Small perturbations of an interface for elastostatic problems

We consider the Lamé system for an elastic medium consisting of an inclusion embedded in a homogeneous background medium. Based on the field expansion method and layer potential techniques, we rigorously derived the asymptotic expansion of the perturbed displacement field because of small perturbations in the interface of the inclusion. We extend these techniques to determine a relationship between traction‐displacement measurements and the shape of the object and derive an asymptotic expansion for the perturbation in the elastic moment tensors because of the presence of small changes in the interface of the inclusion. Copyright © 2016 John Wiley & Sons, Ltd.     

Synthesis and characterisation of a new helically chiral ruthenium complex

A new helically chiral hexacyclic phosphine, containing one thiophene ring was prepared in good yield via a five-step sequence involving a palladium-catalysed Mizoroki-Heck coupling reaction and classical oxidative photocyclisation. A mononuclear air stable ruthenium complex of this phosphine was also prepared and characterised.     

SNAr reactions of substituted pyridines with secondary amines in aqueous solution: Kinetic and reactivity indices in density functional theory

A kinetic study is reported for the reactions of 2-methoxy-3-nitropyridine 1a and 2-methoxy-5-nitropyridine 1b with three secondary amines 2a–c (morpholine, piperidine, and pyrrolidine) in aqueous solution at 20°C. The Brønsted-type plots are linear with β_nuc = 0.52 and 0.55 for pyridines 1a and 1b , respectively, indicating that the reaction proceeds through a S_NAr mechanism in which the first step is the rate-determining step. Additional theoretical calculations using the DFT/B3LYP method confirm that the C-2 carbon being the most electrophilic center for the both pyridines 1a and 1b . The second-order rate constants have been used to evaluate the electrophilicity parameters E of 1a and 1b according to the linear free energy relationship log k (20°C) = s_N (N + E). The E parameters thus derived are compared with the electrophilic reactivities of a large variety of anisoles. The validity of these E values has been satisfactorily verified by comparison of calculated and experimental second-order rate constants for the reactions of pyridines 1a and 1b with anion of ethyl benzylacetate.     

Phase transitions in (C7H12N2)2[SnCl6]Cl2·1.5H2O crystal,studied by NMR and infrared spectroscopy

The (C₇H₁₂N₂)₂[SnCl₆]Cl₂·1.5H₂O complex is a new member of the family of hybrid organic–inorganic perovskite compounds. It exhibits two order–disorder phase transitions with changes in the conformation of aromatic cations at the two transition temperatures 360 and 412 K. Differential scanning calorimetry, nuclear magnetic resonance (NMR), and Fourier-transform infrared (FT-IR) spectroscopy were used to investigate these phase transitions. These transition mechanisms were investigated in terms of the spin–lattice relaxation times T1 for ¹H static NMR and the chemical shifts for ¹³C CP–MAS. The temperature dependence of T1(¹H) and ¹³C chemical shifts are changed near T_C1 and T_C2. Furthermore, the splitting for ¹³C NMR signals in Phases (II) and (III) indicated a ferroelastic characteristic of the compound. In addition, FT-IR results indicate that the ordered conformational structure of aromatic cations undergoes a remarkable disorder with increasing temperature. The NMR and FT-IR studies suggest that the phase transition mechanisms are related to the reorientational motion of [C₇H₁₂N₂]²⁺ cations as a whole. Phase transition was examined in light of the interesting optical properties of this material.     

Helically chiral functionalized [6]helicene: Synthesis,optical resolution,and photophysical properties

A short and efficient synthetic pathway leading to a new chiral π-conjugated system is reported. The X-ray structure of the target compound was determined and showed a helical conformation. Its resolution was successfully accomplished, leading to two enantiomers in high optical purity, and their chiroptical properties were examined experimentally. The photophysical properties of the organic material were also evaluated, showing an emission in the visible region, and HOMO and LUMO levels have been estimated experimentally, demonstrating an electrochemical band gap of 2.37 eV.     

Synthesis and characterization of new heptacyclic helicenes

New helically chiral substituted heptacyclic systems have been prepared from a simple phenanthrene building block in good yields and purity, via a four-step sequence involving palladium-catalysed Heck coupling and oxidative photocyclization. X-ray crystal structure analysis indicated that the conformation resembled that of the unsubstituted heptahelicene. The optical properties of these heptacyclic helicenes were investigated and show interesting behaviour.     

About the Cohomology of the Lie Superalgebra of Vector Fields on ℝ n|n

In this article, we compute the first space of cohomology of Vect (? ^n|n ), the Lie superalgebra of vector fields on the supermanifold ? ^n|n with coefficients in 𝒻 (? ^n|n ), the space of smooth functions on ? ^n|n . We give a super analog of the cohomologies of vector fields that where studied for instance by Fuchs [2 Fuchs , D. B. ( 1986 ). Cohomology of Infinite Dimensional Lie Algebras . New York : Consultants Bureau . [Google Scholar]]. This work allows us to classify the deformations of the action of Vect(? ^n|n ) on 𝒻 (? ^n|n ).     

Aqueous synthesis and enhanced photocatalytic activity of ZnO/Fe2O3 heterostructures

We report a facile synthesis of ZnO/Fe₂O₃ heterostructures based on the hydrolysis of FeCl₃ in the presence of ZnO nanoparticles. The material structure, composition, and its optical properties have been examined by means of transmission electron microscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and diffuse reflectance UV–visible spectroscopy. Results obtained show that 2.9 nm-sized Fe₂O₃ nanoparticles produced assemble with ZnO to form ZnO/Fe₂O₃ heterostructures. We have evaluated the photodegradation performances of ZnO/Fe₂O₃ materials using salicylic acid under UV-light. ZnO/Fe₂O₃ heterostructures exhibited enhanced photocatalytic capabilities than commercial ZnO due to the effective electron/hole separation at the interfaces of ZnO/Fe₂O₃ allowing the enhanced hydroxyl and superoxide radicals production from the heterostructure.     

Nonlinearities effects on optical MIMO systems

Optical Review - Multimode fibers (MMF) are enjoying a renewed attention boosted by recent advances in multimode complex nonlinear optics. Reason behind nonlinearity is occurred either due to...     

In vitro evaluation of the anti-proliferative activities of the wood essential oils of three Cedrus species against K562 human chronic myelogenous leukaemia cells

There are four kinds of Cedar: Cedrus libani naturally occurring in Lebanon, Syria and Turkey, Cedrus atlantica in Morocco and Algeria, Cedrus brevefolia in Cyprus Island and Cedrus deodara which is distributed in Himalayan Mountains. Wood essential oils obtained from C. libani, C. atlantica and C. deodara were tested for the inhibition of K562 cell proliferation and for the induction of erythroid differentiation. The wood essential oils of C. libani, C. atlantica and C. deodara inhibited the proliferation of the K562 cell line exhibiting IC(50) values 23.38?±?1.7, 59.37?±?2.6 and 37.09?±?1.4?μg?mL(-1), respectively. Meanwhile, C. libani wood oils induced a percentage of erythroid differentiation of 15?±?2% at concentration 5?μg?mL(-1). Cedrus deodara wood oil indicated a percentage of erythroid differentiation of 20?±?2% at concentration 25?μg?mL(-1) and C. atlantica wood oils showed a percentage of erythroid differentiation of 12?±?1.8% at concentration 10?μg?mL(-1).