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The paper is concerned with the exponential attractors for the viscoelastic wave model in Ω ⊂ R 3 : u tt - h t (0) Δ u - ∫ 0 ∞ ∂ s h t (s) Δ u (t - s) d s + f (u) = g , with time-dependent memory kernel h t (·) which is used to model aging phenomena of the material. Conti et al. (Am J Math 140(2):349–389, 2018a; Am J Math 140(6):1687–1729, 2018b) recently provided the correct mathematical setting for the model and a well-posedness result within the novel theory of dynamical systems acting on time-dependent spaces, recently established by Conti et al. (J Differ Equ 255:1254–1277, 2013), and proved the existence and the regularity of the time-dependent global attractor. In this work, we further study the existence of the time-dependent exponential attractors as well as their regularity. We establish an abstract existence criterion via quasi-stability method introduced originally by Chueshov and Lasiecka (J Dyn Differ Equ 16:469–512, 2004), and on the basis of the theory and technique developed in Conti et al. (2018a, b) we further provide a new method to overcome the difficulty of the lack of further regularity to show the existence of the time-dependent exponential attractor. And these techniques can be used to tackle other hyperbolic models. [ABSTRACT FROM AUTHOR]

The paper investigates the well-posedness and the regularity of the solutions, the existence and the continuity of the strong attractors for the structurally damped Kirchhoff wave models with subcritical-critical nonlinearities: u tt - (1 + ϵ ‖ ∇ u ‖ 2 ) Δ u + (- Δ) α u t + h (u t) + g (u) = f (x) , where ϵ ∈ [ 0 , 1 ] is a perturbed extensibility parameter, α ∈ [ 1 / 2 , 1) is a dissipative index. We show that when the nonlinearity g(u) is of either critical growth as α ∈ (1 / 2 , 1) or subcritical growth as α = 1 / 2 , while h (u t) is of critical growth depending on α , the model is well-posed and its weak solution is exactly the strong one; the related solution semigroup S ϵ (t) has a strong (X, Y)-global attractor and a strong (X, Y)-exponential attractor, which are also the standard global and exponential attractor of optimal regularity of S ϵ (t) in X, respectively, where X is the energy space and Y is the strong solution space; these global attractors are upper semicontinuous and these exponential attractors are Hölder continuous with respect to perturbed parameter ϵ in the sense of Y-topology, respectively. [ABSTRACT FROM AUTHOR]

The paper investigates the robustness of pullback attractors and pullback exponential attractors of the non-autonomous Kirchhoff wave models with strong nonlinear damping: u tt - (1 + ϵ ‖ ∇ u ‖ 2 ) Δ u - σ (‖ ∇ u ‖ 2) Δ u t + f (u) = g (x , t) , where ϵ ∈ [ 0 , 1 ] is an extensibility parameter. It shows that when the growth exponent p of the nonlinearity f(u) is up to the supercritical range: 1 ≤ p < p ∗ ∗ ≡ N + 4 (N - 4) + , (i) the related process has a pullback attractor A ϵ in natural energy space H = (H 0 1 ∩ L p + 1) × L 2 for each ϵ , and it is upper semicontinuous on the perturbation ϵ ; (ii) the related process has a partially strong pullback exponential attractor M ϵ for each ϵ , and it is Hölder continuous on ϵ ∈ [ 0 , 1 ] . These results deepen and extend those in recent literatures (Chueshov in J Diff Equ 252:1229–1262, 2012; Ding et al. in Appl Math Lett 76:40–45, 2018; Wang and Zhong in Discrete Contin Dyn Syst 7:3189–3209, 2013). The main novelty of this paper is that it provides a new method to investigate the upper semicontinuity of pullback attractors and the stability of pullback exponential attractors in supercritical nonlinearity case. [ABSTRACT FROM AUTHOR]

The Fusarium wilt disease caused by Fusarium oxysporum f. sp. batatas (Fob) is one of the devastating diseases of sweetpotato. However, the molecular mechanisms of sweetpotato response to Fob is poorly understood. In the present study, comparative quantitative proteomic analysis was conducted to investigate the defense mechanisms involved. Two sweetpotato cultivars with differential Fob infection responses were inoculated with Fob spore suspensions and quantitatively analyzed by Tandem Mass Tags (TMT). 2267 proteins were identified and 1897 of them were quantified. There were 817 proteins with quantitative ratios of 1.2-fold change between Fob-inoculated and mock-treated samples. Further, nine differentially expressed proteins were validated by Parallel Reaction Monitoring (PRM). According to Gene Ontology (GO) annotation information, the proteins functioned in molecular metabolism, cellular component formation, and biological processes. Interestingly, the results showed that sweetpotato resistant response to Fob infection included many proteins associated with signaling transduction, plant resistance, chitinase and subtilisin-like protease. The functions and possible roles of those proteins were discussed. The results provides first insight into molecular mechanisms involved in sweetpotato defense responses to Fob. [ABSTRACT FROM AUTHOR]

Introduction: Femur head necrosis (FHN) is a challenging clinical disease with unclear underlying mechanism, which pathologically is associated with disordered metabolism. However, the disordered metabolism in cancellous bone of FHN was never analyzed by gas chromatography-mass spectrometry (GC-MS). Objectives: To elucidate altered metabolism pathways in FHN and identify putative biomarkers for the detection of FHN. Methods: We recruited 26 patients with femur head necrosis and 22 patients with femur neck fracture in this study. Cancellous bone tissues from the femoral heads were collected after the surgery and were analyzed by GC-MS based untargeted metabolomics approach. The resulting data were analyzed via uni- and multivariate statistical approaches. The changed metabolites were used for the pathway analysis and potential biomarker identification. Results: Thirty-seven metabolites distinctly changed in FHN group were identified. Among them, 32 metabolites were upregulated and 5 were downregulated in FHN. The pathway analysis showed that linoleic acid metabolism were the most relevant to FHN pathology. On the basis of metabolites network, L-lysine, L-glutamine and L-serine were deemed as the junctions of the whole metabolites. Finally, 9,12-octadecadienoic acid, inosine, L-proline and octadecanoic acid were considered as the potential biomarkers of FHN. Conclusion: This study provides a new insight into the pathogenesis of FHN and confirms linoleic acid metabolism as the core. [ABSTRACT FROM AUTHOR]

This paper contains new results about the well-posedness and the asymptotic dynamics of solutions for a general abstract coupled system that arises in connection with thermoelastic Balakrishnan–Taylor beam models with fractional operators. [ABSTRACT FROM AUTHOR]

The hydrodynamic problems of water entry of a wedge are investigated by a modified ghost-cell immersed boundary method. The modifications correspond to a newly proposed scheme for dealing with fluid–body interaction, and incorporation of CIP (Constraint Interpolation Profile) method and THINC/SW (Tangent of Hyperbola for Interface Capturing with Slope Weighting) method. The modified ghost-cell immersed boundary method uses a compact interpolation structure and gives the fluid properties to the ghost cell to achieve a more accurate treatment of fluid–body interaction. It can preserve the sharpness of the immersed boundary. To validate the new method, simulations of water entry of symmetric and asymmetric wedges in a single degree of freedom and water entry of an asymmetric wedge in three degrees of freedom are carried out, respectively. The variations of pressure, vertical velocity, vertical acceleration, angular displacement, and angular acceleration against time are focused on. The evolution of the free surface and velocity distributions of fluid is also analyzed. The results of numerical simulations are compared with available experimental results and fairly good agreement is obtained, which indicates that the present model is reliable. [ABSTRACT FROM AUTHOR]

In the abrasive belt grinding process, actual material removal is an important parameter that affects its accuracy. At present, for obtaining the actual material removal, offline measurements are required to establish the mathematical prediction model. To improve the accuracy and efficiency of abrasive belt machine grinding, this paper proposes a novel method for monitoring material removal using multiple sensors and a two-dimensional (2D) convolutional neural network (2D-CNN) learning algorithm. In this method, features of multiple types (color, texture, and shape) are extracted from vision signals, and that of multiple domains (time, frequency, and time–frequency domain) are extracted from sound and tactile signals. These features are constructed into a 2D feature matrix as the input model, and the 2D-CNN prediction model is established between the multisensor features and the material removal rate of the abrasive belt grinding process. An experimental dataset is used to train and verify the established model. The results show that the proposed method can identify that sensor signals are sensitive to the material removal rate. After optimizing and tuning the model parameters, the coefficient of determination of the prediction results is as high as 94.5% and the root mean square error is 0.017. Therefore, the proposed method can be employed for the prediction of material removal rate for different belt specifications and different grinding parameters. Compared to traditional machine learning methods, this method can yield better training results without feature selection and optimization. [ABSTRACT FROM AUTHOR]

TATB (1,3,5-triamino-2,4,6-trinitrobenzene) is a widely used insensitive high-energy explosive. It is significant to study its structural evolution in order to get a credible understand of its properties and performances. Direct mechanical tests such as hardness tests are useful approaches to get information about its mechanical properties and shed light upon the microstructures. However, due to the poor solubility of TATB to most solvents, it is hard to produce large crystals for such tests. Fortunately, microcosmic approaches such as powder diffraction can reinforce it and has low requirement on samples. In this study, series of in-situ neutron diffraction experiments under different pressures are performed to investigate the structural change and mechanical properties of TATB. The recently reported phase transition at 4 GPa is studied. The microstrains in normal TATB (12–17 µm) are analysed to reveal the information of slip system and transitional process. The lattice parameters and bulk moduli of TATB under different conditions are given. These neutron diffraction results are significant supplement to correlative studies and will help to understand the performances of TATB, such as deformation and phase transition. [ABSTRACT FROM AUTHOR]

Weak interfacial interaction and poor surface wettability always restrict and weaken the performances of energetic composites. Conventional surface modifications can hardly achieve a desired result, due to the inadequacy for solving the interfacial incompatibility. We here demonstrated bioinspired hierarchical-structured 2,6-diamino-3,5-dinitropyrazine-1-oxide particles through in situ "grafting from" polymerization of hyperbranched polyurethane (HBPU) on polydopamine surface. Benefiting from the enhanced interfacial interaction and surface wettability which facilitated mechanical performance, the final results revealed that a remarkable mechanical enhancement was successfully achieved through this way. Meanwhile, improved safety performance was gained, and the impact sensitivity was reduced to a large extent which was ascribed to the cushioning and protective effects of HBPU shells with soft segments. We believe this approach of constructing bioinspired hierarchical interface aiming at solving low surface wettability and weak interface will shed light on the design and preparation of high-performance composites through a novel and effective way. [ABSTRACT FROM AUTHOR]

Objectives: Rapid and accurate diagnosis of coronavirus disease 2019 (COVID-19) is critical during the epidemic. We aim to identify differences in CT imaging and clinical manifestations between pneumonia patients with and without COVID-19, and to develop and validate a diagnostic model for COVID-19 based on radiological semantic and clinical features alone. Methods: A consecutive cohort of 70 COVID-19 and 66 non-COVID-19 pneumonia patients were retrospectively recruited from five institutions. Patients were divided into primary (n = 98) and validation (n = 38) cohorts. The chi-square test, Student's t test, and Kruskal-Wallis H test were performed, comparing 1745 lesions and 67 features in the two groups. Three models were constructed using radiological semantic and clinical features through multivariate logistic regression. Diagnostic efficacies of developed models were quantified by receiver operating characteristic curve. Clinical usage was evaluated by decision curve analysis and nomogram. Results: Eighteen radiological semantic features and seventeen clinical features were identified to be significantly different. Besides ground-glass opacities (p = 0.032) and consolidation (p = 0.001) in the lung periphery, the lesion size (1–3 cm) is also significant for the diagnosis of COVID-19 (p = 0.027). Lung score presents no significant difference (p = 0.417). Three diagnostic models achieved an area under the curve value as high as 0.986 (95% CI 0.966~1.000). The clinical and radiological semantic models provided a better diagnostic performance and more considerable net benefits. Conclusions: Based on CT imaging and clinical manifestations alone, the pneumonia patients with and without COVID-19 can be distinguished. A model composed of radiological semantic and clinical features has an excellent performance for the diagnosis of COVID-19. Key Points: • Based on CT imaging and clinical manifestations alone, the pneumonia patients with and without COVID-19 can be distinguished. • A diagnostic model for COVID-19 was developed and validated using radiological semantic and clinical features, which had an area under the curve value of 0.986 (95% CI 0.966~1.000) and 0.936 (95% CI 0.866~1.000) in the primary and validation cohorts, respectively. [ABSTRACT FROM AUTHOR]

The application of aluminum nanoparticle is limited due to its passivation Al2O3 layer even though it owns extreme specific surface and high reaction activity. In this work, the aluminum nanoparticles were modified via in situ grafting onto energetic glycidyl azide polymer (GAP) to improve the stability and energy-releasing performance. The results showed that GAP was grafted on the nano-aluminum surface with chemical bonds of -O-(CO-NH)- formed, and the thickness of shell layer of GAP could be tuned by changing the relative ratio of reactants. Furthermore, modified nanoparticles show hydrophobicity with static water contact angle changing from 20.2° to 142.4°. Significant increasing stability of aluminum nanoparticles is obtained in hot water, which is evidenced by that around 10 wt% of modified aluminum is reacted after 210 min. Based on the core-shell configurations, (Al@GAP)/fluorine composites were prepared. The violent combustion phenomenon and high release rate profiles revealed high energy-releasing performance with the assistance of GAP. This synthetic strategy may provide an effective approach to prepare other metal nanoparticles, and possess potential application value in the fields of metallized explosives and high-energy structure with energy release. [ABSTRACT FROM AUTHOR]

The genomes of two rice cultivars, Nipponbare and 93-11, have been well studied. However, there is little available genetic information about nutraceutical rice cultivars. To remedy this situation, the present study aimed to provide a basic genetic landscape of nutraceutical rice. The genome of Black-1, a black pericarp rice containing higher levels of anthocyanins, flavonoids, and a more potent antioxidant capacity, was sequenced at ≥30 × coverage using Solexa sequencing technology. The complete sequences of Black-1 genome shared more consensus sequences with indica cultivar 93-11 than with Nipponbare. With reference to the 93-11 genome, Black-1 contained 675,207 single-nucleotide polymorphisms, 43,130 insertions and deletions (1-5 bp), 1,770 copy number variations, and 10,911 presence/absence variations. These variations were observed to reside preferentially in Myb domains, NB-ARC domains and kinase domains, providing clues to the diversity of biological functions or secondary metabolisms in this cultivar. Intriguingly, 496 unique genes were identified by comparing it with the genomes of these two rice varieties; among the genes, 119 genes participate in the biosynthesis of secondary metabolites. Furthermore, several unique genes were predicted to be involved in the anthocyanins synthesis pathway. The genome-wide landscape of Black-1 uncovered by this study represents a valuable resource for further studies and for breeding nutraceutical rice varieties. [ABSTRACT FROM AUTHOR]

In order to solve the problems of GaN heteroepitaxy on sapphire substrate, some techniques were explored. Freestanding GaN substrates have been made by hydride vapor phase epitaxy (HVPE), laser lift-off (LLO), and chemical mechanical polishing techniques. Wafer bending and cracking in the HVPE growth were partly settled by pulsed flow modulation method. High-crystal quality was established for 1.2 mm thick GaN substrate by X-ray diffraction measurement, in which the full width of half maximum values were 72, 110 arcsec for (102), (002) peaks. A novel micro-size patterned sapphire substrate (PSS) and a nano PSS were also fabricated. High-power vertical structure light emitting diodes (VSLEDs) have been developed by Au-Sn eutectic wafer bonding, homemade micro-area LLO, and light extraction structure preparation. The high-injection-level active region with low temperature GaN sandwiched layers was used for low-efficiency droop. The light output power of VSLED was achieved as 400 mW driven at 350 mA, and the dominant wavelength is about 460 nm. The structures and properties of strain modulated superlattices (SLs) and quantum wells as well as advanced simulation of carriers transport across the electron blocking layer were investigated in laser diodes. The hole concentration was achieved as high as 1.6 × 10 cm in AlGaN/GaN SLs:Mg by inserting an AlN layer. High-quality AlGaN epilayers and structures were grown by MOCVD. Some device structures of UV LEDs and detectors were demonstrated. The emission wavelength of 262 nm UV LED has been successfully fabricated. At last, high-quality InN and InGaN materials for solar cell were grown by boundary-temperature-controlled epitaxy and growth-temperature-controlled epitaxy. Hall-effect measurement showed a recorded electron mobility of 3,280 cm/(V s) and a residual electron concentration of 1.47 × 10 cm at 300 K. [ABSTRACT FROM AUTHOR]

AlN with different thicknesses were grown as interlayers (ILs) between GaN and p-type AlGaN/GaN superlattices (SLs) by metal organic vapor phase epitaxy (MOVPE). It was found that the edge-type threading dislocation density (TDD) increased gradually from the minimum of 2.5×10 cm without AlN IL to the maximum of 1×10 cm at an AlN thickness of 20 nm, while the screw-type TDD remained almost unchanged due to the interface-related TD suppression and regeneration mechanism. We obtained that the edge-type dislocations acted as acceptors in p-type AlGaN/GaN SLs, through the comparison of the edge-type TDD and hole concentration with different thicknesses of AlN IL. The Mg activation energy was significantly decreased from 153 to 70 meV with a 10-nm AlN IL, which was attributed to the strain modulation between AlGaN barrier and GaN well. The large activation efficiency, together with the TDs, led to the enhanced hole concentration. The variation trend of Hall mobility was also observed, which originated from the scattering at TDs. [ABSTRACT FROM AUTHOR]

The continuous administration of compound danshen dripping pills (CDDP) showed good efficacy in relieving myocardial ischemia clinically. To probe the underlying mechanism, metabolic features were evaluated in a rat model of acute myocardial ischemia induced by isoproterenol (ISO) and administrated with CDDP using a metabolomics platform. Our data revealed that the ISO-induced animal model showed obvious myocardial injury, decreased energy production, and a marked change in metabolomic patterns in plasma and heart tissue. CDDP pretreatment increased energy production, ameliorated biochemical indices, modulated the changes and metabolomic pattern induced by ISO, especially in heart tissue. For the first time, we found that ISO induced myocardial ischemia was accomplished with a reduced fatty acids metabolism and an elevated glycolysis for energy supply upon the ischemic stress; while CDDP pretreatment prevented the tendency induced by ISO and enhanced a metabolic shift towards fatty acids metabolism that conventionally dominates energy supply to cardiac muscle cells. These data suggested that the underlying mechanism of CDDP involved regulating the dominant energy production mode and enhancing a metabolic shift toward fatty acids metabolism in ischemic heart. It was further indicated that CDDP had the potential to prevent myocardial ischemia in clinic. [ABSTRACT FROM AUTHOR]