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The diversity of syntactic units in second language has attracted much scholarly attention. Most existing studies on syntactic diversity have focused on only a small number of syntactic structures, and it is difficult to find studies that consider the full range of syntactic dependencies present in the dataset. Based on a syntactic annotated interlanguage corpus that we constructed, this paper is a quantitative study of dependencies in English-speaking Chinese learners’ interlanguage across proficiency levels. We fit the frequency distributions of dependency type, word class (both as dependent and governor), verb as a governor, and noun as a dependent with a modified right-truncated Zipf-Alekseev distribution and Zipf’s law. Our findings show that: (1) from the mathematical model, interlanguage followed distributional regularities like natural languages in terms of the syntactic structure distribution; (2) most of the determination coefficients’ R 2 were high, indicating that the investigated distributions in interlanguage fit the distributional law finding in natural languages. This also demonstrated that both interlanguages and natural languages consistently conform to the law of linguistic diversity and uniformity; (3) the dependency relation distribution parameters a and b manifest the developmental trend of L2 learners’ proficiency levels, demonstrating that the parameters had universal applicability in reflecting interlanguage proficiency.

The typicality effect delineates a graded membership structure during categorization, whereby a typical item is easier to be judged as a member of a category than is an atypical item. The current study brought experimental evidence of the typicality representation of advanced Thai learners of Chinese, in order to compare the organization of the mental lexicon in the learners’ second language and first language. Three types of instances (i.e., typical in both Chinese and Thai (C1), typical in Chinese but not in Thai (C2), and typical in Thai but not in Chinese (C3)) in five categories (i.e., BIRD, VEGETABLE, FRUIT, FURNITURE, APPLIANCE) were presented in instance-category order. The response time of typicality judgement showed a similarity between natives and L2 learners, but that the response time of second language learners to C1 was not significantly longer than that to C2. These results suggested that high proficiency could modify the construction of a qualitatively native-like typicality representation, and that language-specific typicality was still beyond conceptualization in second language.

A wind turbine is a conversion mechanism that converts wind energy into electrical energy, but the conversion efficiency cannot reach 100%, so there is partial loss. These losses are converted into thermal energy, which in turn causes the wind turbine to heat up and affect generator performance. Therefore, the cooling and temperature field analysis of wind turbines is very important. In this paper, an electromagnetic analysis model is established by using the parameters of a 4 MW wind turbine; the losses of each part of the generator under rated load and three-phase short-circuit conditions are calculated, respectively; and the heat source is imported into the workbench fluent software to determine the cooling mode, so as to obtain the magnetic-thermal-flow field coupling model of permanent magnet synchronous direct drive wind turbine. The temperature distribution and temperature rise of the generator are obtained. Under the rated load condition, the overall maximum temperature rise of the wind turbine is 41.4 °C, about 180 mm near the fluid outlet side, which is as high as the winding temperature rises, because the winding is the main heating body. The maximum temperature rise of the rotor model and the permanent magnet model is about 36 °C. Under the three-phase short circuit condition, the temperature distribution of each component is similar to that under the rated load condition, and the temperature near the fluid inlet is low; the lowest is only 29.8 °C. The higher the temperature at the fluid’s outlet, but not close to it, the higher the temperature is when it is about 180 mm away from the fluid’s outlet side. The temperature difference in the same axial length is relatively large, with a maximum temperature difference of about 120 °C. The temperature distribution and temperature rise of the generator are independent of the operating conditions, which mainly affect the value. Additionally, through experimental verification, the minimum error under the rated load condition is 1.05%, the maximum error is 3.3%, and the average error is 2.30%. The minimum error under the three-phase short-circuit condition is 1.5%, the maximum error is 3.62%, and the average error is 2.26%. The difference with the engineering error range requirements is small, indicating the reasonable and effective effectiveness of this method. This study aims to provide a strong reference for analyzing the cooling and magnetic thermal flow field and a coupling analysis of direct drive wind turbines.

Evaporite salts from saline lakes and playas play active roles in the atmospheric cycles and the climate system, especially in the context of changing climate. Similar processes also occurred on Mars, where large water bodies dried up and formed saline lakes and then salt evaporites and deposits. In this study, various salt samples (brines, lakebed salts, crust salts, playa surface salts, and a series of salts collected at different depths) were collected from two Martian analogue sites (Mang’ai and Dalangtan, MA and DLT) in Qaidam Basin. The salt samples were measured for their ionic compositions and pH as the fundamental characterization, and the effects of sample types and sampling sites are discussed. The hygroscopic properties of solid salts, including crystalized brines, were experimentally determined. The results show strong connections between the ionic composition and hygroscopic properties though discrepancy exists, indicating that the hygroscopicity is sensitive to the molecular forms and the hydrate degrees of salts. Sulfur and chlorine isotopes were measured, and the results are presented as δ34S and δ37Cl. The δ34S values of samples from MA and DLT show great difference. The δ34S values of MA samples are comparable to previously reported fresh water, brines and local precipitation, indicating that the MA samples are strongly influenced by materials exchanged from local environments. The DLT samples have higher δ34S values, which suggest that the material exchanges with surrounding environments are limited. The δ37Cl values are confined within a relatively narrow window compared to literature values. A trend is that the δ37Cl values vary with sample types, i.e., crust > lakebed > brine. This is likely caused by the isotopic fractionation during evaporite precipitation, where the heavier 37Cl isotope is preferably precipitated. The study of salt samples from MA and DLT areas improves the understanding of the active role of evaporite salts in the material cycle and climate system of both Earth and Mars.Keywords: δ34S, δ37Cl, hygroscopicity, climate, Mars, Qaidam Basin

Karst reservoir has great hydrocarbon potential, however karst reservoir prediction is inhibited by the strong lateral and vertical heterogeneity of karstification which in turn results in recognition difficulty when geological and geophysical methods are used in isolation. Combined geological and geophysical methods, including core observation, thin section analysis, well log interpretation, seismic attributes and seismic inversion are applied to understand the depositional environment, types of karstification, the geophysical response and distribution of karst reservoir and the controls over and evolution model of karst reservoir in Permian Yuanba gas field, northern Sichuan Basin. The results show that there are four types of major seismic facies recognized in the study area, which correspond to platform margin reef, carbonate platform, platform margin inter-bay and platform margin slope. Karstification can be divided into three zones: the supergene karst zone, the vertical seepage zone and the horizontal underflow zone, among which the supergene karst zone have the strongest karstification. Karstification is highlighted with low seismic impedance, low Poisson's ratio, and high seismic attenuation on seismic inversion as well as micro scale paleo geomorphology recognized by trend surface analysis. By comparing the distribution of karstification with paleo geomorphology, fault distribution and gas contents, it can be observed that the karstification have a good matching relationship with these factors. The dominant type of karstification is epigenic karst, which is strongly influenced by depositional facies and paleo geomorphology. Fracture networks have contributed to karstification but are not the dominant factor of karst formation. The integration of geological and geophysical methods can predict karst reservoir with high accuracy within large area and can be applied to karst reservoir hydrocarbon exploration of similar geological setting.

In recent years, quantitative methods have been increasingly used in interlanguage studies, but these studies have mostly focused on the micro level with an emphasis on certain syntactic structures, rather than the macro where interlanguage is perceived as a whole. There remains a paucity of quantitative studies on interlanguage from the typological perspective. With the majority of the studies focused on the written interlanguage, there is also a lack of sufficient research on its spoken modality. Based on a syntactically annotated corpus and using the quantitative linguistic metric of dependency direction, we have investigated the typological changes in the Chinese interlanguage in both written and spoken modalities. The findings are as follows: (1) the typological features of interlanguage vary across modalities at both macro and micro levels; (2) dependency direction is proved to be an inappropriate indicator to measure the general typological characteristics of interlanguage development due to its failure to reflect the changes in the spoken modality; (3) both macro and micro perspectives taken into consideration, typological errors in the interlanguage is more likely to occur in the spoken modality than in the written one, in which learners may be restricted by greater time pressure and cognitive load in utterance. These factors may affect the distribution of dependency direction in the oral modality, and may be the reason why it is not appropriate to use dependency direction as a measure of changes in mediated language typological features in the oral modality. It is expected that our study will bring insight into second language research with more objective and holistic evidence.

The power series polynomial constraining method is proposed in this paper. The dynamical model of the cantilever plate can be established by applying the constraint, which is different from the traditional polynomial. Firstly, the characteristic orthogonal polynomial was used to describe the displacement field of the rectangular plate of which all edges are free. Then the four-sided free plate was equivalent to cantilever plate by power series multiplier constraint method. The characteristic equation of the constructed cantilever plate was obtained by the Rayleigh–Ritz method. Natural frequencies and modal shapes of the plate were obtained by solving the characteristic equation. Next, the proposed method was adopted to establish dynamical model of a pair of solar panels clamped on the central platform symmetrically. The convergence of the proposed method was verified by comparing the calculated results of the cantilever plate with that of the finite element software ANSYS 15.0. The optimum order the power series polynomial was obtained by comparing different results. The analysis of the dynamical characteristics of the cantilever plate and the spacecraft demonstrates the validation of the proposed method. This method can provide a new idea for the plate with local edge constrained.

Although integrins are known to be mechanosensitive and to possess many subtypes that have distinct physiological roles, single molecule studies of force exertion have thus far been limited to RGD-binding integrins. Here, we show that integrin α4β1 and RGD-binding integrins (αVβ1 and α5β1) require markedly different tension thresholds to support cell spreading. Furthermore, actin assembled downstream of α4β1 forms cross-linked networks in circularly spread cells, is in rapid retrograde flow, and exerts low forces from actin polymerization. In contrast, actin assembled downstream of αVβ1 forms stress fibers linking focal adhesions in elongated cells, is in slow retrograde flow, and matures to exert high forces (>54-pN) via myosin II. Conformational activation of both integrins occurs below 12-pN, suggesting that post-activation subtype-specific cytoskeletal remodeling imposes the higher threshold for spreading on RGD substrates. Multiple layers of single integrin mechanics for activation, mechanotransduction and cytoskeleton remodeling revealed here may underlie subtype-dependence of diverse processes such as somite formation and durotaxis.

Previous studies have shown that dependency distance and its probability distribution can be applied as syntactic indicators of English as interlanguage. However, the universal application of these...

Correction to: Nonlinear Dyn(2017)89: 937-953 DOI 10.1007/s11071-017-3493-2.

The mechanical characteristics of cemented paste backfill (CPB) are significantly influenced by the loading rate (LR) and initial defects. Therefore, the CPB with prefabricated fracture (PF, PFCPB) was prepared, and uniaxial compressive strength (UCS) tests considering LR and acoustic emission (AE) monitoring were performed. The particle flow code (PFC2D) was introduced to analyze the mesoscopic crack evolution of the filling body, and the moment tensor theory was used to invert the AE signals characteristics. The results show that as the PF angle increased, the UCS and elastic modulus (EM) of PFCPB decreased and then increased, and the 30° PF was the turning point. The mechanical properties of PFCPB were deteriorated by the presence of PF. Meanwhile, the mechanical properties of PFCPB were positively correlated with the LR. The stress-strain curve of PFCB (excluding 90°) showed bimodal curves. After the UCS test, the macro crack of PFCPB sprouted at the tip of PF or converged toward PF. PFCPB mainly suffered from shear failure, accompanied by a few tensile failures. Numerical simulation results showed that the crack initiation stress of PFCPB was reduced by the PF. The number of cracks first dropped and then gradually increased when the PF angle was enhanced, while gradually increased with the LR increased. Meanwhile, the mesoscopic AE characteristics of CPB were strongly in line with the test results. The AE events of 0 ~ 60° PFCPB experienced two slow rising periods and rapid rising periods. The temporal and spatial distribution characteristics of AE corresponded to the crack evolution trend. The PF was prone to stress concentration, especially at the tip and upper and lower surfaces of 0 ~ 45° PF, resulting in rapid crack initiation and reducing the energy storage limit and mechanical behavior of 0 ~ 45° PFCPB. The increasing LR (within a certain range) was in favor of improving the mechanical behavior of the filling body. The research results can provide a basic reference for the stability evaluation of the filling body with initial defects.

Although integrins are known to be mechano-sensitive and to possess many subtypes that have distinct physiological roles, single molecule studies of force exertion have thus far been limited to RGD-binding integrins. Here, we show that integrin α4β1 and RGD-binding integrins (αVβ1 and α5β1) require markedly different tension thresholds to support cell spreading. Furthermore, actin assembled downstream of α4β1 forms cross-linked networks in circularly spread cells, is in rapid retrograde flow, and exerts low forces from actin polymerization. In contrast, actin assembled downstream of αVβ1 forms stress fibers linking focal adhesions in elongated cells, is in slow retrograde flow, and matures to exert high forces (>54-pN) via myosin II. Conformational activation of both integrins occurs below 12-pN, suggesting that post-activation subtype-specific cytoskeletal remodeling imposes the higher threshold for spreading on RGD substrates. Multiple layers of single integrin mechanics for activation, mechanotransduction and cytoskeleton remodeling revealed here may underlie subtype-dependence of diverse processes such as somite formation and durotaxis.

The cemented paste backfill (CPB) has a significant loading rate (LR) effect. The damage evolution process of CPB is closely related to the characteristics of acoustic emission (AE). This paper analyzes the damage evolution law of the filling body under different loading rates using indoor test and numerical simulations. We introduce the moment tensor theory to simulate the AE characteristics of the whole process of filling loading and explore the LR effect of the backfill with the help of the energy conservation. The results indicate the following: (1) when LR increases from 0.1 to 2 mm/min, the UCS of the backfill first increases and then decreases, contributing to the occurance of the critical LR. (2) There are no microcracks occurred in the backfill at the initial stage of loading, and the microcracks increase slowly, which is not obviously affected by LR. After the peak value, the microcracks in backfill expand and propagat rapidly to form mesoscopic cracks. (3) The mesoscopic AE events based on the moment tensor theory are in good agreement with the laboratory tests results, which can be divided into the initial period, quiet period, slow raising period, rapid raising period, and rapid falling period. (4) The temporal and spatial distribution characteristics of AE are consistent with the evolution law of microcracks. There are fewer AE events before the peak value, and AE events increase significantly and frequently with large magnitude events after the peak value. AE events dense zone and AE events with larger magnitude increase under higher LR. (5) Besides, the boundary energy and dissipation energy also gradually increased; at the same time, the strain energy first increased and then decreased. The results can provide a reference for understanding the damage evolution characteristics of backfill by different LR and AE mesoscopic simulation.

The dynamical model of multiple honeycomb plates connected by hinges, including the thermal–structural coupling effect, is investigated in this paper. Under the assumption of small deformations and strains, the classical plate theory is used to establish the dynamical model of the honeycomb plate. The Chebyshev polynomial is adopted to describe the deformation of the plate and the linear torsional spring to represent the elastic hinge. Using the Rayleigh–Ritz method, the characteristic equation of the honeycomb sandwich structure is derived, from which the natural frequencies are obtained. Considering the thermal effect of the plate, the thermal–structural coupling dynamical equation is obtained. The thermal conduction in the thickness direction is calculated by the finite difference method. The present model is validated by comparing with the result generated by an equivalent orthotropic plate model established by the finite element (FE) software MSC Patran. The response analysis reveals the important effect of the metal skin and the hinge stiffness on the dynamic characteristics of the honeycomb sandwich structure. Numerical simulations reveal thermal–structural coupling features for the multi-honeycomb-plate structure from the perspective of the change in dynamic characteristics and the distribution of the temperature gradient. The thermal–structural coupling calculation method adopted herein can be used to solve the thermal conduction of the plate. It serves as the theoretical method for analyzing the dynamical behavior of the solar panel subjected to the solar heat.

Coal mining produces a large amount of gangue that pollutes the environment, causing surface subsidence and damaging the groundwater systems. Backfill mining is an effective technology used to solve this problem, but there is a risk of polluting the groundwater due to the heavy metal ions present in the backfill material. Pb2+ has been determined to be a representative element because of its existence in coal gangue samples but not in fly ash. The risk of gangue-based cemented backfill causing groundwater pollution can be evaluated by studying the Pb2+ leaching from gangue under various conditions. When comparing the leaching amounts of Pb2+ from the coal gangue particles and the test blocks, it was found that cement filling has an obvious consolidation effect on the Pb2+ in coal gangue. The above process shows that cemented backfill has an obvious consolidation effect on the Pb2+ in gangue. The results of the theoretical analysis, X-ray, and SEM show that the consolidation mechanism can be divided into four modes: physical encapsulation, ion exchange, ion adsorption, and chemical reaction. The results are of great significance for revealing the leaching mechanism of the heavy metals in coal gangue, assessing the risk of heavy metal pollution in groundwater via gangue-cemented backfill, and improving the mining theory of the gangue-cemented filling and groundwater protection.

This event-related potentials study explored the processing of Mandarin short passives. We used a syntactic violation paradigm to compare the processing of two auxiliary phrases (i.e., a verb-modifier di-phrase and a noun-modifier de-phrase). In the control condition, the syntactic hierarchy of the di-phrase was lower than that of the de-phrase. In the violation condition, the low-level violation was created by replacing di with de in the auxiliary phrase, while the high-level violation was created by replacing de with di in the auxiliary phrase. The ERP data showed that the noun-modifier elicited the greater left anterior negativity (LAN) and the P600 than the verb-modifier, in both the control condition and the violation condition. We also observed that the LAN induced by the verb-modifier phrase was greater in the control condition than that in the violation condition, while the LAN induced by the noun-modifier was greater in the violation condition than that in the control condition. These results suggested that the greater cortical LAN-P600 might differentiate the high-level hierarchy from the low-level hierarchy. In addition, we tentatively claimed that given the same predicate argument structure, long passives might be the default representational mode of short passives (generally, a constructional alternation might be activated during the processing of the target structure).

Mutations in protein kinases are often associated with the development of cancer, and application of mutant-specific inhibitors as therapeutic measures have shown a remarkable improvement in prolonging patient survival. However, it has also been observed that tumors bearing certain mutation types are more resistant to current approved drugs. Importantly, many resistant mutations are located in regions outside substrate or inhibitor binding sites, indicating allosteric effects. Understanding how mutations trigger effects over a distant site of the protein requires a deeper investigation of the molecular origin of allosteric regulation networks in kinases. In this chapter, we show the application of single-molecule optical tweezers to selectively manipulate specific regions of proteins to trace allosteric signals, thereby allowing the elucidation of allosteric communication networks. We illustrate this approach using as model system the regulatory subunit of protein kinase A. This single-molecule optical tweezers approach, however, can be readily applicable to study other kinases, and can be further expanded to screen potential allosteric drugs for future therapeutics.

The dynamical model for the spacecraft with multiple solar panels and the cooperative controller for such spacecraft are studied in this paper. The spacecraft consists of a rigid platform and two groups of flexible solar panels, where solar panels could be driven to rotate by the connecting shaft. The flexible solar panel involves the use of the orthogonal polynomial in two directions to describe its elastic deformation. By using the Rayleigh–Ritz method, the characteristic equation is derived to obtain natural frequencies and modal shapes of the whole spacecraft. Then the discrete rigid-flexible coupled dynamical equation of the spacecraft is obtained by using the Hamiltonian principle. The equation involves the coupling of the attitude maneuver, solar panels’ driving and vibration suppression. These dynamical behaviors are addressed by the rigid-flexible coupled mode for the first time in this paper. Based on the dynamical equation, the cooperative control scheme is designed by combing the proportional-differential and robust control method. Numerical results show the accuracy of the present modelling method and the validation of the control strategy. The modal analysis implies the complex rigid-flexible coupled characteristic between the central platform and flexible solar panels. The proposed control scheme can maintain the attitude stability while solar panels are being driven, as well as the vibration suppression of flexible solar panels.

Tigecycline is a last-resort antibiotic that is used to treat severe infections caused by extensively drug-resistant bacteria. tet(X) has been shown to encode a flavin-dependent monooxygenase that modifies tigecycline1,2. Here, we report two unique mobile tigecycline-resistance genes, tet(X3) and tet(X4), in numerous Enterobacteriaceae and Acinetobacter that were isolated from animals, meat for consumption and humans. Tet(X3) and Tet(X4) inactivate all tetracyclines, including tigecycline and the newly FDA-approved eravacycline and omadacycline. Both tet(X3) and tet(X4) increase (by 64-128-fold) the tigecycline minimal inhibitory concentration values for Escherichia coli, Klebsiella pneumoniae and Acinetobacter baumannii. In addition, both Tet(X3) (A. baumannii) and Tet(X4) (E. coli) significantly compromise tigecycline in in vivo infection models. Both tet(X3) and tet(X4) are adjacent to insertion sequence ISVsa3 on their respective conjugative plasmids and confer a mild fitness cost (relative fitness of >0.704). Database mining and retrospective screening analyses confirm that tet(X3) and tet(X4) are globally present in clinical bacteria-even in the same bacteria as blaNDM-1, resulting in resistance to both tigecycline and carbapenems. Our findings suggest that both the surveillance of tet(X) variants in clinical and animal sectors and the use of tetracyclines in food production require urgent global attention.

Over time, interlanguage studies have shifted from early qualitative to quantitative studies of specific linguistic structures. However, the focus of these studies is usually on one aspect of an interlanguage instead of the whole system. The ideal object of interlanguage research is a second language (L2) learner language system, for only in this way can the entire L2 learning process can be examined. As a self-organizing and self-regulated system, the panorama of interlanguage can be revealed objectively through a complex network approach. In this study, we construct eight interlanguage dependency syntactic networks of varying proficiency levels and modalities, and conduct a quantitative study of respective network parameters. We find that all syntactic networks of Chinese L2 learners (English native speakers) initially present scale-free and small-world properties. Additionally, there is no sudden syntactic emergence in interlanguage with different modalities. This suggests varying regularities in the development of a syntactic network between interlanguage and native language acquisition. Moreover, the first language plays an important role in L2 development. The network parameters (), L, C, ND, and NC can differentiate interlanguage modalities, and five quantitative parameters, , C, ND, γ′, and NC, can indicate L2 proficiency.

The CD69 molecule, as an early activation marker of lymphocytes, is often used to assess the activation of cellular immunity. However, for pigs, an anti-pig CD69 antibody is not yet available for this purpose after infection or vaccination. In this study, a monoclonal antibody (mAb) against pig CD69 was produced by peptide immunization and hybridoma technique. One mAb (5F12) showed good reactivity with pig CD69 that was expressed in transfected-HEK-293T cells and on mitogen-activated porcine peripheral blood mononuclear cells (PBMCs) by indirect immunofluorescence assay and flow cytometry. This mAb did not cross-react with activated lymphocytes from mouse, bovine, and chicken. Epitope mapping showed that the epitope recognized by this mAb was located at amino acid residues 147–161 of pig CD69. By conjugating with fluorochrome, this mAb was used to detect the early activation of lymphocytes in PRRSV- and ASFV-infected pigs by flow cytometry. The results showed that PRRSV infection induced the dominant activation of CD4 T cells in mediastinal lymph nodes and CD8 T cells in the spleen at 14 days post-infection, in terms of CD69 expression. In an experiment on ASFV infection, we found that ASFV infection resulted in the early activation of NK cells, B cells, and distinct T cell subsets with variable magnitude in PBMCs, spleen, and submandibular lymph nodes. Our study revealed an early event of lymphocyte and T cell activation after PRRSV and ASFV infections and provides an important immunological tool for the in-depth analysis of cellular immune response in pigs after infection or vaccination.

As a basis of hierarchical control structure, this paper proposes an integrated control approach of path following and lateral stability for unmanned autonomous vehicle with decentralized driving system. In the upper layer controller, the Sliding Mode Control theory is used to reduce the path following heading error and lateral offset while ensuring the vehicle stability. In the lower layer controller, the optimal tire force allocation method is used to execute the control demand from the upper controller. The CarSim-Simulink co-simulation results verify the effectiveness of the proposed approach.

Knots are remarkable topological features in nature. The presence of knots in crystallographic structures of proteins have stimulated considerable research to determine the kinetic and thermodynamic consequences of threading a polypeptide chain. By mechanically manipulating MJ0366, a small single domain protein harboring a shallow trefoil knot, we allow the protein to refold from either the knotted or the unknotted denatured state to characterize the free energy profile associated to both folding pathways. By comparing the stability of the native state with reference to the knotted and unknotted denatured state we find that knotting the polypeptide chain of MJ0366 increase the folding energy barrier in a magnitude close to the energy cost of forming a knot randomly in the denatured state. These results support that a protein knot can be formed during a single cooperative step of folding but occurs at the expenses of a large increment on the free energy barrier.

In view of the ocean target quantitative characterization of full-stokes parameters, the laboratory simulated polarimetry system (LPOL) of ocean targets is designed. Carry out the experiments by this system, LPOL can change different relative observation angle under hemisphere space, which can obtain different polarization characteristic values of ocean targets and the background of the water, such as the degree of polarization, the degree of linear polarization and the degree of circular polarization, there is no research concern the influence of the full stokes parameters under hemisphere. In this paper, we systematically quantitative analysis stokes parameters of the experiment data which obtained under different zenith angle. The results indicated that the polarization detection, which use full stokes parameters can effectively distinguish between targets and background. Moreover, ocean targets have certain statistical regularity of polarization characteristics under hemisphere observation geometry space, such as bidirectional polarized reflectance factor. In this paper, the research results can provide a solid technical guidance for detect and recognize the ocean targets.

In this paper, static and dynamic stability analyses taking axial excitation into account are presented for a laminated carbon fiber reinforced polymer (CFRP) cylindrical shell under a non-normal boundary condition. The non-normal boundary condition is put forward to signify that both ends of the cylindrical shell are free and one generatrix of the shell is clamped. The partial differential motion governing the equations of the laminated CFRP cylindrical shell with a non-normal boundary condition is derived using the Hamilton principle, nonlinear von-Karman relationships and first-order deformation shell theory. Then, nonlinear, two-freedom, ordinary differential equations on the radial displacement of the cylindrical shell are obtained utilizing Galerkin method. The Newton-Raphson method is applied to numerically solve the equilibrium point. The stability of the equilibrium point is determined by analyzing the eigenvalue of the Jacobian matrix. The solution of the Mathieu equation describes the dynamic unstable behavior of the CFRP laminated cylindrical shells. The unstable regions are determined using the Bolotin method. The influences of the radial line load, the ratio of radius to thickness, the ratio of length to thickness, the number of layers and the temperature field of the laminated CFRP cylindrical shell on static and dynamic stability are investigated.

Previous studies on the neural cognitive mechanisms of aspectual processing in second language (L2) learners have focused on Indo-European languages with rich inflectional morphology. These languages have aspects which are equipped with inflected verb forms combined with auxiliary or modal verbs. Meanwhile, little attention has been paid to Mandarin Chinese, which has limited morphological inflection, and its aspect is equipped with aspectual particles (e.g., le, zhe, guo). The present study explores the neurocognitive mechanism of Mandarin Chinese aspect processing among two groups of late Mandarin Chinese proficient learners with Thai (with Mandarin Chinese-like aspect markers) and Indonesian (lack of Mandarin Chinese-like aspect markers) as their first language (L1). We measured event-related potentials (ERPs) time locked to the aspect marker le in two different conditions (the aspect violation sentences and the correct sentences). A triphasic ELAN-LAN-P600 effect was produced by the Mandarin Chinese native speakers. However, there was no ELAN and LAN in Indonesian native speakers and Thai native speakers, except a 300–500 ms negativity widely distributed in the right hemisphere and P600-like effect. This suggests that both groups of Mandarin Chinese learners cannot reach the same level as Mandarin Chinese native speakers to process Mandarin Chinese aspect information, probably due to the complex feature of Mandarin Chinese aspect maker, the participants’ L2 proficiency and age of L2 acquisition.

Free vibration and static bending of functionally graded (FG) graphene nanoplatelet (GPL) reinforced composite doubly-curved shallow shells with three distinguished distributions are analyzed. Material properties with gradient variation in the thickness aspect are evaluated by the modified Halpin-Tsai model. Mathematical model of the simply supported doubly-curved shallow shells rests upon Hamilton Principle and a higher order shear deformation theory (HSDT). The free vibration frequencies and bending deflections are gained by taking into account Navier technique. The agreement between the obtained results and ANSYS as well as the prior results in the open literature verifies the accuracy of the theory in this article. Further, parametric studies are accomplished to highlight the significant influence of GPL distribution patterns and weight fraction, stratification number, dimensions of GPLs and shells on the mechanical behavior of the system. Keywords: Functional graded nanocomposite, Graphene nanoplatelets, Doubly-curved shallow shells, Mechanical behavior

This is a study of the collocation of Chinese verbs with different lexical aspects and aspect markers. Using event-related potentials (ERPs), we explored the processing of aspect violation sentences. In the experiment, we combined verbs of various lexical aspect types with the progressive aspect marker zhe, and the combination of the achievement verbs and the progressive aspect marker zhe constituted the sentence’s aspect violation. The participants needed to judge whether a sentence was correct after it was presented. Finally, we observed and analyzed the components of ERPs. The results suggest that when the collocation of aspect markers and lexical aspect is ungrammatical, the N400-like and P600 are elicited on aspect markers, while the late AN is elicited by the word after the aspect marker. P600 and N400-like show that the collocation of Chinese verbs with various lexical aspects and aspect markers involve not only syntactic processing, but also the semantic processing, and the late AN may have been due to the syntax revision and the conclusion at the end of sentences.

Poly(methyl methacrylate) (PMMA), the most common bone cement, has been used as a graft substitute in orthopedic surgeries such as vertebroplasty. However, an undesirable minor crack in the bone-cement interface provoked by shrinkage during polymerization and high elastic modulus of conventional PMMA bone cement dramatically increases the risk of vertebral body refracture postsurgery. Thus, herein, a hydrophilous expandable bone cement was synthesized based on a PMMA commercial cement (Mendec Spine Resin), acrylic acid (AA), and styrene (St). The two synthesized cements (PMMA-PAA, PMMA-PAA-PSt) showed excellent volumetric swelling in vitro and cohesive bone-cement contact in rabbit femur cavity defect. The elastic modulus and compressive strength of the new cements were lower than PMMA. Furthermore, the in vitro analysis indicated that the new cements had lower cytotoxicity than PMMA, including superior proliferation and lower apoptotic rates of Sprague-Dawly rat-derived osteoblasts. Western blotting for protein expression and RT-PCR analysis of osteogenesis-specific genes were conducted on SD rat-derived osteoblasts from both PMMA and new cements films; the results showed that new cements enhanced the expression of osteogenesis-specific genes. Scanning electron microscopy demonstrated improved morphology and attachment of osteoblast on new cement discs compared to the PMMA discs. Additionally, the histological morphologies of the bone-cement interface from the rabbit medial femoral condyle cavity defect model revealed direct and cohesive contact with the bone in the new cement groups in contrast to a minor crack in the PMMA cement group. The sign of a new bone growing into the cement has been found in the new cements after 12 weeks, thereby indicating the osteogenic capacity in vivo. In conclusion, the synthesized hydrophilous expandable bone cements based on PMMA and poly(acrylic acid) (PAA) are promising candidates for vertebroplasty.

Free vibration of the functionally graded material (FGM) sandwich doubly-curved shallow shells under simply supported conditions is presented. Three common types of the shell, namely, the shell with homogeneous hardcore and FGM facesheet (type A), the shell with homogeneous softcore and FGM facesheet (type B) and the shell with FGM core and homogeneous facesheet (type C), are discussed. The dynamics model is derived according to a new shear deformation theory with stretching effects. The dimensionless natural frequency is obtained by Navier method. Numerical examples of the FGM sandwich doubly-curved shallow shells are provided for different gradient material parameters, core thicknesses, radii of curvature, aspect ratios, side-to-thickness ratios and vibration modes to demonstrate the accuracy of the present theory.

In this paper, we extend the classical Melnikov method for smooth systems to a class of planar hybrid piecewise-smooth system subjected to a time-periodic perturbation. In this class, we suppose there exists a switching manifold with a more general form such that the plane is divided into two zones, and the dynamics in each zone is governed by a smooth system. Furthermore, we assume that the unperturbed system is a general planar piecewise-smooth system with non-zero trace and possesses a piecewise-smooth homoclinic orbit transversally crossing the switching manifold. We also define a reset map to describe the instantaneous impact rule on the switching manifold when a trajectory arrives at the switching manifold. Through a series of geometrical analysis and perturbation techniques, we obtain a Melnikov-type function to measure the separation of the unstable manifold and stable manifold under the effect of the time-periodic perturbations and the reset map. Finally, we use the presented Melnikov function to study global bifurcations and chaotic dynamics for a concrete planar piecewise-linear oscillator.

A novel, plasmid-mediated, high-level tigecycline resistance tet (X) gene variant, tet (X5), was detected in a clinical Acinetobacter baumannii isolate from China in 2017. Tet(X5) shows 84.5% and 90.5% amino acid identity to Tet(X3) and Tet(X4), respectively, with similar binding sites and a comparable affinity for tetracyclines. The tet (X5)-containing plasmid could only be transferred to A. baumannii via electrotransformation.

Background\ud \ud Since its discovery in 2015, the mobile colistin resistance gene mcr-1 has been reported in bacteria from > 50 countries. Although aquaculture-associated bacteria may act as a significant reservoir for colistin resistance, systematic investigations of mcr-1 in the aquaculture supply chain are scarce.\ud \ud \ud Objectives\ud \ud We investigated the presence of colistin resistance determinants in the aquaculture supply chain in south China and determined their characteristics and relationships.\ud \ud \ud Methods\ud \ud A total of 250 samples were collected from a duck-fish integrated fishery, slaughter house, and market in Guangdong Province, China, in July 2017. Colistin-resistant bacteria were isolated on colistin-supplemented CHROMagar Orientation plates, and the species were identified by matrix-assisted laser desorption/ionization time-of-flight assay. The presence of mcr genes was confirmed by polymerase chain reaction analysis. We examined the minimum inhibitory concentrations (MICs) of 16 antimicrobial agents against the isolates using agar diffusion and broth microdilution methods. Whole-genome sequencing (WGS) was used to explore the molecular characteristics and relationships of mcr-1-positive Escherichia coli (MCRPEC).\ud \ud \ud Results\ud \ud Overall, 143 (57.2%) colistin-resistant bacteria were isolated, of which, 56 (22.4%, including 54 Escherichia coli and two Klebsiella pneumoniae) and four Aeromonas species were positive for mcr-1 and mcr-3, respectively. The animal-derived MCRPEC were significantly more prevalent in integrated fishery samples (40.0%) than those in market (4.8%, P < 0.01) samples but not in slaughter house (28.0%, P = 0.164). All MCRPEC were highly resistant to ampicillin, tetracycline, and compound sulfamethoxazole (>90%) but were susceptible to carbapenems and tigecycline. WGS analysis suggested that mcr-1 was mainly contained on plasmids, including IncHI2 (29.6%), IncI2 (27.8%), IncX4 (14.8%), and IncP (11.1%). Genomic analysis suggested mcr-1 transmission via the aquatic food chain.\ud \ud \ud Conclusions\ud \ud MCRPEC were highly prevalent in the aquaculture supply chain, with the isolates showing resistance to most antibiotics. The data suggested mcr-1 could be transferred to humans via the aquatic food chain. Taking the “One Health” perspective, aquaculture should be incorporated into systematic surveillance programs with animal, human, and environmental monitoring.

The rapid dissemination of the macrolide resistance gene erm(B) will likely compromise the efficacy of macrolides as the treatment of choice for campylobacteriosis. More importantly, erm(B) is always associated with several multidrug resistance genomic islands (MDRGIs), which confer resistance to multiple other antimicrobials. Continuous monitoring of the emergence of erm(B) and analysis of its associated genetic environments are crucial for our understanding of macrolide resistance in Campylobacter In this study, 290 Campylobacter isolates (216 Campylobacter coli isolates and 74 Campylobacter jejuni isolates) were obtained from 1,039 fecal samples collected in 2016 from pigs and chickens from three regions of China (344 samples from Guangdong, 335 samples from Shanghai, and 360 samples from Shandong). Overall, 74 isolates (72 C. coli isolates and 2 C. jejuni isolates) were PCR positive for erm(B). Combined with data from previous years, we observed a trend of increasing prevalence of erm(B) in C. coli Pulsed-field gel electrophoresis analyses suggested that both clonal expansion and horizontal transmission were involved in the dissemination of erm(B) in C. coli, and three novel types of erm(B)-associated MDRGIs were identified among the isolates. Furthermore, 2 erm(B)-harboring C. jejuni isolates also contained an aminoglycoside resistance genomic island and a multidrug-resistance-enhancing efflux pump, encoded by RE-cmeABC Antimicrobial susceptibility testing showed that most of the isolates were resistant to all clinically important antimicrobial agents used for the treatment of campylobacteriosis. These findings suggest that the increasing prevalence of erm(B)-associated MDRGIs might further limit treatment options for campylobacteriosis.

Cyclic nucleotide binding (CNB) domains are universally conserved signaling modules that regulate the activities of diverse protein functions. Yet, the structural and dynamic features that enable the cyclic nucleotide binding signal to allosterically regulate other functional domains remain unknown. We use force spectroscopy and molecular dynamics to monitor in real time the pathways of signals transduced by cAMP binding in protein kinase A (PKA). Despite being structurally conserved, we find that the response of the folding energy landscape to cAMP is domain-specific, resulting in unique but mutually coordinated regulatory tasks: one CNB domain initiates cAMP binding and cooperativity, while the other triggers inter-domain interactions that lock the active conformation. Moreover, we identify a new cAMP-responsive switch, whose stability and conformation depends on cAMP occupancy. Through mutagenesis and nucleotide analogs we show that this dynamic switch serves as a signaling hub, a previously unidentified role that amplifies the cAMP binding signal during the allosteric activation of PKA.

Two novel phosphoethanolamine transferase genes, eptAv7 and eptAv3, were identified in the chromosome of an Aeromonas jandaei isolate from retail fish. The variants showed 79.9% and 80.0% amino acid identity to MCR-7.1 and MCR-3.1, respectively, and increased colistin resistance 128- to 256-fold in Aeromonas salmonicida. The two variants with no mobile genetic element in the flanking regions were also observed in other Aeromonas species. This finding supports the view that Aeromonas is a reservoir for MCR-3 and MCR-7 mobile colistin resistance.

Free phenolics (F), soluble esterified (SE) and glycosylated (SG) bound phenolics, insoluble (IS), insoluble esterificated (ISE) and glycosylated (ISG) bound phenolics were extracted from coconut mesocarp (CM) and coconut endocarp (CE) by acid-alkali treatment, respectively. Results of Folin-ciocalteu method and HPLC-MS quantitative analysis of 22 typical phenolic compounds showed that the distribution and content of phenolic compounds in a coconut shell were varied with different parts and components. The total phenolic content (TPC) of CM was significantly higher than that of CE. The TPC of soluble phenolics in coconut shell was significantly higher than that of insoluble phenolics. Antioxidant activities by FRAP method and acetylcholinesterase (AChE) inhibition activities of the twelve components were highly correlated with the TPC (RFRAP/TPC = 0.9938, Ranti-AChE/TPC = 0.9616). The correlation between their anti-AChE activities and FRAP values of 11 flavonoids (R = 0.9221) was higher than that of 11 phenolic acids (R = 0.6018). Among identified phenolics, quercetin (71.25%), kaempferol (64.84%) and gallic acid (57.32%) had higher anti-AChE activities, while catechin (– 6.53%), chlorogenic acid (– 9.40%) and epicatechin (– 22.40%) had negative effects. Among the twelve components, CM-SE, F and IS had high polyphenol utilization potential, while CM-SE, IS and CE-SE had high anti-AChE utilization potential. Phenolic components are related to anti-AChE activities, which might attract researchers to further explore the neuroprotective effect of coconut shell extracts.

Phenolic acids may provide health benefits as antioxidants and have potential applications in food and pharmaceutical science. The antioxidant activity and mechanism of sinapic acid (SA), ferulic acid (FA), disinapic acids (DSA) and diferulic acids (DFA) were evaluated by experiments and theoretical calculation. DSA-1–3 and DFA-1–3 were synthesized and identified by HPLC–MS and nuclear magnetic resonance. DSA-1 and DFA-1 (8-8′-dilactone dimers) were identified as adducts in the SA-/FA-DPPH system for the first time, which confirmed the mechanism of radical adduct formation. The orders of their antioxidant activities by DPPH and FRAP assays were consistent with theoretical calculation based on density functional theory, e.g., DSA-3 > DSA-2 > SA > DSA-1, DFA-3 > DFA-2 > FA > DFA-1, and SA group > FA group. These phenolic acids were more likely to occur the HAT mechanism in the gas phase, while occur SETPT and SPLET mechanisms in polar solvents. Moreover, the active phenolic hydroxyls of DSA-2 (4-OH) and DFA-2 (4′-OH) were opposite according to the bond dissociation energy and HOMO distribution. Methoxyl on the benzene rings may play a crucial role in the formation of DSA and DFA, as well as the antioxidant activity and phenolic hydroxyl active center.