Liquid crystalline network (LCN) actuator normally deforms upon thermally or optically induced order-disorder phase transition, switching once between two shapes (shape 1 in LC phase and shape 2 in ...isotropic state) for each stimulation on/off cycle. Herein, we report an LCN actuator that deforms from shape 1 to shape 2 and then reverses the deformation direction to form shape 3 on heating or under light only, thus completing the shape switch twice for one stimulation on/off cycle. The deformation reversal capability is obtained with a monolithic LCN actuator whose two sides are made to start deforming at different temperatures and exerting different reversible strains, by means of asymmetrical crosslinking and/or asymmetrical stretching. This desynchronized actuation strategy offers possibilities in developing light-fueled LCN soft robots. In particular, the multi-stage bidirectional shape change enables multimodal, light-driven locomotion from the same LCN actuator by simply varying the light on/off times.
Information coding, recording, encryption, and decryption are of great importance in the field of anti‐counterfeiting, especially in the current AI information era. Herein, a paper‐like hydrogel ...composed of solely H‐bonded poly(vinyl alcohol) (PVA) and poly(n‐vinylcaprolactam) (PNVCL), namely VAPN, is developed for multiple ways of encryption and decryption based on chemical‐induced phase separation. It not only exhibits excellent ability of ink absorption and retention by the noncovalent H‐bonds and n−π* interactions and good mechanical strength but also maintains a negligible volume change during the phase separation that is crucial for the information fidelity. Given that the noncovalent interactions are the driving force to trigger the phase separation in the hydrogel, available chemical inks are numerous ranging from small molecules to polymers. Furthermore, together with thermally induced phase separation, the different dynamic processes of the association and dissociation between ink molecules and the hydrogel endow the latter with reversible information recording and self‐erasing, temporary or permanent, and customized encryption and decryption.
The phase separation in a hydrogel comprising two polymers is induced by H‐bonding and n−π* interactions between one component and the ink molecules bearing carboxylic acid groups, resulting in optical transmittance change. The large variety of available or easily accessible chemical inks endow the hydrogel with the capacities of multimodal, stable, or dynamic information recording, encryption, and decryption.
Covalent adaptable liquid crystal networks (CALCNs) are highly potential actuating materials due to their actuation properties and shape reprogrammability. Given the importance of network ...crosslinking state in a CALCN actuator, we sought an all‐in‐one strategy to probe and visualize its dynamic network while ensuring actuation and reprogramming. Here, tetraphenylethylene derivatives were incorporated into liquid crystal networks via the Diels–Alder (DA) reaction, acting simultaneously as reversible crosslinkers and aggregation‐induced emission (AIE) fluorescent probes. The thermally tunable fluorescence of the resulting network can correlate to and thus visualize the actuator's crosslinking status, actuation capability and temperature in real‐time and in situ, yielding an intriguing actuation limit‐alerting function. Furthermore, we verified unprecedented reprogrammability of the AIE‐type CALCNs through both associative and dissociative exchange mechanisms of DA chemistry.
Novel covalent adaptable liquid crystal network (CALCN) actuators crosslinked by dynamic AIE luminogens were built based on Diels–Alder chemistry. This all‐in‐one material design “visualizes”, through fluorescing, the crosslinking state and actuation capability for actuation‐guiding in CALCN, while enabling network “re‐bonding” through associative and dissociative exchange mechanisms for unprecedented actuation‐reprogrammability.
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In the present study, a novel biodegradable Zn-0.8Cu coronary artery stent was fabricated and implanted into porcine coronary arteries for up to 24 months. Micro-CT analysis showed ...that the implanted stent was able to maintain structural integrity after 6 months, while its disintegration occurred after 9 months of implantation. After 24 months of implantation, approximately 28 ± 13 vol% of the stent remained. Optical coherence tomography and histological analysis showed that the endothelialization process could be completed within the first month after implantation, and no inflammation responses or thrombosis formation was observed within 24 months. Cross-section analysis indicated that the subsequent degradation products had been removed in the abluminal direction, guaranteeing that the strut could be replaced by normal tissue without the risk of contaminating the circulatory system, causing neither thrombosis nor inflammation response. The present work demonstrates that the Zn-0.8Cu stent has provided sufficient structural supporting and exhibited an appropriate degradation rate during 24 months of implantation without degradation product accumulation, thrombosis, or inflammation response. The results indicate that the Zn-0.8Cu coronary artery stent is promising for further clinical applications.
Although Zn and its alloys have been considered to be potential candidates of biodegradable metals for vascular stent use, by far, no Zn-based stent with appropriate medical device performance has been reported because of the low mechanical properties of zinc. The present work presents promising results of a Zn-Cu biodegradable vascular stent in porcine coronary arteries. The Zn-Cu stent fabricated in this work demonstrated adequate medical device performance both in vitro and in vivo and degraded at a proper rate without safety problems induced. Furthermore, large animal models have more cardiovascular similarities as humans. Results of this study may provide further information of the Zn-based stents for translational medicine research.
Inspired by animal muscles, we developed a kind of tough elastomers combining high strength and high stretchability with autonomous self-healing capability. A key structural feature is the ...construction of a double network (DN) connected by the hydrogen bond and host–guest interactions. The first network is the classic elastomer polyacrylate matrix cross-linked by strong hydrogen bonding. The second network is formed through the host–guest interactions between polycyclodextrin and the adamantane (Ad) groups on the side of the polyacrylate chain. Supramolecular interactions between two networks make them miscible and interpenetrate in the molecular level and then can share the load as the sample was stretched. The host–guest interactions act not only as sacrificial bonds for energy dissipation but also as self-healing driving forces. The tensile strength of the DN elastomer reaches about 6.7 MPa and the strain is as high as about 950%. The DN elastomer can be easy to repair by touching the damaged surface together at ambient conditions when broken or cut. The recovered tensile strength can reach over 4.5 MPa, which is better than the most pristine strength of existing spontaneous self-healing elastomers.
Increasing resistance to humid environments is a major challenge for the application of γ-CD-K-MOF (a green MOF) in real-world utilisation. γ-CD-K-MOF-H
S with enhanced moisture tolerance was ...obtained by simply treating MOF with H
S gas. XPS, Raman and TGA characterizations indicated that the H
S molecules coordinated with the metal centers in the framework. H
S acting as a newly available water adsorption potential well near the potassium centers protects the metal-ligand coordination bond from attack by water molecules and thus improves the moisture stability of MOF. After 7 days exposure in 60% relative humidity, γ-CD-K-MOF-H
S retained its crystal structure and morphology, while γ-CD-K-MOF had nearly collapsed. In addition, the formaldehyde uptake tests indicated that γ-CD-K-MOF retain their permanent porosity after interaction with H
S. This simple and facile one-step strategy would open a new avenue for preparation of moisture stable MOFs for practical applications.
With the development of the Internet and big data, more and more consumer behavior data are used in different forecasting problems, which greatly improve the performance of prediction. As the main ...travel tool, the sales of automobiles will change with the variations of the market and the external environment. Accurate prediction of automobile sales can not only help the dealers adjust their marketing plans dynamically but can also help the economy and the transportation sector make policy decisions. The automobile is a product with high value and high involvement, and its purchase decision can be affected by its own attributes, economy, policy and other factors. Furthermore, the sample data have the characteristics of various sources, great complexity and large volatility. Therefore, this paper uses the Support Vector Regression (SVR) model, which has global optimization, a simple structure, and strong generalization abilities and is suitable for multi-dimensional, small sample data to predict the monthly sales of automobiles. In addition, the parameters are optimized by the Grey Wolf Optimizer (GWO) algorithm to improve the prediction accuracy. First, the grey correlation analysis method is used to analyze and determine the factors that affect automobile sales. Second, it is used to build the GWO-SVR automobile sales prediction model. Third, the experimental analysis is carried out by using the data from Suteng and Kaluola in the Chinese car segment, and the proposed model is compared with the other four commonly used methods. The results show that the GWO-SVR model has the best performance of mean absolute percentage error (MAPE) and root mean square error (RMSE). Finally, some management implications are put forward for reference.
The Shexiang Baoxin Pill (MUSKARDIA) has been used for treating coronary artery disease (CAD) and angina for more than 30 years in China. Nevertheless, methodologically sound trials on the use of ...MUSKARDIA in CAD patients are scarce. The aim of the study is to determine the effects of MUSKARDIA as an add-on to optimal medical therapy (OMT) in patients with stable CAD.
A total of 2674 participants with stable CAD from 97 hospitals in China were randomized 1:1 to a MUSKARDIA or placebo group for 24 months. Both groups received OMT according to local tertiary hospital protocols. The primary outcome was the occurrence of a major adverse cardiovascular event (MACE), defined as a composite of cardiovascular death, non-fatal myocardial infarction (MI), or non-fatal stroke. Secondary outcomes included all-cause mortality, non-fatal MI, non-fatal stroke, hospitalization for unstable angina or heart failure, peripheral revascularization, angina stability and angina frequency.
In all, 99.7% of the patients were treated with aspirin and 93.0% with statin. After 2 years of treatment, the occurrence of MACEs was reduced by 26.9% in the MUSKARDIA group (MUSKARDIA: 1.9% vs. placebo: 2.6%; odds ratio = 0.80; 95% confidence interval: 0.45-1.07; P = 0.2869). Angina frequency was significantly reduced in the MUSKARDIA group at 18 months (P = 0.0362). Other secondary endpoints were similar between the two groups. The rates of adverse events were also similar between the two groups (MUSKARDIA: 17.7% vs. placebo: 17.4%, P = 0.8785).
As an add-on to OMT, MUSKARDIA is safe and significantly reduces angina frequency in patients with stable CAD. Moreover, the use of MUSKARDIA is associated with a trend toward reduced MACEs in patients with stable CAD. The results suggest that MUSKARDIA can be used to manage patients with CAD.
chictr.org.cn, No. ChiCTR-TRC-12003513.
Inspired by the functions of leeches, for the first time homogeneous materials integrating hydrogels and elastomers were achieved by free radical polymerization. 2-Methoxyethyl acrylate (MEA) was ...used as elastomer monomer and Pluronics functionalized with vinyl groups acted as cross-linkers to impart the hydrogel property to the materials. The resulting Pluronic/PMEA gels possess a swelling ratio of about 210% and good water-retaining ability. Compression tests of Pluronic/PMEA gels at swelling equilibrium state show a stress up to 1.6 MPa under 85% strain. The gels act as elastomer after dehydration. Uniaxial tensile fracture stress and the elongation reached 1200 kPa and 500%, respectively, and compression stress was above 22 MPa. Furthermore, the Pluronic/PMEA gels also show self-healing properties. Owing to the excellent mechanical performance in both wet and dry conditions, this hydrogel–elastomer integrated material may have potential applications in tissue engineering, soft robotics, and biomedical devices.
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