y, and Zaxes) at the liquid–air two-phase interface due to the unbalanced mechanical environment. Inspired by meniscus-climbing beetle larva Pyrrhalta, the mechanism of a three-phase (liquid–solid–air) contact line is here proposed to address the aforementioned challenge. A corresponding 3D printed fully soft robotics (named larvobot) based on photoresponsive liquid crystal elastomer/carbon nanotubes composites endowed repeatable programmable deformation and high degree-of-freedom locomotion. Three-dimensional locomotion at the liquid–air interface including twisting and rolling-up has been developed. The equation of motion is established by analyzing the mechanics along the solid–water surface of the larvobot. Meanwhile, ANSYS is used to calculate the stress distribution, which coincides with the speculation. Moreover, soft robotics is remotely driven by light in a precise spatiotemporal control, which provides a great advantage for applications. As an example, we demonstrate the controllable locomotion of the soft robotics inside closed tubes, which could be used for drug delivery and intelligent transportation.

Fracture is the most common damage form of concrete buildings. Due to the opaqueness of concrete, the internal structure can be hardly observed so that it is difficult to predict the occurrence and development of cracks. Therefore, an image-based modeling method using digital image correlation (DIC) is proposed in this work. The realistic distribution of each phase in a concrete structure is captured by a camera, and the corresponding concrete models are then established for further simulation. With the image-based models, a series of three-point and four-point bending experiments are carried out experimentally and numerically, and their fracture processes are compared. It is revealed that the simulation analysis is in good agreement with the experimental result on crack propagation and the trend of strain in three-point bending tests. It should also be remarked that the image-based model needs to be optimized for simulating crack development in four-point bending tests because of the randomness of crack position, although the strain field of simulation is close to one of the experiments.

In2O3/ITO multilayer thin film thermocouple is a new type of semiconductor thin-film thermocouple, which has broad application prospects. The interface diffusion between the layers is the main cause of its thermal oxidation failure. In this paper, an interface diffusion model of multilayer films is established based on Fick's second law. A sample of In2O3/ITO thin-film thermocouple was prepared, then designed and conducted high temperature test. According to the test results, the diffusion of substances between the film layers was analyzed. Based on the established interface diffusion model, a simulation calculation is carried out. The influence of interface diffusion on the life of In2O3 and ITO sensitive layer was quantitatively analyzed.

High-strength steel plays an important role in engineering fields such as infrastructure. For this reason, an accurate determination of its mechanical properties is of critical importance. Considering the inconvenience of conventional mechanical extensometers for the deformation measurement of small-scale specimens, 3D digital image correlation (3D-DIC) was used to measure the deformation of Grade 8.8 bolts and Q690 high-strength steel specimens by means of a uniaxial tensile test, and in this way, stress–strain curves, elastic modulus, yield strength, tensile strength, percentage elongation after fracture, and percentage reduction of area were obtained. Experimental results show that Grade 8.8 bolts and Q690 steel result in higher yield strength and tensile strength than common steel. Moreover, owing to the phenomenon that stress remains constant with strain increase in the yielding stage, the evolution process from elastic deformation to plastic deformation of the specimens during the yielding stage could be studied. Experimental results show that the axial strain of Grade 8.8 bolts increases from 0.3 to 1 % during the yielding stage and for Q690 specimens the corresponding strain increases from 0.4 to 1.8 %.

Thin film thermocouple (TFTC) is widely used in high temperature measurement, which is of short response time, less heat residual and integrated structure. Due to the ultra-thin structure of TFTC, the interfacial diffusion has a great influence on its reliability when exposed to high temperature environment, which leads to its performance degradation. Taking thermocouple on the turbine blade as research object, the parallel diffusion model of multilayer thermocouple is proposed based on Fick’s law. The reliability model of the protective layer, the sensitive layer and the insulating layer are established in the basis of the parallel diffusion model. According to the logical correlation among the multilayer films of TFTC, the TTF model of TFTC is given. Finally, an example of reliability model based on multilayer diffusion is simulated by Monte Carlo method, which demonstrates the feasibility of the method and model.

Despite advances in technologies for cardiac repair after myocardial infarction (MI), new integrated therapeutic approaches still need to be developed. In this study, we designed a perfusable, multifunctional epicardial device (PerMed) consisting of a biodegradable elastic patch (BEP), permeable hierarchical microchannel networks (PHMs) and a system to enable delivery of therapeutic agents from a subcutaneously implanted pump. After its implantation into the epicardium, the BEP is designed to provide mechanical cues for ventricular remodeling, and the PHMs are designed to facilitate angiogenesis and allow for infiltration of reparative cells. In a rat model of MI, implantation of the PerMed improved ventricular function. When connected to a pump, the PerMed enabled targeted, sustained and stable release of platelet-derived growth factor-BB, amplifying the efficacy of cardiac repair as compared to the device without a pump. We also demonstrated the feasibility of minimally invasive surgical PerMed implantation in pigs, demonstrating its promise for clinical translation to treat heart disease.

Despite decades of research, spinal cord injury (SCI) still causes irreparable damage to the human body. Key challenges that hinder the regeneration and extension of neurons following SCI must be overcome, including the overexpressed glial scar formation and strong inflammatory responses in lesion tissue. Transplantation of neural stem cells (NSCs) represents a promising therapeutic method due to its beneficial roles like growth factor secretion and anti-inflammation. However, NSCs usually differentiate into astrocytes, which is considered as one potential limitation of current NSC therapy. Herein, we fabricate an elastic poly(sebacoyl diglyceride) (PSeD) scaffold to mimic the mechanical properties of the natural spinal cord. The PSeD scaffold is coated with poly(sebacoyl diglyceride)-isoleucine-lysine-valine-alanine-valine-serine (PSeD-IKVAVS) to create a bioactive interface. The core point of this topic is divided into two parts. First, PSeD is a bioelastomer and its mechanical properties are similar to those of the natural spinal cord. This feature reduces the direct stimulation to the spinal cord tissue by the elastomer and then reduces the immune response or resistance caused by the host spinal cord tissue. Second, the IKVAVS peptide modifies PSeD to create a bioactive interface to support NSC growth and differentiation. In the in vivostudy, the number of CD68-positive macrophages decreased in the PSeD-IKVAVS/NSC group compared to that in the SCI group (20% vs 60%). The low inflammation induced by the scaffold was beneficial to NSCs, resulting in increased locomotor recovery, as indicated by the increased Basso–Beattie–Bresnahan score (5, the average score in the PSeD-IKVAVS/NSC group, vs 2, the average score in the SCI group). Based on the above two characteristics, a PSeD-IKVAVS bioelastomer is fabricated, which provides a beneficial and bioactive microenvironment for NSCs after transplantation.

Fiber reinforced plastic (FRP) plays an increasingly important role in many engineering fields due to its advantages of light weight, low cost, simple maintenance, and excellent corrosion resistance. The conventional contact methods for deformation measurement, such as strain gauge and mechanical extensometer, have some shortcomings in measuring the strain of FRP rebar specimens with spiral curved surfaces. Therefore, the non-contact three-dimensional digital image correlation (3D-DIC) technique was employed to determine the tensile mechanical properties of two types of FRP rebar specimens, i. e. glass FRP (GFRP) and carbon FRP (CFRP) specimens. Uniaxial tensile tests with three different loading rates were conducted to obtain the stress-strain curves, elastic modulus, tensile strength and percentage total extension at maximum force of these two FRP specimens. Experimental results indicate that the axial-strain field of all FRP rebar specimens present nonuniform distribution and that the stress of GFRP and CFRP rebars varies linearly with the strain. Moreover, no yielding phenomenon was observed from the stress-strain curves, which indicates that both GFRP and CFRP rebars belong to the group of typical brittle materials. The dispersion of elastic moduli obtained using 3D-DIC is better than that using a clip-on extensometer, which demonstrates the validity of 3D-DIC for the determination of tensile mechanical properties of FRP rebars with spiral curved surfaces.

Fiber reinforced plastic (FRP) plays an increasingly important role in many engineering fields due to its advantages of light weight, low cost, simple maintenance, and excellent corrosion resistance. The conventional contact methods for deformation measurement, such as strain gauge and mechanical extensometer, have some shortcomings in measuring the strain of FRP rebar specimens with spiral curved surfaces. Therefore, the non-contact three-dimensional digital image correlation (3D-DIC) technique was employed to determine the tensile mechanical properties of two types of FRP rebar specimens, i. e. glass FRP (GFRP) and carbon FRP (CFRP) specimens. Uniaxial tensile tests with three different loading rates were conducted to obtain the stress-strain curves, elastic modulus, tensile strength and percentage total extension at maximum force of these two FRP specimens. Experimental results indicate that the axial-strain field of all FRP rebar specimens present nonuniform distribution and that the stress of GFRP and CFRP rebars varies linearly with the strain. Moreover, no yielding phenomenon was observed from the stress-strain curves, which indicates that both GFRP and CFRP rebars belong to the group of typical brittle materials. The dispersion of elastic moduli obtained using 3D-DIC is better than that using a clip-on extensometer, which demonstrates the validity of 3D-DIC for the determination of tensile mechanical properties of FRP rebars with spiral curved surfaces.

Long-segment defects remain a major problem in clinical treatment of tubular tissue reconstruction. The design of tubular scaffold with desired structure and functional properties suitable for tubular tissue regeneration remains a great challenge in regenerative medicine. Here, we present a reliable method to rapidly fabricate tissue-engineered tubular scaffold with hierarchical structure via4-axis printing system. The fabrication process can be adapted to various biomaterials including hydrogels, thermoplastic materials and thermosetting materials. Using polycaprolactone (PCL) as an example, we successfully fabricated the scaffolds with tunable tubular architecture, controllable mesh structure, radial elasticity, good flexibility, and luminal patency. As a preliminary demonstration of the applications of this technology, we prepared a hybrid tubular scaffold viathe combination of the 4-axis printed elastic poly(glycerol sebacate) (PGS) bio-spring and electrospun gelatin nanofibers. The scaffolds seeded with chondrocytes formed tubular mature cartilage-like tissue both via in vitroculture and subcutaneous implantation in the nude mouse, which showed great potential for tracheal cartilage reconstruction.

Hainan Island is located in the northwestern South China Sea at the boundary of two tectonic plates. Surface features and actual drilling have confirmed that there are rich geothermal resources in the area, with predicted resources of 480 million GWh. On the basis of the 1:200,000 gravity and 1:10 aeromagnetic data and constrained by the well-explored Fushan Depression and Baocheng Rock Mass, we conducted a systematic study of hot dry rocks and evaluated the development potential of the geothermal resources of the medium-depth and deep hot dry rocks in Hainan Island for the first time. The island is structurally active, with extensive granites, strong volcanic and earthquake activities, and many hot springs, indicating that the geothermal geological conditions are favorable. There are two types of hot dry rocks, sedimentary basin type and uplifted mountain type, on the island. The sedimentary basin-type hot dry rocks are mainly found in the north of the island and have an area of 2657 km2, an average depth of 2480 m, and an average heat reservoir temperature of 230 °C at 6000 m depth. Uplifted mountain-type hot dry rocks with a total area of 13,000 km2mainly occur in Danzhou in the north of the island and Baocheng in the south. The heat reservoirs of these rocks are Yanshanian intrusive plutons and the average temperature is 236 °C at 6000 m depth. Nine favorable hot dry rock targets are identified, of which five are sedimentary basin-types and four are uplifted mountain types. The Fushan and Eman depressions in north Hainan Island and the Baocheng Rock Mass in the south of the island are the preferred exploration targets.

The state of health (SOH) estimation of lithium-ion batteries (LIBs) is crucial for battery management system, but the accuracy and generalizability of the widely used data-driven methods are strongly dependent on the selection of LIBs health features (HFs). In this paper, four types of LIBs with different anode types from four datasets, including NASA dataset, CALCE dataset, Oxford dataset and UL-PUR dataset, were selected to extract the area of constant current charging and discharging voltage curves as two sets of HFs, and then the high correlation between the HFs and SOH is verified by their Pearson coefficient. Secondly, with the two sets of HFs, the SOH of selected batteries in the four datasets are evaluated under Gaussian Process Regression, Long and Short-Term Memory neural network and Back Propagation neural network respectively. With a training/test set ratio model of 50/50 and cross-validation method, all algorithms obtain accurate SOH estimation results. Finally, the estimation results are compared with reference data under the same dataset and training mode, and it is found that the proposed method shows better estimation accuracy and robustness than other evaluation methods by multiple HFs or even complex algorithms.

Shape memory polymers are of great interest for biomedical applications. However, most stimuli used to trigger shape memory processes, including heat, light, electricity, magnetism, and pH are inconvenient and maybe harmful to the body. Here, we designed and fabricated a new shape memory porous scaffold using biocompatible and readily available water as the trigger. This scaffold was based on poly(fumaricacid-co-1,7-octadiene diepoxide-co-terephthalic acid) (PFOT) synthesized via epoxide ring-opening polymerization in one step. The PFOT scaffold promoted the adhesion, spreading, proliferation and function of cardiomyoblast H9C2 cells in a manner comparable to that for the poly(lactic-co-glycolic acid) scaffold. It exhibited an excellent water-responsive shape memory effect with a fixity and recovery ratio >97% and a shape-recovery process of several minutes, suitable for surgery. In addition, the PFOT scaffold presented good in vitro biodegradation. More importantly, PFOT contains extensive free hydroxyl groups and could be facilely functionalized and would be a promising smart material for multiple biomedical applications.

One of the pivotal factors that limits the clinical applications of tissue engineering is the inability to create complex three-dimensional (3D) tissues due to the lack of a long-range mass transport capability. Here we present a simple versatile strategy to fabricate perfusable and permeable hierarchical microchannel-networks (PHMs) viathe combination of one-pot 3D printed sacrificial caramel templates and polymer coating with integrated phase separation. The patterned PHMs possess a biomimetic three level vascular structure including a custom-made scalable 3D framework, interconnected microchannels and permeable walls with controllable micropores. The fabrication process can be adapted to various polymers and integrated with diverse matrices including hydrogels, particle leached porous scaffolds, electrospun nanofibers, and bacterial cellulose. We demonstrated the power of PHMs to facilitate mass exchange in tissue engineering constructs by showing that the PHMs could maintain the metabolic functions of heart cells in vitro, facilitate in vivoangiogenesis and tissue integration, and efficiently treat myocardial infarction.

Three-dimensional (3D) printing offers great potential to customize sophisticated constructs for a myriad of applications. However, many thermosets require long-term curing under harsh conditions, which is not compatible with rapid 3D printing processing. 3D printing of these thermosets remains a challenge. Here, we report a new strategy for direct 3D printing of various thermosets viareadily available extrusion-based technology using sacrificial sodium chloride particles as a removable thickener for printing and a reinforcer for curing, exemplified by crosslinked polyester, polyurethane and epoxy resins. Specifically, the 3D constructs exhibited hierarchical and porous architectures, which are highly desired for many applications, including regenerative medicine, sensors, actuators, catalyst supports, and energy absorbers. As a proof-of-concept demonstration, we 3D printed vapomechanical sensors and actuators featuring fast, large, robust, and gradient responsiveness, in addition to biodegradable scaffolds to promote vascularization and tissue ingrowth in vivoand elastic myocardial patches to efficiently treat myocardial infarction. We expect that this study will pave a new way to tailor sophisticated 3D structures of thermosets and will be very useful for diverse applications.

Tissue engineering is emerging as a promising approach for cartilage regeneration and repair. Endowing scaffolds with cartilaginous bioactivity to obtain bionic microenvironment and regulating the matching of scaffold degradation and regeneration play a crucial role in cartilage regeneration. Poly(glycerol sebacate) (PGS) is a representative thermosetting bioelastomer known for its elasticity, biodegradability, and biocompatibility and is widely used in tissue engineering. However, the modification and drug loading of the PGS scaffold is still a key challenge due to its high temperature curing conditions and limited reactive groups, which seriously hinders its further functional application. Here, a simple versatile new strategy of super swelling‐absorption and cross‐linked networks locking is presented to successfully create the 3D printed PGS‐CS/Gel scaffold for the first time based on FDA‐approved PGS, gelatin (Gel) and chondroitin sulfate (CS). The PGS‐CS/Gel scaffold exhibits the desirable synergistic properties of well‐organized hierarchical structures, excellent elasticity, improved hydrophilicity, and cartilaginous bioactivity, which can promote the adhesion, proliferation, and migration of chondrocytes. Importantly, the rate of cartilage regeneration can be well‐matched with degradation of PGS‐CS/Gel scaffold, and achieve uniform and mature cartilage tissue without scaffold residual. The bioactive scaffold can successfully repair cartilage in a rabbit trochlear groove defect model indicating a promising prospect of clinical transformation. The harsh curing conditions and limited reactive groups of poly(glycerol sebacate) (PGS) seriously restrict its bio‐modification. 3D printed PGS‐CS/Gel scaffold is fabricated by swelling‐absorption and networks‐locking strategy with cartilaginous bioactivity. The scaffold can significantly promote growth of chondrocytes and BMSCs to obtain dense cartilage tissue without scaffold residual, and to repair articular defect with clear interface between cartilage and subchondral bone.

The 3D digital image correlation technique has been employed to measure the 3D profile and normal deformation of the marble free surface of Jinping hydropower station under biaxial compression to ensure the safety of the engineering structure. The 3D profile is consistent with the pattern of rock cutting, which shows that the digital image correlation method shows a high precision of engineering measurement. From the diagram of the displacement gradient and the load, it is concluded that the displacement gradient increases sharply before the destruction of the specimen, which proves that the destruction and the displacement gradient has close correlation. Due to the fact that the displacement contour is a relatively dense area which is more prone to produce tension effects than the maximum normal displacement, it is easier to destroy the cracks. Based on the above conclusions, the distribution of free surface contours of the displacement field can determine the area which is more likely to show free surface damage cracks.