Anisotropic janus magnetic polymeric nanoparticles prepared via miniemulsion polymerization

Anisotropic Janus magnetic polymeric nanoparticles are prepared via the miniemulsion polymerization of styrene and acrylic acid monomers in the presence of oleic acid‐coated magnetic nanoparticles (MNPs). The controllable phase separation between the polymer matrix and the encapsulated MNPs is a key success factor to produce Janus morphology. The effects of MNPs, 2,2′‐azobis(2‐isobutyronitrile) and sodium dodecyl sulfate contents, on the morphology, chemical composition and colloidal stability of the prepared Janus hybrid particles are investigated. Besides the determination of polymerization conversion, zeta potential, size analysis, TGA, and TEM are applied for characterization of the anisotropic particles. The results show the stable spherical Janus particles containing MNPs (15 wt % magnetic content) located on one side of each polymer particle. The anisotropic submicron Janus magnetic polymeric particles (250 nm) can be easily separated by an external magnet. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4779–4785     

Chemical variability of <Emphasis Type="Italic">Artemisia herba-alba</Emphasis> Asso essential oils from East Morocco

Chemical compositions of 16 Artemisia herba-alba oil samples harvested in eight East Moroccan locations were investigated by GC and GC/MS. Chemical variability of the A. herba-alba oils is also discussed using statistical analysis. Detailed analysis of the essential oils led to the identification of 52 components amounting to 80.5–98.6 % of the total oil. The investigated chemical compositions showed significant qualitative and quantitative differences. According to their major components (camphor, chrysanthenone, and α- and β-thujone), three main groups of essential oils were found. This study also found regional specificity of the major components.     

Condition P for singular real analytic differential forms in the plane

The focus of this work is the solvability of a class of first order partial differential equations with singularity at the origin. The method of blowing-up is used to determine a necessary and sufficient condition for solvability.     

Généralisation d'identités de Carlitz,Howard et Lehmer

Divided differences provide an efficient method for computing with functions of several variables.In this note, we use them to generalize the Newton interpolation formula, and obtain an orthogonality relation (3.3). From this, we deduce two inversion formulas (3.4) and (3.8) involving two infinite sets of variables.The generating functions (1.1) to (1.4) of Carlitz and Howard are obtained by a mere specialization of variables in the preceding inversion formulas.As an illustration, we show how to recover several identities due to Carlitz and Lehmer, and we give a newq-analog of the generating series of the Howard numbers (formulas 4.22 and 4.23).

     

Global solvability of real analytic complex vector fields in two variables

This paper deals with the global solvability of a complex vector field with real analytic coefficients in two real variables. The vector field is assumed to satisfy the Nirenberg-Treves condition (P) for local solvability. Normal forms for the vector field near the one-dimensional orbits are obtained and a generalization of the Riemann-Hilbert problem is considered.     

Sol-gel synthesis of a new composition of bioactive glass in the quaternary system SiO2-CaO-Na2O-P2O5: Comparison with melting method

New sol-gel experimental conditions were tested to prepare a new SiO₂-based bioactive glass with high Na₂O content. The aim of this work is to investigate the real influence of the synthesis route (sol-gel versus melting) on the glass intrinsic properties and then, later, on the glass behavior and particularly on bioactivity. The obtained glass and its melt derived counterpart were characterized from structural and morphological (porosity, specific surface area) point of view. It could be noticed that the synthesis mode has no significant influence on glass structure. Conversely, the synthesis mode greatly influences the glass texture. The sol-gel derived glass exhibits a greatly higher specific surface area and pore volume than melt derived glass. This parameter may be a key factor of glass bioactivity.     

ChemInform Abstract: The Interpenetrated Three‐Dimensional Framework of a New Mixed Lithium/Ammonium Perchlorate Growth in a Gel Medium.

Li_9.41(NH₄)_0.59ClO₄ is synthesized by slow diffusion of aqueous lithium oxalate and ammonium oxalate dissolved in perchloric acid through agar agar gel at ambient temperature.     

Effect of pore expansion and amine functionalization of mesoporous silica on CO2 adsorption over a wide range of conditions

Adsorption of CO₂ was investigated over a wide range of conditions on a series of mesoporous silica adsorbents comprised of conventional MCM-41, pore-expanded MCM-41 silica (PE-MCM-41) and triamine surface-modified PE-MCM-41 (TRI-PE-MCM-41). The isosteric heat of adsorption, calculated from adsorption isotherms at different temperatures (298–328 K), showed a significant increase in CO₂–adsorbent interaction after amine functionnalization of PE-MCM-41, consistent with the high CO₂ uptake in the very low range of CO₂ concentration. The CO₂ adsorption isotherm and kinetics data showed the high potential of TRI-PE-MCM-41 material for CO₂ removal in gas purification and separation applications. With TRI-PE-MCM-41, the CO₂ selectivity over N₂ was drastically improved over a wide range of conditions compared to pure mesoporous silica. Moreover, the adsorption was reversible and fast, and the adsorbent was thermally stable and tolerant to moisture.     

Quelques Formules d'Inversion à Plusieurs Variables

In this paper, we use divided differences to give algebraic identities involving a finite number of infinite sets of variables (Propositions 6, 7, and 12). Specializing the sets of variables, we recover the formulas of Carlitz (Corollaries 15 and 20), and an inversion formula of Chu Wenchang (Corollary 16). We also prove a q-analog of their results, and we give a mixed case (Proposition 19).