A strong consistency of a nonparametric estimate of entropy under random censorship

The purpose of this Note is to provide the rate of strong consistency for a nonparametric estimator of entropy under random censorship. We also establish an uniform-in-bandwidth consistency for this estimator. To cite this article: S. Bouzebda, I. Elhattab, C. R. Acad. Sci. Paris, Ser. I 347 (2009).     

Exponential decay for a quasilinear viscoelastic equation

We consider the following nonlinear viscoelastic equation together with Dirichlet-boundary conditions, in a bounded domain Ω and ρ > 0. We prove an exponential decay result for a class of relaxation functions. Our result is established without imposing the usual relation between g and its derivative (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

SERS study of methylated and nonmethylated ribonucleosides and the effect of aggregating agents

We present surface‐enhanced Raman scattering (SERS) spectra of the RNA nucleosides adenosine, cytidine, guanosine and uracil and the methylated derivatives 5‐methylcytidine and 7‐methylguanosine, a class of important nucleic acid components that has not previously been well characterised using SERS spectroscopy. Our work shows that the selection of aggregating agent plays a crucial role for SERS analysis of these nucleosides with K₂SO₄ generating immediate enhancement while NaCl only gave immediate enhancement for the pyrimidine nucleosides. The SERS spectra contain a number of marker bands that are highly sensitive to structural differences between these nucleosides, in particular methylation, and at lower concentration ranges than are possible for conventional Raman scattering. Finally, spectral analyses and assignments of the vibrational modes responsible for these marker bands are also presented, and the effect of the aggregating agent on these modes is discussed in terms of interactions between each nucleoside and the metal surface. Copyright © 2011 John Wiley & Sons, Ltd.     

Determination of Meloxicam Using Europium Sensitized Luminescence in the Presence of Co-Luminescence Reagents

A sensitive time- resolved luminescence method for the determination of meloxicam (MX) in methanol and in aqueous solution is described. The method is based on the luminescence sensitization of europium (Eu³⁺) by formation of ternary complex with MX in the presence of 1,10- phenanthroline as coligand, Tween-80 as surfactant and gadolinium ion as a co-luminescence reagent. The signal for Eu- MX-1, 10- phenanthroline is monitored at λ_ex = 360 nm and λ_em = 620 nm. Optimum conditions for the formation of the complex in aqueous system were 0.01 M TRIS buffer, pH 8.0, 1,10- phenanthroline (6.0 × 10⁻⁶ M) , Gd³⁺ (7.0 × 10⁻⁶ M), Tween-80 (0.28%) and 1.75 mM of Eu³⁺ which allows the determination of 20–800 ppb of MX with limit of detection (LOD) of 7 ppb. The relative standard deviations of the method range between 0.1 and 1.1% indicating excellent reproducibility of the method. The proposed method was successfully applied for the assay of MX in pharmaceutical formulations, plasma and in urine samples. Average recoveries of 99.8 ± 1.1%, 100.2 ± 0.9% and 100.9 ± 1.1% were obtained for MX in tablet, plasma and urine sample respectively.     

Synthesis and properties of some 2,3‐disubstituted 6‐fluoro‐7‐(4‐methyl‐1‐piperazinyl)quinoxalines

The 2,3‐disubstituted 6‐fluoro‐7‐(4‐methyl‐1‐piperazinyl)‐quinoxalines ( 3–11 ) were synthesized for bioassay via reaction of 1.2‐diamino‐4‐fluoro‐5‐(4‐methyl‐1‐piperazinyl)benzene (2) with the appropriate 1,2‐dicarbonyl compounds. However, none of the tested compounds 3–11 showed significant in vitro activ ity against E. coli ATCC11229, S. aureus ATCC6538 and C.albicans SATCC10231.     

Formation of Copper Oxide Nanotextures on Porous Calcium Carbonate Templates for Water Treatment

The necessity of providing clean water sources increases the demand to develop catalytic systems for water treatment. Good pollutants adsorbers are a key ingredient, and CuO is one of the candidate materials for this task. Among the different approaches for CuO synthesis, precipitation out of aqueous solutions is a leading candidate due to the facile synthesis, high yield, sustainability, and the reported shape control by adjustment of the counter anions. We harness this effect to investigate the formation of copper oxide-based 3D structures. Specifically, the counter anion (chloride, nitrate, and acetate) affects the formation of copper-based hydroxides and the final structure following their conversion into copper oxide nanostructures over porous templates. The formation of a 3D structure is obtained when copper chloride or nitrate reacts with a Sorites scaffold (marine-based calcium carbonate template) without external hydroxide addition. The transformation into copper oxides occurs after calcination or reduction of the obtained Cu₂(OH)₃X (X = Cl⁻ or NO₃⁻) while preserving the porous morphology. Finally, the formed Sorites@CuO structure is examined for water treatment to remove heavy metal cations and degrade organic contaminant molecules.     

Similarity-Based Virtual Screen Using Enhanced Siamese Multi-Layer Perceptron

Traditional drug development is a slow and costly process that leads to the production of new drugs. Virtual screening (VS) is a computational procedure that measures the similarity of molecules as one of its primary tasks. Many techniques for capturing the biological similarity between a test compound and a known target ligand have been established in ligand-based virtual screens (LBVSs). However, despite the good performances of the above methods compared to their predecessors, especially when dealing with molecules that have structurally homogenous active elements, they are not satisfied when dealing with molecules that are structurally heterogeneous. The main aim of this study is to improve the performance of similarity searching, especially with molecules that are structurally heterogeneous. The Siamese network will be used due to its capability to deal with complicated data samples in many fields. The Siamese multi-layer perceptron architecture will be enhanced by using two similarity distance layers with one fused layer, then multiple layers will be added after the fusion layer, and then the nodes of the model that contribute less or nothing during inference according to their signal-to-noise ratio values will be pruned. Several benchmark datasets will be used, which are: the MDL Drug Data Report (MDDR-DS1, MDDR-DS2, and MDDR-DS3), the Maximum Unbiased Validation (MUV), and the Directory of Useful Decoys (DUD). The results show the outperformance of the proposed method on standard Tanimoto coefficient (TAN) and other methods. Additionally, it is possible to reduce the number of nodes in the Siamese multilayer perceptron model while still keeping the effectiveness of recall on the same level.     

Chlorosulfonyl styrene–divinylbenzene copolymer characteristics as a function of chlorosulfonation and chlorination reaction parameters

Chlorosulfonyl substituted styrene–divinylbenzene copolymer is a highly reactive intermediate used in organic synthesis. It is obtained in three steps: (1) the polymeric support in the form of spherical beads is prepared by free radical polymerization of styrene; (2) the divinylbenzene mixture and the aromatic styrene groups of the obtained copolymer are sulfonated with chlorosulfonic acid in dichloroethane and (3) this is followed by chlorination of the sulfonyl groups with PCl₅/POCl₃ mixture. Chemical analysis shows that chlorosulfonation leads to both sulfonyl and chlorosulfonyl products in which content and ratio vary as a function of reaction parameters: maximum total group content of 5.1 meq/g is reached after 3 hr reaction, at 40°C with styrene to a chlorosulfonic acid molar ratio of 12.4:1. In the chlorination reaction, sulfonyl to chlorosulfonyl conversion is also observed to vary as a function of time and chlorinating mixture composition: 99.6 mol% conversion degree is attained after 2 hr reaction with styrene/PCl₅/POCl₃ in a molar ratio of 1:4:23. © 1997 John Wiley & Sons, Ltd.     

Photodissociation of sodium iodide and resonant ionization of sodium atom produced

Resonant ionization spectroscopy (RIS) and resonant ionization mass spectroscopy (RIMS) are employed to detect the photodissociation product of sodium iodide molecules in a molecular beam in an intense laser field in the absence of the buffer gases. Time of flight mass spectra is recorded. In particular, the appearances of multiphoton ionization are discussed.     

On averaging of the non-periodic conductivity coefficient using two-scale extensions

We consider a second order elliptic equation with known rapidly oscillated coefficient. The equation appears to describe such problems as heat transfer in composite materials, flow in non-homogeneous porous media as well as in many others. For the periodic coefficient the averaging procedure is well known. The non-periodic case is still a challenging problem. We present a two-scale extension approach and apply it on one numerical example in 2D. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)