Synthesis of nanocrystalline zinc manganese oxide by thermal decomposition of new dinuclear manganese(III) precursors

Nanocrystalline manganese-doped zinc oxide was synthesized by thermal decomposition of a zinc oxide sol with two new dinuclear manganese(III) complexes as precursor. Thermal analysis results indicated that the decomposition of manganese precursors occurred at 269 and 314 °C. X-ray structural analysis shows the presence of dimanganese core in the complexes and the binding of the ligands to the manganese(III) is through N₂O₂. The manganese-doped zinc oxide composite was characterized by means of X-ray diffraction, scanning electron microscopy, and UV–Vis spectroscopy. Structural properties of the composites elucidated that the manganese ions have substituted the zinc ions without changing the wurtzite structure of zinc oxide.     

Nanoengineered polymeric S-layers based capsules with targeting activity

Nanostructured polymeric capsules are regarded as highly promising systems with different potential applications ranging from drug delivery, biosensing and artificial cells. To fully exploit this potential, it is required to produce bio-activated stable and biocompatible capsules. To this purpose, in present work we proposed the combination of the layer-by-layer self assembly method with bacterial S-layer technology to fabricate stable and biocompatible polymeric capsules having a well defined arrangement of functional groups allowing the covalent attachment of antibody molecules. Hollow microcapsules were obtained by the layer-by-layer self assembly of oppositely charged polyelectrolytes onto colloidal particles, followed by removal of the cores at acidic pH. S-layers were crystallized onto the shell of the obtained capsules. Quartz crystal microbalance was used to characterize the crystallization process onto planar surfaces. S-layer containing capsules were investigated by atomic force microscopy. Immunoenzymatic tests were performed to assess the effective modification of the S-layer with antibody molecules both on planar surfaces and on hollow capsules. Fluorescent microscopy was employed to visualize the presence of the antibody molecules onto the capsule shell and immunological tests used to assess the bioactivity of the immobilized antibodies. Finally, the in vitro cytotoxicity of fabricated S-layer containing capsules was studied. The obtained results demonstrated the possibility to fabricate bio-activated S-layer containing capsules with improved features in terms of biocompatibility.     

A comparative study of energy consumption and physical properties of microfibrillated cellulose produced by different processing methods

Microfibrillated celluloses (MFCs) with diameters predominantly in the range of 10–100 nm liberated from larger plant-based fibers have garnered much attention for the use in composites, coatings, and films due to large specific surface areas, renewability, and unique mechanical properties. Energy consumption during production is an important aspect in the determination of the “green” nature of these MFC-based materials. Bleached and unbleached hardwood pulp samples were processed by homogenization, microfluidization, and micro-grinding, to determine the effect of processing on microfibril and film properties, relative to energy consumption. Processing with these different methods affected the specific surface area of the MFCs, and the film characteristics such as opacity, roughness, density, water interaction properties, and tensile properties. Apparent film densities were approximately 900 kg/m³ for all samples and the specific surface area of the processed materials ranged from approximately 30 to 70 m²/g for bleached hardwood and 50 to 110 m²/g for unbleached hardwood. The microfluidizer resulted in films with higher tensile indices than both micro-grinding and homogenization (148 Nm/g vs. 105 Nm/g and 109 Nm/g, respectively for unbleached hardwood). Microfluidization and micro-grinding resulted in films with higher toughness values than homogenization and required less energy to obtain these properties, offering promise for producing MFC materials with lower energy input. It was also determined that a refining pretreatment required for microfluidization or homogenization can be reduced or eliminated when producing MFCs with the micro-grinder. A summary of the fiber and mechanical energy costs for different fibers and processing conditions with economic potential is presented.     

Significant redistribution of Ce 4d oscillator strength observed in photoionization of endohedral Ce@C82+ ions

Mass-selected beams of atomic Ceq+ ions (q = 2, 3, 4), of C82+ and of endohedral Ce@C82+ ions were employed to study photoionization of free and encaged cerium atoms. The Ce 4d inner-shell contributions to single and double ionization of the endohedral Ce@C82+ fullerene have been extracted from the data and compared with expectations based on theory and the experiments with atomic Ce ions. Dramatic reduction and redistribution of the ionization contributions to 4d photoabsorption is observed. More than half of the Ce 4d oscillator strength appears to be diverted to the additional decay channels opened by the fullerene cage surrounding the Ce atom.