Boussinesq Systems of Bona-Smith Type on Plane Domains: Theory and Numerical Analysis

We consider a class of Boussinesq systems of Bona-Smith type in two space dimensions approximating surface wave flows modelled by the three-dimensional Euler equations. We show that various initial-boundary-value problems for these systems, posed on a bounded plane domain are well posed locally in time. In the case of reflective boundary conditions, the systems are discretized by a modified Galerkin method which is proved to converge in L ² at an optimal rate. Numerical experiments are presented with the aim of simulating two-dimensional surface waves in realistic (plane) domains with a variety of initial and boundary conditions, and comparing numerical solutions of Bona-Smith systems with analogous solutions of the BBM-BBM system.     

Inhibition of vascular endothelial growth factor prevents retinal ischemia-associated iris neovascularization in a nonhuman primate

The antiestrogenic drug tamoxifen induces liver tumors in rats by a genotoxic mechanism. The key step has been proposed to be the formation of a reactive carbocation from the metabolite alpha-hydroxytamoxifen. This compound reacts with DNA in vitro to a small extent (1 in 10(5) DNA bases), giving products identical to those found in rat liver cells treated with tamoxifen. Now we have prepared the more reactive alpha-acetoxytamoxifen, which reacts with DNA in vitro to a much greater extent (1 in 50 bases). The products of this reaction were subjected to 32P postlabeling and shown by both TLC and reverse-phase liquid chromatography to be identical to those isolated from DNA treated with alpha-hydroxytamoxifen and to those found in the liver DNA of rat hepatocytes treated with tamoxifen or of the livers of rats treated with tamoxifen. The major product was also isolated as the nucleoside and characterized by UV, mass, and proton magnetic resonance spectroscopy. It is an adduct of tamoxifen and deoxyguanosine in which the alpha position of tamoxifen is linked covalently to the exocyclic amino group of deoxyguanosine.     

未来变速箱面临的挑战

现代传动系统必需满足足的燃油经济性，较少的有害气体排放和日益增大的舒适性要求，本文提出了可有助于达到这些目的方法，它可实现最佳的高效的自动变速箱和最佳的传动系操纵。     

Technical assessment of LNG based polygeneration systems for non-interconnected island cases using SOFC

Liquefied Natural Gas (LNG) is one of the most promising fuels with high calorific value and low specific GHG emissions that offers several advantages as an energy carrier for power generation. In this paper, a novel polygeneration concept based on LNG fired plant for power, cooling and drinking water production in island systems is presented. Two Solid Oxide Fuel Cell based energy systems (one simple SOFC and another hybrid concept of SOFC combined with GT) are modelled in Aspen Plus and compared with two conventional combustion based technologies (internal combustion engine and Gas Turbine Combined Cycle) in terms of overall efficiency. Furthermore, a Low Temperature Multi-Effect Distillation (LT-MED) plant was modelled and coupled with the energy systems to evaluate the waste heat recovery potential for desalinated water production. Moreover, three concepts for cold recovery from the LNG regasification plant were presented and modelled. Process simulations results revealed that the hybrid SOFC-GT plant is the best solution in terms of energy efficiency and the heat recovery of the exhaust gas in a LT-MED unit is a promising option for drinking water production with almost no energy cost. Last, from exergetic point of view, the cryogenic energy storage (CES) via the production of liquid air was evaluated as the best option for waste cold utilization during LNG regasification.     

Second-order boundary-layer theory of laminar jet flows

Summary Laminar jet flows are investigated by asymptotic expansions in terms of large Reynolds numbers and large distances from an orifice in a wall. For two-dimensional flow, previously known results are modified and extended. For axisymmetric flow, the expansion breaks down as the distance from the orifice tends to infinity. An error analysis indicates that the range of applicability of classical boundary layer theory is severely limited.With 4 Figures     

Calprotectin and Imbalances between Acute-Phase Mediators Are Associated with Critical Illness in COVID-19

The trajectory from moderate and severe COVID-19 into acute respiratory distress syndrome (ARDS) necessitating mechanical ventilation (MV) is a field of active research. We determined serum levels within 24 h of presentation of 20 different sets of mediators (calprotectin, pro- and anti-inflammatory cytokines, interferons) of patients with COVID-19 at different stages of severity (asymptomatic, moderate, severe and ARDS/MV). The primary endpoint was to define associations with critical illness, and the secondary endpoint was to identify the pathways associated with mortality. Results were validated in serial measurements of mediators among participants of the SAVE-MORE trial. Levels of the proinflammatory interleukin (IL)-8, IL-18, matrix metalloproteinase-9, platelet-derived growth factor (PDGF)-B and calprotectin (S100A8/A9) were significantly higher in patients with ARDS and MV. Levels of the anti-inflammatory IL-1ra and IL-33r were also increased; IL-38 was increased only in asymptomatic patients but significantly decreased in the more severe cases. Multivariate ordinal regression showed that pathways of IL-6, IL-33 and calprotectin were associated with significant probability for worse outcome. Calprotectin was serially increased from baseline among patients who progressed to ARDS and MV. Further research is needed to decipher the significance of these findings compared to other acute-phase reactants, such as C-reactive protein (CRP) or ferritin, for the prognosis and development of effective treatments.     

Asymptotic nonlinear and dispersive pulsatile flow in elastic vessels with cylindrical symmetry

The asymptotic derivation of a new family of one-dimensional, weakly nonlinear and weakly dispersive equations that model the flow of an ideal fluid in an elastic vessel is presented. Dissipative effects due to the viscous nature of the fluid are also taken into account. The new models validate by asymptotic reasoning other non-dispersive systems of equations that are commonly used, and improve other nonlinear and dispersive mathematical models derived to describe the blood flow in elastic vessels. The new systems are studied analytically in terms of their basic characteristic properties such as the linear dispersion characteristics, symmetries, conservation laws and solitary waves. Unidirectional model equations are also derived and analysed in the case of vessels of constant radius. The capacity of the models to be used in practical problems is being demonstrated by employing a particular system with favourable properties to study the blood flow in a large artery. Two different cases are considered: A vessel with constant radius and a tapered vessel. Significant changes in the flow can be observed in the case of the tapered vessel.     

On the Galerkin/Finite-Element Method for the Serre Equations

A highly accurate numerical scheme is presented for the Serre system of partial differential equations, which models the propagation of dispersive shallow water waves in the fully-nonlinear regime. The fully-discrete scheme utilizes the Galerkin / finite-element method based on smooth periodic splines in space, and an explicit fourth-order Runge–Kutta method in time. Computations compared with exact solitary and cnoidal wave solutions show that the scheme achieves the optimal orders of accuracy in space and time. These computations also show that the stability of this scheme does not impose very restrictive conditions on the temporal stepsize. In addition, solitary, cnoidal, and dispersive shock waves are studied in detail using this numerical scheme for the Serre system and compared with the ‘classical’ Boussinesq system for small-amplitude shallow water waves. The results show that the interaction of solitary waves in the Serre system is more inelastic. The efficacy of the numerical scheme for modeling dispersive shocks is shown by comparison with asymptotic results. These results have application to the modeling of shallow water waves of intermediate or large amplitude.