Pyrrolizidine Alkaloids-Free Extract from the Cell Culture of Lithospermum officinale with High Antioxidant Capacity

The benefits of Lithospermum officinale has encouraged people to continue using its extract (CAS 90063-58-4) in both medicinal and cosmetic industries despite the fact that chemical analysis confirms the presence of pyrrolizidine alkaloids (PAs) in the extract. While the cultivation of L. officinale takes, at least, 2 years to produce usable crops, its callus culture proliferated 8.3 times with 4.9-fold biomass in less than 30 days under the applied conditions in this study. Under the applied conditions, the cell extract contained no toxic PAs while phenylpropanoid pathway was active toward phenolic acids formation not toward naphthoquinone derivatives. Rosmarinic acid was produced as the main constituent. Total phenolic content and antioxidant capacity of the proliferated cell extracts were similar to those of the extracts of the natural plant tissues, in particular from the root. These results support the idea that the extract of L. officinale cells can be a reliable substitute for the extract of the natural plant tissues.

     

General initial value problem for the nonlinear shallow water equations: Runup of long waves on sloping beaches and bays

We formulate a new approach to solving the initial value problem of the shallow water-wave equations utilizing the famous Carrier–Greenspan transformation (Carrier and Greenspan (1957) [9]). We use a Taylor series approximation to deal with the difficulty associated with the initial conditions given on a curve in the transformed space. This extends earlier solutions to waves with near shore initial conditions, large initial velocities, and in more complex U-shaped bathymetries; and allows verification of tsunami wave inundation models in a more realistic 2-D setting.     

Electrosynthesis and characterization of poly aniline/garnet nanoparticles for high-performance electrochemical capacitors

In this work, supercapacitive performance of polyaniline/yttrium aluminum garnet (YAG: Y₃Al₅O₁₂) nanoparticles (PANI/YAGNPs) was studied. YAG nanoparticles were synthesized by pulse electro-deposition method and after that, PANI/YAGNPs electrodeposited on the surface of glassy carbon electrodes through cyclic voltammetry. Morphological studies show that YAG nanoparticles were distributed in the structure of PANI filaments uniformly. XRD and FTIR were used to perform a structural study of materials. Different electrochemical techniques such as cyclic voltammetry (CV), galvano static charge discharge (CD), and impedance spectroscopy (EIS) were used to evaluate the applicability of using PANI/YAGNPs as an active material for supercapacitors. The specific capacitance (SC) of PANI and PANI YAG NPs electrodes calculated using CV technique are 240 and 440 F/g, respectively. Increasing the conductivity and stability of composite electrodes during continuous CD cycles compared to PANI ones are some features of using YAG NPs in the structure of polymer electrodes. Stability of composite electrodes remains about 98% through 1000 continuous cycles whereas the polymeric electrode loses about 91% of its capacitance during this time range.     

Modelling the yield point phenomena during deformation at elevated temperatures: case study on Inconel 600

The discontinuous yield behaviour (DYB) of Inconel 600 was studied during hot compression tests at temperatures in range of 850–1150°C and strain rates of 0.001–1?s^?1. The yield point phenomena were observed in the temperature range of 850–1000°C and strain rates of 0.001–0.1 s^?1. The DYB was modelled by considering the evolution of dislocation density at the early stages of yielding. The opposite effects of dislocation multiplication, dislocation interaction (work hardening) and dynamic recovery (DRV) were considered. It was shown that the dislocation multiplication and DRV result in flow softening, while the dislocation interaction leads to work hardening. The model was established in a way to consider the effects of various microstructural evolutions on the σ(ε) function. The discontinuous flow curves were fitted by the developed model with acceptable precision. The variations of material constants with temperature and strain rate were found physically meaningful. The dislocation multiplication parameter was determined at various temperatures and strain rates. It was concluded that the rate of dislocation multiplication increases as temperature rises or strain rate declines. Accelerated dislocation multiplication leads to less drop in yield stress between the upper and lower yield points.     

Synthesis and morphological study on the nanocomposite hydrophilic coatings

Hydrophilic nanocomposite coatings based on epoxy silane were prepared with incorporation of aminoethylaminopropyltrimethoxysilane by a sol-gel process. It was found out that the hydrophilicity is affected remarkably in the presence of non-ionic surfactant. Moreover, scanning electron microscopy (SEM) and Si mapping micrographs indicated that there is a uniform distribution of silica particles in the coatings with either lower or higher amounts of aminoethylaminopropyltrimethoxysilane. Furthermore, the effect of aminoethylaminopropyltrimethoxysilane on transparency of the coatings was evaluated in the absence and presence of surfactant. Fourier transform infrared (FT-IR) and attenuated total reflectance infrared spectroscopy (ATR-IR) techniques were employed to study the different steps of nanocomposite hybrid coating synthesis. Surface topography of the coatings investigated by atomic force microscopy (AFM) technique and transmission electron microscopy (TEM) indicated that the silica particles’ dimensions are at the nano-scale.     

A heuristic method to simulate the pulse propagation in nonlinear fiber bragg gratings

In this paper we simulated the pulse propagation and the switching effects in nonlinear fiber Bragg gratings using a combination of Fourier series analysis technique and Jacobi iterative method. The effects of nonlinearity and dispersion on the pulse propagation have been studied extensively. An all optical self switch was designed by this simulation. This switch is operated based on the input power.     

On the analytical solution of viscous fluid flow past a flat plate

In this Letter, we propose a simple approach using HAM to obtain accurate totally analytical solution of viscous fluid flow over a flat plate. First, we show that the solution obtained using HPM is not a reliable one; moreover, we show that HPM is only a special case of HAM and its basic assumptions are restrictive rather than useful. We set ?=−1 for the case of comparison of our results to those obtained using HPM. Afterwards, we introduce an extra auxiliary parameter and a straightforward approach to find best values of this auxiliary parameter which plays a prominent role in the frame of our solution and makes it more convergent in comparison to previous works.     

Passive and temporally continuous optical spectral analyzer of RF signals via wavelength coding

A novel approach realizing an optical spectrum analyzer for photonic detection of an unknown RF carrier signals is presented. The described module may be part of an electronic warfare system in which detection of a narrow band RF signal is required. Moreover, The RF signal is characterized by an unknown time varying carrier frequency embedded in wide band noise. The system uses a passive, fiber based photonic configuration. It allows the spectrum mapping of an incoming electronic RF signal modulated on an optical carrier. The spectral analyzer configuration uses a finite impulse response (FIR) filter that is realized by two different optical paths of parallel fibers which generate a spectral notch filter. Hence, a wavelength coding is realized by chromatic dispersion such that each wavelength is filtered by a different FIR filter. Therefore, the energy at a WDM demux output channels is actually proportional to the spectrum of the input RF signal. This spectral mapping is obtained without lose of temporal RF information.     

Robust quantum error correction via convex optimization

We present a semidefinite program optimization approach to quantum error correction that yields codes and recovery procedures that are robust against significant variations in the noise channel. Our approach allows us to optimize the encoding, recovery, or both, and is amenable to approximations that significantly improve computational cost while retaining fidelity. We illustrate our theory numerically for optimized 5-qubit codes, using the standard [5,1,3] code as a benchmark. Our optimized encoding and recovery yields fidelities that are uniformly higher by 1-2 orders of magnitude against random unitary weight-2 errors compared to the [5,1,3] code with standard recovery.     

A high-order accurate unstructured finite volume Newton–Krylov algorithm for inviscid compressible flows

A fast implicit Newton–Krylov finite volume algorithm has been developed for high-order unstructured steady-state computation of inviscid compressible flows. The matrix-free generalized minimal residual (GMRES) algorithm is used for solving the linear system arising from implicit discretization of the governing equations, avoiding expensive and complex explicit computation of the high-order Jacobian matrix. The solution process has been divided into two phases: start-up and Newton iterations. In the start-up phase an approximate solution with the general characteristics of the steady-state flow is computed by using a defect correction procedure. At the end of the start-up phase, the linearization of the flow field is accurate enough for steady-state solution, and a quasi-Newton method is used, with an infinite time step and very rapid convergence. A proper limiter implementation for efficient convergence of the high-order discretization is discussed and a new formula for limiting the high-order terms of the reconstruction polynomial is introduced. The accuracy, fast convergence and robustness of the proposed high-order unstructured Newton–Krylov solver for different speed regimes is demonstrated for the second, third and fourth-order discretization. The possibility of reducing computational cost required for a given level of accuracy by using high-order discretization is examined.