Dynamics of a system comprising a pre-stressed orthotropic layer and pre-stressed orthotropic half-plane under the action of a moving load

This paper investigates the dynamic response to a moving load of a system comprising an initially stressed covering layer and initially stressed half-plane, within the scope of the piecewise-homogeneous body model utilizing three-dimensional linearized wave propagation theory in the initially stressed body. It was assumed that the materials of the layer and half-plane are anisotropic (orthotropic), and that the velocity of the line-located moving load is constant as it acts on the free face of the covering layer. The investigations were made for a two-dimensional problem (plane-strain state) under subsonic velocity of the moving load for complete and incomplete contact conditions. Corresponding numerical results were obtained for the stiffer layer and soft half-plane system in which the modulus of elasticity of the covering layer material (for the moving direction of the load) is greater than that of the half-plane material, which was assumed to be isotropic. Numerical results are presented and discussed for the critical velocity and stress distribution for various values of the problem parameters. In particular, it was established that, the critical velocity of the moving load is controlled mainly with a Rayleigh wave speed of a half-plane material and the initial stretching of the covering layer causes to increase these values.     

Schatten class Hankel and $$\overline{\partial }$$ ∂ ¯ -Neumann operators on pseudoconvex domains in $$\mathbb {C}^{n}$$ C n

Monatshefte für Mathematik - Let $$\Omega $$ be a $$C^2$$ -smooth bounded pseudoconvex domain in $$\mathbb {C}^n$$ for $$n\ge 2$$ and let $$\varphi $$ be a holomorphic function on $$\Omega $$...     

Precision glycopolymers and their interactions with lectins

Glycopolymers are synthetic polymers with carbohydrate groups attached and have a great potential to be utilized in drug delivery applications and nanomedicines as a result of their recognition properties. Sugar code is running in living entities with extreme precision and every small difference in the oligosaccharide structure significantly affects the recognition by lectins. Therefore, controlling the sequence of sugars along the polymer backbone is vital to achieve selective lectin binding and cell signalling. The preparation of sequence controlled glycopolymers has recently been in the focus of several research groups and the cons and pros of three recently published approaches are discussed in this minireview.     

Phytochemical profiling,antioxidant, enzyme inhibition and cytotoxic potential of Bougainvillea glabra flowers

Abstract

In this study, phytochemical composition, antioxidant, enzyme inhibition and cytotoxic activities of methanol and dichloromethane (DCM) extracts of Bougainvillea glabra (B. glabra) flowers were investigated. Methanol extract was found to have higher total bioactive contents and UHPLC-MS analysis of methanol extract revealed the presence of well-known phenolic and flavonoid compounds. Antioxidant activities were performed by radical scavenging (DPPH and ABTS), reducing power (FRAP and CUPRAC), phosphomolybdenum (TAC) and metal chelating assays. From our result, we observed that methanol extract had many antioxidant compounds. The DCM extract exhibited higher cholinesterases and α-glucosidase enzyme inhibition, while methanol extract showed significant urease inhibition. Both extracts exhibited strong to moderate cytotoxicity against MCF-7, MDA-MB-231, CaSki, DU-145 and SW-480 cancer cells with IC₅₀ values ranging from 88.49 to 304.7 µg/mL. The findings showed the B. glabra to possess considerable antioxidant, enzyme inhibition and cytotoxic potentials and therefore has potential to discover novel bioactive molecules.     

SERS‐based assays for sensitive detection of modafinil

In this paper, we proposed two sensitive surface‐enhanced Raman spectroscopy assays for the determination of modafinil in urine matrix. In the first assay, modafinil was extracted by solid phase extraction and determined after sandwiching with silver nanoparticles. In the second assay, modafinil was extracted by non‐specific interaction with magnetic gold nanoparticles and determined by sandwiching with magnetic gold and silver nanoparticles. The non‐specific magnetic extraction does not require any analyte specific agent like antibody, aptamer, or molecularly imprinted polymer, therefore, the cost and complexity of the assay is very low. Both assays are capable for application to urine samples with the detection limits under the minimum required performance limit of modafinil. The assays were validated in terms of accuracy, precision, detection limits, and ranges. Copyright © 2015 John Wiley & Sons, Ltd.     

Investigation of temperature dependent electrical and impedance characteristics of bulk Zn0.95Co0.05O

Journal of Sol-Gel Science and Technology - Zn0.95Co0.05O was synthesized by sol-gel method and then Zn0.95Co0.05O pellet was prepared to investigate its structural, morphological, electrical, and...     

Light-scattering experiments in dye-doped liquid crystals both to determine crystal parameters and to construct consistent neural network empirical physical formulas for scattering amplitudes

The aim of this paper is two-fold. Firstly, static laser light-scattering amplitude measurements in azo-dye doped nematic liquid crystals (NLCs) were made versus scattering angle, temperature and applied bias voltage. Three NLC parameters were determined: the elastic constant ratios K₁₁/K₂₂ by regression, phase transition temperatures, and Freedericksz voltages from the graphs. They were all doping ratio dependent. Secondly, as a novel approach, by a nonlinear universal function approximator layered feedforward neural network (LFNN) we constructed an explicit form of empirical physical formulas (EPFs) for theoretically unknown nonlinear azo-dye doped NLC scattering amplitude functions. Excellent LFNN test set (i.e. yet-to-be measured experimental data) predictions prove that the constructed LFNN-EPPs estimate unknown amplitude functions consistently. The LFFN-EPFs, too, confirmed the doping-ratio dependency. Also, comparing LFNN and regression amplitude fits, the LFNN fits were significantly better. In conclusion, physical laws embedded in the physical data can be consistently extracted by LFNN. One major potential application in the nonlinear optics domain is that these LFNN-EPFs, by differentiation, integration, minimization, etc., can be used to obtain further NLC scattering amplitude related molecular structural physical quantities. This could in turn help us to develop new nonlinear optical materials.