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A new theoretical calculation method for the load-slip curve and the shear stiffness of the stud based on Winkler’s elastic foundation beam theory and deflection differential equation of the stud is proposed. Different stress characteristics of the elastic and plastic zones of the concrete are considered in the proposed method. The accuracy of the theoretical calculation method is validated by the test results. Moreover, the effect of concrete strength, stud diameter, and yield strength on the stud load-slip curve is analyzed. The results show that the proposed model can effectively reflect the change process of the load-slip curve of the test specimen stud connector. The stud diameter, stud yield strength, and concrete strength affect the peak slip, shear stiffness, and shear capacity of stud shear connectors. With an increase in stud diameter, the peak slip, shear stiffness, and shear bearing capacity of the stud are all increased. An increase in the yield strength of the stud increases its elastic slip, peak slip, and shear capacity. Lastly, with an increase in concrete strength, the elastic slip and peak slip of the stud both decrease, whereas the shear stiffness and shear bearing capacity are increased.

Rational construction of strong electron-transfer materials remains a challenging task. Herein, we show a fundamental design rule for construction of strong electron-transfer materials through covalently integrating electron-donoring Cu(I) clusters and electron-withdrawing triazine monomers together. As expected, the two resultant Cu(I)-triazine frameworks (Cu-CTFs) showed strong electron transfer up to 0.46|e| from each Cu(I) metal center to each adjacent triazine fragment, and the size of triazine monomer was found to give tunable ability for electron transfer. Accompanied to the stronger electron transfer is the observation of more narrow bang gap and good spatial separation of HOMO and LUMO level. This finally leads to good spatial separation of photo-generated electron-hole pairs and function units for boosting photocatalytic reduction of uranium under ambience and no sacrificial agent with ultrahigh removal efficiency up to 99.7%, and good charge separation of [I+][I5-] for boosting I2 immobilization under extremely rigorous conditions with benchmark I2 uptake of 0.32 g/g. The results not only have opened up a structural design principle to access electron-transfer materials, but also solved several challenging tasks in the field of radionuclide capture and CTFs.

Background Lung cancer is the leading cause of cancer-related deaths in the world. Non-small cell lung cancer (NSCLC) accounts for 85% of all lung cancer cases. For lack of conveniently sensitive and specific biomarkers, the majority of patients are in the late stage at initial diagnosis. Long non-coding RNAs (LncRNAs), a novel type of non-coding RNA, have recently been recognized as critical factors in tumor initiation and progression, but the role of exosomal LncRNAs has not been thoroughly excavated in NSCLC yet. Methods We isolated exosomes from the serum of patients with NSCLC and healthy controls. Exosome RNA deep sequencing was subsequently performed to detect differentially expressed exosomal LncRNAs. qRT-PCR assay was then utilized to validate dysregulated LncRNAs in both testing and multicentric validation cohort. Receiver operating characteristic (ROC) curve was used to detect the diagnostic capability of exosomal biomarkers. Furthermore, Kaplan–Meier analysis was applied to evaluate the prognostic values of these molecules. Results On the basis of analysis, we found that novel exosomal LncRNA RP5-977B1 exhibited higher levels in NSCLC than that in the healthy controls. The area under the curve (AUC) value of exosomal RP5-977B1 was 0.8899 and superior to conventional biomarkers CEA and CYFRA21-1 both in testing and multicentric validation cohort. Interestingly, the diagnostic capability of exosomal RP5-977B1 was also validated in early-stage patients with NSCLC. Furthermore, high expression of exosomal RP5-977B1was closely related with worse prognosis in NSCLC (P = 0.036). Conclusions Our results suggested that exosomal RP5-977B1 might serve as a novel “liquid biopsy” diagnostic and prognostic biomarker to monitor NSCLC and improve possible therapy.

The n-π* electronic transition in polymeric carbon nitride (PCN) can remarkably harvest visible light, which thus potentially promotes the photocatalytic hydrogen H2 generation. However, awaking the n-π* electronic transition has proven to be a grand challenge. Herein, we reported on the awakening of n-π* electronic transition by microwave thermolysis of urea pellet, which yielded the PCN with absorption edge of 600 nm, near 140 nm red-shift from 460 nm of pristine PCN. The n-π* electronic transition endows PCN with an increased photocatalytic H2 generation, with a highest H2 rate of 61.7 μmol h−1 under visible light exposure, which is near 6 times higher than that by using the PCN from the thermolysis of urea pellets in an electric furnace (10.6 μmol h−1). Furthermore, the n-π* transition in PCN leads to the longest wavelength of 535 nm that can initiate H2 generation, remarkably longer than the absorption edge of pristine PCN (460 nm). This work manifests the advantages of microwave sintering route to awaken the n-π* electronic transition in PCN for an increased photocatalytic performance.

Modeling, evaluation and prediction of slab track damage and its evolution are nowadays challenge and hot topics, in which the computer modeling program lies a foundation for vehicle-track dynamic analysis subject to slab track damage except the experimental research. In this work, the finite element modeling methods and related computer modules are presented to compile a simulation program to evaluate the slab track damage evolution accompanied by vehicle-track dynamic interaction, where the moving vehicle is modeled as a multi-rigid-body system with the primary and secondary suspensions, and the Bernoulli-Euler beam, thin-plate and solid finite element and spring-dashpots are introduced to model the track system. The fatigue damage constitutive models of the concrete slabs and viscoelastic filling layers, and the interfacial cohesive zone model, are set as the criteria to control and characterize the damage evolution of slab tracks. Apart from model validations, numerical studies are conducted to quantitatively show influence of track irregularities on slab track damage evolution and the slab track damage on vehicle-track system response. It illustrates the necessity of considering the combined fatigue and interfacial damages of slab tracks instead of separately accounting for the fatigue or interfacial damage.

Unsupervised graph representation learning(GRL) aims to distill diverse graph information into task-agnostic embeddings without label supervision. Due to a lack of support from labels, recent representation learning methods usually adopt self-supervised learning, and embeddings are learned by solving a handcrafted auxiliary task(so-called pretext task). However, partially due to the irregular non-Euclidean data in graphs, the pretext tasks are generally designed under homophily assumptions and cornered in the low-frequency signals, which results in significant loss of other signals, especially high-frequency signals widespread in graphs with heterophily. Motivated by this limitation, we propose a multi-view perspective and the usage of diverse pretext tasks to capture different signals in graphs into embeddings. A novel framework, denoted as Multi-view Graph Encoder(MVGE), is proposed, and a set of key designs are identified. More specifically, a set of new pretext tasks are designed to encode different types of signals, and a straightforward operation is propxwosed to maintain both the commodity and personalization in both the attribute and the structural levels. Extensive experiments on synthetic and real-world network datasets show that the node representations learned with MVGE achieve significant performance improvements in three different downstream tasks, especially on graphs with heterophily. Source code is available at \url{https://github.com/G-AILab/MVGE}., Comment: 20 pages, 10 figures, accepted by ACM Transaction on Knowledge Discovery in Data

The mechanical properties of reinforced concrete (RC) structures are closely related to the bond stress-slip relationship of rebar-concrete interface. In this paper, a novel bond stress-slip model under monotonic and cyclic loading is proposed. For interfacial behaviour under monotonic loading, an innovative micro-element model, consisting of a spring element, a friction element and a switch element, is proposed to effectively characterize the interfacial micro-damage mechanical behaviours in a physical sense. By adopting a parallel system of micro-elements and setting the fracture threshold of individual spring element as a random variable, the expressions of the bond stress-slip relationship and interfacial damage variable are derived. Subsequently, succinct practical expressions for the bond strength, peak slip under monotonic loading are formulated. The bond stress-slip model for rebar-concrete interface under monotonic loading are further established. For cyclic constitutive model of rebar-concrete interface, a new method of cyclic correction factor for the degradation law of bond strength is developed. The bond strength degradation under cyclic loading affected by the number of cycles, maximum slip value and opposite loading can be reflected with reasonable accuracy. Furthermore, the predictions calculated by the proposed model under monotonic and cyclic loading are in favorable agreement with experimental results. All parameters in the model have clear physical meaning.

ZnO plays a very important role in many catalytic processes involving H

To disclose the possible dynamic behaviours of vehicle-track systems subject to an entire railway network, random vibration analysis is of great concern in railway engineering due to the system geo...

The development of fatigue damage in reinforced concrete (RC) beams is affected by various factors such as repetitive loads and material properties, and there exists a complex nonlinear mapping relationship between their fatigue performance and each factor. To this end, a fatigue performance prediction model for RC beams was proposed based on the deep belief network (DBN) optimized by particle swarm optimization (PSO). The original database of fatigue loading tests was established by conducting fatigue loading tests on RC beams. The mid-span deflection, reinforcement strain, and concrete strain during fatigue loading of RC beams were predicted and evaluated. The fatigue performance prediction results of the RC beam based on the PSO-DBN model were compared with those of the single DBN model and the BP model. The models were evaluated using the R2 coefficient, mean absolute percentage error, mean absolute error, and root mean square error. The results showed that the fatigue performance prediction model of RC beams based on PSO-DBN is more accurate and efficient.

The concrete track slab and the base slab of the high-speed railway CRTS II track structure are prone to transverse cracks in the initial service period, which are subjected to environmental action and train load. In order to investigate the influence of transverse cracks on chloride ingress of concrete track slab and base slab in a coastal environment, drying-wetting cycle chloride erosion tests were carried out on reinforced concrete track slab and base slab specimens with cracks ranging from 0 mm to 0.6 mm, subjected to continuous bending moment. The chloride ion concentration of concrete along the depth direction was collected during the test process. The experimental results show that the chloride ion concentration of concrete at the crack section is much higher than that at the intact section, and it increases with the increase of crack width in the range of 0.2 mm to 0.6 mm. A chloride diffusion coefficient model of cracked concrete is proposed for slab track based on the experimental results, which can comprehensively consider the effects of surface chloride ion concentration, chloride binding effect, time-varying effect, temperature, relative humidity, and transverse crack width.

Random dynamic responses caused by the uncertainty of structural parameters of the coupled train-ballasted track-subgrade system under train loading can pose safety concerns to the train operation. This paper introduced a computational model for analyzing probabilistic dynamic responses of three-dimensional (3D) coupled train-ballasted track-subgrade system (TBTSS), where the coupling effects of uncertain rail irregularities, stiffness and damping properties of ballast and subgrade layers were simultaneously considered. The number theoretical method (NTM) was employed to design discrete points for the multi-dimensional stochastic parameters. The time-histories of stochastic dynamic vibrations of the TBSS with systematically uncertain structural parameters were calculated accurately and efficiently by employing the probability density evolution method (PDEM). The model-predicted results were consistent with those by the Monte Carlo simulation method. A sensitivity study was performed to assess the relative importance of those uncertain structural parameters, based on which a case study was presented to explore the stochastic probability evolution mechanism of such train-ballasted track-subgrade system.

In order to evaluate the effect of seismic isolation on random seismic response characteristics of a track-bridge system, in this paper, a three-dimensional detailed nonlinear dynamic model consists of rail, CRTS II slab ballastless track, high-speed railway simple supported bridges, isolated bearings, piers, pile foundations from top to bottom, is established by OpenSEES. The stochastic process of ground motion constructed by the random harmonic function is taking as random excitation, and the probability density evolution method (PDEM) is applied to investigate and analyze the system from the random perspective. On this basis, the influence of FPB bearing and the different FPB parameters (such as equivalent radius) on the random seismic response of the track-bridge system is studied. Thereby, aplenty probabilistic information (probability density evolution function, mean value and standard deviation) can be gained of seismic response of isolated bridges with different isolation parameters and non-isolated bridges of the high-speed railway track-bridge system under the excitation of random earthquakes by case study. Through the comparison of random seismic responses of non-isolated bridge and isolated bridges with different parameters under random ground motions, the favorable and unfavorable effects of seismic isolation for high-speed railway bridges are explored and demonstrated from a random point of view. The comparison of the random seismic response under different cases are discussed and significant outcomes are drawn. Results show that: The use of isolation bearing can reduce the response of track structure and pier, but meanwhile, increase the response of bearings. The change of the equivalent radius of the isolation bearing has no obvious influence on the random response of the pier and the track structure, but will to some extent bring the change of the bearing response. The results can be used for the seismic design and maintenance of the railway high-speed bridge.

In the era of energy conservation and environmental protection, as well as the industrialization of buildings, precast concrete (PC) structures have been developed and increasingly applied in construction industries due to their advantages of outstanding workability and ecofriendliness. In order to verify the reliability of overlapping U-bar loop connections and a modified form of these connections, and study the seismic performance of PC wall–beam–slab joints with these connection methods, three full-scale wall–beam–slab joints were designed and tested under low reversed cyclic loading, including one cast-in-place (CIP) specimen and two PC specimens. Based on the test results, the seismic performance of the PC joints was studied by comparing their damage process, hysteretic loops and skeleton curves, load-carrying capacity, ductility, equivalent stiffness, and energy dissipation with those of the CIP joint. After analyzing the experimental results, the following conclusions can be drawn: the overlapping U-bar loop connection and its modified form are effective and reasonable; the specimen with the modified connection form showed slightly better mechanical properties; the failure mode of the PC joints was consistent with that of the CIP joint; and the generation, distribution, and development of cracks in the PC specimens were similar to those in the CIP specimen. In addition, the stiffness of the PC joints was similar to that of the CIP joint, and the load-carrying capacity, ductility, and energy dissipation of the PC joints were better than those of the CIP joint. Moreover, the research in this paper can also provide some guidance for assembling wall–beam–slab joints in PC shear wall structures.

Steel-reinforced concrete-filled circular steel tubular (SRCFT) stub columns is a novel type of composite columns, which have a great potential to be used as piers or columns in practical engineering. Hence, it is essential to comprehend the compressive performance of SRCFT stub columns and suitably predict the compressive strength for the engineering design and applications. This paper aims to investigate the compressive behavior of SRCFT stub columns through combined experimental and numerical studies. A total of 8 specimens were tested to investigate the compressive performance of SRCFT stub columns in detail, in terms of the axial load-strain curve, ultimate bearing capacity, ductility, strength-weight-ratio and strain ratio. The SRCFT stub columns exhibited better ductility than CFT stub columns. The inserted steel section can effectively prevent shear cracks in the core concrete from propagating quickly. Furthermore, finite element model was established and verified by comparing the experimental and FE results. Then, the complex composite action among the steel tube, core concrete and steel section was discussed and clarified comprehensively. In addition, the capacity of the energy dissipation for SRCFT stub columns was discussed. Finally, a novel simplified formula was proposed to predict the ultimate bearing capacity of SRCFT stub columns. The studies may provide a considerable reference for designing this type of structures in engineering practice.

In this paper, modelling methods are developed to achieve dynamics exploration for the vehicle–track system and its substructures. First, a coupled model, with the satisfaction of wheel–rail displa...

Due to the demand for increasing trainload and enhancing some existing heavy-haul railways, the low reserve value of bearing capacity is a problem for the 32 m-span simply supported beam. The fatigue behavior of prestressed concrete beams in a heavy-haul railway loaded by 33 t and larger axle weight of trains was experimentally investigated. The experimental results of the fatigue behaviors, including fatigue deformation, crack propagation behavior, and strains of classical materials were obtained and analyzed. A fatigue behavior assessment model was established to investigate the residual stiffness and yield point degradation of the beams loaded by the trainload. The effects of train fatigue cycles and prestress loss on the residual stiffness and yield point degradation models of the beams were analyzed. The results indicated that the crack development process had three stages during the fatigue process: the derivative stage, gradual development stage, and fatigue failure stage. Trainload was the main external factor influencing the fatigue behavior of prestressed concrete beams. The increase in trainload accelerated the degradation rate of the residual stiffness of the beams and yield point, reducing the fatigue life. The prestressing strand was primarily used to delay the concrete cracking in the tension zone. When the beam was not cracked, the prestressed concrete beam showed good fatigue performance, and the degree of prestressing did not affect the fatigue life of the beams. When the maximum fatigue load exceeded the cracking load of the beam, prestress loss in beams became a critical issue that accelerated the degradation rate of fatigue strength and reduced fatigue life. The higher the fatigue damage degree, the more pronounced the effect of prestress loss on the fatigue strength of the beams. The fatigue failure of prestressed concrete beams occurred in the bottom tensile steel bar. Therefore, when the trainload of a heavy-haul railway is greater than the cracking load of the beam, it is recommended to strengthen the beam by prestressing and strictly control the trainload to avoid yield failure.

The secondary development of ABAQUS was carried out to calculate the shrinkage and creep of concrete, and a finite element model of the China Railway Track System (CRTS) II slab ballastless track was established. Then, the interlaminar stress of CRTS II slab ballastless track at different ages of the track slab during laying (AOTSL) caused by concrete shrinkage and creep was studied. The obtained results showed that the stress redistribution occurred in the sliding layer, which resulted in the generation of a gap. Although the gap length was slightly reduced due to the shear cogging, the sliding layer at the slab edge is more prone to produce gaps. Under the effect of shrinkage and creep of the ballastless track, large additional shear stress, up to 0.676 MPa, was induced at the interface between CA mortar and the track slab. Meanwhile, the appearance of additional vertical and lateral forces of the shear cogging was caused by the shrinkage and creep of the ballastless track. Additionally, by further analysis, the recommended AOTSL ranges from 120 days to 180 days.

In this work a three-dimensional vehicle-ballasted track-subgrade interaction model is developed, where the vehicle is modeled as a multi-rigid-body system, the track-subgrade interaction is modelled by finite element method (FEM) with the rail modelled as beam elements, the sleeper and the subgrade layers modelled as solid elements, and the vehicle and the track-subgrade system are coupled by unified matrix formulations and solved simultaneously and time-dependently. As the modelling advancement, the versatility for FEM construction of track-subgrade systems has been promoted, where the elemental scale can be arbitrarily chosen without consideration of the node-to-node matching principle as the conventional methods; besides the vehicle and the track-subgrade systems have been coupled effectively by wheel-rail contact models. The applicability of various wheel-rail contact models has been discussed, and to reveal the effectiveness of this model in solving engineering problems such as the soil elasticity unevenness and the contact break of “hanging sleepers”, numerical examples have also been presented with referencable conclusions.

To study the effects of concrete creep and temperature gradients on the cooperative working performance of a longitudinal slab ballast-less track prestressed concrete simply supported box girder system (girder-rail system), a girder-rail system model was established based on the ANSYS software. Then, the deformation of the girder-rail system caused by concrete creep and temperature gradient was studied in addition to the normal stress redistribution of the sliding layer and the normal stress variation of the interface between the cement asphalt mortar (CA mortar) and track slab. The results showed that the mid-span creep camber of the box girder under the girder-rail system was smaller than that of the single box girder, to which a uniform load (converted from the ballast-less track system) was applied. Concrete creep and temperature gradients led to the camber deformation of the ballast-less track, and then caused a redistribution of interlayer stress. At 1500 days, the creep camber of the box girder caused the appearance of a void in the sliding layer close to the end of the box girder (approximately 2 m). Voids appeared in the sliding layers at the middle and edge of the base plate under positive and negative temperature gradients, respectively. Under the creep camber of the box girder, tensile stress at the interface between the CA mortar and track slab appeared at the end of the box girder. This tensile stress appeared at the interface in the middle and edge of the track slab under positive and negative temperature gradients, respectively. Under the effects of creep camber of the box girder and temperature gradient, the maximum normal tensile stress of the interface was 264.8 kPa at day 1500, which was less than the normal cohesive strength of the interface and indicated that there was no interface separation.

The influences of temperature, relative humidity (RH) and carbon dioxide (CO2) concentration on concrete carbonation in a simulated environment were investigated. The carbonation depth, compressive strength and surface strain of concrete under different simulated environments were tested. The results showed that the effects of temperature, RH and carbon dioxide concentration on carbonation depth and compressive strength were significant. There was a linear relation between temperature and carbonation depth as well as compressive strength of concrete. A power function existed between carbon dioxide concentration and carbonation depth, and there was an exponential function between carbon dioxide concentration and compressive strength. The carbonation of concrete was more significant when the RH was within the range 60­–80%. Significant differences of phase composition and hydration products were observed before and after the carbonation, mainly manifested as attenuation and disappearance of diffraction peaks of hydration products.

In this work, an entire multi-rigid-body system with two-stage suspension systems is assumed to run on a slab track system, where the elastoplasticity of the track slab is modeled by Mindlin plate theory considered in a framework of three-dimensional vehicle–track dynamic system. Considering the elastoplasticity of track slabs, the nonlinearity and time- and stress-dependent track slab stiffness matrices must be accounted for in the time-domain dynamic solutions; therefore, a two-step iterative algorithm separating the vehicle–track system into vehicle–rail subsystem and track slab system is developed to solve the dynamic equations of motion for vehicle–track interactions. The numerical studies have shown the accuracy and efficiency of this method in calibrating the vehicle–track dynamic behavior in conditions of track slab elastoplastic deformation. Besides, it has shown that the longitudinal unevenness of the track support stiffness has significant influence on the plasticity of track slabs.

BACKGROUND Ovarian cancer is usually not diagnosed until the late stage, and it is resistant to platinum and other standard chemotherapy drugs, resulting in high mortality. OBJECTIVES To investigate the effects of miR-140-5p on cell proliferation, apoptosis, invasion, and migration capability in the SKOV3 and OVCAR3 ovarian cancer cell lines through Wnt signaling pathway. MATERIAL AND METHODS Expression levels of miR-140-5p were checked using quantitative real-time polymerase chain reaction (qRT-PCR). The expression of miR-140-5p was upregulated by transfecting cells with a miR-140-5p mimic or a mimic negative control (NC). Cell proliferation was assessed using a CCK8 assay, and cell cycle distribution and apoptosis percentage were detected with flow cytometry. A transwell invasion assay was employed to evaluate cell migration and invasion ability. The target complementary relationship between miR-140-5p and WNT1 was verified using a dual-luciferase reporter assay while â-catenin in the nuclei was observed using immunofluorescence. The expression of Wnt signaling pathway-related proteins was examined using western blot and qRT-PCR. RESULTS The relative expression level of miR-140-5p in SKOV3 and OVCAR3 cells was obviously decreased compared with that in the IOSE80 cells (p < 0.05). Besides, upregulated miR-140-5p effectively suppressed cell proliferation and increased the apoptosis ratio of SKOV3 and OVCAR3 cells (p < 0.05). In addition, the invasion and migration capability of SKOV3 and OVCAR3 cells in miR-140-5p mimic group was largely suppressed compared with the NC group (p < 0.05). What is more, the target complementary relationship between miR-140-5p and the WNT1 gene was revealed; upregulated miR-140-5p suppressed the expression of Wnt signaling-related genes, and restrained nuclear transfer of â-catenin (p < 0.05). CONCLUSIONS The overexpression of miR-140-5p restricted the proliferation, migration and invasion abilities, and accelerated cell apoptosis in ovarian cancer cell lines SKOV3 and OVCAR3 through the Wnt signaling pathway.