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Damage identification based on deep learning has become a hot topic recently. Damage identification and classification methods based on neural networks are much concerned, and therefore, reducing manual participation in labeling data as much as possible has attracted increasing attention. This article presents the work on developing a damage detection method by using limited information features to improve the performance of clustering in unsupervised learning. In order to improve the accuracy of unsupervised clustering algorithm, a damage classification method is proposed by using measured data based on deep learning network. A generative adversarial network (GAN) is introduced into the unsupervised clustering process, which is able to extract effective multiscale features and has better generalization ability. The structure and training method of GAN-spectral clustering (SC) are studied, and the GAN and SC algorithm are combined for damage diagnosis. The proposed GAN-SC framework harnesses the synergy of GAN’s ability to extract effective multiscale features and SC’s potential to generate virtual labels, improving generalization capabilities. Some signal preprocessing methods are used to reduce the noise of the original data while retaining the high features of the fault data as much as possible. The proposed method is verified by a numerical bridge dataset and a popular experiment dataset from Case Western Reserve University (CWRU), using cluster evaluation indices [normalized mutual information (NMI) and adjusted Rand index (ARI)]. The results show that the superior recognition capabilities of GAN-SC emphasize its potential for real-world applications in structural damage detection by generating virtual labels through SC.

The clinical application of random flaps in wound repair has been a topic of discussion. Random flaps are prone to necrosis due to the lack of well-defined vascular blood supply during transfer surgery. Their clinical utility is restricted, financial and psychological burdens is imposed on patients due to this limitation. The survival of random skin flaps depends on factors such as ischemia–reperfusion injury, oxidative stress, local inflammatory response, and neovascularization. This review aims to provide an overview of the evidence supporting the use of random flaps in clinical practice. In addition, this review explores the impact of different medications on signaling pathways within the flap’s local microcirculation and investigates the interconnections between these pathways.

The low-cycle fatigue properties of titanium alloys suffering cyclic loading determines the safety in service for their components used in submarine shells. It has been reported that tensile property could be improved by making use of Fe alloying element partitioning effect. However, the fatigue property and mechanism of titanium alloys with Fe addition remain unknown. In this study, the low-cycle fatigue property and cyclic deformation mechanism of Ti–6Al–4V-0.55Fe and Ti–6Al–4V ELI with a duplex microstructure were systematically investigated. With the addition of Fe element, Ti–6Al–4V-0.55Fe with longer lasting cyclic hardening behavior and lower cyclic softening rate, showed higher fatigue life under selected strain amplitudes. Under low strain amplitude, effect of Fe on dislocation motion, interface resistance, lattice distortion, and micro strain were responsible for the enhanced fatigue life. While under high strain amplitude, Fe brought out the pinning effect on interface. Besides, Fe addition also limited the fatigue crack propagation.

Efficient solvers for traveling salesman problem (TSP) have great significance in the field of consumer electronic systems and devices. Existing studies require independent and repetitive runs for similar TSPs. To utilize useful knowledge buried in the twin TSP which is similar to the target TSP, a twin learning framework based on task matching and mapping strategy is proposed. We use an autoencoder to extract the feature vectors of the historical tasks and the target task to find the twin task. If not found, construct a twin task based on a graph-filter. Further, we get the solution of the target task with the optimized twin task by learning a mapping matrix from the twin task to the target task. Finally, we incorporate local search algorithms into the twin learning framework, which called strategy mapping solver (SMS) to further improve the quality of the solution. The efficacy of the SMS is evaluated through comprehensive empirical studies with commonly used TSP benchmarks, against meta-heuristic algorithms and a learning improvement heuristics algorithm, demonstrating its effectiveness for TSP. Moreover, a real-world combinatorial optimization application, laser engraving path planning, is presented to further confirm the efficacy of SMS.

The cloud type product 2B-CLDCLASS-LIDAR based on CloudSat and CALIPSO from June 2006 to May 2017 is used to examine the temporal and spatial distribution characteristics and interannual variability of eight cloud types (high cloud, altostratus, altocumulus, stratus, stratocumulus, cumulus, nimbostratus, and deep convection) and three phases (ice, mixed, and water) in the Arctic. Possible reasons for the observed interannual variability are also discussed. The main conclusions are as follows: (1) More water clouds occur on the Atlantic side, and more ice clouds occur over continents. (2) The average spatial and seasonal distributions of cloud types show three patterns: high clouds and most cumuliform clouds are concentrated in low-latitude locations and peak in summer; altostratus and nimbostratus are concentrated over and around continents and are less abundant in summer; stratocumulus and stratus are concentrated near the inner Arctic and peak during spring and autumn. (3) Regional averaged interannual frequencies of ice clouds and altostratus clouds significantly decrease, while those of water clouds, altocumulus, and cumulus clouds increase significantly. (4) Significant features of the linear trends of cloud frequencies are mainly located over ocean areas. (5) The monthly water cloud frequency anomalies are positively correlated with air temperature in most of the troposphere, while those for ice clouds are negatively correlated. (6) The decrease in altostratus clouds is associated with the weakening of the Arctic front due to Arctic warming, while increased water vapor transport into the Arctic and higher atmospheric instability lead to more cumulus and altocumulus clouds.

The storage of hydrogen is key to its applications. Developing adsorbent materials with high volumetric and gravimetric storage capacities, both of which are essential for the efficient use of hydrogen as a fuel, is challenging. Here we report a controlled catenation strategy in hydrogen-bonded organic frameworks (RP-H100 and RP-H101) that depends on multiple hydrogen bonds to guide catenation in a point-contact manner, resulting in high volumetric and gravimetric surface areas, robustness and ideal pore diameters (~1.2–1.9 nm) for hydrogen storage. This approach involves assembling nine imidazole-annulated triptycene hexaacids into a secondary hexagonal superstructure containing three open channels through which seven of the hexagons interpenetrate to form a seven-fold catenated superstructure. RP-H101 exhibits high deliverable volumetric (53.7 g l−1) and gravimetric (9.3 wt%) capacities for hydrogen under a combined temperature and pressure swing (77 K/100 bar → 160 K/5 bar). This work illustrates the virtues of supramolecular crystals as promising candidates for hydrogen storage.

Evolutionary neural architecture search (ENAS) methods have been successfully used to design convolutional neural network (CNN) architectures automatically. These methods have achieved excellent performance in creating a specific neural architecture for a single task but are less efficient for multiple tasks. Existing ENAS frameworks always repeatedly perform the search from scratch for each task, even though these tasks may be solved by similar CNN architectures. This work presents an evolutionary multitask convolutional neural architecture search (MTNAS) framework to enable efficient architecture searches in multitask scenarios by incorporating architectural similarities. The proposed MTNAS constructs architectures for different tasks simultaneously by implementing a knowledgesharing mechanism among multiple search processes. Specifically, promising architectures found in one search process can be transferred and reused to generate high-quality architectures for others. Furthermore, we devise an adaptive strategy to dynamically adjust the frequency of knowledge transfer, aiming to alleviate the potential effect of negative transfer. Extensive experiments demonstrate that MTNAS can outperform stateof- the-art neural architecture search (NAS) methods or achieve comparable performance in different tasks but with $2\times $ less search cost.

Under intermittent noncollocated boundary measurement (BM), this article introduces a dynamic intermittent boundary output-feedback control for reaction–diffusion systems (RDSs). Since the system state is not fully available and intermittent noncollocated BM makes the intermittent acrlong BC design very difficult, an observer-based control technique is given to surmount this design difficulty. Initially, a acrlong PDE state observer under intermittent noncollocated BM is provided to estimate the RDS state. Then, the exponential stability of closed-loop RDSs is ensured by constructing an observer-based controller. Sufficient conditions of such dynamic controller are subsequently presented by linear matrix inequalities (LMIs) via employing a switching time-dependent acrlong LF and inequality techniques. Finally, two numerical examples are presented to demonstrate the effectiveness of the proposed design approach.

A novel ultrawideband circularly polarized (CP) phased array antenna was developed by combining the low-profile design of a stripline-to-slotline balun with the wide scanning characteristics of a tightly coupled dipole array (TCDA). This antenna boasts a low voltage standing wave ratio (VSWR) and low axial ratio (AR). To address the common-mode resonance issue, a circular slotline cavity was implemented as a four-stage series fan-shaped cavity. This design effectively extends the length of the short-circuit stub, enhancing the short-circuit impedance value and expanding the scanning bandwidth from 3:1 to 6.4:1. Notably, a rotating wide-angle impedance matching layer was introduced for the CP TCDA, marking the first time this approach has been employed. This innovation not only increased the number of matching network stages for achieving a low VSWR but also enhanced the consistency of the main polarization, reducing the cross-polarization ratio to achieve a low AR. The resulting 8 × 8 CP phased array antenna demonstrated exceptional performance, operating over a remarkable 6:1 bandwidth (2–12 GHz). It satisfies the criteria of Active VSWR < 2.5 and AR < 2.7 dB within a ±60° scanning range.

Urapidil is an important drug for the treatment of essential hypertension and intravenously in hypertensive emergencies. Herein, an improved route to Urapidil was introduced. The new designed synthetic route starts with the addition reaction of 1-(2-methoxyphenyl)piperazine and oxetane catalyzed by Yb(OTf)3in acetonitrile to form the key intermediate 3-(4-(2-methoxyphenyl)piperazin-1-yl)propan-1-ol. Additionally, 3-(4-(2-methoxyphenyl)piperazin-1-yl)propan-1-ol was purified by recrystallization from the optimized solvents, which was beneficial to large scale production. Intermediate 3-(4-(2-methoxyphenyl)piperazin-1-yl)propyl-4-methylbenzenesulfonate was cast directly for the subsequent reaction without further purification. The overall yield of this route is about 45%. The structure of the final product was well confirmed by 1H-NMR, 13C-NMR and HRMS.

With recent advances in wireless communications, much attentions have been paid to data services in vehicular ad hoc networks (VANETs). Network coding has been considered as a promising approach to improving the bandwidth efficiency in the field of wireless communications. However, due to the heterogeneities of vehicular networks, such as diverse size of data items and different data transmission rates, current data scheduling methods cannot achieve expected performance in heterogenous VANETs. In this paper, we propose a novel system architecture integrated with software defined network (SDN) and fog computing as well as a dedicated algorithm for cooperative data services to enhance performance in heterogeneous VANETs. In particular, first, we present a novel service architecture in heterogeneous VANETs, which integrates both software defined network and fog computing. Then, we formulate a problem called Fog-Assisted Heterogeneous Data Services (FAHDS), which aims to minimize the service delay. In addition, we prove that FAHDS is NP-hard by constructing a polynomial-time reduction from the minimum clique cover (MCC) problem. Further, we propose a greedy algorithm implemented at the SDN controller, which makes coding decisions for cloud nodes and notifies the cooperative operations among fog nodes and vehicles. Finally, a comprehensive simulation is carried out for performance evaluation. The simulation results demonstrate the effectiveness of the proposed architecture and algorithm.

Recently, a number of domain adaptation (DA) methods have been proposed for knowledge transfer in evolutionary multitasking (EMT). However, the learned mappings in these methods often have unique biases in representing the connection between source and target tasks. Few studies have paid attention to the complementarity of different mappings in knowledge transfer. To fill this research gap, this article proposes an ensemble method to combine multiple DA methods for knowledge transfer in EMT by considering the efficacy and diversity of these methods. First, a hierarchical clustering method is used to divide the population of each task into multiple clusters. Then, when two parental solutions are selected for knowledge transfer across tasks, the solutions within the same cluster are checked. In particular, if none of these solutions has been transferred before, the efficacy of DA methods is considered first by using roulette wheel selection based on the corresponding performance improvements in the evolutionary optimization process. Otherwise, the diversity of DA methods is emphasized by randomly selecting one of the DA methods for knowledge transfer. The effectiveness of our proposed ensemble method is validated by embedding it into existing state-of-the-art EMT algorithms, and the experimental results show that our algorithm outperforms several recently proposed EMT algorithms on most cases of two multitasking benchmark suites and one practical case.

Compared with carbon dioxide, fluorinated greenhouse gases (F-type gases), such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6), have a stronger greenhouse effect, and their global warming potential can reach thousands or even tens of thousands of times that of carbon dioxide. Thus, the rapid online accurate detection of fluorinated greenhouse gases is highly desired and it can provide a basis for the evaluation of the greenhouse effect and a yardstick for the formulation of emission reduction measures. Unfortunately, these highly noble chemical gas molecules, especially at trace concentration levels, are extremely difficult to detect with conventional rapid screening methods. The use of the most common gas sensing techniques, semiconducting metal oxides, in the detection of HFCs and PFCs has not appeared within the scope of our knowledge. Herein, we report a novel N-doped tin oxide semiconducting metal oxide prepared by using a facile hydrothermal method. The experimental characterization results showed that the as-prepared materials were uniform spherical nanoparticles. The doping ratio of N-doped tin oxide was further optimized, and gas-sensing tests using these materials were carefully conducted. The results showed that the sensor had good detection performance for F-type gases, represented by SF6, C2F6and C2H2F4, including low working temperature (200 °C), high selectivity, good repeatability, relatively high response, and low limit of detection (LOD ∼7 ppb). To the best of our knowledge, this is the first report on an F-type gas sensor based on semiconductor metal oxide. The ultra-fine particle size and uniform morphology of spherical particles, high concentration of oxygen vacancy defects and N doping contribute to the excellent performance of the sensor.

Converging the fibrous flexibility and resilience with the advantageous electrical properties of organic electrochemical transistors (OECTs), fiber-shaped OECTs possess great potential in wearable electronics. However, limited by current highly recognized fabrication techniques for film devices, micrometer-scale patterning capability of electrodes and semiconductor channels on the curved surface of fibers is still challenging. In addition, the well-defined short channel length of fiber-shaped OECTs is highly desired to narrow the performance gap with planar OECT devices. In this study, the fabrication of photopatterned vertical OECT devices on fiber surfaces (fiber-shaped vOECTs) is achieved. Moreover, the first n-type fiber-shaped vOECTs and high-performance p-type fiber-shaped vOECTs are realized. The fiber-shaped vOECT devices work in enhancement mode, with remarkable maximum transconductance (p-type: 41.10 mS, n-type: 2.25 mS) and current on/off ratio (∼104), together with good cycling stability (maintaining over 90% of performance beyond 500 cycles). Furthermore, by using knitting and weaving fabric textures, complementary inverter, NAND and NOR logic gates integrated through fiber-shaped vOECTs are derived and showcased. This study demonstrates the potential of this approach as a universal platform for fabricating high-performance semiconductor devices.

Phase transformation, microstructure evolution, and mechanical properties of Ti–3Al–5Mo–4Cr–2Zr–1Fe alloy were investigated during a continuous heating process. Three microstructures, specifically lath, duplex, and lamellar structures, were examined. The activation energies for phase transition in these structures were measured as 277, 220, and 193 kJ mol−1, respectively. The phase transition follows: For the lath structure, β transforms into αacicular(550–660°C), αacicularconverts to β (660–785°C), αlathdoes to β (660–850°C); For the duplex structure, β transforms into αacicular(545–660°C), αacicularconverts to β (660–770°C), αlathdoes to β (660–850°C); For the lamellar structure, β transforms into αsecondary(560–615°C), αsecondaryconverts to β (615–705°C), αlamellardose to β (615–850°C). The lath and duplex structures exhibited favorable comprehensive properties compared to lamellar microstructure.

Neural architecture search (NAS) has attracted much attention in recent years. It automates the neural network construction for different tasks, which is traditionally addressed manually. In the literature, evolutionary optimization (EO) has been proposed for NAS due to its strong global search capability. However, despite the success enjoyed by EO, it is worth noting that existing EO algorithms for NAS are often very computationally expensive, which makes these algorithms unpractical in reality. Keeping this in mind, in this article, we propose an efficient memetic algorithm (MA) for automated convolutional neural network (CNN) architecture search. In contrast to existing EO algorithms for CNN architecture design, a new cell-based architecture search space, and new global and local search operators are proposed for CNN architecture search. To further improve the efficiency of our proposed algorithm, we develop a one-epoch-based performance estimation strategy without any pretrained models to evaluate each found architecture on the training datasets. To investigate the performance of the proposed method, comprehensive empirical studies are conducted against 34 state-of-the-art peer algorithms, including manual algorithms, reinforcement learning (RL) algorithms, gradient-based algorithms, and evolutionary algorithms (EAs), on widely used CIFAR10 and CIFAR100 datasets. The obtained results confirmed the efficacy of the proposed approach for automated CNN architecture design.

The molecular-level design of non-fullerene acceptors (NFAs) is crucial for enhancing the efficiency of polymer solar cells (PSCs). Here, we investigate the influence of NFA symmetry on bulk-heterojunction (BHJ) PSC performance. Our study introduces a series of closely related asymmetric NFA architectures (A-D-D type and A-DA'D-D type) and compares them with traditional symmetric NFAs. We find that BHJ PSCs using symmetric NFAs outperform those with asymmetric NFAs, achieving power conversion efficiencies (PCEs) of 10%–17% compared with 0.1%–3% for asymmetric NFAs. Analysis reveals that the lower performance of asymmetric NFAs results from disrupted end group-end group stacking in the NFA crystal network, which further causes reduced electron mobility, weaker crystallinity, slower hole transfer, and higher rates of exciton recombination in BHJ blends. These findings provide valuable insights for designing high-performance NFAs in the future.

This article investigates robust non-fragile event-triggered sampled-data fuzzy (ETSDF) control for uncertain nonlinear delayed distributed parameter systems. Initially, a T-S fuzzy delayed partial differential equation model is presented to exactly describe the uncertain nonlinear delayed distributed parameter systems (DPS). secondly, a robust non-fragile ETSDF control strategy is proposed to reduce the unnecessary SD and cope with the uncertainties in controller and system. Then, based on an appropriate Lyapunov functional, the exponential stability conditions of closed-loop nonlinear delayed DPS via linear matrix inequalities are presented. Lastly, one example is presented to illustrate the design method.

Vehicle routing problems (VRPs) are essential in logistics. In the literature, many exact and heuristic optimization algorithms have been proposed to solve the VRPs. These traditional approaches, however, generally start the optimization from scratch and ignore the experiences of solving related VRPs, which may lead to unnecessary computational costs in searching repeated problems and reduce the efficiency of vehicle routing. Recently, transfer optimization (TO) has been presented to speed up vehicle routing by reusing the knowledge learned from similarly solved VRPs. However, existing TO methods build connections across VRPs in a low-dimensional Euclidean space, which has limited modeling ability in the cases of having nonlinear correlations. Keeping this in mind, this article presents a study of TO equipped with the kernel method for fast vehicle routing. In contrast to existing TO methods, in this work, the learning of connections across VRPs for knowledge transfer is conducted in a reproducing kernel Hilbert space (RKHS), which thus has greater modeling capacity in nonlinear customer relationships between VPRs. To evaluate the performance of the proposed method, comprehensive empirical studies have been conducted using well-known VRP benchmarks, against existing state-of-the-art TO methods for vehicle routing. Finally, a well-known real-world VRP application given by a routing company (Jingdong), namely, the package delivery problem (PDP), is investigated to further assess the efficacy of our proposed method.

For nonlinear space-varying parabolic distributed parameter systems, this paper introduces an H ∞ fuzzy intermittent boundary control, where the output measurements are only available at some specified boundary position (i.e., boundary measurements). Initially, a Takagi–Sugeno fuzzy parabolic partial differential equation is used to precisely describe the nonlinear space-varying parabolic distributed parameter system. Then, under boundary measurements, an H ∞ fuzzy intermittent boundary control design based on the Takagi–Sugeno fuzzy parabolic partial differential equation model ensuring the exponential stability with an H ∞ performance for closed-loop space-varying distributed parameter system is subsequently obtained via spatial linear matrix inequalities by employing inequality techniques and piecewise switching-time-dependent Lyapunov function. Furthermore, in order to solve the H ∞ fuzzy intermittent boundary controller design of nonlinear space-varying parabolic distributed parameter systems under boundary measurements, we express spatial linear matrix inequalities as linear matrix inequalities and further present some linear matrix inequality based fuzzy intermittent boundary control design conditions respecting the property of membership functions. Finally, two simulation examples are offered to demonstrate the effectiveness of the proposed H ∞ fuzzy intermittent boundary control method. [ABSTRACT FROM AUTHOR]

Objectives: To study the effects of age on the olfactory function recovery of chronic rhinosinusitis patients after endoscopic sinus surgery and related risk factors.Methods: A total of 176 chronic rhinosinusitis (CRS) patients enrolled from February 2017 to October 2019 were divided into child, youth, middle-aged, and elderly groups. Their baseline data, T&T olfactory test score, visual analogue scale (VAS) olfactory score, sinus computed tomography (CT) Lund-Mackay score, and Lund-Kennedy score were compared. Based on postoperative olfactory function, they were divided into good and poor improvement groups.Results: Complication with nasal polyps, allergic rhinitis history, and sinus surgery history had significant differences among patients of different ages (P< .05). Three months after surgery, T&T olfactory, VAS olfactory, Lund-Mackay, and Lund-Kennedy scores all rose with increasing age, with significant differences between any 2 groups (P< .05). The improvement of postoperative olfactory function became poorer with aging (P< .05). T&T and VAS olfactory scores had significant positive correlations with Lund-Mackay and Lund-Kennedy scores (P< .001). Age, preoperative Lund-Mackay and Lund-Kennedy scores, complication with nasal polyps, allergic rhinitis history, sinus surgery history, and postoperative complications were risk factors for the poor improvement of postoperative olfactory function. Doctor-directed treatment was a protective factor for good improvement.Conclusions: The improvement of olfactory function of CRS patients after endoscopic sinus surgery declines with aging. Age, preoperative Lund-Mackay and Lund-Kennedy scores, complication with nasal polyps, allergic rhinitis history, sinus surgery history, and postoperative complications are risk factors for the poor improvement of postoperative olfactory function. Doctor-directed treatment is a protective factor for good improvement.

Evolutionary transfer optimization (ETO) has been becoming a hot research topic in the field of evolutionary computation, which is based on the fact that knowledge learning and transfer across the related optimization exercises can improve the efficiency of others. However, rare studies employ ETO to solve large-scale multiobjective optimization problems (LMOPs). To fill this research gap, this article proposes a new multitasking ETO algorithm via a powerful transfer learning model to simultaneously solve multiple LMOPs. In particular, inspired by adversarial domain adaptation in transfer learning, a discriminative reconstruction network (DRN) model (containing an encoder, a decoder, and a classifier) is created for each LMOP. At each generation, the DRN is trained by the currently obtained nondominated solutions for all LMOPs via backpropagation with gradient descent. With this well-trained DRN model, the proposed algorithm can transfer the solutions of source LMOPs directly to the target LMOP for assisting its optimization, can evaluate the correlation between the source and target LMOPs to control the transfer of solutions, and can learn a dimensional-reduced Pareto-optimal subspace of the target LMOP to improve the efficiency of transfer optimization in the large-scale search space. Moreover, we propose a real-world multitasking LMOP suite to simulate the training of deep neural networks (DNNs) on multiple different classification tasks. Finally, the effectiveness of the proposed algorithm has been validated in this real-world problem suite and the other two synthetic problem suites.

A linker design strategy is developed to attain novel polynuclear rare-earth (RE) metal–organic frameworks (MOFs) with unprecedented topologies. We uncover the critical role of ortho-functionalized tricarboxylate ligands in directing the construction of highly connected RE MOFs. The acidity and conformation of the tricarboxylate linkers were altered by substituting with diverse functional groups at the ortho position of the carboxyl groups. For instance, the acidity difference between carboxylate moieties resulted in forming three hexanuclear RE MOFs with novel (3,3,3,10,10)-c wxl, (3,12)-c gmx, and (3,3,3,12)-c joetopologies, respectively. In addition, when a bulky methyl group was introduced, the incompatibility between the net topology and ligand conformation guided the co-appearance of hexanuclear and tetranuclear clusters, generating a novel 3-periodic MOF with a (3,3,8,10)-c kywnet. Interestingly, a fluoro-functionalized linker prompted the formation of two unusual trinuclear clusters and produced a MOF with a fascinating (3,8,10)-c lfgtopology, which could be gradually replaced by a more stable tetranuclear MOF with a new (3,12)-c leetopology with extended reaction time. This work enriches the polynuclear clusters library of RE MOFs and unveils new opportunities to construct MOFs with unprecedented structural complexity and vast application potential.

Rotaxanes with well‐defined ring sequences are attractive synthetic goals in the construction of functional materials associated with molecular shuttles and switches, molecular electronics, and information storage. Sequence‐controlled synthesis of oligo‐ and polyrotaxanes is important in the context of the development of both sequence‐defined polymers and dynamic functional materials. To date, examples of sequence‐controlled rotaxanes are limited to oligorotaxanes on account of the synthetic challenges they pose. This Review sheds light on the pivotal role that sequence isomerism plays in rotaxanes. Synthetic approaches, including orthogonal templation, active‐metal templation, self‐sorting and snapping, cooperative‐capturing, ring‐through‐ring‐shuttling, and molecular pumping, for the construction of sequence‐controlled rotaxanes are all discussed in this Review. By comparing the advantages and disadvantages of these different approaches, several possible synthetic strategies are proposed in an attempt to foretell the future of sequence‐controlled synthesis of polyrotaxanes.

Far-field optical beam steering is a fast-growing technology for communications, spatial ranging, and detections. Nonmechanical optical phased arrays based on straight waveguides have been studied recently, where the beam emission angle to the propagation axis can be scanned by conveniently tuning the wavelength. However, the dispersion of the waveguide limits the wavelength sensitivity of beam steering and the deliberately created emitters inevitably introduce in-line backscattering on-chip. To overcome these limitations, here, we report a robust and back-reflection-free topological photonic integrated circuit, where different functionalities, such as beam splitting, routing, and far-field steering, are defined by strategic arrangements of lattices with different topological modulations simply controlled by a single lattice deformation parameter. Benefiting from the robust topological scheme, an extra band flattening is applied to achieve far-field steering with high wavelength sensitivity.

Stable metal–organic frameworks (MOFs) with mesopores (2–50 nm) are promising platforms for immobilizing nanosized functional compounds, such as metal-oxo clusters, metal-sulfide quantum dots, and coordination complexes. However, these species easily decompose under acidic conditions or high temperatures, hindering their in situencapsulation in stable MOFs, which are usually synthesized under harsh conditions involving excess acid modulators and high temperatures. Herein, we report a route for the room-temperature and acid-modulator-free synthesis of stable mesoporous MOFs and MOF catalysts with acid-sensitive species encapsulated: (1) we initially construct a MOF template by connecting stable Zr6clusters with labile Cu-bipyridyl moieties; (2) Cu-bipyridyl moieties are subsequently exchanged by organic linkers to afford a stable version of Zr-MOFs; (3) acid-sensitive species, including polyoxometalates (POMs), CdSeS/ZnS quantum dots, and Cu-coordination cages, can be encapsulated in situinto the MOFs during step 1. The room-temperature synthesis allows the isolation of mesoporous MOFs with 8-connected Zr6clusters and reotopology as kinetic products, which are inaccessible by traditional solvothermal synthesis. Furthermore, acid-sensitive species remain stable, active, and locked within the frameworks during MOF synthesis. We observed high catalytic activity for VX degradation by the POM@Zr-MOF catalysts as a result of the synergy between redox-active POMs and Lewis-acidic Zr sites. The dynamic bond-directed method will accelerate the discovery of large-pore stable MOFs and offer a mild route to avoid the decomposition of catalysts during MOF synthesis.

This study investigates the effect of the ω phase on the microstructure evolution and mechanical properties of the Ti–3Al–5Mo–4Cr–2Zr–1Fe (Ti-35421) near β titanium alloy. The study employed a solution treatment at 850 °C followed by two aging treatments, namely, Double Aging (DA) and Isothermal Annealing (IA). The results show that the DA alloy had finer precipitation and fewer Precipitation-Free Zones (PFZs) than the IA alloy. While the Ultimate Tensile Strength (UTS) of the DA alloy was higher (1376 MPa) than that of the IA alloy (1272 MPa), its plasticity was lower. On the other hand, the IA alloy exhibited a better balance between UTS (1272 MPa) and ductility (8.12%). The nucleation mechanism of DA was attributed to the presence of the α stable element Al, which diffused in the microstructure and aggregated in the ω phase, creating favorable nucleation sites for the precipitation of the secondary α phase during low temperature aging. As a result, the PFZs decreased, and the dispersion distribution strengthened the β matrix structure. Conversely, the high aging temperature during IA made it difficult to form the ω phase, resulting in coarser precipitation and increased PFZs as the temperature increased. This paper revealed the influence of ω on the relative precipitation during the phase transition, the microstructure and properties of the Ti–3Al–5Mo–4Cr–2Zr–1Fe, providing valuable insights for optimizing its heat treatment process.

While trinuclear [FexM3–x(μ3-O)] cluster-based metal–organic frameworks (MOFs) have found wide applications in gas storage and catalysis, it is still challenging to identify the structure of open metal sites obtained through proper activations and understand their influence on the adsorption and catalytic properties. Herein, we use in situ variable-temperature single-crystal X-ray diffraction to monitor the structural evolution of [FexM3–x(μ3-O)]-based MOFs (PCN-250, M = Ni2+, Co2+, Zn2+, Mg2+) upon thermal activation and provide the snapshots of metal sites at different temperatures. The exposure of open Fe3+sites was observed along with the transformation of Fe3+coordination geometries from octahedron to square pyramid. Furthermore, the effect of divalent metals in heterometallic PCN-250 was studied for the purpose of reducing the activation temperature and increasing the number of open metal sites. The metal site structures were corroborated by X-ray absorption and infrared spectroscopy. These results will not only guide the pretreatment of [FexM3–x(μ3-O)]-based MOFs but also corroborate spectral and computational studies on these materials.

The sodium–chloride cotransporter (NCC) is critical for kidney physiology1. The NCC has a major role in salt reabsorption in the distal convoluted tubule of the nephron2,3, and mutations in the NCC cause the salt-wasting disease Gitelman syndrome4. As a key player in salt handling, the NCC regulates blood pressure and is the target of thiazide diuretics, which have been widely prescribed as first-line medications to treat hypertension for more than 60 years5–7. Here we determined the structures of human NCC alone and in complex with a commonly used thiazide diuretic using cryo-electron microscopy. These structures, together with functional studies, reveal major conformational states of the NCC and an intriguing regulatory mechanism. They also illuminate how thiazide diuretics specifically interact with the NCC and inhibit its transport function. Our results provide critical insights for understanding the Na–Cl cotransport mechanism of the NCC, and they establish a framework for future drug design and for interpreting disease-related mutations.

Metal–organic frameworks (MOFs) demonstrate promise for a multitude of applications owing to their high porosity and surface area. However, the majority of conventional MOFs possess only micropores with very limited accessibility to substances larger than 2 nm—especially functional biomacromolecules like some proteins. It is challenging to create an appropriately large pore size while avoiding framework collapse in MOFs. Herein, we present the generation of mesopores in microporous MOFs through three facile and effective techniques, namely Soxhlet washing, linker hydrolysis and linker thermolysis. These postsynthetic elimination approaches have been applied in selected MOFs, including PCN-250, PCN-160 and UiO-66, and controllably generate MOFs with hierarchical pores and high stability. Our work demonstrates reproducible and straightforward methods resulting in hierarchically porous materials that possess the benefits of mesoporosity while borrowing the robustness of a micropore framework. All the procedures can be conducted reliably at a multigram scale and operation time less than 6 h, representing a significant effort in the field of MOF synthesis. These hierarchically porous MOFs show great promise in a wide range of applications as efficient adsorbents, catalysts and drug carriers.

Organic electrochemical transistors (OECTs) and OECT-based circuitry offer great potential in bioelectronics, wearable electronics and artificial neuromorphic electronics because of their exceptionally low driving voltages (<1 V), low power consumption (<1 µW), high transconductances (>10 mS) and biocompatibility1–5. However, the successful realization of critical complementary logic OECTs is currently limited by temporal and/or operational instability, slow redox processes and/or switching, incompatibility with high-density monolithic integration and inferior n-type OECT performance6–8. Here we demonstrate p- and n-type vertical OECTs with balanced and ultra-high performance by blending redox-active semiconducting polymers with a redox-inactive photocurable and/or photopatternable polymer to form an ion-permeable semiconducting channel, implemented in a simple, scalable vertical architecture that has a dense, impermeable top contact. Footprint current densities exceeding 1 kA cm−2at less than ±0.7 V, transconductances of 0.2–0.4 S, short transient times of less than 1 ms and ultra-stable switching (>50,000 cycles) are achieved in, to our knowledge, the first vertically stacked complementary vertical OECT logic circuits. This architecture opens many possibilities for fundamental studies of organic semiconductor redox chemistry and physics in nanoscopically confined spaces, without macroscopic electrolyte contact, as well as wearable and implantable device applications.

To precisely evaluate the potential of metal–organic frameworks (MOFs) for gas separation and purification applications, it is crucial to understand how various molecules competitively adsorb inside MOFs. In this paper, we combine in situ infrared spectroscopy with ab initio calculations to investigate the mechanisms associated with coadsorption of several small molecules, including CO, NO, and CO2inside the prototypical structure Ni-MOF-74. Surprisingly, we find that the displacement of CO bound inside Ni-MOF-74 (binding energy of 53 kJ/mol) is readily driven by CO2exposure, even though CO2has a noticeably weaker binding energy of only 41 kJ/mol; meanwhile, the significantly more strongly binding NO molecule (90 kJ/mol) is not able to easily displace bound CO inside Ni-MOF74. These results show that single-phase binding energies of a molecule inside the MOF cannot completely describe their interaction with the MOF in the presence of other guest molecules. We unveil many crucial factors, such as the kinetic barrier, partial pressure, secondary binding sites, and guest–host/lateral interactions that control the coadsorption process and, combined with the binding energy, are better descriptors of the behavior and adsorption of gas mixtures inside MOFs.

In this paper, a joint design of both transmit waveform and imaging filters for synthetic aperture radar (SAR) is proposed to improve its information acquisition capability. First, the mutual information between SAR image and target scattering characteristics is considered as the performance metric, and its equivalent analytical version is derived in the 2-D frequency domain. The design is formulated as an optimization problem with an energy condition and a similarity constraint. Then, to tackle the resultant non-convex problem, by referring to the Dinkelbach's method, an algorithm is derived to find the desired solution via a cyclic maximization procedure alternating between three subproblems. Based on minorization-maximization, a unified optimization method with an increasing penalty on constraint violation is proposed to solve all subproblems. Convergence of the developed algorithm is analytically proved. Finally, numerical examples are presented to demonstrate the effectiveness of the proposed design.

The content of saikosaponins in genus Bupleurumis increased with numbers of lateral root, but the genetic mechanisms are largely unknown. This study aims to identify the heme oxygenase (HO) gene family members of B. chinenseand B. scorzonerifolium, and assess their role in the root development in Bupleurum.

This study used waste chicken fat oil (CFO) to regenerate aged asphalt binder. The molecular composition of the CFO was assayed by gas chromatography-mass spectrometry. The performance grade of the CFO-rejuvenated recycled asphalt was compared with that of the original asphalt, while the high-temperature rutting performance of CFO-rejuvenated asphalt was assessed by the multiple stress creep recovery test, and the fatigue cracking ability of the rejuvenated asphalt was determined by a linear amplitude sweep test. It is obvious that CFO can soften aged asphalt. The performance grade of low-temperature 6% CFO-rejuvenated asphalt is superior to that of the original asphalt. The sulfoxide index can be utilised to evaluate the aging recovery degree of CFO-rejuvenated asphalt. The addition of CFO can improve the fatigue properties of aged binder and delay the fatigue damage of asphalt. It is suggested that 6% CFO should be used in recycling aged asphalt binder.

Integrated photonics, because of its intrinsic high speed, large bandwidth and unlimited parallelism, is critical in the drive to ease the increasing data traffic. Its technological enabler is high-precision lithography, which allows for the fabrication of high-resolution photonic structures. Here, in complete contrast to the state of the art, where photonic functions are predefined by lithographically modulating the real index, we report a lithography-free paradigm for an integrated photonic processor, targeting dynamic control of spatial-temporal modulations of the imaginary index on an active semiconductor platform, without the need for lithography. We demonstrate an imaginary-index-driven methodology to tailor optical-gain distributions to rationally execute prescribed optical responses and configure desired photonic functionality to route and switch optical signals. Leveraging its real-time reconfigurability, we realize photonic neural networks with extraordinary flexibility, performing in situ training of vowel recognition with high accuracy. The programmability and multifunctionality intrinsically arising from the lithography-free characteristics can lead to a new paradigm for integrated photonic signal processing to conduct and reconfigure complex computation algorithms, accelerating the information-processing speed to achieve long-term performance requirements.

Paper-based optical sensors have emerged as a promising technology for pesticide detection and attracted extensive attention. However, in practical analytical applications, it may suffer from limited sensitivity with traditional signal amplification strategies. Here, we developed a novel mesoporous silica-modified paper-based sensor for a sensitive capture and analysis of the pesticide paraquat. Carboxylatopillar[5]arene was covalently introduced into the nanochannels for the rapid capture of target paraquat molecules due to the mass transfer confinement effect within nanopores. In addition, the large specific surface area of mesoporous silica enabled high-abundance immobilization of the capture agent and promoted its binding efficiency, which, in turn, contributed to improving the sensitivity. This work highlights the great potential of nanochannels as a development platform for sensitive paper-based sensors that can be used to develop new systems for the detection of paraquat and even other pesticides.

The phase transformation and mechanical properties of Ti6Al4V-0.55Fe alloy were investigated during the continuous cooling process. The curves of α phase precipitation exhibit a typical S-shaped pattern, which indicated that β→α phase transformation is a nucleation-growth-controlled process. The average activation energy is 231 kJ mol−1calculated by Kissinger–Akahira–Sunose method. The Avrami exponent during β→α transformation significantly changes with the increasing transformed volume fraction. It is found that the thickness of α phase lamellar decreased, while the strength and hardness increased with the increasing cooling rate. Moreover, the fracture morphology of the samples gradually changes from ductile fracture to brittle fracture under the cooling rate from 1 to 15 K min−1, which illuminates that the plasticity of the alloy will decrease.

Maize (Zea mayL.)–soybean [Glycine max(L.) Merr.] intercropping is popular in many countries because of its high productivity. However, no studies have explored maize–soybean intercropping via bibliometric methods. Taking the Web of Science database, the visualization applications of CiteSpace and VOSviewer were used to visually analyze the literature related to research in the field of maize–soybean intercropping, with the aim of studying keyword hotspots and evolving trends, and analyzing the future research directions. The results showed that the annual number of publications on maize–soybean intercropping showed rapid growth from 2010 to 2021. The top three publishing countries were China, the United States, and India, and the top three institutions were Sichuan Agricultural University, the Ministry of Agriculture and Rural Affairs of China, and China Agricultural University. Th three most popular journals were Field Crops Research, Agronomy Journal, and Indian Journal of Agronomy. Agronomy, multidisciplinary agriculture and plant science were the most popular research categories. A keyword analysis indicated that “maize” was the most popular study area. Crop root coupling processes, biological nitrogen fixation, efficient utilization of resources, carbon sequestration and emission reduction, microbial communities, and interspecific relationships are the current hot research topics. This study review and analyzed the current research hotspots and future research trends to provide an important reference for scientists to better respond to food security issues. There has been a rapid increase in maize–soybean intercropping research.China, Chinese institutions, and Chinese scholars have conducted much of this research.Maize–soybean intercropping has shown an interdisciplinary distribution.Keywords showed the heterogeneity in maize–soybean intercropping publications across years.

Cellular senescence affects the efficacy of mesenchymal stem cells (MSCs)-mediated tissue regeneration. Insulin-like growth factor binding proteins-7 (IGFBP7), as a member of the IGF family, is associated with osteogenic differentiation and the senescence of MSCs, but its exact function and mechanism remain unclear. We found IGFBP7 promoted the osteogenic differentiation and prevented the senescence of dental pulp-derived MSCs (DPSCs), as observed in the gain-of-function and loss-of-function analyses, the senescence-associated marker p21 showed the most pronounced expression changes. We demonstrated that IGFBP7 activated the biological activity of SIRT1 deacetylase via metabolism, resulting in a deacetylation of H3K36ac and a decrease of the binding affinity of H3K36ac to p21 promoter, thereby reducing the transcription of p21, which ultimately prevents DPSCs senescence and promotes tissue regeneration. The activation of the mitochondrial electron transport chain (ETC) by Coenzyme Q10 could rescue the promotion of DPSC senescence induced by the knockdown of IGFBP7, whereas the inhibition of ETC by rotenone attenuated the prevention of DPSC senescence induced by IGFBP7 overexpression. In conclusion, our present results reveal a novel function of IGFBP7 in preventing DPSC senescence via the metabolism-induced deacetylation of H3K36ac and reduction of p21 transcription, suggesting that IGFBP7 is a potential target for promoting tissue regeneration in an aging environment.

Women have been reported to be at greater risk of left ventricular hypertrophy (LVH) than men in South Asia, but whether the sex disparity is affected by central obesity and blood pressure has not been well studied. We examined prospectively the interaction of sex with waist circumference and systolic blood pressure at baseline on LVH measured after a median of 8-year follow-up among 539 individuals with hypertension in Karachi, Pakistan, and found that the risk of LVH for women vs men increased with higher baseline waist circumference and systolic blood pressure. Our results underscore the urgency for public health programs to prevent obesity and control hypertension in women in South Asia.

The global emergency caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic can only be solved with effective and widespread preventive and therapeutic strategies, and both are still insufficient. Here, we describe an ultrathin two-dimensional CuInP2S6(CIPS) nanosheet as a new agent against SARS-CoV-2 infection. CIPS exhibits an extremely high and selective binding capacity (dissociation constant (KD) < 1 pM) for the receptor binding domain of the spike protein of wild-type SARS-CoV-2 and its variants of concern, including Delta and Omicron, inhibiting virus entry and infection in angiotensin converting enzyme 2 (ACE2)-bearing cells, human airway epithelial organoids and human ACE2-transgenic mice. On association with CIPS, the virus is quickly phagocytosed and eliminated by macrophages, suggesting that CIPS could be successfully used to capture and facilitate virus elimination by the host. Thus, we propose CIPS as a promising nanodrug for future safe and effective anti-SARS-CoV-2 therapy, and as a decontamination agent and surface-coating material to reduce SARS-CoV-2 infectivity.

Optical resonators are structures that utilize wave interference and feedback to confine light in all three dimensions. Depending on the feedback mechanism, resonators can support either standing- or traveling-wave modes. Over the years, the distinction between these two different types of modes has become so prevalent that nowadays it is one of the main characteristics for classifying optical resonators. Here, we show that an intermediate link between these two rather different groups exists. In particular, we introduce a new class of photonic resonators that supports a hybrid optical mode, i.e. at one location along the resonator the electromagnetic fields associated with the mode feature a purely standing-wave pattern, while at a different location, the fields of the same mode represent a pure traveling wave. The proposed concept is general and can be implemented using chip-scale photonics as well as free-space optics. Moreover, it can be extended to other wave phenomena such as microwaves and acoustics.

Wetland ecosystems are the most important natural methane (CH4) sources, whose fluxes periodically fluctuate. Methanogens (methane producers) and methanotrophs (methane consumers) are considered key factors affecting CH4fluxes in wetlands. However, the symbiotic relationship between methanogens and methanotrophs remains unclear. To help close this research gap, we collected and analyzed samples from four soil depths in the Dajiuhu subalpine peatland in January, April, July, and October 2019 and acquired seasonal methane flux data from an eddy covariance (EC) system, and investigated relationships. A phylogenetic molecular ecological networks (pMENs) analysis was used to identify keystone species and the seasonal variations of the co-occurrence patterns of methanogenic and methanotrophic communities. The results indicate that the seasonal variations of the interactions between methanogenic and methanotrophic communities contributed to CH4emissions in wetlands. The keystone species discerned by the network analysis also showed their importance in mediating CH4fluxes. Methane (CH4) emissions in wetlands were lowest in spring; during this period, the most complex interactions between microbes were observed, with intense competition among methanogens while methanotrophs demonstrated better cooperation. Reverse patterns manifested themselves in summer when the highest CH4flux was observed. Methanoregula formicicawas negatively correlated with CH4fluxes and occupied the largest ecological niches in the spring network. In contrast, both Methanocella arvoryzaeand Methylocystaceae demonstrated positive correlations with CH4fluxes and were better adapted to the microbial community in the summer. In addition, soil temperature and nitrogen were regarded as significant environmental factors to CH4fluxes. This study was successful in explaining the seasonal patterns and microbial driving mechanisms of CH4emissions in wetlands.

In recent studies, proxy XCH4retrievals from the Japanese Greenhouse gases Observing SATellite (GOSAT) have been used to constrain top-down estimation of CH4emissions. Still, the resulting interannual variations often show significant discrepancies over some of the most important CH4source regions, such as China and Tropical South America, by causes yet to be determined. This study compares monthly CH4flux estimates from two parallel assimilations of GOSAT XCH4retrievals from 2010 to 2019 based on the same Ensemble Kalman Filter (EnKF) framework but with the global chemistry transport model (GEOS-Chem v12.5) being run at two different spatial resolutions of 4° × 5° (R4, lon × lat) and 2° × 2.5° (R2, lon × lat) to investigate the effects of resolution-related model errors on the derived long-term global and regional CH4emission trends. We found that the mean annual global methane emission for the 2010s is 573.04 Tg yr−1for the inversion using the R4 model, which becomes about 4.4 Tg yr−1less (568.63 Tg yr−1) when a finer R2 model is used, though both are well within the ensemble range of the 22 top-down results (2008–17) included in the current Global Carbon Project (from 550 Tg yr−1to 594 Tg yr−1). Compared to the R2 model, the inversion based on the R4 tends to overestimate tropical emissions (by 13.3 Tg yr which is accompanied by a general underestimation (by 8.9 Tg yr−1) in the extratropics. Such a dipole reflects differences in tropical-mid-latitude air exchange in relation to the model’s convective and advective schemes at different resolutions. The two inversions show a rather consistent long-term CH4emission trend at the global scale and over most of the continents, suggesting that the observed rapid increase in atmospheric methane can largely be attributed to the emission growth from North Africa (1.79 Tg yr−2for R4 and 1.29 Tg yr−2for R2) and South America Temperate (1.08 Tg yr−2for R4 and 1.21 Tg yr−2for R2) during the first half of the 2010s, and from Eurasia Boreal (1.46 Tg yr−2for R4 and 1.63 Tg yr−2for R2) and Tropical South America (1.72 Tg yr−2for R4 and 1.43 Tg yr−2for R2) over 2015–19. In the meantime, emissions in Europe have shown a consistent decrease over the past decade. However, the growth rates by the two parallel inversions show significant discrepancies over Eurasia Temperate, South America Temperate, and South Africa, which are also the places where recent GOSAT inversions usually disagree with one other.

High-cost viral nucleic acid detection devices (e.g., qPCR system) are limited resources for developing counties and rural areas, leading to underdiagnosis or even pandemics of viral infectious diseases. Herein, a novel virus detection strategy is reported. Such detection method is enabled by TR512-peptide-based biorthogonal capture and enrichment of commercially available Texas red fluorophore labeled nucleic acid on the functionalized paper. The GST-TR512 fusion protein electrostatically immobilized on the paper is constructed to retain the binding affinity of TR512-peptide toward Texas red fluorophore labeled nucleic acid released in the preamplification process, then the enrichment of analytes enhances fluorescence signal for rapid detection as volume of sample filters through the paper. The method is generally applicable to different nucleic acid preamplification strategies (PCR, RAA, CRISPR) and different virus types (Hepatitis B virus (HBV), African swine fever virus (ASFV), human papillomavirus (HPV), and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2 or 2019 nCoV)). Finally, a full-set virus detection device is developed in house to detect the presence of Hepatitis B virus (HBV) viral gene in patients’ blood samples. Taken together, we first apply TR512-peptide in the signal enrichment and the novel detection strategy may offer an inexpensive, rapid, and portable solution for areas with limited access to a standard diagnosis laboratory.