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• Underwater explosion induced cavitation near sacrificial coatings are studied. • RKDG-FE-GFM-IsenCav is developed to study the cavitation effects. • Five benchmark problems are studied. • Effects of geometrical and physical properties of the model are discussed. The load resulting from cavitation collapse is a major threat to structures exposed to underwater explosions. Protective structures for warships, such as sacrificial coatings, which are sandwich structures attached to the wet face of the ship hull. They have energy absorbing cores made of cellular or composite materials that can significantly influence the effects of cavitation. In this study, a physical model consisting of water, an explosion bubble, and a sacrificial coating is established to investigate the effects of cavitation near sacrificial coatings subjected to underwater explosions. A numerical method is developed that couples the Runge-Kutta discontinuous Galerkin method, the finite element method, a Ghost Fluid Method-based numerical technique, and an isentropic one-fluid cavitation model to capture the physical phenomena of shock wave propagation, cavitation inception, expansion and collapse, and explosion bubble expansion and contraction. To ensure the accuracy of the mathematical model, five benchmark problems and a convergence test of the numerical solution are studied. The study comprehensively discusses the influences of core strengths, face sheet thickness, stand-off distances, and structure curvature on the evolution of the cavitation region, pressure profiles near the structure, and structure responses. [ABSTRACT FROM AUTHOR]

We use Sentinel‐1 and ALOS‐2 Interferometric Synthetic Aperture Radar (InSAR), and Global Navigation Satellite System (GNSS) data to investigate the mechanisms of coseismic and postseismic deformation due to the 2021 M7.4 Maduo (China) earthquake. We present a refined coseismic slip model constrained by the rupture trace and precisely located aftershocks. The InSAR time series corrected for the atmospheric and decorrelation noise reveal postseismic line of sight displacements up to ∼0.1 m. The displacements are discontinuous along the fault trace, indicating shallow afterslip and velocity‐strengthening friction in the top 2–3 km of the upper crust. The magnitude of shallow afterslip is however insufficient to compensate for the coseismic slip deficit, implying substantial off‐fault yielding. The observed surface deformation does not exhibit obvious features that could be attributed to poroelastic effects. We developed a fully coupled model that accounts for both stress‐driven creep on a deep localized shear zone and viscoelastic relaxation in the bulk of the lower crust. The mid‐ to near‐field data can be reasonably well explained by deep afterslip and/or non‐Maxwellian visco‐elasticity. Our results suggest a power‐law stress exponent of ∼4–4.5 assuming a power‐law rheology, and transient and steady‐state viscosities of 1018 and 1019 Pa s, respectively, assuming a bi‐viscous (Burgers) rheology. However, a good fit to the GNSS data cannot be achieved assuming the bulk viscoelastic relaxation alone, and requires a contribution of deep afterlip and/or a localized shear zone extending through much of the lower crust. Plain Language Summary: A large earthquake occurred in the north‐east Tibetan Plateau (Qinghai Province, China) on 21 May 2021. We use data collected by orbiting satellites to measure subtle (millimeter to centimeter‐scale) displacements of the Earth's surface that occurred in 1 year following the Maduo earthquake. The observed rates and spatial patterns of surface displacements are used to infer the mechanisms of stress relaxation and mechanical properties of rocks at depth. We find evidence of continued slip on the fault that produced the Maduo earthquake, both near the surface, and below the seismogenic zone. Our results suggest that major faults that cut through the Tibetan Plateau are associated with deep roots that extend into the lower crust. The observed shallow slip is insufficient to compensate for the near‐surface slip deficit that accrued during the earthquake. This suggests that some amount of the near‐surface coseismic shear was distributed over a wider zone around the earthquake rupture. Key Points: We present a new method for modeling geometrically complex ruptures in heterogeneous media using distributed point sourcesPostseismic deformation is best explained by models that include a deep shear zone below the earthquake ruptureUp to ∼0.2 m of shallow afterslip occurred within 1 year after the earthquake, insufficient to compensate for the coseismic shallow slip deficit [ABSTRACT FROM AUTHOR]

Microplastics have become a worldwide pollutant, widely discovered in soil, air and aquatic environment. Microplastics have been found in habitats where crayfish (Procambarus clarkii) cultivated, but the impact of microplastics on crayfish remains unclear. In this study, after 21-day dietary exposure, polyethylene (PE) particles were found to accumulate in intestine, hepatopancreas, gills and hemolymph of crayfish. Furthermore, PE particles can still be detected in these tissues after a 7-day depuration in clean water. PE retained in these tissues caused oxidative stress responses, as indicated by the change of oxidative-stress-related index, such as the increase of H 2 O 2 level and SOD activity. PE exposure also caused hemocytic encapsulation in crayfish hepatopancreas and increase of mucus secretion in intestine. Moreover, PE exposure affected the microbiota balance in crayfish, by reducing the total microbiota abundance and altering the proportions of many bacterial families. Interestingly, results showed that PE exposure led to of lower numbers of hemocytes and declination of phenoloxidase activity. Finally, PE exposure induced the expression of immune-related genes, including transcription factors and antimicrobial peptides. Taken these together, we conclude that PE microplastics exert considerable toxic effects on crayfish and are a potential threat to crayfish aquaculture and consumption. This study provides basic toxicological data toward quantifying and illuminating the impact of PE microplastics on freshwater animals. [Display omitted] • Polystyrene microplastics accumulated in several tissues of crayfish and caused histopathological changes. • Polystyrene microplastics induced oxidative stress and immune responses in crayfish. • Polystyrene microplastics induced gut microbiota dysbiosis in crayfish. [ABSTRACT FROM AUTHOR]

The 2015 M7.2 Sarez (Pamir) earthquake occurred at the north‐west margin of the Tibetan Plateau. We use Sentinel‐1 and ALOS‐2 Synthetic Aperture Radar and Global Navigation Satellite System data to investigate coseismic and postseismic deformation due to the Sarez earthquake. Kinematic inversions show that the earthquake ruptured a ∼80 km long, sub‐vertical fault producing the maximum surface offset of 3–4 m on the south‐west and central fault segments. In contrast, the largest postseismic displacements are observed at the north‐east end of the earthquake rupture, predominantly on the west (hanging wall) side of the fault with an average rate of 20–30 mm/yr in the satellite line of sight. We use the derived coseismic and postseismic slip models to investigate mechanisms of time‐dependent relaxation, stress transfer and possible triggering relationships between the Sarez earthquake and a sequence of strong M6+ events that occurred within ∼100 km of the 2015 earthquake. We find that the near‐field postseismic displacements are best explained by shallow afterslip driven by the coseismic stress changes. The data also allow some contribution from poroelastic rebound, but do not show a clear signature of viscoelastic relaxation in the lower crust and upper mantle during the observation period, suggesting a lower bound on the effective viscosity of ∼1019 Pa s. A pair of M6+ events that occurred within 100 km and several months of the 2015 mainshock have experienced near‐zero and in some cases negative static Coulomb stress changes, suggesting either delayed dynamic triggering, or no relation to the mainshock. Plain Language Summary: Large earthquakes are often followed by slow deformation that results from redistribution and relaxation of coseismic stress changes in the host rocks. The patterns and rates of postseismic deformation can be used to learn about the properties of rocks at depth. We analyzed surface deformation that occurred during and after a major (magnitude 7.2) earthquake that occurred in the Pamir orogen at the north‐west margin of Tibet. We used radar imagery from satellites of the European and Japanese space agencies, as well as data from the Global Navigational Satellite System to measure subtle (centimeter‐scale) displacements of the Earth's surface that occurred within 100 km from the earthquake epicenter. A combination of coseismic and postseismic displacement data reveals that the earthquake rupture split into two branches as it was propagating from south‐west to north‐east. We found evidence of slow aseismic creep ("afterslip") at the north‐east end of the earthquake rupture. In contrast, we do not observe a broad pattern of displacements expected from enhanced viscous flow in the lower crust and/or upper mantle. The lack of the respective signal argues for a relatively strong "ductile" portion of the Tibetan lithosphere. Key Points: Near‐field postseismic deformation is dominated by shallow afterslip and poroelastic relaxation at the NE end of the earthquake ruptureData do not show a clear signal expected of viscoelastic relaxation, indicating effective viscosity of the lower crust >1019 Pa sWe investigate triggering relationships between the M7.2 and subsequent M6+ events that occurred within 1 year and 100 km of the mainshock [ABSTRACT FROM AUTHOR]

The 2021 Maduo earthquake ruptured a 150 km‐long left‐lateral fault in the northeast Tibet. We used Synthetic Aperture Radar data collected by the Sentinel‐1A/B satellites within days of the earthquake to derive a finite fault model and investigate the details of slip distribution with depth. We generated coseismic interferograms and pixel offsets from different look directions corresponding to the ascending and descending satellite orbits. At the eastern end the rupture bifurcated into two sub‐parallel strands, with larger slip on the northern strand. Inversions of coseismic displacements show maximum slip to the east of the epicenter. The averaged coseismic slip has a peak at depth of 3–4 km, similar to slip distributions of a number of shallow strike‐slip earthquakes. Postseismic observations over several weeks following the Maduo earthquake reveal surface slip with amplitude up to 0.1 m that at least partially eliminated the coseismic slip deficit in the uppermost crust. Plain Language Summary: A large earthquake occurred in a remote area of north‐east Tibet (Qinghai Province, China) on May 21, 2021. The earthquake produced a 150 km‐long rupture with surface offsets up to several meters. We used data collected by orbiting satellites to map motions of the Earth's surface that occurred during and shortly after the earthquake. The measured surface displacements were used to constrain the rupture geometry and slip distribution at depth. Best‐fitting models suggest that rupture occurred on a sub‐vertical fault steeply dipping to the north, with most of slip occurring to the east of the earthquake epicenter. The maximum coseismic slip occurred in the uppermost crust, in the depth interval of 3–4 km below the Earth's surface. A decrease in the fault offsets toward the Earth's surface is likely caused by an increased frictional resistance of the shallow layer to rapid coseismic slip. Satellite observations made in the first month after the earthquake reveal that the shallow part of the fault is slowly catching up with a deeper part to make up for the difference in the amount of slip produced during the earthquake. Key Points: We use Sentinel‐1 Synthetic Aperture Radar data to derive a finite fault model for the 2021 M7.4 Maduo (Qinghai, China) earthquakeThe along‐strike averaged coseismic slip has a maximum at depth of 3–4 km, with an amplitude of ∼2.5 mUp to 0.1 m of afterslip occurred on the fault trace in the first month following the earthquake [ABSTRACT FROM AUTHOR]

Two models have previously been commonly used to predict the isolation performance of a hydraulic leveraged dynamic anti-resonance vibration isolator. The models have deficiencies, however, in considering the volumetric stiffness of the isolator. In this paper, a new model is proposed to improve the accuracy by reasonably taking the volumetric stiffness into consideration. The model is validated by a carefully designed experiment. The influence of the volumetric stiffness on the isolation performance of the isolator is investigated by the validated model. The results indicate that the volumetric stiffness of the isolator and its location in a mathematical model have a significant influence on the isolation frequency and the second natural frequency of the isolator. The dependence of the volumetric stiffness on the isolation frequency, the attenuation capacity at the isolation frequency, and the bandgap of the isolator is presented. The investigation will enhance the understanding of the hydraulic leveraged dynamic anti-resonance vibration isolator, and facilitate the design and exploitation of this type of isolator in the field of vibration isolation. [ABSTRACT FROM AUTHOR]

• Precise velocity fields solved by two-dimensional multi-physical coupling model. • A porous electrode layer to describe the mass transfer resistance. • Polarization current curves precisely reproduced under different rotation speeds. • An improved Tafel method to obtain more intrinsic transfer coefficient. Rotating disk electrodes with porous layers are commonly used to obtain the oxygen reduction reaction kinetic parameters. In this paper, to eliminate the severe error in the intrinsic reaction kinetic measurement of porous layers of the rotating disk electrode, a flow-electrochemical multi-physical model with porous electrode layer is developed for the detailed simulation of the mass transfer and electrochemistry reaction process. The multi-physical model is solved by finite element method, whose results are validated with the porous electrode layer generated by NGHMs. It turned out that the multi-physical model can reproduce the results of physical experiments by fitting the effective diffusion coefficient in the porous structure. Based on this model, the classical Tafel method is improved, so that it can be applied to porous electrodes and more accurate intrinsic reaction kinetic parameters can be obtained as a result. All of the above proves that the measurement accuracy of the electrocatalytic performance of porous rotating disk electrode can be greatly enhanced. [ABSTRACT FROM AUTHOR]

A numerical procedure that couples the Runge–Kutta discontinuous Galerkin method (RKDG), the boundary element method (BEM) and the finite element method (FEM) is developed to study the dynamics of an underwater explosion bubble near a sandwich structure efficiently and accurately. The numerical approach is validated by a near-field underwater explosion experiment. The numerical predicted bubble shape, cavitation and the free field pressure are in good agreement with the experimental results. The validated code is then used to determine the effects of the foam core strengths, the stand-off distances and the boundary condition of the back face sheet on the fluid response, the bubble behaviors, and the deformation of the sandwich structure. The results are beneficial for guiding the design of the protection structures. • Dynamics of an underwater explosion bubble near a sandwich structure is studied. • A numerical procedure that couples RKDG, BEM and FEM is developed. • Deformation of sandwich structures has significant effects on the bubble behaviors. [ABSTRACT FROM AUTHOR]

The dynamics of an underwater explosion bubble interacting with a moveable plate with basic characteristics of a sandwich structure are investigated numerically using boundary element method. The response of sandwich structures is assumed to be a moveable plate with a given velocity profile. The influence of the plate velocity profile, the standoff distance and the scale of the plate on the bubble behaviors are discussed. Within the scope of discussions, the bubble volume and period are a decreasing function of the maximum crushing velocity, the core compression, and the plate dimension, and an increasing function of the standoff distance. Three different regimes of bubble behaviors are distinguished: (1) jet directing towards the plate; (2) the bubble splitting into multiple bubbles or oscillating spherically without jet; (3) jet directing away from the plate. The results indicate that the sandwich plate which can provide larger deformation and larger maximum deformation velocity is beneficial for altering the jet direction to direct away from the plate. [ABSTRACT FROM AUTHOR]

Antimicrobial peptides (AMPs) are members of humoral immunity and particpate in resisting microbial invasion. In this study, an AMP gene hepcidin was obtained from the oriental loach Misgurnus anguillicaudatus and named Ma-Hep. This Ma-Hep encodes a peptide of 90 amino acids, with a predicted active peptide segment (Ma-sHep) of 25 amino acids at C terminus. Stimulation by a bacterial pathogen Aeromonas hydrophila resulted in significant up-regulation of Ma-Hep transcripts in loach midgut, head kidney, and gill. Ma-Hep and Ma-sHep proteins were expressed in Pichia pastoris and their antibacterial activity was examined. Results showed that Ma-sHep possessed stronger antibacterial activity against various Gram-positive and Gram-negative bacteria, compared to Ma-Hep. Scanning electron microscopy showed that Ma-sHep might kill bacteria by destroying bacterial cell membranes. Moreover, we found that Ma-sHep had an inhibitory effect on blood cell apoptosis induced by A. hydrophila and facilitated the bacterial phagocytosis and clearance in loach. Histopathological analysis indicated Ma-sHep could protect liver and gut of loach from bacterial infection. Ma-sHep has high thermal stability and PH stability, which is conducive to further feed addition. Feed supplemented with Ma-sHep expressing yeast improved the intestinal flora of loach by increasing the dominant bacteria and decreasing the harmful bacteria. Feed supplemented with Ma-sHep expressing yeast also regulated the expression of inflammatory related factors in various tissues of loach and reduced the mortality of loach upon bacterial infection. These findings show that the antibacterial peptide Ma-sHep is involved in the antibacterial defense of loach and can be used as a candidate for new antimicrobial agents in aquaculture. • The Hepcidin from Misgurnus anguillicaudatus was cloned and identified. • Ma-sHep possessed strong antibacterial activity against various bacteria. • Ma-sHep had an inhibitory effect on blood cell apoptosis induced by A. hydrophila. • Ma-sHep could protect loach tissues from bacterial infection. • Feed supplemented with Ma-sHep expressing yeast enhance immune capacity of loach. [ABSTRACT FROM AUTHOR]

The cellular materials are well known to mitigate shock loadings. However, they may attenuate or enhance the shock transmitted to the protected structures. This paper is devoted to derive an explicit expression of the effective foam thickness when subjected to deep underwater explosion. Hereinafter, the effective foam thickness represents the crushed foam when the shock energy is just completely absorbed, i.e. the attenuation/enhancement boundary. One-dimensional (1D) analytical model which can consider the core crushing, the fluid-structure interaction (FSI), the cavitation phenomenon and the initially applied static pressure is proposed to solve the problem. The analytical model is then used for the parametric study. Finally, the empirical formulae of the effective foam thickness is derived from the results of the parametric study. In practical applications, the empirical formulae for the effective foam thickness can guide the design of such cellular claddings to water blast. [ABSTRACT FROM AUTHOR]

A numerical solver coupling the Runge-Kutta discontinuous Galerkin method to the finite element method is proposed to solve the two-dimensional (2D) or axisymmetric response of deformable sandwich structures with metallic foam cores subjected to underwater explosion, in which the interactions of the gas bubble, the shock wave, the sandwich structure and cavitation are taken into account. The coupling method combines the advantages of the ghost fluid method (GFM) and the modified ghost fluid method (MGFM), where the Lagrangian interface velocity is directly set as the solution of the Riemann problem and the interface pressure and the fluid density are obtained by solving the Riemann problem (with the pre-known interface velocity). The obtained interface pressure then serves as the boundary condition to the Lagrangian domain. For the Eulerian domain, the remaining procedure is similar to the MGFM. The method proposed in this paper is material independent in simulating the fluid-structure interaction which is its major advantage compared with the original MGFM. The method is successfully validated by using analytical, numerical, and experimental results. [ABSTRACT FROM AUTHOR]

A fluid model is developed and used in combination with Abaqus/Explicit to investigate the effects of graded foam cores on the loading of a sandwich spherical shell subject to underwater explosion from the inner side, after having validated the modeling technique by reproducing results by other authors. Based on the relation between the core strength and the stiffness of the outer face sheet (OFS), four different situations are considered to discuss the graded effects. It is demonstrated that for the case of relatively strong cores and the OFS with low stiffness or soft cores and the OFS with high stiffness, the core arrangement of low/medium/high (relative density from the inside to the outside) has the best performance to shock loadings which is a consequence of the effects of the fluid–structure interaction and the energy absorption capability; on the other hand, for the case of intermediate core strengths and stiffness of the OFS where the pulling-back force due to the stretching of the OFS is close to the core strength, the configuration of high/medium/low has the best performance due to its higher energy absorption efficiency of the foam and lower transmitted stress. [ABSTRACT FROM AUTHOR]

The TOC and TIC complexes are essential translocons that facilitate the import of the nuclear genome-encoded preproteins across the two envelope membranes of chloroplast, but their exact molecular identities and assembly remain unclear. Here, we report a cryoelectron microscopy structure of TOC-TIC supercomplex from Chlamydomonas , containing a total of 14 identified components. The preprotein-conducting pore of TOC is a hybrid β-barrel co-assembled by Toc120 and Toc75, while the potential translocation path of TIC is formed by transmembrane helices from Tic20 and YlmG, rather than a classic model of Tic110. A rigid intermembrane space (IMS) scaffold bridges two chloroplast membranes, and a large hydrophilic cleft on the IMS scaffold connects TOC and TIC, forming a pathway for preprotein translocation. Our study provides structural insights into the TOC-TIC supercomplex composition, assembly, and preprotein translocation mechanism, and lays a foundation to interpret the evolutionary conservation and diversity of this fundamental translocon machinery. [Display omitted] • Chlamydomonas TOC-TIC supercomplex contains a total of 14 identified components • Toc120 and Toc75 form a hybrid β-barrel pore of TOC for preprotein conducting • Tic20 and YlmG constitute a potential translocation path of TIC with lateral opening • An IMS scaffold bridges the TOC and TIC to form a preprotein translocation pathway Cryoelectron microscopy structure of TOC-TIC supercomplex from Chlamydomonas reveals its composition, assembly, and the mechanism for chloroplast preprotein translocation. [ABSTRACT FROM AUTHOR]

Warships and submarines can be severely damaged by underwater explosion (UNDEX) shock loadings, so improving shock resistance ability of such weapons is of great importance. However, studies on the shock resistance ability of submersible hull subjected to deep UNDEX shock wave are rare. In this paper, the transient response of bare/coated submersible hull subjected to combined loads of hydrostatic pressure and shock wave is analyzed numerically by Abaqus, with special attention on shock mitigation capability of cellular cladding coated on the pressure hull. The local cavitation in water and transient response of bare and coated hulls are obtained. Additionally, the effects of the initially applied hydrostatic pressure on the system response are discussed. The results indicate that the cellular cladding coated on the pressure hull is very effective on reducing hull deformation, velocity and acceleration response, and the soft cladding is more effective than the strong cladding if the cladding is not fully densified. Otherwise, the stress enhancement appears which can amplify the local response of coated hull. The research results are useful in designing surface shields for submersible hull so as to enhance its resistance to underwater shock damage. [ABSTRACT FROM AUTHOR]

One-dimensional (1D) response of single/double-layer cellular claddings to water blast, including the core crushing, fluid-structure interaction (FSI) and cavitation phenomenon, is investigated by analytical approaches and finite element (FE) simulations. Analyses are focused on the shock mitigation mechanism of cellular cladding and optimization design of double-layer cladding (DLC) with particular interests in shortening cladding thickness without increasing the transmitted stress to the main structure. It is demonstrated that the actual incident wave impinged on the cladding and interface pressure at the wet face are highly dependent on the core crushing, FSI effects and cavitation phenomenon under identical incident wave. The actual incident wave will be enhanced due to the collapse of cavitation bubbles, especially for soft core. The total pressure at the wet face typically exhibits a rapid decline followed by a long pressure plateau whose value approximately equals to the quasi-static stress of the core being compressed. The high pressure loading incident on the cladding is converted into a lower magnitude load with much longer duration, which is beneficial for shock mitigation. Parametric analyses of the single-layer cladding (SLC) indicate that strong core cladding can largely shorten the total foam thickness needed to dissipate the shock energy. However, the transmitted stress to the main structure increases correspondingly. Therefore, a DLC with strong core being placed at the impinged end is proposed to shorten the foam thickness without increasing the transmitted stress. Comparisons of shock mitigation ability between the DLC and its single counterpart are conducted in terms of the total foam thickness, partial impulse imparted to the cladding and absorbed energy. The results reveal that the DLC can absorb more energy and reduce the total foam thickness when the face sheet of the soft core is properly designed. Finally, design guides for the DLC against water blast are presented. [ABSTRACT FROM AUTHOR]

In previous studies, the response of sandwich structures to water blast is solved by envisaging the plate adjacent to water as a rigid one, while the effects of the elasticity in the longitudinal direction of the plate are rarely studied. In this paper, a monolithic elastic coating with varying stiffness and thickness is investigated by a one-dimensional analytical approach, based on linear wave motion theory, to reveal the elastic effect of the plate on the incident wave. One side of the coating is loaded by a planar shock wave; on the opposite side, rigid boundary or air-backed boundary is imposed. The fluid–structure interaction (FSI), cavitation phenomenon and large deformation of the coating are taken into account. In particular, the initiation and evolution of cavitation, including the propagations of breaking fronts and closing fronts, as well as the pressure histories of radiated wave by the closing front, are examined. The analytical solution has been compared with finite element (FE) predictions. The results are found to be in excellent agreement for the propagation of breaking front and closing front, as well as the pressure and particle velocity histories at the wet face before the cavitation reaches the wet face. However, when the wet face cavitates, the predictions provided by the analytical method are less accurate and the analytically-computed particle velocity can only be compared in an average sense with the FE predictions. For air-backed case, Taylor׳s model prior to cavitation becomes a trivial case of the analytical model and the comparison also indicates the validity of the analytical model. The validated analytical model is used to determine the dependence of the peak pressure at the wet face and the impulse transmitted to the coating on the coating properties, including the wave impedance and thickness. [ABSTRACT FROM AUTHOR]

Underwater explosion seriously affects the combat performance and vitality of submarines. In order to improve the blast resistance of stiffened double cylindrical shells, a new type of stiffened style that replaces the traditional T-shaped stiffeners with circular tube stiffeners, namely O-shaped stiffeners are studied. A series of comparative underwater explosion tests are carried out on two scaled stiffened double cylindrical shells with O and T-shaped stiffeners. Based on the tests, more detailed numerical simulations are made to explore the influence of the structure parameters on the shock performance of the whole structure. It is shown that the O-shaped stiffeners show more superior crushing performance than T-shaped ones when the large plastic deformation appears on the shells. As the plastic deformation of the T-shaped stiffeners is dominated by harmonic buckling while that of the O-shaped stiffeners is dominated by the flattening deformation of circular tubes, the latter can produce greater plastic deformation and absorb more shock energy to reduce the internal energy of pressure hull and thin hull. The shock response spectrums measuring at pressure hull can also be significantly attenuated at high frequency band. Therefore, the O-shaped stiffeners may be more effective sacrificial connected structures in the submarine. • Circular tube is proposed as the stiffener of double cylindrical shells to improve the blast resistance. • Comparative non-contact underwater explosion tests are carried out on the stiffened double cylindrical shells. • The circular tube stiffeners are effective sacrificial connected structures to protect the inner and outer hull. [ABSTRACT FROM AUTHOR]

Human mitochondrial pyruvate carriers (hMPCs), which are required for the uptake of pyruvate into mitochondria, are associated with several metabolic diseases, including type 2 diabetes and various cancers. Yeast MPC was recently demonstrated to form a functional unit of heterodimers. However, human MPC-1 (hMPC-1) and MPC-2 (hMPC-2) have not yet been individually isolated for their detailed characterization, in particular in terms of their structural and functional properties, namely, whether they exist as homo- or heterodimers. In this study, hMPC-1 and hMPC-2 were successfully isolated in micelles and they formed stable homodimers. However, the heterodimer state was found to be dominant when both hMPC-1 and hMPC-2 were present. In addition, as heterodimers, the molecules exhibited a higher binding capacity to both substrates and inhibitors, together with a larger structural stability than when they existed as homodimers. Taken together, our results demonstrated that the hetero-dimerization of hMPCs is the main functional unit of the pyruvate metabolism, providing a structural insight into the transport mechanisms of hMPCs. [ABSTRACT FROM AUTHOR]

• This work deals with the shock mitigation effects of sacrificial coatings plastered on the stiffened double cylindrical shell. • The physical experiments of a stiffened double cylindrical shell under non-contact underwater explosion are carried out. • The coating on the thin hull plays the key role to mitigate shock loadings while the coating on the pressure hull has limited effects. Underwater explosion shock loadings can seriously damage the vitality and fighting capacity of warships. Plastering a layer of sacrificial coating on the ship hull is one of effective strategies to isolate shock impulses and absorb shock energy. In this paper, the shock mitigation effects of sacrificial coatings plastered on a stiffened double cylindrical shell are analyzed numerically. The numerical models are validated by conducting a series of physical experiments of a stiffened double cylindrical shell under noncontact underwater explosion. Three different configurations are considered: both the pressure and thin hulls are plastered with sacrificial coatings; only the thin hull is plastered with sacrificial coatings; and only the pressure hull is plastered with sacrificial coatings. The total pressure field in water and the dynamic response of the stiffened double cylindrical shell are obtained. The results indicate that the deformation and motion of the sacrificial coatings can more easily generate rarefaction wave, which can decrease the total shock impulse acting on the structure. Among three configurations, the configuration of the coating plastered on the thin hull has a better capability of isolating the shock impulse and reducing the shock loadings transmitted to the pressure hull. The dynamic stress and velocity responses of the shell are effectively decreased. Comparisons between different configurations suggest that the coating on the thin hull plays a key role in mitigating shock loadings, while the coating on the pressure hull has limited effects. Moreover, comparison results between the bare hull and the equivalent model which increases the thickness of the thin or pressure hulls under the same mass conditions indicate that the method of using a sacrificial coating is more effective in improving the blast resistance of the structure. The research results are useful in guiding the shock resistance design of stiffened double cylindrical shells. [ABSTRACT FROM AUTHOR]

Understanding the structure and functional mechanisms of cyanobacterial halorhodopsin has become increasingly important, given the report that Synechocystis halorhodopsin (Sy HR), a homolog of the cyanobacterial halorhodopsin from Mastigocladopsis repens (Mr HR), can take up divalent ions, such as SO 4 2−, as well as chloride ions. Here, the crystal structure of Mr HR, containing a unique "TSD" chloride ion conduction motif, was determined as a homotrimer at a resolution of 1.9 Å. The detailed structure of Mr HR revealed a unique trimeric topology of the light-driven chloride pump, with peculiar coordination of two water molecules and hydrogen-mediated bonds near the TSD motif, as well as a short B–C loop. Structural and functional analyses of Mr HR revealed key residues responsible for the anion selectivity of cyanobacterial halorhodopsin and the involvement of two chloride ion-binding sites in the ion conduction pathway. Alanine mutant of Asn63, Pro118, and Glu182 locating in the anion inlet induce multifunctional uptake of chloride, nitrate, and sulfate ions. Moreover, the structure of N63A/P118A provides information on how Sy HR promotes divalent ion transport. Our findings significantly advance the structural understanding of microbial rhodopsins with different motifs. They also provide insight into the general structural framework underlying the molecular mechanisms of the cyanobacterial chloride pump containing Sy HR, the only molecule known to transport both sulfate and chloride ions. Unlabelled Image • The structure of the cyanobacterial chloride pump containing a unique "TSD" motif was solved at 1.9 Å resolution. • The homotrimeric topology and key ion-conducting residues of MrHR differ with general halorhodopsins. • Mutations in the chloride inlet induce multifunctional uptake of Cl−, NO 3 −, SO 4 2− ions. • The mutant structure of chloride inlet provides structural evidence on different anion accessibilities. [ABSTRACT FROM AUTHOR]

• A eulerian compressible fluid model combines the isentropic single fluid model to solve shock wave propagation and water cavitation of water-filled double plate model. • A freestanding or softly supported outer plate has a minimal effect on the impulse transmitted to the inner plate and its motion. • Stiff support spring of the outer plate can reduce the shock wave transmitted to the gap water and also the motion of the inner plate. • Cavitation initiates in gap water near the inner plate and spreads towards the external water. • Stiff support spring of the inner plate will suppress water cavitation. Water-filled double hulls are a prevalent design for underwater warships. Studying the propagation of underwater shock wave in such structures is essential to comprehend their shock resistance. The aim of this paper is to investigate the propagation of underwater shock wave and water cavitation in a water-filled double plate. To achieve this objective, the paper establishes a Eulerian compressible fluid model that combines the isentropic single fluid model and Newton's second law. The accuracy of the numerical solver is confirmed through validation tests. The reflection and transmission characteristics of shock wave, the dynamic response of the plate, and the cavitation in external and gap water are analyzed. It also examines the effects of the supporting springs of outer and inner plates and the area density of the outer plate on the shock wave propagation and cavitation evolution. The findings indicate that the transmitted wave in the gap water is influenced by the area density and supporting spring of the outer plate. A thicker outer plate can reduce the peak value of the transmitted wave, and a stiffer supporting spring can decrease the transmitted impulse. On the other hand, if the outer plate is freestanding or softly supported, it has minimal effects on the response of the inner plate. Moreover, the water cavitation is determined by the supporting spring of the inner plate in the case of a softly supported outer plate, and the cavitation initially develops in the gap water near the inner plate before expanding towards the external water. When the supporting spring of the outer plate is stiff, it significantly reduces the occurrence of cavitation in the external water, while the cavitation in the gap water is still determined by the support spring of the inner plate. These research findings are valuable for analyzing the shock resistance of typical double-hull submarines. [Display omitted] [ABSTRACT FROM AUTHOR]

The investigation of pressure-bearing capacity design for underwater structures is of significant importance. This study focuses specifically on composite shell structures and conducts stress–strain experiments using strain gauges and 3D-DIC (digital image correlation) in a high-pressure underwater environment of 15 MPa, utilizing a 3D-DIC underwater shield. Numerical simulations were carried out to verify the feasibility of the 3D-DIC testing system in underwater high-pressure environments, and a scientific underwater DIC testing method was proposed. The experimental and numerical results show that strain gauges have limited accuracy and random measurements due to the large size ratio (5.5) between the strain gauges and small structural components, and the high strain gradient (41.0 μ ɛ /mm) at the small structural components, with limited measurement points. On the other hand, the 3D-DIC system has a minimum measurement unit that is 0.12 times smaller than the size of small structural components, accurately measuring stress–strain results over a larger measurement area. Based on the DIC and numerical results, this study explores the mechanical performance of the composite shell structure. The stress and strain at the ribs were relatively small compared to the adjacent ribs, with a difference of 71.3 MPa in average Mises stress and 479.2 μ ɛ in average strain, effectively improving the structural anti-deformation ability and enhancing structural strength. • A 3D-DIC testing method in a deepwater high-pressure environment was proposed. • An underwater pressure experiment was conducted on composite shells. • The 3D-DIC method, strain gauges, and numerical results were compared. • The proposed method can accurately measure the stress–strain results. [ABSTRACT FROM AUTHOR]

Underwater explosions can cause significant damage to ship structures, and quickly assessing the extent of the damage is crucial for improving warship combat capability. This paper proposes the use of machine learning algorithms to rapidly assess the damage of stiffened plates subjected to underwater explosions. The algorithms use structural responses of the plates obtained by numerical simulations, which are benchmarked by experimental results, as a database. Fractures and plastic deformations are both taken into consideration. The support vector machine algorithm is used to determine the criterion for fractures or plastic deformations, while a back propagation neural network model and a support vector regression model are both used to predict the plastic deformation and fracture area of the plates. The support vector machine model accurately classified different cases of fractures or plastic deformation with a training accuracy of 99.4%. The back propagation neural network model has regression values of 0.99 for predicting fractures and 0.97 for predicting plastic deformation, both of which are higher than those predicted by the support vector regression model (0.96 for the prediction of fracture and 0.90 for the prediction of plastic deformation). Therefore, the back propagation neural network model provides a more accurate assessment of damage to stiffened plates subjected to underwater explosions and can be used for rapid assessment. • Machine learning algorithms are employed to predict the structural response. • The responses of stiffened plates subjected to underwater explosions are studied. • The criterion for fractures or plastic deformations is determine by the SVM model. • The BP neural network model and the SVR model are compared. • Rapid assessment of fractures or plastic deformation can be achieved. [ABSTRACT FROM AUTHOR]

[Display omitted] • Adjusting catalytic activity by a multicomponent high-entropy oxide system. • The AlNiCoFeCrMoV combination is highly active for OER. • Mixing highly ORR active CoNC with the AlNiCoFeCrMoV for the bifunctional electrocatalysis. • The performance of HEO/CoNC -based Zn-air battery is outstanding. Noble metal-free electrocatalysts for both oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are crucial to rechargeable metal-air batteries. Nanoporous high-entropy spinels have recently been studied as bifunctional ORR/OER electrocatalysts due to the adjustable surface electronic structure and catalytic activity. In this work, we adjust catalytic activities of HEO by varying the composition and proportion of the metal elements and find an optimal seven-component AlNiCoFeCrMoV prepared by a scalable two-step dealloying strategy. The seven-component HEO is highly active for OER while it exhibits a relatively poor ORR activity, much worse than the commercial Pt/C. Thus, the highly ORR active Co-N-C is rationally integrated with the seven-component HEO to construct a highly bifunctional HEO/Co-N-C nanocomposite electrocatalyst. Importantly, when used in a Zn-air battery, small charge/discharge voltage differences and ultralong lifespan (at 2, 5, 10 mA cm−2) can be achieved. This work highlights the rapid screening and rational design of highly bifunctional catalysts by function integration in multicomponent high-entropy system. [ABSTRACT FROM AUTHOR]

Background: PDZ-binding kinase/T-lymphokine-activated killer cell-derived protein kinase (PBK/TOPK) is a potential prognostic indicator for patients with breast cancer. The objective of the present study was to explore the relationship between PBK/TOPK expression and clinicopathological indicators as well as the survival of patients with breast cancer. Methods: Immunohistochemical staining was used to detect the expression of PBK/TOPK in 202 cases of breast cancer tissues. The relationship between PBK/TOPK and clinicopathological parameters was evaluated using Spearman's rank-order correlation. The difference in PBK/TOPK expression among different molecular types was analyzed with the chi-square test. Kaplan-Meier analysis was used to create a survival curve and the log rank test was used to analyze the overall survival (OS) and disease-free survival (DFS). Prognostic correlation was assessed using univariate and multivariate Cox regression analyses. Results: Among 202 breast cancer samples, PBK/TOPK was expressed ("+" and "++") in 182 samples (90.1%). In addition, the histological grade, TNM stages, lymph node metastasis, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2), and Ki-67 were positively associated with PBK/TOPK expression. With regard to the molecular type, the expression of PBK/TOPK is different. The expression level of PBK/TOPK was negatively correlated with both the OS and DFS of breast cancer patients. The difference in the above results is meaningful (P < 0.05). Conclusions: PBK/TOPK is overexpressed in breast cancer, and the expression is closely related to the clinicopathological characteristics of the disease. Breast cancer patients with high expression of PBK/TOPK have a poor prognosis. Therefore, healthcare providers can optimize breast cancer management using this indicator. [ABSTRACT FROM AUTHOR]

Members of the Fos family (c-Fos, FosB) dimerize with Jun proteins to form the activator protein 1 transcription factor complex and regulate diverse cellular processes including immunity. In the current study, a c-Fos homologue with six isoforms were identified from the oriental river prawn, Macrobrachium nipponense , and these six MnFos isoforms were produced by alternative splicing of first exon and/or exon skipping. The MnFos transcripts were detected in all tissues examined, with the highest level in the hepatopancreas. Moreover, these MnFos transcripts were significantly induced after immune stimulation by white spot syndrome virus (WSSV). Interestingly, silencing of MnFos in vivo by dsRNA interference led to a lower mortality of WSSV-infected prawns, as well as a great decrease in the expression of viral envelope protein VP28. Furthermore, silencing of MnFos induced the expression of multiple antimicrobial peptide genes in normal or WSSV-infected prawns, including crustins and anti-lipopolysaccharide factors. All these findings indicated that MnFos plays a negative role in prawn immunity against WSSV infection, possibly by its negative regulation on the expression of antimicrobial peptides. Such discovery is of great significance for further understanding of the interaction between WSSV and the immune system of prawns. • A novel c-Fos gene with 6 isoforms was obtained from Macrobrachium nipponense. • Knockdown of MnFos led to lower virion loads and higher survivability of WSSV-infected prawns. • MnFos suppressed the expression of several antimicrobial peptides. • MnFos plays a negative role in prawn immunity against WSSV infection. [ABSTRACT FROM AUTHOR]

Near-field underwater explosions can cause serious local damage to ship hulls. A protective shield sticking on the outer surface of a ship hull can effectively attenuate the shock loadings from these explosions. The present paper aims to experimentally and numerically analyze the anti-shock effects of a protective shield, which consists of rigid polyurethane foam (R–PUF) with certain thickness, and thin rubber skin, coated onto a circular plate in a near-field underwater explosion. The underwater explosion experiment was conducted in a man-made lake for both the bare and coated circular plates. The experimental results indicate that the protective shield can reduce the overall deformation of the circular plate by 41.1% on average under the experimental conditions. Then a Eulerian compressible fluid model is developed and used in combination with Abaqus/Explicit software in a numerical simulation to explore the anti-shock effects of protective shields. The overall deformation, velocity and displacement of the circular plate, and the pressure and velocity of the fluid are calculated. Comparisons between the experimental results and numerical simulations indicate that the developed compressible fluid model can effectively calculate the fluid response and the overall deformation of the circular plate effectively. The simulated results illustrate that the protective shield can effectively mitigate the peak value and the duration of pressure on the wetted surface in the initial stage. Then, two situations are considered to deeply investigate the shock mitigation effects of the protective shield. When the protective shield is kept unchanged while the detonation distance is changed (situation I), it was found that softer protective shields are needed for far detonation distance while stronger protective shields are needed for near detonation distance. Moreover, when the shock environment remains unchanged and the mechanical properties of the protective shield are changed (situation II), it was found that the protective shield should be as soft as possible to generate a sufficient energy absorption capacity. These research results are useful in protective shield design for ship hulls subjected to near-field underwater explosions. • The anti-shock effects of rigid polyurethane foam to near-field underwater explosion are analyzed. • A compressible fluid model is developed to solve the near-field underwater explosion problem. • The matching between the strength of the protective shield and the shock environment has significant influences on the anti-shock effects. [ABSTRACT FROM AUTHOR]

C-type lectins (CTLs) function as pattern recognition receptors (PRRs) by recognizing invading microorganisms, thereby triggering downstream immune events against infected pathogens. In this study, a novel CTL containing a low-density lipoprotein receptor class A (LDLa) domain was obtained from Litopenaeus vannamei , designed as LvLDLalec. Stimulation by the bacterial pathogen Vibrio anguillarum (V. anguillarum) resulted in remarkable up-regulation of LvLDLalec, as well as release of LvLDLalec into hemolymph. The rLvLDLalec protein possessed broad-spectrum bacterial binding and agglutinating activities, as well as hemocyte attachment ability. Importantly, LvLDLalec facilitated the bacterial clearance in shrimp hemolymph and protected shrimp from bacterial infection. Further studies revealed that LvLDLalec promoted hemocytes phagocytosis against V. anguillarum and lysosomes were involved in the process. Meanwhile, LvLDLalec participated in humoral immunity through activating and inducing nuclear translocation of Dorsal to regulate phagocytosis-related genes and antimicrobial peptides (AMPs) genes, thereby accelerated the removal of invading pathogens in vivo and improved the survival rate of L. vannamei. These results unveil that LvLDLalec serves as a PRR participate in cellular and humoral immunity exerting opsonin activity to play vital roles in the immune regulatory system of L. vannamei. • LvLDLalec is activated by V. anguillarum and promotes bacterial clearance. • LvLDLalec binds to the surface of hemocytes to promote phagocytosis and lysis of ingested V. anguillarum in phagosomes. • LvLDLalec regulates the expression of immune-related genes by promoting the nuclear translocation of Dorsal. • LvLDLalec protectes shrimp from infection from V. anguillarum to improve the survival rate of L. vannamei. [ABSTRACT FROM AUTHOR]

Abstract Background Long noncoding RNAs (lncRNAs) have been proven to be involved in carcinogenesis and to be released into peripheral blood. Our objective was to develop a circulating lncRNA as a novel biomarker to predict lung cancer. Methods We analyzed the lncRNA expression profile in lung cancer patients by lncRNA array and identified lncRNA XLOC_009167 as a circulating biomarker using qRT-PCR in whole blood of lung cancer patients. The diagnostic value of was analyzed by area under curve (AUC) and the receiver operating characteristic (ROC) test. Results LncRNA XLOC_009167 was screened as a candidate biomarker for lung cancer and was up-regulated in both lung cancer tissues and cell lines. Notably, lncRNA XLOC_009167 in whole blood of lung cancer patients was highly expressed as compared with that in healthy controls or in patients with pneumonia. The values of AUC of lung cancer vs. healthy controls, and that of lung cancer vs. pneumonia were 0.7398 (95%CI = 0.6493 to 0.8303) and 0.7005 (95%CI = 0.5771 to 0.8240), respectively. Intriguingly, the ROC showed lncRNA XLOC_009167 was a better diagnostic potential compared to the traditional biomarkers (CYFR21-1, NSE and CA72-4), and the circulating lncRNA XLOC_009167 was found to be stable in whole blood under different conditions. Conclusions LncRNA XLOC_009167 could serve as a novel diagnostic biomarker to distinguish lung cancer from benign lung disease and healthy controls. Highlights • lncRNA XLOC_009167 was screened and identified as a candidate biomarker for lung cancer. • lncRNA XLOC_009167 was highly expressed in lung cancer tissues, cell lines and whole blood. • lncRNA XLOC_009167 expression was positively correlated with TNM stages and was very stable in whole blood under different conditions. • circulating lncRNA XLOC_009167 could be used to distinguish lung cancer from healthy controls or in patients with pneumonia. [ABSTRACT FROM AUTHOR]

Irisin, a recently identified hormone secreted by skeletal muscle in response to exercise, exhibits anabolic effects on the skeleton primarily through the stimulation of bone formation. However, the mechanism underlying the irisin-stimulated anabolic response remains largely unknown. To uncover the underlying mechanism, we biosynthesized recombinant irisin (r-irisin) using an Escherichia coli expression system and used it to treat several osteoblast cell types. Our synthesized r-irisin could promote proliferation and differentiation of osteoblasts as evidenced by enhanced expression of osteoblast-specific transcriptional factors, including Runt-related transcription factor-2 ( Runx2 ), Oster ( Osx ), as well as early osteoblastic differentiation markers such as alkaline phosphatase ( Alp ) and collagen type I alpha 1 ( Col1a1 ). Furthermore, we showed that the promotion of r-irisin on the proliferation and differentiation of osteoblast lineage cells are preferentially through aerobic glycolysis, as indicated by the enhanced abundance of representative enzymes such as lactate dehydrogenase A (LDHA) and pyruvate dehydrogenase kinase 1 (PDK1), together with increased lactate levels. Suppression of r-irisin-mediated aerobic glycolysis with Dichloroacetate blunted its anabolic effects. The favorite of the aerobic glycolysis after r-irisin treatment was then confirmed in primary calvarial cells by metabolic analysis using gas chromatography–mass spectrometry. Thus, our results suggest that the anabolic actions of r-irisin on the regulation of osteoblast lineage cells are preferentially through aerobic glycolysis, which may help to develop new irisin-based bone anabolic agents. [ABSTRACT FROM AUTHOR]

Sarcomatoid carcinoma is a biphasic neoplasm composed of highly complex, intimately admixed malignant epithelial and mesenchymal elements. We herein report a rare case of cutaneous metastasis of pulmonary sarcomatoid carcinoma that contains liposarcomatous, rhabdosarcomatous and chondrosarcomatous heterologous differentiation, and review relevant literatures to lead to a better understanding of this rare but highly aggressive tumor. [ABSTRACT FROM AUTHOR]

HIV-1 integrase (HIV-1 IN) is an enzyme produced by the HIV-1 virus that integrates genetic material of the virus into the DNA of infected human cells. HIV-1 IN acts as a key component of the Retroviral Pre-Integration Complex (PIC). Protein dynamics could play an important role during the catalysis of HIV-1 IN; however, this process has not yet been fully elucidated. X-ray free electron laser (XFEL) together with nuclear magnetic resonance (NMR) could provide information regarding the dynamics during this catalysis reaction. Here, we report the non-cryogenic crystal structure of HIV-1 IN catalytic core domain at 2.5 Å using microcrystals in XFELs. Compared to the cryogenic structure at 2.1 Å using conventional synchrotron crystallography, there was a good agreement between the two structures, except for a catalytic triad formed by Asp64, Asp116, and Glu152 (DDE) and the lens epithelium-derived growth factor binding sites. The helix III region of the 140–153 residues near the active site and the DDE triad show a higher dynamic profile in the non-cryogenic structure, which is comparable to dynamics data obtained from NMR spectroscopy in solution state. [ABSTRACT FROM AUTHOR]

CXCR1, a member in G-protein coupled receptor (GPCR) family, binds to chemokine interleukin-8 (IL-8) specifically and transduces signals to mediate immune and inflammatory responses. Despite the importance of CXCR1, high-resolution structure determination is hindered by the challenges in crystallization. It has been shown that properly designed mutants with enhanced thermostability, together with fusion partner proteins, can be useful to form crystals for GPCR proteins. In this study, in silico protein design was carried out by using homology modeling and molecular dynamics simulations. To validate the computational modeling results, the thermostability of several mutants and the wild type were measured experimentally. Both computational results and experimental data suggest that the mutant L126W has a significant improvement in the thermostability. This study demonstrated that in silico design can guide protein engineering and potentially facilitate protein crystallography research. [ABSTRACT FROM AUTHOR]