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Non-Hermitian systems with parity–time (PT)-symmetry have been extensively studied and rapidly developed in resonance wireless power transfer (WPT). The WPT system that satisfies PT-symmetry always has real eigenvalues, which promote efficient energy transfer. However, meeting the condition of PT-symmetry is one of the most puzzling issues. Stable power transfer under different transmission conditions is also a great challenge. Bound state in the continuum (BIC) supporting extreme quality-factor mode provides an opportunity for efficient WPT. Here, we propose theoretically and demonstrate experimentally that BIC widely exists in resonance-coupled systems without PT-symmetry, and it can even realize more stable and efficient power transfer than PT-symmetric systems. Importantly, BIC for efficient WPT is universal and suitable in standard second-order and even high-order WPT systems. Our results not only extend non-Hermitian physics beyond PT-symmetry, but also bridge the gap between BIC and practical application engineering, such as highperformance WPT, wireless sensing and communications. [ABSTRACT FROM AUTHOR]

Polytetrafluoroethylene (PTFE) has great potential for applications in water-lubricated bearings; however, in heavy load conditions at low speeds, PTFE suffers from severe friction and abrasion because of its poor wear resistance. In this study, silicon carbide (SiC) content and particle size are investigated in relation to PTFE water-lubricated composites' tribological properties. The results show that the wear resistance of PTFE composites can be significantly improved when the filling amount of SiC particles was between 3 and 5 wt.%, and the composites containing 5 wt.% SiC reduced wear loss by 99.44%. The composites' friction and wear properties decreased as SiC particle size increased, and wear mechanism for the composites shifted from adhesive to abrasive. Wear loss on PTFE composites filled with 40 nm SiC particles was reduced by 97.03%, showing the best wear resistance. This study provides an experimental basis for the development of high-performance PTFE water-lubricated bearings. [ABSTRACT FROM AUTHOR]

Purpose: From a clinical point of view, how to force a transition from insomnia brain state to healthy brain state by external driven stimulation is of great interest. This needs to define brain state of insomnia disorder as metastable substates. The current study was to identify recurrent substates of insomnia disorder in terms of probability of occurrence, lifetime, and alternation profiles by using leading eigenvector dynamics analysis (LEiDA) method. Methods: We enrolled 32 patients with insomnia disorder and 30 healthy subjects. We firstly obtained the BOLD phase coherence matrix from Hilbert transform of BOLD signals and then extracted all the leading eigenvectors from the BOLD phase coherence matrix for all subjects across all time points. Lastly, we clustered the leading eigenvectors using a k-means clustering algorithm to find the probabilistic metastable substates (PMS) and calculate the probability of occurrence and associated lifetime for substates. Results: The resulting 3 clusters were optimal for brain state of insomnia disorder and healthy brain state, respectively. The occurred probabilities of the PMS were significantly different between the patients with insomnia disorder and healthy subjects, with 0.51 versus 0.44 for PMS-1 (p < 0.001), 0.25 versus 0.27 for PMS-2 (p = 0.051), and 0.24 versus 0.29 for PMS-3 (p < 0.001), as well as the lifetime (in TR) of 36.65 versus 33.15 for PMS-1 (p = 0.068), 14.36 versus 15.43 for PMS-2 (p = 0.117), and 14.80 versus 16.34 for PMS-3 (p = 0.042). The values of the diagonal of the transition matrix were much higher than the probabilities of switching states, indicating the metastable nature of substates. Conclusion: The resulted probabilistic metastable substates hint the characteristic brain dynamics of insomnia disorder. The results may lay a foundation to help determine how to force a transition from insomnia brain state to healthy brain state by external driven stimulation. [ABSTRACT FROM AUTHOR]

Motivated by unique topological semimetals in condensed matter physics, we propose an effective Hamiltonian with four degrees of freedom to describe evolutions of photonic double Weyl nodal line semimetals in one-dimensional hyper-crystals, which supports the energy bands translating or rotating independently in the form of Weyl quasiparticles. Especially, owing to the unit cells without inversion symmetry, a pair of reflection-phase singularities carrying opposite topological charges emerge near each nodal line, and result in a unique bilateral drumhead surface state. After reducing radiation leakages and absorption losses, these two singularities gather together gradually, and form a quasi-bound state in the continuum (quasi-BIC) ring at the nodal line ultimately. Our work not only reports the first realization of controllable photonics Weyl nodal line semimetals, establishes a bridge between two independent topological concepts−BICs and Weyl semimetals, but also heralds new possibilities for unconventional device applications, such as dual-mode schemes for highly sensitive sensing and switching. One-dimensional photonic crystals provide a platform to modulate Weyl quasiparticles with properties of bound states in the continuum both dynamically (transition and rotation) and topologically (singularities in bilateral drumhead surface states). [ABSTRACT FROM AUTHOR]

A compatible spanning circuit in an edge-colored graph G (not necessarily properly) is defined as a closed trail containing all vertices of G in which any two consecutively traversed edges have distinct colors. The existence of extremal compatible spanning circuits (i.e., compatible Hamilton cycles and compatible Euler tours) has been studied extensively. Recently, sufficient conditions for the existence of compatible spanning circuits visiting each vertex at least a specified number of times in specific edge-colored graphs satisfying certain degree conditions have been established. In this paper, we continue the research on sufficient conditions for the existence of such compatible s-panning circuits. We consider edge-colored graphs containing no certain forbidden induced subgraphs. As applications, we also consider the existence of such compatible spanning circuits in edge-colored graphs G with κ(G) ≥ α(G), κ(G) ≥ α(G) − 1 and κ (G) ≥ α(G), respectively. In this context, κ(G), α(G) and κ (G) denote the connectivity, the independence number and the edge connectivity of a graph G, respectively. [ABSTRACT FROM AUTHOR]

With the development of green tribology in the shipping industry, the application of water lubrication gradually replaces oil lubrication in stern bearings and thrust bearings. In terms of large-scale and high-speed ships, water-lubricated bearings with high performance are more strictly required. However, due to the lubricating medium, water-lubricated bearings have many problems such as friction, wear, vibration, noise, etc. This review focuses on the performance of marine water-lubricated bearings and their failure prevention mechanism. Furthermore, the research of marine water-lubricated bearings is reviewed by discussing its lubrication principle, test technology, friction and wear mechanism, and friction noise generation mechanism. The performance enhancement methods have been overviewed from structure optimization and material modification. Finally, the potential problems and the perspective of water-lubricated bearings are given in detail. [ABSTRACT FROM AUTHOR]

With the growing public attention on sustainable development and green ecosystems, the efficient management of fuzzy sewage treatment processes (FSTPs) has been a major concern in academia. Characterized by strong abstraction and analysis abilities, data mining technologies provide a novel perspective to solve this problem. In recent years, data-driven management for FSTP has been widely investigated, resulting in a number of typical approaches. However, almost all existing technical approaches consider FSTP a unidirectional, sequential process, ignoring the bidirectional temporality caused by backflow operations. Therefore, we propose a data-driven management mechanism for FSTP based on hybrid neural computing (IM-HNC for short). This mechanism attempts to capture the bidirectional time-series features of FSTP with the aid of a bidirectional long short-term memory model, and further introduces a convolutional neural network to construct feature spaces with a stronger expression capability. Empirically, we implement a series of experiments on three datasets under different parameter settings to test the efficiency and robustness of the proposed IM-HNC. The experimental results manifest that the IM-HNC has an average performance improvement of approximately 5% compared to the baselines. [ABSTRACT FROM AUTHOR]

Lignum vitae, one of the earliest manufacturing materials used in water-lubricated bearings, is renowned for its exceptional tribological performance. The key factor behind this remarkable wear resistance lies in Lignum vitae's internal vessel structure. In this study, a lubrication model based on the natural hollow-tube vessel was conducted to simulate the hydrodynamic lubrication of Lignum vitae in actual working condition and a novel biomimetic composite was manufactured. The influence of the hollow-tube structure on tribological performance was investigated both theoretically and experimentally. Through an extensive series of simulations, wear tests, and characterization under water-lubricated conditions, the results demonstrated that the presence of the hollow-tube structure positively impacts tribological performance. Moreover, it is found that the size and density of these tubes are directly correlated with this improvement; specifically reducing the coefficient of friction by 47 percent and reducing the wear volume by 69 percent. By combining simulation and experimental data, our discussion reveals that the hollow-tube structure significantly enhances lubricant storage capacity and reduces abrasion at frictional interfaces. This comprehensive analysis sheds light on Lignum vitae's internal structural parameters while establishing clear correlations between these parameters and its tribological performance. [ABSTRACT FROM AUTHOR]

The interaction between cavity field and atoms plays an important role in exploring the abundant non-Hermitian physics and constructing powerful wave function devices. In this work, we propose theoretically and realize experimentally unidirectional perfect absorption in a non-Hermitian acoustic system with the help of the topological bound state in the continuum (BIC), which is established by the hybrid interaction between one trivial BIC and another conventional resonant state. In the 2D parameter space spanned by frequency and distance between the two resonators, the topological scattering singularities appear in pairs and are associated with topological distinguished charges. Meanwhile, we reveal the origin of topological charges and their continuous evolution with the loss factor. At a specific loss factor, two topological charges just annihilate together, and acoustic perfect absorption induced by topological BIC is realized at the left incidence, while there is no phase singularity and near-total reflection is observed at the right incidence, hence the system presents extreme asymmetry. Our work bridges the gap between scattering characteristics of non-Hermitian acoustic systems and topological scattering singularities, which may contribute to the research of novel non-Hermitian physics and the practical applications of advanced absorbers and sensors. [ABSTRACT FROM AUTHOR]

Objective: Insomnia disorder with objective short sleep duration (ISS) has been considered as a biologically severe subtype. The aim of this meta-analysis was to reveal the association of the ISS phenotype and cognitive performance. Methods: We searched PubMed, EMBASE, and the Cochrane Library for studies that observed an association of cognitive performance and insomnia with objective short sleep duration (ISS) phenotype. The "metafor" and "MAd" packages in R software (version 4.2.0) were used to calculate the unbiased standardized mean difference (Hedge's g), which was adjusted so that a negative value indicated worse cognitive performance. Results: The pooled analysis with 1339 participants revealed that the ISS phenotype was associated with overall cognitive impairments (Hedges' g = − 0.56 [− 0.89, − 0.23]), as well as specific cognitive domains including attention (Hedges' g = − 0.86 [− 1.25, − 0.47]), memory (Hedges' g = − 0.47 [− 0.82, − 0.12]), and executive function (Hedges' g = − 0.39 [− 0.76, − 0.02]). However, cognitive performance was not significantly different between insomnia disorder with objective normal sleep duration (INS) and good sleepers (p >.05). Conclusion: Insomnia disorder with the ISS phenotype, but not the INS phenotype, was associated with cognitive impairments, suggesting the possible utility of treating the ISS phenotype to improve cognitive performance. [ABSTRACT FROM AUTHOR]

Light propagates in various ways depending on environment, including uniform medium, surface/interface and photonic crystals, which appears ubiquitously in daily life and has been exploited for advanced optics technology. We unveiled that a topological photonic crystal exhibits unique electromagnetic (EM) transport properties originating from the Dirac frequency dispersion and multicomponent spinor eigenmodes. Measuring precisely local Poynting vectors in microstrips of honeycomb structure where optics topology emerges upon a band gap opening in the Dirac dispersion and a p-d band inversion induced by a Kekulé-type distortion respecting C6v symmetry, we showed that a chiral wavelet induces a global EM transportation circulating in the direction counter to the source, which is intimately related to the topological band gap specified by a negative Dirac mass. This brand-new Huygens-Fresnel phenomenon can be considered as the counterpart of negative refraction of EM plane waves associated with upwardly convex dispersions of photonic crystals, and our present finding is expected to open a new window for photonic innovations. Huygens-Fresnel features are useful for harnessing light in unique ways. Here the authors demonstrate a chiral light source that induces globally a counter energy flow in a topological photonics structure with Dirac-type frequency dispersion. [ABSTRACT FROM AUTHOR]

Since wastewater treatment processes (WTP) are generally accompanied with intense coupling and fuzziness, conventional biochemical mechanisms-based methods cannot comprehensively express the WTP due to limited computational ability. In response to the challenge caused by fuzziness, this paper proposes a hybrid control and prediction system for modeling WTP with the fuse of Activated Sludge model, Convolutional neural network and Long short-term memory neural networks (AS-CL) with knowledge and data-driven characteristics. Moreover, the activated sludge model is employed to model the wastewater treatment process based on the perspective of knowledge. Besides, the hybrid neural network that combines convolutional neural network and long short-term memory model is adopted to model the WTP from the perspective of data. Then, a multi-layer perception model is set up to realize collaborative awareness of data and knowledge. Lastly, the proposed AS-CL has been evaluated by a real-world data-set collected from a real sewage treatment plant. The results show that compared with typical existing methods, the proposal improves modeling efficiency. With the collaborative modeling scheme, influence from fuzziness on WTP can be reduced to some extent. Compared with five benchmark methods of the two evaluation indexes, the results of AS-CL show that the average performance of this method exceeds 7% of the baseline. [ABSTRACT FROM AUTHOR]

A compatible Euler trail (tour) in an edge-colored graph is an Euler trail (tour) in which each two edges traversed consecutively along the Euler trail (tour) have distinct colors. In this paper, we show that the problem of counting compatible Euler trails in edge-colored graphs is # P-complete, and develop O(mN) time algorithms for enumerating compatible Euler trails (tours) in edge-colored graphs with m edges and N compatible Euler trails (tours). It is worth mentioning that our algorithms can run in O(N) time when there is no vertex v with degree 4 and maximum monochromatic degree 2. [ABSTRACT FROM AUTHOR]

Since medical diagnosis runs through the whole journey of human health, the traditional medical diagnosis methods cannot ensure the diagnosis accurate due to the interference of multiple external factors. In response, this paper proposes a multimedia medical management method supported by the data-driven intelligent decision (MMD-DI). This method can be used to predict the survival time of cancer patients under the help of gradient boosting decision tree (GBDT) and hybrid neural network model. First, the feature factors were scanned to match the conditions by GBDT, according to the set value domain; Then the factors were inputted into the neural network. The hybrid neural network was employed to predict the survival time of cancer patients, and it was constructed by combining the convolutional neural network (CNN) and the long short-term memory (LSTM) model. Finally, the stability of the proposed MMD-DI was analyzed, and performance was compared with a series of commonly exploited baseline methods: the mean of cross-validated RMSE (Root Mean Squared Error) evaluation results is 0.183, the mean of cross-validated MAE (Mean Absolute Error) evaluation results is 0.147, the two indicators are both much lower than the commonly exploited baseline methods. A series of experiments proved that MMD-DI has excellent performance and can be used in the multimedia medical management systems. [ABSTRACT FROM AUTHOR]

Water-lubrication bearings are critical components in ship operation. However, studies on their maintenance and failure detection are highly limited. The use of sensors to continually monitor the working operation of bearings is a potential approach to solve this problem, which is collectively called intelligent bearings. In this literature review, the recent progress of electrical resistance strain gauges, Fiber Bragg grating, triboelectric nanogenerators, piezoelectric nanogenerators, and thermoelectric sensors for in-situ monitoring is summarized. Future research and design concepts on intelligent water-lubrication bearings are also comprehensively discussed. The findings show that the accident risks, lubrication condition, and remaining life of water-lubricated bearings can be evaluated with the surface temperature, coefficient of friction, and wear volume monitoring. The research work on intelligent water-lubricated bearings is committed to promoting the development of green, electrified, and intelligent technologies for ship propulsion systems, which have important theoretical significance and application value. [ABSTRACT FROM AUTHOR]

Marine water-lubricated stern bearings usually suffer severe abrasion and poor lubrication under the conditions of low-speed and heavy-load. A large number of studies have demonstrated that the addition of microcapsules and modified lubricants can improve the lubricating properties of the materials at the expense of mechanical properties. In order to simultaneously improve the combination property of bearing material, the current study investigates the effect of aramid fiber modification and its addition on ultra-high molecular weight polyethylene (UHMWPE) properties. The results revealed that the addition of aramid fibers into UHMWPE could improve the ultimate tensile strength and shore hardness of the composites; however, the tribological properties are not significantly altered. The synergistic modification effect of microcapsules and aramid fibers leads to an optimal combination of tribological and mechanical properties. Overall, the current work presents a novel strategy for the design of water-lubricated bearing materials for low-speed and heavy load conditions. [ABSTRACT FROM AUTHOR]

The running-in of cylinder liner-piston rings (CLPRs) is the most important process that must be performed before a marine diesel engine can be operated. The quality of running-in directly affects the reliability of a CLPR. The surface texture of a CLPR has been proven to significantly affect its lubrication performance. In this study, the tribological behavior of a CLPR during running-in is investigated. Three types of surface textures are generated on the CLPR via laser processing: dimple texture on piston rings, groove texture on cylinder liners, and co-texture on both sides. Subsequently, a series of tests are performed on a slice tester. A load of 300 N (1.64 MPa) is applied, and two speeds (50 and 100 rpm) are adopted. The CLPR running-in quality is characterized based on three parameters, i.e., the friction coefficient, contact resistance, and wear topography. Experimental results show that, compared with a non-textured surface, the three types of surface textures mentioned above improved the friction performance during running-in. The lubricant supply capacity of the dimple texture on the piston ring, as a mobile oil reservoir, is stronger than that of the groove texture on the cylinder liner serving as a static oil reservoir. By contrast, the wear resistance of the dimple texture, as a movable debris trap on the piston ring, is weaker than that of the groove texture on the cylinder liner, which serves as a static debris trap. It is demonstrated that the co-texture combines the advantages of dimples and groove textures. Compared with non-textured surfaces, the friction coefficient decreased the most at 100 rpm (44.5%), and the contact resistance improved the most at 50 rpm (352.9%). The coupling effect provides the surface with improved running-in quality by optimizing the tribological performance, particularly at the dead center. This study provides guidance for the tribological design and manufacturing of CLPR in marine diesel engines. [ABSTRACT FROM AUTHOR]

With the development of automatic measurement and data storage, vast quantities of data can be recorded and analyzed for heat transfer processes, which provides an opportunity to discover the transient heat transfer governing laws from the data. In this study, a machine learning-based sequential threshold ridge regression (STRidge) approach is applied to extract partial differential equations (PDEs) and tested on the heat conduction equation and conductive–convective heat transfer equation subjected to different boundary conditions, data volumes, and noise levels. Moreover, we studied the learning of governing equation of nonlinear transient heat transfer and used the improved STRidge with genetic algorithm to learn PDE with incomplete candidate library. The results showcase highly accurate identification of governing equations for heat transfer. And our results reveal the vast potential of the data-driven method in complex geothermal problems. [ABSTRACT FROM AUTHOR]

Ultra-high molecular weight polyethylene (UHMWPE) has great potential in the field of water-lubricated bearings. However, water-lubricated bearing made of pure UHMWPE produce significant heat and undergo physical damage under low speed and heavy load conditions. These performance issues can be improved by reinforcement with fibers that have excellent complementary properties to UHMWPE. Polyester fibers (PETFs) have high compressive strength and wear resistance, and corresponding oriented-fiber-reinforced-composites (OFRCs) wherein PETF acts as reinforcement show even better mechanical and tribological properties. In this study, the influence of PETF density on UHMWPE was investigated by systematic testing of different OFRCs. The results show that the optimal fiber density of composites with PETF oriented along the axial direction was between 1.1 wt% and 2.2 wt%, and that for heavy loads, performance deteriorated with increasing fiber density. Compared with UHMWPE, OFRCs with the optimal fiber density obtained from this study reduced friction coefficient by up to 25.93 % and wear volume by 22.67 %, respectively. Considering the low cost, high durability, and relatively low content (<2.2 wt%) necessary for enhanced properties, reinforcement with oriented PETF is a viable approach to enhance water lubrication performance of UHMWPE. [ABSTRACT FROM AUTHOR]

Water-lubricated stern tube bearings are widely used in marine shaft systems, where their lubrication performance determines the efficiency and navigation safety of ships. The hardness of materials is an important factor affecting the tribological performance of water-lubricated bearings under sediment conditions. This study investigated the wear behavior of thermoplastic polyurethane (TPU) materials with different shore hardnesses under sediment conditions. Four kinds of TPU with different shore hardness were selected. The test results showed that the shore hardness of TPU depended on the content of the TPU hard segment. With increasing hardness, the absorption peak strength of the functional groups increased, and the increase in hardness could enhance the tensile strength of the TPU materials. In all test groups, the friction coefficient of TPU with 60 and 70 A hardness was relatively stable. The total wear volume of TPU with 70 A hardness was 45.9% lower than that of TPU with 60 A hardness. TPU with 70 A hardness had better ductility and embedded possession. The wear modes of TPU with 70 A hardness were crimping and micro-plowing. Only mild wear occurred on the wear surface of TPU with 70 A hardness. The main wear mechanisms of the TPU with 70 A hardness were abrasive wear and fatigue wear under sediment conditions. In summary, TPU with 70 A hardness was the most suitable for water-lubricated stern bearings under sediment conditions. The data from this study provide deep insight into the wear process of TPU materials with different hardness under sediment conditions and may be useful for selecting the proper TPU material hardness for water-lubricated stern bearings. [ABSTRACT FROM AUTHOR]

It is widely believed that effective water resource management can optimize the scheduling of water supply plans, which is essential for sustainable development. The core of management is to accurately predict future water consumption. However, existing studies generally face two challenges. First, a reliable bottom platform for the support of online data integration is absent. In addition, multisource factors that primarily affect water consumption are neglected when modeling. To solve the above problems, this paper proposes a data-driven peer-to-peer blockchain framework to predict water consumption. Fundamentally, it utilizes a blockchain system with a peer-to-peer network to serve as the decision support platform hardware. On this basis, an intelligent prediction algorithm that combines the grey model and long short-term memory model is developed to drive the hardware infrastructure. After that, the performance of the proposed method is evaluated by carrying out experiments on a real-world dataset, and three typical approaches are selected for comparison. The experimental results show that the proposal exceeds general prediction models by approximately 8%. [ABSTRACT FROM AUTHOR]

Several soft tissues residing in the living body have excellent hydration lubrication properties and can provide effective protection during relative motion. In order to apply this advantage of soft matters in practical applications and try to avoid its disadvantage, such as swelling and weakening in water, a design strategy of a soft/hard double network (DN) hydrogel microsphere modified ultrahigh molecular weight polyethylene (UHMWPE) composite is proposed in this study. A series of microspheres of urea-formaldehyde (UF), polyacrylamide (PAAm) hydrogel, UF/PAAm double network, and their composites were prepared. The mechanical properties, swelling, wettability, friction properties, and the lubrication mechanisms of the composites were investigated. The results show that DN microspheres can have an excellent stability and provide hydration lubrication. The performance of 75 DN-1 composite was superior to others. This finding will provide a novel strategy for the development of water-lubricated materials and have wide application in engineering fields. [ABSTRACT FROM AUTHOR]

As an important part of the marine propulsion system, the water-lubricated stern bearing has a major impact on ship safety. In order to improve the reliability of water-lubricated stern bearing under actual working conditions, hydrophilic PVA fibers were added to a typical water-lubricated bearing material, the thermoplastic polyurethane (TPU), to fabricate TPU/PVA fiber composites. The sliding friction-wear test, under water-lubricated conditions, of the TPU composites/QSn7-0.2 friction pairs were analyzed using a designed testing apparatus. The friction coefficients, worn surfaces and the wear losses from the test samples were examined. The results revealed that the addition of appropriate hydrophilic PVA fibers can effectively improve the tribological properties of TPU materials. The hydrophilic PVA fibers not only improved the affinity and the material surface storage ability to water medium but also absorbed water and formed swelling convex texture under water environment, thereby enhanced the hydrodynamic lubrication effect. When the mass fraction of PVA fiber reached 15 % or more, the debris gathered under the action of loading and fiber connection, formed solid lubrication film. Thus, it effectively improved the self-lubrication performance of the material. But that is not conducive to the tribological performances of the composites when the mass fraction of PVA fiber reached 30 %. Generally, the materials with 15 % to 20 % PVA fiber content showed better tribological properties under the experimental conditions. This work provides a new idea for the research of new water-lubricated bearing materials. [ABSTRACT FROM AUTHOR]

The association of mortality risk and insomnia disorder with daytime impairments has been plausible. The purpose of this study was to evaluate the strength of evidence for this relationship. We performed a comprehensive literature search for clinical Cohort trials including annual cumulative time-to-event data that evaluated the risk of mortality in insomnia disorder patients with daytime impairments. We used pooled hazard ratio (HR) as the main outcome measure and Kaplan-Meier survive curve to display outcome measures. The weighted cumulative mortality of 4.5% for patients with insomnia disorder was higher than that of 2.6% for those without insomnia (p<0.001). Higher risk of mortality presented in patients with insomnia disorder when compared to those without insomnia (HR = 1.66, 95% CI = 1.25–2.19, p<0.001). Patients with duration of more than 10 years were at a greater risk of annual cumulative mortality (R2 = 0.891, p<0.001). Insomnia disorder with daytime impairments increased the risk of mortality, and patients with duration of more than 10 years were at a greater risk of annual cumulative mortality. [ABSTRACT FROM AUTHOR]

A compatible spanning circuit in a (not necessarily properly) edge-colored graph G is a closed trail containing all vertices of G in which any two consecutively traversed edges have distinct colors. Sufficient conditions for the existence of extremal compatible spanning circuits (i.e., compatible Hamilton cycles and Euler tours), and polynomial-time algorithms for finding compatible Euler tours have been considered in previous literature. More recently, sufficient conditions for the existence of more general compatible spanning circuits in specific edge-colored graphs have been established. In this paper, we consider the existence of (more general) compatible spanning circuits from an algorithmic perspective. We first show that determining whether an edge-colored connected graph contains a compatible spanning circuit is an NP-complete problem. Next, we describe two polynomial-time algorithms for finding compatible spanning circuits in edge-colored complete graphs. These results in some sense give partial support to a conjecture on the existence of compatible Hamilton cycles in edge-colored complete graphs due to Bollobás and Erdős from the 1970s. [ABSTRACT FROM AUTHOR]

Water quality improvement is the most efficient way to prevent arsenic exposure. After the cessation of arsenic ingestion, arsenic methylation capacity of the exposed population can change significantly. The factors associated with these changes remain poorly understood. Therefore, arsenic methylation capacity in a study cohort was estimated before and after water quality improvement in the present study. Results indicated that urinary content of the arsenic species in the study cohort significantly decreased after water quality improvement. In addition, the proportions of inorganic arsenic (%iAs) and monomethyl arsenic acid (%MMA) were significantly decreased, while proportions of dimethyl arsenic (%DMA) increased. The primary methylation index (PMI) and secondary methylation index (SMI) increased from 0.85 to 0.92 and 0.82 to 0.84, respectively. Arsenic species urinary content and arsenic methylation index varied slightly between the study cohort after water quality improvement and the control cohort. The rate of increase in PMI was higher than that in SMI. The study group aged 31–50 years had the highest increase in PMI. Logistic regression revealed that %DMA before water quality improvement was negatively associated with the increase in PMI, while %iAs were positively related, and %MMA were positively associated with the increase in SMI. It is concluded that urinary arsenic species content and arsenic methylation capacity increased to the levels of the control cohort after water quality improvement. An increase in primary arsenic methylation capacity may be a burden on the secondary arsenic methylation capacity. The main role of arsenic methylation capacity recovery may be the cessation of arsenic exposure. [ABSTRACT FROM AUTHOR]

Background: Recently, several functional neuroimaging studies have been conducted in patients with persistent insomnia disorder, but these studies have yielded diverse findings. We aimed to identify convergence in function across the heterogeneity of patients, modalities, and methods for insomnia disorder by performing a quantitative coordinate-based meta-analysis. Materials and methods: We performed a quantitative, voxel-wise meta-analysis of resting-state fMRI studies using seed-based d mapping to find convergence of functional alterations in persistent insomnia disorder. Results: We included 28 studies comprising 287 peak foci involving 951 patients with insomnia disorder and 884 healthy controls. Patients with persistent insomnia disorder showed that increased activity was more frequently reported in right parahippocampal gyrus (p < 0.001) and left median cingulate/paracingulate gyri (p < 0.001); while decreased activity was more frequently reported in right cerebellum (p < 0.001) and left superior frontal gyrus/medial orbital (p < 0.001). Conclusion: The altered functional networks in patients with persistent insomnia disorder converge in median cingulate/paracingulate gyri and right parahippocampal gyrus with increased activity, and cerebellum and superior frontal gyrus/medial orbital with reduced activity. As a potential target in future, the identification of these altered or unbalanced networks is very important because they may be noninvasively rebalanced to sleep homeostasis by noninvasive brain stimulation methods. [ABSTRACT FROM AUTHOR]

Gene rearrangements, such as anaplastic lymphoma kinase (ALK), c-ros oncogene 1 receptor tyrosine kinase (ROS1), rearranged during transfection (RET) and neurotrophic receptor tyrosine kinase 1 (NTRK1), identified in cancer have been indicated to be robust therapeutic targets in lung carcinomas. However, a few studies have focussed on locally advanced rectal cancer (LARC). The discovery of novel gene fusions is also valuable for LARC research. We used mass spectrometry-based assays and RNA sequencing to detect both known ALK, ROS1, RET and NTRK1 rearrangements and novel gene fusions in LARC patients. FusionMap was also used to find gene fusions. None of the ALK, ROS1, RET or NTRK1 gene fusions were detected by mass spectrometry-based assays or RNA sequencing. Three fusion candidates, integrin subunit beta 7 (ITGB7)-ROS1, lamin A/C (LMNA)-NTRK1 and Golgi-associated PDZ and coiled-coil motif containing (GOPC)-keratin 8 (KRT8), showed relatively high junction-spanning reads by the FusionMap algorithm, but did not pass validation. These results suggest that no ALK, ROS1 or RET rearrangements were found in LARC. [ABSTRACT FROM AUTHOR]

Few studies have been conducted to compare arsenic exposure, metabolism, and methylation in populations exposed to arsenic in drinking water and from coal combustion. Therefore, arsenic concentrations in the environment and arsenic speciation in the urine of subjects exposed to arsenic as a consequence of coal combustion in a rural area in Shaanxi province (CCA) and in drinking water in a rural area in Inner Mongolia (DWA) were investigated. The mean arsenic concentrations in drinking water, indoor air, and soil in CCA were 4.52 μg/L, 0.03 mg/m, and 14.93 mg/kg, respectively. The mean arsenic concentrations in drinking water and soil in DWA were 144.71 μg/L and 10.19 mg/kg, respectively, while the level in indoor air was lower than the limit of detection. The total daily intakes of arsenic in DWA and CCA were 4.47 and 3.13 μg/day·kg, respectively. The mean urinary concentrations of inorganic arsenic (iAs), monomethylarsonic acid (MMA), dimethylarsenic acid (DMA), and total arsenic (TAs) for subjects with skin lesions in DWA were 50.41, 47.01, 202.66, and 300.08 μg/L. The concentrations for subjects without skin lesions were 49.76, 44.20, 195.60, and 289.56 μg/L, respectively. The %iAs, %MMA, and %DMA in the TAs in the urine of subjects from CCA were 12.24, 14.73, and 73.03%, while the corresponding values from DWA were 17.54, 15.57, and 66.89%, respectively. The subjects in DWA typically had a higher %iAs and %MMA, and a lower %DMA, and primary and secondary methylation index (PMI and SMI) than the subjects in CCA. It was concluded that the arsenic methylation efficiency of subjects in DWA and CCA was significantly influenced by chronic exposure to high levels of arsenic in the environment. The lower PMI and SMI values in DWA revealed lower arsenic methylation capacity due to ingestion of arsenic in drinking water. However, it remained unclear if the differences in arsenic metabolism between the two groups were due to differences in exposure levels or in exposure route. [ABSTRACT FROM AUTHOR]

In order to figure out the prevalence of skin lesions and methylation capacity for migrant and native adult women in an endemic area for arsenic poisoning in Inner Mongolia, China, 207 adult women were selected for study subjects. The results showed that the prevalence of skin lesions for the external group, provincial group and native group was 36.54, 26.15 and 35.56 %, respectively. The nail content of arsenic and urinary concentrations of dimethylarsenic (DMA), monomethylarsenic (MMA) and inorganic arsenic (iAs) were significantly higher in women with skin lesions than in those without skin lesions. The highest urinary concentrations of DMA, MMA and iAs were 213.93, 45.72 and 45.01 μg/L in the native group. The arsenic methylation capacity index revealed that the external group had the greatest capacity, while the native group had the lowest. The odds ratios of skin lesions in relation to arsenic metabolites and arsenic methylation capacity varied widely among the three groups. Urinary MMA and iAs concentrations were positively associated with risk of skin lesions in the three groups of adult women, while primary and secondary methylation capacities were negatively related to risk of skin lesions in native and provincial groups. The external group might be more susceptible to MMA and iAs, while the provincial and native groups were more tolerance to MMA and iAs. Lower primary and secondary arsenic methylation capacities increased the risk of skin lesions in native and provincial groups. Moreover, higher nail arsenic concentration increased the risk of skin lesions of adult women. [ABSTRACT FROM AUTHOR]

The dynamics of air entrainment and suppression schemes in a pump sump are investigated. Four different turbulence models (standard k-ε model, realizable k-ε model, renormalization group (RNG) k-ε model and shear-stress transport (SST) k-ε model) and the volume of fluid (VOF) multiphase model are employed to simulate the three-dimensional unsteady turbulent flow in a pump sump. The dynamic processes of air entrainment are simulated under conditions of relatively high discharge and low submergence; the mechanism of air entrainment is discussed in detail. Then suppression means for air entrainment is adopted by placing a circular plate on the intake pipe at three different heights. The results show: the position and structure of the free-surface vortices, sidewall-attached vortices, back wall-attached vortices, and floor-attached vortices calculated by SST k-ε turbulence model agree well with the experimental data. The two main contributors for air entrainment are pressure difference and vortex strength. By placing a circular plate in the middle of the intake pipe under water, air entrainment is suppressed because vortex strength is reduced. [ABSTRACT FROM AUTHOR]

More than 0.3 million individuals are subject to chronic exposure to arsenic via their drinking water in Inner Mongolia, China. To determine arsenic methylation capacity profiles for such individuals, concentrations of urinary arsenic metabolites were measured for 548 subjects using high-performance liquid chromatography and a hydride generator combined with inductively coupled plasma-mass spectrometry. Mean urinary concentrations of dimethylarsonic acid (DMA), monomethylarsonic acid (MMA), inorganic arsenic (iAs), and total arsenic (TAs) were 200.50, 46.71, 52.96, and 300.17 μg/L, respectively. The %iAs, %DMA, and %MMA were 15.98, 69.72, and 14.29 %. Mean urinary %iAs and %MMA were higher in males, while urinary %DMA was higher in females. There was a strong positive correlation between %iAs and %MMA, with negative correlations between %iAs and %DMA, and %iAs and %MMA. In addition, %iAs and %MMA were positively associated with total arsenic in drinking water (WAs), while %DMA was negatively related with WAs. Regression analysis indicated that the primary methylation index (PMI) and secondary methylation index (SMI) generally decreased with increasing WAs. Females had a higher arsenic methylation capacity compared to males. Younger subjects had lower primary arsenic methylation capacity. However, the secondary arsenic methylation capacity was hardly affected by age. Moreover, both primary and secondary arsenic methylation capacities were negatively related to WAs. [ABSTRACT FROM AUTHOR]

Condition monitoring of tool wear is paramount for guaranteeing the quality of workpiece and improving the lifetime of the cutter. To improve the training speed and the flexibility of the incremental learning, a modified Fuzzy ARTMAP classifier is developed in which the resonance layer is linked with the category node directly by many to one mapping. Therefore, the weight value and model structure can be updated simultaneously during the online incremental learning process. To testify the effectiveness of the presented method, experiments of tool condition classification in the process of end milling of Titanium alloy are carried out and two incremental learning cases are simulated. The analysis of online learning process in both cases shows that the structure and parameters of the model can be adjusted automatically without requiring access to the previous training data. At the same time, the accuracy analysis demonstrates that the presented method has strong ability to learn the new knowledge without forgetting the previous knowledge. [ABSTRACT FROM AUTHOR]

Wear particle analysis can be developed as an effective method for assessment of the running conditions of concaved cylinder liners. The aim of this study was to numerically characterize the topographical features of wear particles generated from different surface textured cylinder liners and to investigate their changes with alternations in both rotational speeds and surface textures. To achieve this goal, cylinder liners with three different surface textures were prepared and tested in four different speeds. In addition to an untreated surface, concave cylinder liner surfaces with two different diameters (1 and 2 mm) and two different depths (200 and 300 μm) were investigated. Wear particles were extracted from the lubrication oil; three-dimensional images of the wear debris were acquired using laser confocal microscopy; and their topographical features were analyzed quantitatively. This study has revealed that running-in conditions and stable state can be detected using wear debris analysis techniques at a micrometer scale. It has also been discovered that concave B cylinder liner with a depth-diameter ratio of 0.1 always generated wear particles different to those from the other two cylinder liners on each rotational speed. It is believed that the quantitative surface topography characterization results obtained in this study provide a practical base for developing a new, non-intrusive tool for monitoring the operation conditions of cylinder liner-piston rings in diesel engines. [ABSTRACT FROM AUTHOR]

Tool wear prediction plays an important role in guaranteeing the workpiece quality and improving the production efficiency. However, because of the uncertainty and complexity of tool wear process, it is hard to ensure that the samples related to all tool wear values can be collected during the training stage. Therefore, the accuracy of tool wear prediction for these uncovered data will deteriorate severely. In this paper, partial least square regression is presented to realize the tool wear prediction based on force signal. The main characteristic of this method is that the regression analysis is in the principal component space so that the multicollinearity between explanatory variables can be avoided effectively. Side milling experiment was carried out to validate the effectiveness of the proposed model. The analysis and comparison under different number of uncovered data show that the partial least square regression based tool wear prediction is more accurate. [ABSTRACT FROM AUTHOR]

In this study, finite element analysis combined with experimental observation was conducted to clarify the effects of substrate hardness and spray angle on the deposition behavior of cold-sprayed Ti particles. It is found that metallurgical bonding is highly possible to occur between the Ti particle and Cu substrate due to the intensive metal jet at the rim of the interface which helps to remove the cracked oxides. Because metallurgical bonding and large interfacial contact area can guarantee high adhesion strength, the thick Ti coating is achieved after deposition on the Cu substrate. As for the soft Al substrate, the first layer Ti particles are embedded in and then trapped by the soft substrate material, which results in the occurrence of mechanical interlock at the interface. As a consequence, the final coating thickness is also relatively large. When using hard stainless steel as the substrate, the essential conditions for forming the mechanical interlock are lacked due to the high hardness of the substrate material. In addition, the metal jet at rim of the interface is less prominent and also the interfacial contact area is smaller in comparison with the Ti-Cu case. Therefore, the particle-substrate bonding strength and the consequent coating thickness are relatively low. Besides, it is also found that the particle deformation and coating quality are significantly affected by the spray angle. The deformation of the particle localizes at only one side due to the additional tangential momentum. Also, such localized deformation becomes increasingly intensive with decreasing the spray angle. Moreover, the coating thickness is found to reduce with the decrease in spay angle, but the coating porosity shows a reverse trend. [ABSTRACT FROM AUTHOR]

This study investigates the effect of spray angle on the temperature distribution within the metallic substrate in cold spraying. Computational fluid dynamic approach is employed in this work to achieve this objective. The simulated results show that spray angle significantly influences the temperature distribution within the substrate. For the perpendicular spraying, the temperature gradient contours present regularly annular shape, which means the temperature distribution is only dependent on the radial position. Furthermore, the peak value of the surface temperature is not at the geometric center (stagnation point) but at the position slight away from the center, which may result from the transition of the flow from laminar to turbulent state. Along the radial direction, there exists a secondary peak of the temperature arising from the expansion waves in the adherence jet. With decreasing the spray angle, the secondary peak in the uphill direction disappears. But in the downhill direction, the secondary peak still exits and the distance from the geometric center increases with the decrease in spray angle. In addition, the temperature distribution within the substrate indicates that the residual tensile stress inside the substrate mainly exists near the front zone, but for the angular spraying at the uphill direction, it appears near the back surface. Besides, the simulated results indicate that the best way to preheat the substrate at the angular condition is to move the nozzle from uphill toward the downhill direction. [ABSTRACT FROM AUTHOR]

A marine diesel engine, where the cylinder liner-piston ring (CLPR) pair is one of the most important rubbing pairs, is the heart of a marine system. Studying the lubrication characteristics of the CLPR will provide a guide for rational design of the CLPR to reduce wear and prolong its service life. The surface texture features have a significant impact on the lubricating performance of the CLPR. In this study, the tribological system of the CLPR was investigated. Different surface textures (such as different sizes of surface concaves and grooves, etc.) were designed and produced on the cylinder liners using surface treatment. A series of experimental tests were then carried out in a specially designed diesel engine tester to investigate the tribological characteristics of the treated CLPR pairs. The comparison analyses of the worn surface texture features, element content of the lubrication oil, and abrasive particle characteristics were conducted under different wear surface texture features and cylinder liner speeds. The analysis results showed that there were significant differences in the tribological and lubrication properties of the rubbing pairs in different wear surface texture features. The wear performance of the CLPR pair with a regular concave texture was superior to that of the concave and groove, and regular groove textures. In addition, the regular concave with a depth-diameter ratio of 0.1 was the most effective surface texture to improve the lubrication and wear properties of the CLPR pairs. It is believed that the knowledge obtained in this study provides the real practical basis for tribological design and manufacturing of CLPR pair in marine diesel engines. [ABSTRACT FROM AUTHOR]

The prediction of continuous tool wear process plays an important role in realizing adaptive control and optimizing manufacturing process so as to improve production efficiency and quality of the workpiece. However, the complexity of the tool wear process and the unpredictable disturbance during milling process make it difficult to realize robust and accurate estimation of the tool wear value. In this paper, the Gaussian mixture regression (GMR) model is proposed to realize continuous tool wear prediction based on features extracted from cutting force signal. The main characteristic of the GMR model is that the relationship between the tool wear value and the features is built by the combination of the Gaussian mixture model in which the variation of the training data is described by the probability density of the Gaussian distribution, and the wild data can be abandoned if its probability is small enough. To test the effectiveness of the proposed method, the experiment of titanium alloy milling was carried out, and the spectrum peak value corresponding to the harmonic of tooth passing frequency was extracted as the explanatory variables to predict the tool wear value. In addition, multiple linear regression, radius basis function, and back propagation neural network are also adopted to make a comparison with the GMR model. The analysis of four performance criteria shows that the GMR-based method is the most accurate among these methods. [ABSTRACT FROM AUTHOR]

The convection in an annular container with heated bottom, cooled top and insulated side walls are studied by both linear instability analysis and direct numerical simulation. The onset of convection is investigated by linear stability analysis and corresponding pattern selection mechanisms are discussed. The nonlinear evolution of different flow patterns and the convective heat transfer are simulated. The transition to oscillatory flow is also given by stability analysis where the base flow is a steady three dimensional flow. The stability predictions are in good agreement with the numerical simulations, including both the growth rate and the dimensionless frequency. [ABSTRACT FROM AUTHOR]

Marine diesel engines, a critical component to provide power for entire ships, have been received and still need considerable attentions to ensure their safety operation. Vibration and wear debris analysis are currently the most popular techniques for diesel engine condition monitoring and fault diagnosis. However, they are usually used independently in practice, and limited work has been done to address the integration of data collected using the two techniques. To enhance early fault detections, a new fault diagnosis technique for the marine diesel engine has been proposed by the information fusion of the vibration and wear particle analyses in this paper. A new independent component analysis with reference algorithm (ICA-R) using the empirical mode decomposition based reference extraction scheme was adopted to identify the characteristic source signals of the engine vibration collected from multi-channel sensors. The advantage of this approach performed at a data fusion level is that the ICA-R can extract only the relevant source directly related to the engine fault features in one separation cycle via incorporating prior knowledge. The statistical values of the recovered source signals were then calculated. The above vibration features, along with the wear particle characteristics, were used as the feature vectors for the engine fault detection. Lastly, the improved simplified fuzzy ARTMAP (SFAM) was applied to integrate the distinctive features extracted from the two techniques at a decision level to detect faults in a supervised learning manner. Particularly, the immune particle swarm optimization was used to tune the vigilance parameter of the SFAM to improve the identification performance. The experimental tests were implemented on a diesel engine set-up to evaluate the effectiveness of the proposed diagnosis approach. The diagnosis results have shown that distinguished fault features can be extracted and the fault identification accuracy is satisfactory. Moreover, the fault detection rate of the integration approach has been enhanced by 16.0 % or better when compared with using the two techniques separately. [ABSTRACT FROM AUTHOR]

Purpose: Peripheral benzodiazepine receptors (PBRs) are overexpressed in brain tumors compared to normal brain, and could serve as a target to selectively increase anticancer drug delivery through a PBR ligand-drug conjugate system. We have previously synthesized PBR ligand-gemcitabine conjugates based on the model PBR ligand, PK11195. The goal of the current study was to examine this new drug delivery strategy in an intracerebral xenograft model by measurement of steady-state drug distribution following administration of gemcitabine (GEM) and PK11195-GEM.Methods: In vitro PBR receptor binding and cytotoxicity assays were used to screen three different PK11195-GEM conjugates (GG01, GG02, GG03) in human SF126 glioma cells. Based on these findings and the favorable chemical stability of GG01, here referred as PK11195-GEM, pharmacokinetic investigations of PK11195-GEM and GEM were conducted in male rats. These studies consisted of single-dose and steady-state dosing regimen studies, the latter to assess drug distribution in normal brain and brain tumors. PK11195-GEM and GEM were measured in blood and tissue samples by HPLC.Results: All PBR-GEM conjugates demonstrated appreciable receptor binding affinity and cytotoxicity with mean IC50 values ranging from 248 to 376 nM and 5.6 to 29.1 nM, respectively. The cytotoxicity of GEM was comparable with a mean IC50 value of 5.9 nM. Following administration of single 8 mg/kg doses of PK11195-GEM to rats (n=4), PK11195-GEM had a mean total clearance of 126.3 +/- 29.6 ml/min per kg, and a volume of distribution at steady-state of 1,261.9 +/- 31.05 ml/kg that resulted in a very short elimination half-life of 16.1 +/- 5.8 min. In comparison GEM had a similar volume of distribution (993.8 +/- 131.6 ml/kg), reduced clearance (3.4 +/- 0.8 ml/ min per kg), and longer half-life (235.6 +/- 26.7 min). In nude rats bearing intracerebral tumors, mean steady-state tumor/plasma, tumor/right brain, and tumor/left brain PK 11195-GEM concentration ratios were 1.75 +/- 0.46, 5.49 +/- 5.2, and 9.96 +/- 3.2, respectively. The analogous values following GEM administrations were 0.81 0.5, 3.67 1.57, and 5.21 +/- 1.95, respectively. These values indicate a minimum twofold increase in tumor target selectivity for the conjugate delivery system compared to GEM treatment.Conclusion: Targeting intracellular PBRs is a new drug delivery strategy based on the use of low molecular weight drug conjugates that can be administered systemically. It was demonstrated under steady-state conditions that PK11195-GEM possessed a twofold enhancement in brain tumor selectivity compared to GEM alone. This type of target selectivity would allow higher tumor concentrations to be achieved in conjunction with lower drug concentrations in normal or non-target tissues. [ABSTRACT FROM AUTHOR]

New structures with richer electromagnetic properties are in high demand for developing novel microwave and optic devices aimed at realizing fast light-based information transfer and information processing. Here we show theoretically that a topological photonic state exists in a hexagonal LC circuit with short-range textures in the inductance, which is induced by a band inversion between p- and d-like electromagnetic modes carrying orbital angular momentum, and realize this state experimentally in planar microstrip arrays. Measuring both amplitude and phase of the out-of-plane electric field accurately using microwave near-field techniques, we demonstrate directly that topological interfacial electromagnetic waves launched by a linearly polarized dipole source propagate in opposite directions according to the sign of the orbital angular momentum. The open planar structure adopted in the present approach leaves much room for including other elements useful for advanced information processing, such as electric/mechanical resonators, superconducting Josephson junctions and SQUIDs. Both photonic topological structures and optical angular momentum have been investigated over the last few years. Here, the authors propose and demonstrate that a honeycomb LC circuit can support topological photonic states with band inversion between modes that carry orbital angular momentum. [ABSTRACT FROM AUTHOR]

The polarization controlled optical signal routing has many important applications in photonics such as polarization beam splitter. By using two-dimensional transmission lines with lumped elements, we experimentally demonstrate the selective excitation of guided modes in waveguides composed of two kinds of single-negative metamaterials. A localized, circularly polarized emitter placed near the interface of the two kinds of single-negative metamaterials only couples with one guided mode with a specific propagating direction determined by the polarization handedness of the source. Moreover, this optical spin-orbit locking phenomenon, also called the photonic spin Hall effect, is robust against interface fluctuations, which may be very useful in the manipulation of electromagnetic signals. [ABSTRACT FROM AUTHOR]