Dapson in Heterocyclic Chemistry,Part III: Synthesis,Antimicrobial, and Antitumor Activities of Some New Bisheterocyclic Compounds Containing Biologically Active Diphenylsulfone Moiety

The key intermediate diisothiocyanate 2 was allowed to react with 5-amino-3-methyl-pyrazole-4-carbonitrile 3, ethyl 5-amino-1-phenyl-pyrazole-4-carboxylate 6, 2-amino-tetrahydrobenzo[b]thiophene-3-car-bonitrile 9, ethyl-2-amino-tetra-hydrobenzo[b]thiophene-3-carboxylate 12, and/or 1,2,4-triazole 15 to give the corresponding biscompounds 4, 5, 7, 8, 10, 11, 13, 14, and 16, respectively. The structure of the synthesized compounds was elucidated by elemental analyses and spectral data. Some of the prepared compounds were tested for their antimicrobial and antitumor activities.     

The study on the ZnO and Zn0.95Mn0.05O added YBCO system: Investigation of microstructure and transport properties

The effect of nano-size Zn_0.95Mn_0.05O and ZnO (30 nm) addition on the microstructure and the normal state transport properties of polycrystalline YBa₂Cu₃O_y (YBCO) was systematically studied. Samples were synthesized in air using a standard solid state reaction technique by adding nano-sized particles up to 10 wt.%. When Zn_0.95Mn_0.05O and ZnO are added to the YBCO the orthorhombic structure maintained even at the highest concentration. TEM and EDS analyses show the presence of inhomeginities embedded in the superconducting matrix. To interpret the normal state properties of the samples, the percolation theory based on localized states is applied. A cross-over between variable-range hopping and Coulomb gap mechanisms is observed as a result of increasing the nano-particles concentration. The ZnO addition modifies the electrical behavior of samples from metallic to insulating with a much lower concentration comparatively to Zn_0.95Mn_0.05O addition. The calculated values of the localization length, d, are greater in the case of Zn_0.95Mn_0.05O addition. This result can be interpreted by the internal structure defects.     

Uniqueness for an ill-posed parabolic system

The purpose is the uniqueness for an ill-posed parabolic system. This result enables us to state the identifiability for the problem of detecting pointwise organic pollution sources in surface waters.     

The Mortar finite element method with Lagrange multipliers

Summary. The present paper deals with a variant of a non conforming domain decomposition technique: the mortar finite element method. In the opposition to the original method this variant is never conforming because of the relaxation of the matching constraints at the vertices (and the edges in 3D) of subdomains. It is shown that, written under primal hybrid formulation, the approximation problem, issued from a discretization of a second order elliptic equation in 2D, is nonetheless well posed and provides a discrete solution that satisfies optimal error estimates with respect to natural norms. Finally the parallelization advantages consequence of this variant are also addressed. Received December 1, 1996 / Revised version received November 23, 1998 / Published online September 24, 1999     

Dapson in Heterocyclic Chemistry,Part I: Novel Synthesis of Sulfone Biscompounds for Antimicrobial and Antitumor Activities

This article describes the synthesis of some novel sulfone bis-compounds bearing the biologically active thioether 3–6 ; thioureido 7, 8, 15, 16; triazole 10, 11; thiosemicarbazido 9, 12, 13; and 1,3,4-thiadiazole 14, 17 moieties starting with 4,4′-diisothiocyanato-1,1-diphenylsulfone 2. The structures of newly synthesized compounds were confirmed by elemental analysis, IR, ¹ H-NMR and mass spectral data. Compound 3 was found to be the most active compound against Escherichia coli. Also, compound 15 acted as potent cytotoxic agent.     

Dapson in Heterocyclic Chemistry,Part IV: Synthesis of Some Novel Diphenylsulfones Containing Acetamide,Pyrrolidine, Piperazine,and Thiomorpholine Moieties as Antimicrobial and Antitumor Agents

Interaction of dapson [bis(4-aminophenyl)sulfone] 1 with [bis-(methylsulfonyl) methylidine]malononitrile 2 yielded the corresponding dicyano derivative 3, which was reacted with acetic anhydride, succinic anhydride, 4-chlorobenzaldehyde, phenyl isothiocyanate to give the corresponding acetamide 4, succinamic acid 5, pyrrolidine 6, Shiff base 7 and thiourea 8, respectively. Treatment of 3 with chloroacetyl chloride afforded the aminoacetyl chloride derivative 9. Further, the interaction of compound 9 with thioglycolic acid, malononitrile, ethyl glycinate hydrochloride, and/or potassium thiocyanate furnished compounds 10–15, respectively. The structural characterization of the prepared compounds was based on microanalytical and spectroscopic analyses. Some of the prepared compounds were tested for their antimicrobial and antitumor activities. Compounds 9 and 12 showed promising antitumor activity compared with Doxorubicin as positive control.     

Error bounds in high-order Sobolev norms for POD expansions of parameterized transient temperatures

In this work, we analyze the convergence of the POD expansion for the solution to the heat conduction parameterized with respect to the thermal conductivity coefficient. We obtain error bounds for the POD approximation in high-order norms in space that assure an exponential rate of convergence, uniformly with respect to the parameter whenever it remains within a compact set of positive numbers. We present some numerical tests that confirm this theoretical accuracy.     

On the Obstacle Problem for a Naghdi Shell

Starting with the Naghdi model for a shell in Cartesian coordinates, we derive a model for the contact of this shell with a rigid body. We also prove the well-posedness of the resulting system of variational inequalities.     

Waves and energy in random elastic guided media through the stochastic wave finite element method

Energy propagation in random viscoelastic media is considered in this Letter. The forced response of uncertain waveguide subject to time harmonic loading is treated. This energy model is based on a spectral approach called the “Stochastic Wave Finite Element” (SWFE) method which is detailed in this Letter. Assuming that the random properties are spatially homogeneous in the media, the SWFE is a hybridization of the deterministic wave finite element and a parametric probabilistic approach. The proposed model is applicable in a wide frequency band with reduced time consumption. Numerical examples show the effectiveness of the proposed approach to predict the statistics of kinematic and quadratic variables of guided wave propagation. The results are compared to Monte Carlo simulations.     

Rheology, morphology and mechanical properties of polyethylene/ethylene vinyl acetate copolymer (PE/EVA) blends

Rheology, morphology and mechanical properties of binary PE and EVA blends together with their thermal behavior were studied. The results of rheological studies showed that, for given PE and EVA, the interfacial interaction in PE-rich blends is higher than EVA-rich blends, which in turn led to finer and well-distributed morphology in PE-rich blends. Using two different models, the phase inversion composition was predicted to be in 45 and 47 wt% of the PE phase. This was justified by morphological studies, where a clear co-continuous morphology for 50/50 blend was observed. The tensile strength for PE-rich blends showed positive deviation from mixing rule, whereas the 50/50 blend and EVA-rich blends displayed negative deviation. These results were in a good agreement with the results of viscoelastic behavior of the blends. The elongation at break was found to follow the same trend as tensile strength except for 90/10 PE/EVA blend. The latter was explained in terms of the effect of higher co-crystallization in 90/10 composition, which increased the tensile strength and decreased the elongation at break in this composition. The results of thermal behavior of the blends indicated that the melting temperatures of PE and EVA decrease and increase, respectively, due to the dilution effect of EVA on PE and nucleation effect of PE on EVA.