Wound Healing Attributes of Polyelectrolyte Multilayers Prepared with Multi‐l‐arginyl‐poly‐l‐aspartate Pairing with Hyaluronic Acid and γ‐Polyglutamic Acid

Biodegradable multi‐l ‐arginyl‐poly‐l ‐aspartate (MAPA), more commonly cyanophycin, prepared with recombinant <i>Escherichia coli</i> contains a polyaspartate backbone with lysine and arginine as side chains. Two assemblies of polyelectrolyte multilayers (PEMs) are fabricated at three different concentration ratios of insoluble MAPA (iMAPA) with hyaluronic acid (iMAPA/HA) and with γ‐polyglutamic acid (iMAPA/γ‐PGA), respectively, utilizing a layer‐by‐layer approach. Both films with iMAPA and its counterpart, HA or γ‐PGA, as the terminal layer are prepared to assess the effect on film roughness, cell growth, and cell migration. iMAPA incorporation is higher for a higher concentration of the anionic polymer due to better charge interaction. The iMAPA/HA films when compared to iMAPA/γ‐PGA multilayers show least roughness. The growth rates of L929 fibroblast cells on the PEMs are similar to those on glass substrate, with no supplementary effect of the terminal layer. However, the migration rates of L929 cells increase for all PEMs. γ‐PGA incorporated films impart 50% enhancement to the cell migration after 12 h of culture as compared to the untreated glass, and the smooth films containing HA display a maximum 82% improvement. The results present the use of iMAPA to construct a new layer‐by‐layer system of polyelectrolyte biopolymers with a potential application in wound dressing.     

Preliminary selection of clay minerals for the removal of pharmaceuticals,bisphenol A and triclosan in acidic and neutral aqueous solutions

Pharmaceuticals, personal care products and endocrine disruptors demonstrate huge potential to cause adverse ecological health effects at very low concentration in aquatic environment. There is a need to improve current purification technologies used in sewage and drinking-water treatment plants. This article aims at providing new insights into the recent development of natural and modified clay-based sorbents for the removal of aqueous contaminants such as pharmaceuticals and personal care products. The removal of six widely used pharmaceuticals: ibuprofen, diclofenac, ketoprofen, carbamazepine, as well as endocrine disrupting chemicals – bisphenol A and a bactericidal agent, triclosan – was examined by sorption onto eight adsorbents. Sorption was performed using natural and modified clay minerals – montmorillonite (Mt), vermiculite (VER), bentonite (B), kaolinite (K), commercial acid activated montmorillonites K10 and K30, and two carbonaceous-mineral nanocomposites, MtG5%T, BAlG3%C. This study showed that among the tested natural clays, vermiculite is the most promising sorbent for the removal of pharmaceuticals in purification processes. Among the modified clay minerals, the best results were achieved for carbonaceous bentonite and two acid activated montmorillonites K10 and K30. However, the removal of acidic pharmaceuticals on montomorillonite K10 and carbonaceous bentonite was strongly dependent on the pH value. In the case of vermiculite and acid-modified montmorillonite K30, the sorption of the selected compounds was not significantly affected by pH, which is crucial in wastewater treatment. The sorption constant divided by the specific surface area (<em>K</em><sub>d</sub>/<em>A</em>) is proposed to assess whether the surface area or chemical properties of the materials control the sorption process. <em>K</em><sub>d</sub>/<em>A</em> values were relatively high in the case of vermiculite, so it should be noticed that individual and specific surface properties of vermiculite were of crucial importance for sorption.     

The Identification of a Novel Highly Condensed Pentacyclic Heteroaromatic Ring System 1,3,5,5b,6,8,10,10b‐Octaazacyclopenta[h,i]Aceanthrylene and its Application in the Synthesis of 5,7‐Substituted Pyrazolo[4,3‐d]Pyrimidines

Pyrazolo[4,3‐d]pyrimidines are of interest as potential kinase inhibitors. This article describes the formation of a novel highly conjugated, condensed, centrosymmetric heteroaromatic compound, 4,9‐dichloro‐2,7‐diisopropyl‐1,3,5,5b,6,8,10,10b‐octaazacyclopenta[h,i]aceanthrylene ( 3 ), during the chlorination of 5,7‐dihydroxypyrazolo[4,3‐<i>d</i>]pyrimidine ( 1 ) with phenylphosphonic dichloride. The nucleophilic attack of benzylamine on 3 afforded N‐benzyl‐5‐chloro‐3‐isopropyl‐1H‐pyrazolo[4,3‐d]pyrimidin‐7‐amine ( 6 ), which was further substituted to yield a pyrazolo[4,3‐<i>d</i>]pyrimidine analogue of roscovitine, a well‐known cyclin‐dependent kinase inhibitor.     

Macroscopic and Micromechanical Approaches to the Modelling of the Osmotic Swelling in Clays

The osmotic swelling in clays has been extensively studied at the physico-chemical scale. The present paper addresses the question of the modelling of this phenomenon from the mechanical point of view. First, the classical macroscopic thermodynamic framework for saturated porous continua is extended in order to take into account the solid-salt interaction through the concept of macroscopic activity coefficient of the salt. The micromechanical approach then incorporates this interaction through the concept of swelling pressure which is used for describing the internal forces in the fluid phase at the microscopic scale. The results of a physico-chemical theory for the solid-salt interaction, such as the e.d.l. theory, can be introduced in both approaches. Each of them leads to the identification of a deviation, of chemical origin, to Terzaghi's effective stress principle. Besides, the micromechanical approach allows us to clearly differentiate the mechanical and the chemical parts of clay materials elasticity.     

An experimental study on effects of solid concentration and ζ-potential on pseudoplastic flow of suspensions

The pseudoplastic flow of suspensions, alumina or styrene-acrylamide copolymer particles in water or an aqueous solution of glycerin has been studied by the step-shear-rate method. The relation between the shear rate,<i>D</i>, and the shear stress,<i><img src="/content/l80322415l257t05/xxlarge964.gif" alt="tau" align="BASELINE" BORDER="0"></i>, in the step-shear-rate measurements, where the state of dispersion was considered to be constant, was expressed as<i><img src="/content/l80322415l257t05/xxlarge964.gif" alt="tau" align="BASELINE" BORDER="0"> = AD</i> <sup>1/2</sup> +<i>CD</i>. The effective solid volume fraction,<i>ø</i> <sub>F</sub>, and<i>A</i> were dependent on the shear rate and expressed by<i>ø</i> <sub>F</sub> =<i>aD</i> <sup>b</sup> and<i>A = <img src="/content/l80322415l257t05/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">D</i> <sup><img src="/content/l80322415l257t05/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></sup>. Combining the above relations, the steady flow curve was expressed by<i><img src="/content/l80322415l257t05/xxlarge964.gif" alt="tau" align="BASELINE" BORDER="0"> = <img src="/content/l80322415l257t05/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">D</i> <sup>1/2 + <img src="/content/l80322415l257t05/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></sup> +<i><img src="/content/l80322415l257t05/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0"></i> <sub>0</sub> (<i>1 – a D</i> <sup>b</sup>/0.74)<sup>–1.85</sup> <i>D</i>, where<i><img src="/content/l80322415l257t05/xxlarge951.gif" alt="eegr" align="MIDDLE" BORDER="0"></i> <sub>0</sub> is the viscosity of the medium.With an increase in solid volume fraction and a decreases in the absolute value of the<i><img src="/content/l80322415l257t05/xxlarge950.gif" alt="zeta" align="MIDDLE" BORDER="0"></i>-potential, the flow behavior of the suspensions changed from Newtonian (<i><img src="/content/l80322415l257t05/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> = <img src="/content/l80322415l257t05/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"> = b</i> = 0), slightly pseudoplastic (<i><img src="/content/l80322415l257t05/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"> = b</i> = 0), pseudoplastic (<i><img src="/content/l80322415l257t05/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"></i> = 0) to a Bingham-like behavior.The change in viscosity of the medium had an effect on the change in the effective volume fraction.     

Thermoelastoplastic axisymmetric stress-strain state of laminated orthotropic shells

A method is proposed for the numerical analysis of the thermoelastoplastic stress-strain state of laminated shells of revolution, made of isotropic and orthotropic materials, under axisymmetric loading. The method is based on the Kirchhoff-Love hypotheses for a layer stack, the theory of deformation along paths of small curvature for isotropic materials, and Hill<img src="/content/l275t645jvk01618/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0">s theory of flow with isotropic hardening for orthotropic materials. The problem is solved by the method of successive approximations. A numerical example is given.__________Translated from Prikladnaya Mekhanika, Vol. 40, No. 12, pp. 84–91, December 2004.     

An experimental study of the regimes of motion of spheres falling or ascending freely in a Newtonian fluid

This paper presents the results of an experimental investigation aimed at verifying some of the interesting conclusions of the numerical study by Jenny et al. concerning the instability and the transition of the motion of solid spheres falling or ascending freely in a Newtonian fluid. The phenomenon is governed by two dimensionsless parameters: the Galileo number <em>G</em>, and the ratio of the density of the spheres to that of the surrounding fluid <em>ρ</em><sub>s</sub>/<em>ρ</em>. Jenny et al. showed that the (<em>G</em>, <em>ρ</em><sub>s</sub>/<em>ρ</em>) parameter space may be divided into regions with distinct features of the trajectories followed eventually by the spheres after their release from rest. The characteristics of these ‘regimes of motion’ as described by Jenny et al., agree well with what was observed in our experiments. However, flow visualizations of the wakes of the spheres using a Schlieren optics technique raise doubts about another conclusion of Jenny et al., namely the absence of a bifid wake structure.     

l‐Proline‐functionalized Fe3O4 nanoparticles as a novel magnetic chiral catalyst for the direct asymmetric Mannich reaction

l ‐Proline has been successfully anchored on the surface of magnetic nanoparticles and characterized using powder X‐ray diffraction, scanning electron microscopy, vibrating sample magnetometry and Fourier transform infrared spectroscopy. These nanoparticles as a chiral catalyst have been employed to promote the direct asymmetric Mannich reaction. The corresponding products are obtained in high yields with high level of diastereoselectivity (up to 99:1 dr) in the presence of Fe<sub>3</sub>O<sub>4</sub>– l ‐proline. Also this heterogeneous catalyst can be recovered easily and reused many times without significant loss of its catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd.