Vibrio fluvialis is an emerging foodborne pathogen that produces VFH (Vibrio fluvialis hemolysin) and δVFH (delta-Vibrio fluvialis hemolysin). The function of δVFH is unclear. Currently, no ...pathogenic V. fluvialis from deep sea has been reported. In this work, a deep-sea V. fluvialis isolate (V13) was examined for pathogenicity. V13 was most closely related to V. fluvialis ATCC 33809, a human isolate, but possessed 262 unique genes. V13 caused lethal infection in fish and induced pyroptosis involving activation of the NLRP3 inflammasome, caspase 1 (Casp1), and gasdermin D (GSDMD). V13 defective in VFH or VFH plus δVFH exhibited significantly weakened cytotoxicity. Recombinant δVFH induced NLRP3-Casp1-GSDMD-mediated pyroptosis in a manner that depended on K+ efflux and intracellular Ca2+ accumulation. δVFH bound several plasma membrane lipids, and these bindings were crucial for δVFH cytotoxicity. Together these results provided new insights into the function of δVFH and the virulence mechanism of V. fluvialis.
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•The deep-sea isolate V13 caused lethal infection in fish and induced pyroptosis•The δVFH of V13 induced pyroptosis in a NLRP3-, K+-, and Ca2+- dependent manner•δVFH interactions with plasma membrane lipids were critical for pyroptosis induction
structures
Designing and building structures that will withstand the unique challenges that exist in subsea operations is no easy task. As deepwater wells are drilled to greater depths, engineers are confronted ...with a new set of problems such as water depth, weather conditions, ocean currents, equipment reliability, and well accessibility, to name just a few. A definitive reference for engineers designing, analyzing and instilling offshore structures, this book provides an expert guide to the key processes, technologies and equipment that comprise contemporary offshore structures. Written in a clear and easy to understand language, the book is based on the authors 30 years of experience in the design, analysis and instillation of offshore structures. This book answers the above mentioned crucial questions as well as covers the entire spectrum of subjects in the discipline, from route selection and planning to design, construction, installation, materials and corrosion, inspection, welding, repair, risk assessment, and applicable design solutions. It yields a roadmap not only for the subsea engineer but also the project managers, estimators and regulatory personnel hoping to gain an appreciation of the overall issues and directed approaches to subsea engineering design solutions.
The dynamic through-soil interaction between underground station and nearby pile supported structure on viscous–elastic soil layer, under vertically incident S wave, is numerically studied. To this ...end, a commercial software for finite element analysis, ANSYS, has been further developed and enhanced for calculation in frequency domain, in which damping of hysteretic type can be considered for both the soil and the structures, so that structure–soil–structure interaction (SSSI) can be investigated making use of a direct methodology. The influence of arrangement of structures, shaking direction of seismic wave, distances between structures, shear wave velocity, damping of soil, burial depth and number of spans of underground structure on SSSI, in terms of horizontal acceleration magnification factor of ground structure, is addressed. For ground structure, different lengths of pile, stiffnesses, styles, and numbers of storeys and structures are considered. Maximum acceleration responses are also presented for 12 seismic inputs. Arrangement and shaking direction are two of the most important factors. The system response can be either amplified or attenuated according to the distance between adjacent buildings, which has been related to dynamic properties of the overall system. Those neighboring low-slung buildings around underground structure are heavily affected.
•We reviewed studies about interaction of ground structure and underground structure.•ANSYS has been further developed and enhanced for damping of hysteretic type.•We discussed the influence of subway station on the neighboring ground structure.•We examined the influence parameter of the dynamic interaction.
The question of stability against diffusional mixing at the prototypical LaAlO3/SrTiO3(001) interface is explored using a multi-faceted experimental and theoretical approach. We combine analytical ...methods with a range of sensitivities to elemental concentrations and spatial separations to investigate interfaces grown using onaxis pulsed laser deposition. We also employ computational modeling based on the density function theory as well as classical force fields to explore the energetic stability of a wide variety of intermixed atomic configurations relative to the idealized, atomically abrupt model. Statistical analysis of the calculated energies for the various configurations is used to elucidate the relative thermodynamic stability of intermixed and abrupt configurations. We find that on both experimental and theoretical fronts, the tendency toward intermixing is very strong. We have also measured and calculated key electronic properties such as potential energy gradients and valence band discontinuity at the interface. We find no measurable electric field in either the LaAlO3 or SrTiO3, and that the valence band offset is near zero, partitioning the band discontinuity almost entirely to the conduction band edge. Significantly, we find it is not possible to account for these electronic properties theoretically without including extensive intermixing in our physical model of the interface. The atomic configurations which give the greatest electrostatic stability are those that eliminate the interface dipole by intermixing, calling into question the conventional explanation for conductivity at this interface – electronic reconstruction. Rather, evidence is presented for La indiffusion and doping of the SrTiO3 below the interface as being the cause of the observed conductivity.
The influence of soil on the dynamic response of soil‐structure systems is usually studied on a stand‐alone (SA) structure, even though closely adjacent structures form the vast majority of the ...population, especially in large cities. When structures are closely adjacent to each other, the wavefield in the soil, generated by the vibration of the footings, produces a complex interaction between them. Scant attention, especially by physical experiments, has been paid to this interaction. This work addresses the seismic response of a single degree‐of‐freedom structure (structure of focus) considering the influence of one and two closely adjacent neighbours. Experiments were performed using a large laminar box filled with sand sitting on a shake table. Results from utilising four recorded ground motions from the 2010–2011 Canterbury earthquake sequence are analysed. The effect of adjacent structures on the acceleration and displacement of the top mass of each structure, as well as the uplift of the footings, are discussed. Changes in the fundamental frequency due to the presence of neighbouring structures are identified. The use of the SA system, without consideration of closely adjacent structures, may result in a significant error in the estimation of the response of the structure of focus. In general, acceleration, lateral displacement and uplift reduced in comparison with that of the corresponding SA case. A footing settlement mechanism, resulting from uplift of the system that reflects the influence of adjacent structures, is also revealed.
We demonstrate the continuous tuning of the electronic structure of atomically thin MoS2 on flexible substrates by applying a uniaxial tensile strain. A redshift at a rate of ∼70 meV per percent ...applied strain for direct gap transitions, and at a rate 1.6 times larger for indirect gap transitions, has been determined by absorption and photoluminescence spectroscopy. Our result, in excellent agreement with first principles calculations, demonstrates the potential of two-dimensional crystals for applications in flexible electronics and optoelectronics.
The electronic properties of graphene, a two-dimensional crystal of carbon atoms, are exceptionally novel. For instance, the low-energy quasiparticles in graphene behave as massless chiral Dirac ...fermions which has led to the experimental observation of many interesting effects similar to those predicted in the relativistic regime. Graphene also has immense potential to be a key ingredient of new devices, such as single molecule gas sensors, ballistic transistors and spintronic devices. Bilayer graphene, which consists of two stacked monolayers and where the quasiparticles are massive chiral fermions, has a quadratic low-energy band structure which generates very different scattering properties from those of the monolayer. It also presents the unique property that a tunable band gap can be opened and controlled easily by a top gate. These properties have made bilayer graphene a subject of intense interest. In this review, we provide an in-depth description of the physics of monolayer and bilayer graphene from a theorist's perspective. We discuss the physical properties of graphene in an external magnetic field, reflecting the chiral nature of the quasiparticles near the Dirac point with a Landau level at zero energy. We address the unique integer quantum Hall effects, the role of electron correlations, and the recent observation of the fractional quantum Hall effect in the monolayer graphene. The quantum Hall effect in bilayer graphene is fundamentally different from that of a monolayer, reflecting the unique band structure of this system. The theory of transport in the absence of an external magnetic field is discussed in detail, along with the role of disorder studied in various theoretical models. Recent experminental observations of a metal-insulator transition in hydrogenated graphene is discussed in terms of a self-consistent theory and compared with related numerical simulations. We highlight the differences and similarities between monolayer and bilayer graphene, and focus on thermodynamic properties such as the compressibility, the plasmon spectra, the weak localization correction, quantum Hall effect and optical properties. Confinement of electrons in graphene is non-trivial due to Klein tunnelling. We review various theoretical and experimental studies of quantum confined structures made from graphene. The band structure of graphene nanoribbons and the role of the sublattice symmetry, edge geometry and the size of the nanoribbon on the electronic and magnetic properties are very active areas of research, and a detailed review of these topics is presented. Also, the effects of substrate interactions, adsorbed atoms, lattice defects and doping on the band structure of finite-sized graphene systems are discussed. We also include a brief description of graphane-gapped material obtained from graphene by attaching hydrogen atoms to each carbon atom in the lattice.
The plasma membrane protein Orai forms the pore of the calcium release—activated calcium (CRAC) channel and generates sustained cytosolic calcium signals when triggered by depletion of calcium from ...the endoplasmic reticulum. The crystal structure of Orai from Drosophila melanogaster, determined at 3.35 angstrom resolution, reveals that the calcium channel is composed of a hexameric assembly of Orai subunits arranged around a central ion pore. The pore traverses the membrane and extends into the cytosol. A ring of glutamate residues on its extracellular side forms the selectivity filter. A basic region near the intracellular side can bind anions that may stabilize the closed state. The architecture of the channel differs markedly from other ion channels and gives insight into the principles of selective calcium permeation and gating.
•Novel bio-inspired hierarchical multi-cell square (BHMS) tubes were proposed.•The SEA of the BHMS tube was improved compared to that of the conventional tubes.•The deformation mode for the BHMS ...tubes was classified.•A theoretical model for the mean crushing force of the BHMS tubes was developed.•An imperfection analysis was carried out using the linear and post-buckling methods.
In this study, the dynamic crushing behaviour and energy absorption characteristics of a novel bio-inspired hierarchical multi-cell square (BHMS) tubes were numerically and theoretically investigated. The proposed structures were constructed mimicking the gradient distribution of cell sizes in the biological structures such as bone and bamboo. A series of compression tests were numerically carried out for the BHMS structures with different hierarchical orders and mass of the structures. The results indicated that the specific energy absorption (SEA) of the 3rd order BHMS tube is 178.4% higher than that of the 0th order BHMS tube. Comparing with the conventional square and multi-cell square tube, the maximum increment of the SEA of the BHMS tube reaches up to 173.7% and 128.1%, respectively. Moreover, the undulation of the load-carrying capacity (ULC) used for evaluating the stability of the BHMS tubes under dynamic crushing was also considered. The ULC of the 3rd order BHMS tube reduces up to 88.8% and 85.7% compared to the square and multi-cell tubes. It indicates that the BHMS tube has a larger potential to improve energy absorption than the square tube and conventional multi-cell square tube. Finally, a theoretical study for the mean crushing force (MCF) was developed for the proposed tubes, which was in good agreement with the numerical results. This study provides an effective guide for the design of a multi-cell energy absorber with excellent energy absorption efficiency.
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We report electronic transport measurements of devices based on monolayers and bilayers of the transition-metal dichalcogenide MoS2. Through a combination of in situ vacuum annealing and ...electrostatic gating we obtained ohmic contact to the MoS2 down to 4 K at high carrier densities. At lower carrier densities, low-temperature four probe transport measurements show a metal–insulator transition in both monolayer and bilayer samples. In the metallic regime, the high-temperature behavior of the mobility showed strong temperature dependence consistent with phonon-dominated transport. At low temperature, intrinsic field-effect mobilities approaching 1000 cm2/(V·s) were observed for both monolayer and bilayer devices. Mobilities extracted from Hall effect measurements were several times lower and showed a strong dependence on density, likely caused by screening of charged impurity scattering at higher densities.
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