4'-Acetamidochalcone derivatives as potential antinociceptive agents

Nine acetamidochalcones were synthesized and evaluated as antinociceptive agents using the mice writhing test. Given intraperitoneally all the compounds were more effective than the two reference analgesic drugs (acetylsalicylic acid and acetaminophen) used for comparison. N-{4-[(2E)-3-(4-nitrophenyl)prop-2-enoyl]phenyl}acetamide (6) was the most effective compound and was therefore selected for more detailed studies. It caused dose-related inhibition in the writhing test, being about 32 to 34-fold more potent than the standard drugs. It was also effective in the second phase of the formalin test and the capsaicin test. These acetamidochalcones, especially compound 6, might be further used as models to obtain new and more potent analgesic drugs.     

Self-assembly of amphiphilic glycoconjugates into lectin-adhesive nanoparticles

This work describes the synthesis and self-assembly of carbohydrate-clicked rod-coil amphiphilic systems. Copper-catalyzed Huisgen cycloaddition was efficiently employed to functionalize the hydrophilic extremity of PEG-b-tetra(p-phenylene) conjugates by lactose and N-acetyl-glucosamine ligands. The resulting amphiphilic systems spontaneously self-assembled into nanoparticles when dissolved in aqueous media, as evidenced by dynamic light scattering (DLS), transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS). The formation of highly monodisperse micelles having a mean diameter of 10 nm was observed for systems containing a PEG 900 core, and a decrease in the hydrophilic moiety (PEG 600) led to the formation of vesicles with a broader size distribution. The presence of carbohydrate residues on the surfaces of the micelles and their ability to establish specific interactions with wheat germ agglutinin (WGA) and peanut agglutinin (PNA) were further highlighted by light-scattering measurements, thus confirming the attractive applications of such sugar micelles in biosensor devices.     

Influence of process parameters on microstructure and mechanical properties of starch-cellulose acetate/silver sulfadiazine matrices prepared by melt extrusion

Starch-cellulose acetate matrices containing silver sulfadiazine were produced using melt extrusion for application in drug delivery devices (DDDs). The influence of the extrusion parameters (screw speed and temperature) on the morphological and mechanical properties of the matrices was evaluated at three different levels. The microstructural characterization of all matrices showed that an increase in the screw speed enhances the porosity and drug dispersion, while an increase in the extrusion temperature decreases the pore diameter of the matrices. Mechanical results did not show significant differences between the elastic modulus values for the matrices; however, a faster screw speed led to higher ultimate strength and strain at failure values. Results obtained in the dynamic mechanical analysis showed that the glass transition and loss tangent (tan δ) peak values became higher with increasing screw speed and temperature.     

Electroless plating of nickel–phosphorous on surface-modified poly(ethylene terephthalate) films

Chemical surface preparation for Ni–P electroless metallization of poly(ethylene terephthalate) (PET) films without using Chromium-based chemicals, was studied. The applicability of this method was verified by a subsequent metallization process. Thermal analysis was conducted to observe the main thermal transitions and stability of the polymer and metallized films. Contact angle analysis was performed to assess the surface hydrophilicity so as to optimize the substrate preparation process. X-ray diffraction, EDAX and SEM analysis were used to understand the composition and morphology of the polymeric substrate and Ni–P coat growing process. Adherence strength, contact sheet resistivity and optical diffuse reflection were measured on the metallized films. The time of chemical etching affects the polymer surface hydrophilicity, polymer/metal adherence strength, surface resistance and optical diffuse reflection, while Ni coating morphology is controlled by the pH of the electroless bath. High wettability of the polymer surface, adherence strength of 800 N cm⁻², high optical diffuse reflection and low surface resistivity of the Ni coating, were found for films etched for 60 min. Metallizations performed at pH 7.5 produce Ni–P coatings with 12.0 wt.% phosphorous content, which were amorphous and flexible. The contact sheet resistivity of the plated films is sensitive to roughness variations of the substrate. The method proposed in this work allows the production of metallized films appropriate for the fabrication of flexible circuits.     

Electroanalytical Method for Determining Pyrogallol in Biodiesel in the Presence of a Surfactant

A sensitive, straightforward electroanalytical method for determining pyrogallol (PY) in biodiesel in the presence of a surfactant was developed using a voltammetric technique and screen‐printed electrodes. The influence of surfactant addition (sodium dodecyl sulfate (SDS), Triton X‐100 (TX‐100), cetyltrimethylammonium bromide (CTAB), tetrabutylammonium iodide (TBAI), tetrabutylammonium bromide (TBAB), or tetraethylammonium bromide (TEAB)) on the supporting electrolyte (0.04 mol L^?1 Britton? Robinson buffer) was evaluated. Only CTAB significantly increased the oxidation peak current. Under optimal conditions, the method demonstrated linearity over the concentration range of 0.8–9.0×10^?6 mol L^?1, with limits of detection and quantification of 4.9×10^?7 and 1.5×10^?6 mol L^?1, respectively. The results were satisfactory, relative to those obtained using high‐performance liquid chromatography (HPLC).     

Untersuchung von Eiern, bezw. Eierwaren

Ohne Zusammenfassung     

Characterization,morphology, thermal and mechanical properties of conductive polyaniline‐functionalized EPDM elastomers obtained by casting

Conductive elastomeric blends based on ethylene–propylene–5‐ethylidene–2‐norbornene terpolymer (EPDM) and polyaniline doped with 4‐dodecylbenzenesulfonic acid [PAni(DBSA)] were cast from organic solvents. Functionalization of the elastomer was promoted by grafting with maleic anhydride. Vulcanization conditions were optimized with an oscillating disk rheometer. The conductivity, morphology, thermal stability, compatibility, and mechanical behavior of the obtained mixtures were analyzed by in situ direct current conductivity measurements, atomic force microscopy, transmission electron microscopy, wide‐angle X‐ray scattering, thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical thermal analysis, stress–strain and hysteresis tests. The vulcanization process was affected by temperature, the PAni content, and maleic anhydride. A reinforcement effect was promoted by the vulcanizing agent. The formation of links between the high‐molar‐mass phases and oligomers of PAni(DBSA) in the elastomeric matrix enhanced the thermal stability and ultimate properties of the blends. By the appropriate control of the polymer blends' composition, it was possible to produce elastomeric materials with conductivities in the range of 10^?5–10^?4 S · cm^?1 and excellent mechanical properties. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1767–1782, 2004     

Application of solid-phase microextraction and gas chromatography-mass spectrometry for the determination of chlorophenols in leather

This paper proposes a new analytical procedure based on the headspace solid‐phase microextraction (HS‐SPME) technique and gas chromatography‐selected ion monitoring‐mass spectrometry (GC‐SIM‐MS) for the determination of 16 phenols extracted from leather samples. The optimized conditions for the HS‐SPME were obtained through two experimental designs – a two‐level fractional factorial design followed by a central composite design – using the commercial SPME fiber polyacrylate 85 μm (PA). The best extraction conditions were as follows: 200 μL of derivatizing agent (acetic anhydride), 20 mL of saturated aqueous NaCl solution and extraction time and temperature of 50 min and 75°C, respectively. All optimized conditions were obtained with fixed leather sample mass (250 mg), vial volume (40 mL) and phosphate buffer pH (12) and concentration (50 mmol/L). Detection limits ranging from 0.03 to 0.20 ng/g, and relative standard deviation (RSD) lower than 10.23% (n=6) for a concentration of 800 ng/g (chlorophenols) and 1325 ng/g (2‐phenylphenol) in the splitless mode were obtained. The recovery was studied at three concentration levels by adding different amounts of phenols to the leather sample and excellent recoveries ranging from 90.0 to 107.2% were obtained. The validated method was shown to be suitable for the quantification of phenols in leather samples, as it is simple, relatively fast and sensitive.     

Nucleon-Deuteron Breakup Scattering in Configuration Space

The configuration-space Faddeev equations for the breakup scattering problem are solved using a new method of partial inversion. Unlike other computations this one keeps the incoming wave in the asymptotic condition. Thus all computations otherwise needed to separate the incident wave are avoided and the number of non-zero components of the inhomogeneous term in the algebraic equations is reduced to one. Speed as well as accuracy improves and we are able to solve the algebraic problem with partial inversion only. Using the standard spline-decomposition for the angle variable and the finite-difference approximation for the hyperradius optimizes considerably the inversion due to the sparse block structure of the matrix. We report on calculations of the inelasticities and phase shifts for nucleon-deuteron scattering for laboratory energies 4.0, 14.1, and 42.0MeV. The results are compared with calculations by other authors.Received November 11, 2001; accepted October 18, 2002 Published online June 27, 2003