Regularity properties of perturbed Hille-Yosida operators and retarded differential equations

In this work we give sufficient conditions on the semigroup (T ₀ (t)) _t\geq0 , generated by the part of a Hille—Yosida operator in the closure of its domain, in order that certain perturbations preserve some regularity properties of (T ₀ (t)) _t\geq0 , like the norm continuity, compactness and differentiability. An application of our abstract results to retarded differential equations is given.     

Di-n-butyltin and diethyltin monofluorobenzoates: Synthesis,spectroscopic characterization and in vitro antitumor activity

The di-n-butyltin(IV) and diethyltin(IV) fluorobenzoates [FC₆H₄COO]₂SnR₂ and (FC₆H₄COOR₂Sn)₂O have been synthesized and characterized spectroscopically. Their in vitro antitumor activity against two human tumor cell lines, MCF-7, a mammary tumor, and WiDr, a colon carcinoma, as well as against the NCI cell panel, is satisfactory.     

Tetraethylammonium (diorgano)halogeno-(2, 6-pyridinedicarboxylato)stannates: Synthesis,characterization and in vitro antitumour activity

The synthesis and characterization of tetraethylammonium (diorgano)halogeno(2, 6-pyridinedicarboxylato)stannates are described. The solution structures of these complexes in CDCl₃ and DMSO are discussed on the basis of ¹¹⁹Sn and ¹⁹F NMR data. Their in vitro antitumour activities against two human tumour cell lines, MCF-7 and WiDr, are presented.     

Multi-objective stochastic programming for portfolio selection

Generally, in the portfolio selection problem the Decision Maker (DM) considers simultaneously conflicting objectives such as rate of return, liquidity and risk. Multi-objective programming techniques such as goal programming (GP) and compromise programming (CP) are used to choose the portfolio best satisfying the DM’s aspirations and preferences. In this article, we assume that the parameters associated with the objectives are random and normally distributed. We propose a chance constrained compromise programming model (CCCP) as a deterministic transformation to multi-objective stochastic programming portfolio model. CCCP is based on CP and chance constrained programming (CCP) models. The proposed program is illustrated by means of a portfolio selection problem from the Tunisian stock exchange market.     

Design and synthesis of new ethylenediamine or propylenediamine diacetic acid derivatives for Re(I) organometallic chemistry

A general synthetic approach for a novel range of bifunctional chelating agent (BCA) for the ‘fac-[M(CO)₃]⁺‘ core (M=^99mTc, ⁹⁹Tc or Re) has been developed. The strategy includes the facile preparation of these tridentate ligands possessing a tertiary amine bearing two carboxylic acid functions as coordinating site and an aromatic amino group for coupling to a biovector. First complexation study has shown that these compounds act exclusively as tridentate ligands (via the two acids and the tertiary amine functions). The convenient synthesis of these new ligands coupled with their high affinity for Re(I) make them quite promising for biomedical applications.     

Orthogonal Synthesis of Xeno Nucleic Acids

Sequence‐defined peptide triazole nucleic acids (PTzNA) were synthesized by means of a solid‐phase orthogonal “AB+CD” iterative strategy. In this approach, AB and CD building blocks containing carboxylic acid (A), azide (B), alkyne (C), and primary amine (D) functions are assembled together by successive copper‐catalyzed azide–alkyne cycloaddition (CuAAC) and acid–amine coupling steps. Different PTzNA genetic sequences were prepared using a library of eight building blocks (i.e., four AB and four CD building blocks).     

Viscosity and Rheological Properties of Graphene Nanopowders Nanofluids

The dynamic viscosity and rheological properties of two different non-aqueous graphene nano-plates-based nanofluids are experimentally investigated in this paper, focusing on the effects of solid volume fraction and shear rate. For each nanofluid, four solid volume fractions have been considered ranging from 0.1% to 1%. The rheological characterization of the suspensions was performed at 20 ∘C, with shear rates ranging from 10−1s−1 to 103s−1, using a cone-plate rheometer. The Carreau–Yasuda model has been successfully applied to fit most of the rheological measurements. Although it is very common to observe an increase of the viscosity with the solid volume fraction, we still found here that the addition of nanoparticles produces lubrication effects in some cases. Such a result could be very helpful in the domain of heat extraction applications. The dependence of dynamic viscosity with graphene volume fraction was analyzed using the model of Vallejo et al.     

Time dependent Lyapunov functions for some Kolmogorov semigroups perturbed by unbounded potentials

We study global regularity properties of transition kernels associated to second order differential operators in \mathbb R^N{\mathbb {R}^N} with unbounded drift and potential terms. Under suitable conditions, we prove pointwise upper bounds. We use time dependent Lyapunov function techniques allowing us to gain a better time behaviour of such kernels.     

A double degenerated finite element for modeling the crack tip singularity

The objective of this paper is to propose a modified finite element called double quarter point finite element (DQPE) for modeling the singularity near the crack tip. Two techniques of evaluation (displacement correlation technique DCT and quarter point displacement technique QPDT) were used to estimate numerically the calibration factor for CN specimen. This study appears that the DQPE element is more effective than the QPE element. Not only that, but the length of the double quarter point finite element (DQPE) has little impact on the results. Numerical experiments are provided to demonstrate the effectiveness and robustness of the proposed element.