Densitometric Kinetic Stability Studies of Some Plant Extracts Using Different Regression Methods

JPC – Journal of Planar Chromatography – Modern TLC -     

Deposition of Phosphate Nanoparticles onto Textile Fabrics via Sol-gel Method and Their Kinetics Desorption Studies

In this paper, phosphate nanoparticles were coated on cotton(CO) and polyester(PES) textile surfaces by sol-gel method using tetraethylorthosilicate(TEOS) and chloropropyltriethoxysilane(CPTS) as silica precursors. The deposited nanoparticles were observed with scanning electronic microscopy energy-dispersive X-ray spectroscopy (SEM-EDX). The release kinetics of phosphorus(P) from these textiles into the aqueous medium(Aq), acid(Ac), and basic(Ba) artificial sweats were then studied. The released amount of phosphorus was evaluated by the inductively coupled plasma(ICP) according to ISO NF EN 16711-2 procedure. The results revealed that the release of P into the aqueous medium is lower than in the artificial sweat. The kinetics data[the phosphorus desorption amount(mg/g) as a function of time] were modeled according to five models:the first order, the second order, the third order, simple Elovich and parabolic diffusion. The suitable model was chosen based on the coefficient of determination(R²) and the calculation of the sum of the absolute errors(EABS), which describes the error between the theoretical and experimental values. SEM observations were also carried out on the fabrics after desorption in order to show the impact of desorption on their morphology. Furthermore, the impact of P release on the tensile strength of CO and PES fabrics was investigated using a uniaxial tensile test. The thermal stability of all samples before and after desorption was assessed by thermogravimetric analysis(ATG).     

Polyacrylic acid/polyaniline composite as efficient adsorbent for uranium extraction from nuclear industrial effluent

Journal of Radioanalytical and Nuclear Chemistry - Polyacrylic acid/polyaniline composite (a three-dimensional cross-linked hydrophilic chelating polymeric sorbent) was improved for promoted...     

Simulation of the embryonic stage of ZnS formation from aqueous solution

We investigate the processes of cluster formation and growth of ZnS from aqueous solution using molecular dynamics simulation techniques. The influence of both temperature and concentration is studied. We show that, at lower temperatures, the crucial process is the transformation of an outer-sphere Zn/S complex to an inner-sphere ion pair. Further growth of the latter is fast to generate negatively charged planar clusters. These clusters interact to form more stable, closed structures, which are found to be the global minima configurations in vacuo. At higher temperatures, no outer-sphere ion pairs are formed, and the larger cluster configurations form much more quickly.     

Chemistry of Phosphorus Ylides. Part 22 [1]. Effect of Newly Synthesized Niclosamide Mannich Bases, Phosphopyranones, Phosphoranylidenes, and Oxaphosphinin on Some Metabolic Aspects of Biomphalaria Alexandrina

Niclosamide reacts with secondary amines and formaldehyde under the condition of Mannich reaction, to give new Mannich bases. The reaction of these niclosamide Mannich bases with active phosphacumulene ylides affords the corresponding phenyliminopyranone, pyranone, and pyranthione, respectively. When Wittig reaction was carried out on the pyranone, using p-nitrobenzaldehyde, a new arylidene and triphenylphosphine oxide were obtained. On the other hand, stabilized phosphonium ylides affect the transylidation of niclosamide Mannich bases to the corresponding phosphoranylidenes. When diphenylmethylenetriphenylphosphorane reacts with a niclosamide Mannich base, an oxaphosphinin was obtained. The molluscicidal potency of the newly synthesized derivatives against Biomphalaria alexandrina was studied, too.     

Large-scale separation of metallic and semiconducting single-walled carbon nanotubes

In the applications of single-walled carbon nanotubes (SWNTs), it is extremely important to separate semiconducting and metallic SWNTs. Although several methods have been reported for the separation, only low yields have been achieved at great expense. We show a separation method involving a dispersion-centrifugation process in a tetrahydrofuran solution of amine, which makes metallic SWNTs highly concentrated to 87% in a simple way.     

Terephthalamide derivatives as mimetics of helical peptides: disruption of the Bcl-x(L)/Bak interaction

A series of Bcl-x(L)/Bak antagonists, based on a terephthalamide scaffold, was designed to mimic the alpha-helical region of the Bak peptide. These molecules showed favorable in vitro activities in disrupting the Bcl-x(L)/Bak BH3 domain complex (terephthalamides 9 and 26, K(i) = 0.78 +/- 0.07 and 1.85 +/- 0.32 microM, respectively). Extensive structure-affinity studies demonstrated a correlation between the ability of terephthalamide derivatives to disrupt Bcl-x(L)/Bak complex formation and the size of variable side chains on these molecules. Treatment of human HEK293 cells with the terephthalamide derivative 26 resulted in disruption of the Bcl-x(L)/Bax interaction in whole cells with an IC(50) of 35.0 microM. Computational docking simulations and NMR experiments suggested that the binding cleft for the BH3 domain of the Bak peptide on the surface of Bcl-x(L) is the target area for these synthetic inhibitors.     

Determination of flumequine in channel catfish by liquid chromatography with fluorescence detection.

Rapid methods are described for determination of flumequine (FLU) residues in muscle and plasma of farm-raised channel catfish (Ictalurus punctatus). FLU residues were extracted from tissues with an acidified methanol solution, and extracts were cleaned up on C18 solid-phase extraction cartridges. FLU concentrations were determined by liquid chromatography (LC) using a C18 analytical column and fluorescence detection (excitation, 325 nm; emission, 360 nm). Mean recoveries of FLU from fortified muscle were 87-94% at 5 levels ranging from 10 to 160 ppb (5 replicates per level). FLU recoveries from fortified plasma were 92-97% at 5 levels ranging from 20 to 320 ppb. Limits of detection (signal-to-noise ratio, 3:1) for the method as described were 3 and 6 ppb for muscle and plasma, respectively. Relative standard deviations (RSDs) for recoveries were < or = 12%. Live catfish were dosed with 14C-labeled or unlabeled FLU to generate incurred residues. Recoveries of 14C residues throughout extraction and cleanup were 90 and 94% for muscle and plasma, respectively. RSDs for incurred FLU at 2 levels in muscle and plasma ranged from 2 to 6%. The identity of FLU in incurred tissues was confirmed by LC/mass spectrometry.     

Generalized Clifford algebras and certain infinite dimensional Lie algebras

The embedding of certain infinite dimensional Lie algebras in generalized Clifford algobras C(N, p) is given. The correspondence between C(N,2) andgl(N, C) asN⇌∞ is pointed out.     

On the oscillation of fourth order strongly superlinear and strongly sublinear dynamic equations

We establish some new criteria for the oscillation of fourth order nonlinear dynamic equations on a time scale. We investigate the case of strongly superlinear and the case of strongly sublinear equations subject to various conditions. Some examples are given here to illustrate our main results.