Small Molecule Inhibitors of White Spot Syndrome Virus: Promise in Shrimp Seedling Culture

Rapid production of prawn (Litopenaeus vannamei) under artificial pressure can result in a series of obvious challenges and is vulnerable to serious losses related to aquatic environmental issues and the unrestrained outbreak of white spot syndrome (WSS). However, to date, there are no therapeutic strategies to contain the spread of the virus. Here, we synthesized 27 coumarin deriv-atives and evaluated their anti-white spot syndrome virus (WSSV) activity in L. vannamei larvae. We demonstrated that electron-withdrawing and electron-giving substituent groups play an im-portant role in reducing toxicity and WSSV replication, respectively. Two coumarin C2 (2-amino-5-oxo-4-(p-tolyl)-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile) and C7 (2-amino-4-(4-chlorophenyl)-5-oxo-4H,5H-pyrano[3,2-c]chromene-3-carbonitrile) were regarded as the most promising anti-WSSV compounds with maximum antiviral response <5% and median effective concentration <10 mg/L. The mortality of WSSV-infected larvae decreased by more than 60% after exposure to C2 and C7. With continuous immersion of C2 and C7 exchange, the mortality further decreased to 40% at 120 h.Additionally, C2 and C7 are the relatively stable in aquacultural water, making these agents

A Phase-Change Gel based Pressure Sensor with Tunable Sensitivity for Artificial Tactile Feedback System

The somatosensory system in the skin plays an essential role for human hands to perform adaptive interactions with external environments, such as tactile sensing and handling objects. For artificial pressure...

The possible hierarchical scales of observed clumps in high-redshift disc galaxies

ABSTRACTGiant clumps on ∼kpc scales and with masses of $10^8\rm {-}10^9 \, \mathrm{M_{\odot }}$ are ubiquitous in observed high-redshift disc galaxies. Recent simulations and observations with high spatial resolution indicate the existence of substructure within these clumps. We perform high-resolution simulations of a massive galaxy to study the substructure formation within the framework of gravitational disc instability. We focus on an isolated and pure gas disc with an isothermal equation of state with T = 104 K that allows capturing the effects of self-gravity and hydrodynamics robustly. The main mass of the galaxy resides in rotationally supported clumps which grow by merging to a maximum clump mass of $10^8 \, \mathrm{M_{\odot }}$ with diameter ∼120 pc for the dense gas. They group to clump clusters (CCs) within relatively short times ($\ll 50 \, \mathrm{Myr}$), which are present over the whole simulation time. We identify several mass and size scales on which the clusters appear as single objects at the corresponding observational resolution between ${\sim } 10^8 \,\rm{and}\, 10^9 \, \mathrm{M_{\odot }}$. Most of the clusters emerge as dense groups and for larger beams they are more likely to be open structures represented by a single object. In the high-resolution runs higher densities can be reached, and the initial structures can collapse further and fragment to many clumps smaller than the initial Toomre length. In our low-resolution runs, the clumps directly form on larger scales 0.3–1 kpc with $10^8\rm {-}10^9 \, \mathrm{M_{\odot }}$. Here, the artificial pressure floor which is typically used to prevent spurious fragmentation strongly influences the initial formation of clumps and their properties at very low densities.

Detoxification of Heterophase Wastes Using Controlled Gas-Contact Technologies

The methods of natural and forced supply and removal of gases in arrays of heterophase wastes of various nature used in controlled gas-contact detoxification technologies are considered. The classification of the main parameters of the waste is divided into groups – mechanical, filtration, temperature, chemical and biological. Based on the analysis of the parameters, generalized criteria for determining the scope of application of gas-contact technologies are proposed. The implementation of gas flow control technology is described, an example of which are complexes biothermal treatment of oil-contaminated soils. The main element of this complex is the combined aeration system, which is necessary to increase the rate of biochemical decomposition of hardly decomposable hydrocarbons in oil waste. The results of the experiment conducted in the framework of the calculation and design of the aeration system due to the insufficiency of the initial data are presented. Shown the need to create a general theoretical model of controlled gas flows in porous, water-saturated, hard plastic media, both in natural conditions and under the action of an artificial pressure drop.

Calculation of the Parameters for the Process of Gas Injection into a Reservoir Saturated with Methane and Its Hydrate

Deposits of gas hydrates are considered by several researchers as a promising source of hydrocarbon raw materials. For their industrial use, it is necessary to solve a number of complex problems, including the creation and justification of methods for developing gas hydrate deposits.<br> This paper describes the various methane extraction methods from gas hydrate formations: temperature increase in the formation; artificial pressure reduction at the boundary of the hydrate-containing deposit (depressive effect on porous medium); injection inhibitors and a method of substituting CO₂-CH₄ in methane hydrate. In the plane-parallel approximation, the formulation of the problem of pumping a warm (with a temperature above the initial temperature of the formation) gas into a porous layer initially saturated with methane and its hydrate is presented. A mathematical model of non-isothermal gas filtration is proposed with allowance for the phase transition. A numerical study of how the volumetric flow of methane from the hydrate containing reservoir depends on the parameters of the injected coolant, the permeability, and initial hydration of the reservoir is carried out.

Smoothing Analysis of Distributive Red-Black Jacobi Relaxation for Solving 2D Stokes Flow by Multigrid Method

Smoothing analysis process of distributive red-black Jacobi relaxation in multigrid method for solving 2D Stokes flow is mainly investigated on the nonstaggered grid by using local Fourier analysis (LFA). For multigrid relaxation, the nonstaggered discretizing scheme of Stokes flow is generally stabilized by adding an artificial pressure term. Therefore, an important problem is how to determine the zone of parameter in adding artificial pressure term in order to make stabilization of the algorithm for multigrid relaxation. To end that, a distributive red-black Jacobi relaxation technique for the 2D Stokes flow is established. According to the 2h-harmonics invariant subspaces in LFA, the Fourier representation of the distributive red-black Jacobi relaxation for discretizing Stokes flow is given by the form of square matrix, whose eigenvalues are meanwhile analytically computed. Based on optimal one-stage relaxation, a mathematical relation of the parameter in artificial pressure term between the optimal relaxation parameter and related smoothing factor is well yielded. The analysis results show that the numerical schemes for solving 2D Stokes flow by multigrid method on the distributive red-black Jacobi relaxation have a specified convergence parameter zone of the added artificial pressure term.

A TV-Based Iterative Regularization Method for the Solutions of Thermal Convection Problems

Linear/nonlinear and Stokes based-stabilizations for the filter equations for damping out primitive variable (PV) solutions corrupted by uniformly distributed random noises are numerically studied through the natural convection (NC) as well as the mixed convection (MC) environment. The most recognizable filter-scheme is based on a combination of the negative Laplace equation multiplied with the selection of the spatial scale and a linear function in order to preserve the uniqueness of the filtered solution. A more complicated filter-scheme, based on a Stokes problem which couples a filtered velocity and a filtered (artificial) pressure (or Lagrange multiplier) in order to enforce the incompressibility constraint, is also studied. Linear and Stokes based-filters via nested iterative (NI) filters and the consistent splitting scheme (CSS) are proposed for the NC/MC problems. Inspired by the total-variation (TV) model of image diffusion, well preserved feature flow patterns from the corrupted NC/MC environment are obtained by TV-Stokes based-filters together with the CSS. Our experimental results show that our proposed algorithms are effective and efficient in eliminating the unwanted spurious oscillations and preserving the accuracy of thermal convective fluid flows.