Sorption of propylene and propane in polyurethane membranes containing silver nanoparticles

The preparation of a facilitated transport membrane of polyurethane (PU) containing silver nanoparticles is reported. The propylene and propane sorption was investigated aiming at the selective separation from C3s mixtures. The silver particles were photogenerated in situ into the polyurethane matrix using UV light radiation and silver triflate (AgCF₃SO₃) as precursor. The morphological properties of these membranes (PUAg) reveled great dispersion of silver particles, which size was smaller than 110 nm. The propylene solubility in PUAg resulted more than four times superior to the one for the pure PU membrane, revealing the high affinity between silver and propylene. Flory–Huggins theory was more accurate to describe the propylene sorption behavior in PUAg than Henry's model. The ideal solubility selectivity of PUAg membrane resulted 24.4, indicating that there is a good potential for an industrial application aiming at the separation of propylene/propane. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42916.     

Multidrug Idebenone/Naproxen Co-loaded Aspasomes for Significant in vivo Anti-inflammatory Activity

The use of proper nanocarriers for dermal and transdermal delivery of anti-inflammatory drugs recently gained several attentions in the scientific community because they pass intact and accumulate payloads in the deepest layers of skin tissue. Ascorbyl palmitate-based vesicles (aspasomes) can be considered a promising nanocarrier for dermal and transdermal delivery due to their skin whitening properties and suitable delivery of payloads through the skin. The aim of this study was the synthesis of multidrug Idebenone/naproxen co-loaded aspasomes for the development of an effective anti-inflammatory nanomedicine. Aspasomes had suitable physicochemical properties and were safe in vivo if topically applied on human healthy volunteers. Idebenone/naproxen co-loaded aspasomes demonstrated an increased therapeutic efficacy of payloads compared to the commercially available Naprosyn® gel, with a rapid decrease of chemical-induced erythema on human volunteers. These promising results strongly suggested a potential application of Idebenone/naproxen multidrug aspasomes for the development of an effective skin anti-inflammatory therapy.     

Influence of Surface Finishing on the Tribological Behavior of Self-Lubricating Iron-Based Composites

Recently, we presented the tribological evaluation of self-lubricating sintered steels produced by taking advantage of the powder injection molding process, the recently introduced plasma-assisted debinding and sintering process, and the in situ formation of solid lubricant particles. This new processing route promotes the in situ generation of nanostructured turbostratic graphite particles during silicon carbide dissociation. In this work, we present the influence of surface finishing on the tribological behavior of self-lubricating composites sintered at 1150°C with (3 and 5 wt%) and without SiC additions. We discuss the effects of the surface topography (R_a) on the friction coefficient and wear rates of specimens and counterbodies. The tribological behavior was analyzed using linear reciprocating sliding tests (constant load of 7 N, 60-min duration). It was shown that the reduction in surface roughness increased both the friction coefficients and wear rates of specimens and counterbodies, probably due to plastic deformation and consequent graphite reservoir sealing. Chemical analyses of the wear scars using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis showed a tribolayer that was composed predominantly of carbon and oxygen. Analyses of the wear scars showed traces of plastic deformation on both samples and counterbodies and the predominance of abrasion as the main wear mechanism.     

Hybrid membranes based on SiO2/polyether-b-polyamide: Morphology and applications

Hybrid materials were prepared incorporating silica networks by the sol–gel process into the poly(amide-b-polyether) block copolymer PEBAX®. PEBAX®/silica hybrids were characterized by transmission electron microscopy, atomic force microscopy, differential scanning calorimetry, and X-ray diffraction. The pervaporation of phenol from dilute aqueous solutions through hybrid membranes was investigated. Films prepared with lower silica contents showed better dispersed inorganic networks and were more selective in the pervaporation of phenol/water solutions. Films prepared with higher silica contents had a clear phase-separated morphology with lower performance in pervaporation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 178–185, 2001     

Effects of solvent and alkaline earth metals on the heat-induced precipitation process of sodium caseinate

The precipitation temperatures of sodium caseinate in H₂O and D₂O in the presence of Mg²⁺, Ca²⁺, Sr²⁺ and Ba²⁺ were investigated through fluorescence, turbidity and conductivity experiments.     

Effects of sulfate ions and slightly acidic pH conditions on Cr(VI) adsorption onto silica gelatin composite

The feasibility of utilizing CTAB–silica gelatin composite (C-SGC) to remove hexavalent chromium from aqueous solutions under different conditions was investigated. Removal of chromate was assessed through evaluation of the adsorption kinetics of chromate ions on the composite under equilibrium conditions in the presence of sulfate ions and at a slightly acidic pH condition (pH 5.8). Adsorption competition tests in the presence of sulfate ions showed that Cr(VI) was still effectively adsorbed from aqueous solution regardless of the presence of the competing anions. In fact, the adsorption kinetics performed at different initial chromate concentrations were unaffected by the presence of 100 mg L^?1 sulfate ions (pH 7.5). The equilibrium adsorption data were fitted by Freundlich adsorption isotherms which confirmed that the adsorption efficiency of chromium on the CTAB–silica gelatin composite was unchanged in the presence of sulfate ions. Further, the adsorption process was shown to be pH dependent and more efficient at slightly acidic pH (5.8). These findings demonstrated a high specificity of the CTAB–silica gelatin composite for chromium, and highlight the possibility of using this matrix for efficient removal of chromium from industrial wastewater without the need to eliminate contaminant sulfate ions.     

Conductometric behaviour of alkali metal halides in non-aqueous solvents containing crown-ethers

The conductometric behaviour of NaCl, KCl and RbCl in ethanol solutions, in the presence of dicyclohexyl-18-crown-6, and of KI in acetonitrile solutions, in the presence of 12-crown-4, 15-crown-5, 18-crown-6, dibenzo-18-crown-6 and dicyclohexyl-18-crown-6, has been investigated. The analysis of data has been performed by means of the Fuoss-Onsager-Skinner equations and the results compared with the parameters of the same salts in pure solvents. The addition of crown-ether to the ethanol solutions gives rise to a greater decrease in conductivity for KCl and RbCl than for NaCl, so that the maximum difference in the Λ_o values which is 4.7 Λ unit in pure ethanol, decreases to 0.9 Λ unit. Also the association constant to ion pairs of the three salts which is appreciable in pure ethanol, decreases to zero when the crown-ether is added. In acetonitrile the difference in the Λ_o values for systems with and without crowns is small for 12-crown-4 (～2.9 Λ unit); it increases according to the complexity of the added crown (～21 Λ unit for the 15-crown-5, ～24 Λ unit for the 18-crown-6, ～ 30 Λ unit for the dicyclo- and dibenzo-18-crown-6). A small association constant value was found for the systms KI with 12-crown-4 and with 15-crown-5 in this solvent. The results of the above systems are discussed in terms of competitive interaction forces of the crown-ethers and the solvent molecules on the ionic species present in solution.     

Mining the impact of evolution categories on object-oriented metrics

Despite the relevance of the software evolution phase, there are few characterization studies on recurrent evolution growth patterns and on their impact on software properties, such as coupling and cohesion. In this paper, we report a study designed to investigate whether the software evolution categories proposed by Lanza can be used to explain not only the growth of a system in terms of lines of code (LOC), but also in terms of metrics from the Chidamber and Kemerer (CK) object-oriented metrics suite. Our results show that high levels of recall (ranging on average from 52 to 72 %) are achieved when using LOC to predict the evolution of coupling and size. For cohesion, we have achieved smaller recall rates (<27 % on average).