Synthesis and biological evaluation of (S)-4-aminoquinazoline alcohols

A simple synthetic method for the preparation of enantiomerically pure (S)-4-aminoquinazoline alcohols from (S)-quinazolinone alcohols by key steps including chlorination, nucleophilic ipso substitution, and deacetylation is presented. Mutagenic and antimutagenic properties of the (S)-4-aminoquinazoline alcohols were investigated by using Salmonella typhimurium TA1535, and Escherichia coli WP2uvrA tester strains at 0.01, 0.1, and 1 μg/plate concentrations. (S)-4-aminoquinazoline alcohols were found to be genotoxically safe at the tested concentrations. Among the tested (S)-4-aminoquinazoline alcohols, the best antimutagenic activity was obtained with a methyl derivative at 0.1 μg/plate dose.     

A 3D-CMOS compatible silicon photo-sensor with a large vertical photosensitive area

This paper introduces design and simulation of a three-dimensional complementary metal–oxide–semiconductor CMOS compatible photo-sensor based on a silicon substrate. In the structure of photo-sensor, a vertical n+/p junction as a photosensitive area is formed on one side of a U-groove, and perpendicular to a lateral n-i-p structure on top-side of the silicon surface. This configuration enables a direct butt-coupling of a fiber-optic to the photosensitive area, which is a privilege for many remote monitoring applications. The device analysis is carried out by a two-dimensional simulation using SILVACO TCAD simulator. The thickness of the photo-sensitive area is investigated by considering the figures of merit for the two different thicknesses of 30 and 50 µm. The simulated results (according to the parameters defined for the Si substrate) show a very low dark current of 70 and 100 (fA/μm) for the 30 and 50 µm thicknesses, respectively. In addition, a high photo-current to dark current ratio of ~3000 is achieved under an intensity of 2 mW/cm² at 633 nm wavelength, according to the wavelength of red He–Ne laser. The sensor demonstrates a responsivity of 0.33 A/W corresponding to 65% external quantum efficiency and a ?3 dB frequency response of 0.2 GHz under a small signal of 2 mW/cm² at 633 nm wavelength for 10 V reverse bias.     

Study of the <Superscript>190</Superscript>Hg Nucleus: Testing the Existence of U(5) Symmetry

In this paper, we have considered the energy spectra, quadrupole transition probabilities, energy surface, charge radii, and quadrupole moment of the¹⁹⁰Hg nucleus to describe the interplay between phase transitions and configuration mixing of intruder excitations. To this aim, we have used four different formalisms: (i) interacting boson model including configuration mixing, (ii) Z(5) critical symmetry, (iii) U(6)-based transitional Hamiltonian, and (iv) a transitional interacting boson model Hamiltonian in both interacting boson model (IBM)-1 and IBM-2 versions which are based on affine \( \widehat{SU\left(1,1\right)} \) Lie algebra. Results show the advantages of configuration mixing and transitional Hamiltonians, in particular IBM-2 formalism, to reproduce the experimental counterparts when the weight of spherical symmetry increased.     

Effect of the kinematic hardening on the plastic anisotropy parameters for metallic sheets

The initial plastic anisotropy parameters are conventionally determined from the Lankford strain ratios defined by $r^{\psi }=\frac{{\epsilon }_{22}^{\mathrm{p}\psi }}{{\epsilon }_{33}^{\mathrm{p}\psi }}$ (ψ being the direction of the loading path). They are usually considered as constant parameters that are determined at a given value of the plastic strain far from the early stage of the plastic flow (i.e. equivalent plastic strain of ${\epsilon }_{\mathrm{eq}}^{\mathrm{p}}=0.2\text{\%}$) and typically at an equivalent plastic strain in between 20% and 50% of plastic strain failure (or material ductility). What prompts to question about the relevance of this determination, considering that this ratio does not remain constant, but changes with plastic strain. Accordingly, when the nonlinear evolution of the kinematic hardening is accounted for, the Lankford strain ratios are expected to evolve significantly during the plastic flow.In this work, a parametric study is performed to investigate the effect of the nonlinear kinematic hardening evolution of the Lankford strain ratios for different values of the kinematic hardening parameters. For the sake of clarity, this nonlinear kinematic hardening is formulated together with nonlinear isotropic hardening in the framework of anisotropic Hill-type (1948) yield criterion. Extension to other quadratic or non-quadratic yield criteria can be made without any difficulty. This parametric study is completed by studying the effect of these parameters on simulations of sheet metal forming by large plastic strains.     

Preparation and characterization of 1,2,3‐triazole‐cured polymers from endcapped azides and alkynes

Fourteen commercial polyols have been characterized by GPC, NMR spectroscopy, and elemental analysis. From these, eight corresponding tosylates, six nitrate esters, seven mesylates, 13 alkynes, and 14 azides have been prepared and all these derivatives have been fully characterized. Five alkyne monomers and eight azide monomers were also prepared. Twelve alkynes and 13 azides (functionality 2–4) were combined in 1,3‐dipolar cycloaddition reactions under neat conditions to prepare triazole‐cured polymers, avoiding any heavy metal catalyst. Characterization by NMR spectroscopy, elemental analysis, and gel permeation chromatography indicated triazole polymers 14 , 22 , 23 , 28 , and 30 with degrees of polymerization of 17–28 to be the best candidates for future work. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 238–256, 2008     

New results for global stability of a class of neutral-type neural systems with time delays

This paper studies the global convergence properties of a class of neutral-type neural networks with discrete time delays. This class of neutral systems includes Cohen–Grossberg neural networks, Hopfield neural networks and cellular neural networks. Based on the Lyapunov stability theorems, some delay independent sufficient conditions for the global asymptotic stability of the equilibrium point for this class of neutral-type systems are derived. It is shown that the results presented in this paper for neutral-type delayed neural networks are the generalization of a recently reported stability result. A numerical example is also given to demonstrate the applicability of our proposed stability criteria.